Add DocBlock to WatchConfig (#1467 )

* Add DocBlock to WatchConfig Added a small description of the WatchConfig(). So that you can understand in the ide why you could use it. * Update viper.go * update viper.go Signed-off-by: Mark Sagi-Kazar <mark.sagikazar@gmail.com> Signed-off-by: Mark Sagi-Kazar <mark.sagikazar@gmail.com> Co-authored-by: Márk Sági-Kazár <sagikazarmark@users.noreply.github.com> Co-authored-by: Mark Sagi-Kazar <mark.sagikazar@gmail.com>
feat: add multiple endpoints support for remote
2024-04-21 12:31:38 +00:00 · 2023-01-19 16:38:18 +01:00 · 2023-01-19 16:34:22 +01:00 · 2023-01-19 15:27:42 +00:00 · 2023-01-19 15:20:14 +00:00 · 2023-01-19 16:18:37 +01:00
47 changed files with 2496 additions and 582 deletions
@@ -11,5 +11,5 @@ trim_trailing_whitespace = true
 [*.go]
 indent_style = tab

-[{Makefile, *.mk}]
+[{Makefile,*.mk}]
 indent_style = tab
@@ -19,6 +19,8 @@ body:
        required: true
      - label: I am not looking for support or already pursued the available [support channels](https://github.com/spf13/viper/issues/new/choose) without success.
        required: true
+      - label: I have checked the [troubleshooting guide](https://github.com/spf13/viper/blob/master/TROUBLESHOOTING.md) for my problem, without success.
+        required: true
 - type: input
  attributes:
    label: Viper Version
@@ -1,4 +1,4 @@
-name: 🚀 Feature request
+name: 🎉 Feature request
 description: Suggest an idea for Viper
 labels: [kind/enhancement]
 body:
@@ -0,0 +1,30 @@
+changelog:
+  exclude:
+    labels:
+      - release-note/ignore
+  categories:
+    - title: Exciting New Features 🎉
+      labels:
+        - kind/feature
+        - release-note/new-feature
+    - title: Enhancements 🚀
+      labels:
+        - kind/enhancement
+        - release-note/enhancement
+    - title: Bug Fixes 🐛
+      labels:
+        - kind/bug
+        - release-note/bug-fix
+    - title: Breaking Changes 🛠
+      labels:
+        - release-note/breaking-change
+    - title: Deprecations ❌
+      labels:
+        - release-note/deprecation
+    - title: Dependency Updates ⬆️
+      labels:
+        - area/dependencies
+        - release-note/dependency-update
+    - title: Other Changes
+      labels:
+        - "*"
@@ -0,0 +1,18 @@
+name: PR Checks
+
+on:
+  pull_request:
+    types: [opened, labeled, unlabeled, synchronize]
+
+jobs:
+  release-label:
+    name: Release note label
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check minimum labels
+        uses: mheap/github-action-required-labels@v3
+        with:
+          mode: minimum
+          count: 1
+          labels: "release-note/ignore, kind/feature, release-note/new-feature, kind/enhancement, release-note/enhancement, kind/bug, release-note/bug-fix, release-note/breaking-change, release-note/deprecation, area/dependencies, release-note/dependency-update"
@@ -0,0 +1,85 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+jobs:
+  build:
+    name: Build
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - goos: js
+            goarch: wasm
+          - goos: aix
+            goarch: ppc64
+
+    steps:
+      - name: Set up Go
+        uses: actions/setup-go@v3
+        with:
+          go-version: 1.19
+
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: Build
+        run: go build .
+        env:
+          GOOS: ${{ matrix.goos }}
+          GOARCH: ${{ matrix.goarch }}
+
+  test:
+    name: Test
+    runs-on: ${{ matrix.os }}
+    strategy:
+      # Fail fast is disabled because there are Go version specific features and tests
+      # that should be able to fail independently.
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        go: ['1.17', '1.18', '1.19']
+    env:
+      GOFLAGS: -mod=readonly
+
+    steps:
+      - name: Set up Go
+        uses: actions/setup-go@v3
+        with:
+          go-version: ${{ matrix.go }}
+
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: Test
+        run: go test -race -v ./...
+        if: runner.os != 'Windows'
+
+      - name: Test (without race detector)
+        run: go test -v ./...
+        if: runner.os == 'Windows'
+
+  lint:
+    name: Lint
+    runs-on: ubuntu-latest
+    env:
+      GOFLAGS: -mod=readonly
+
+    steps:
+      - name: Set up Go
+        uses: actions/setup-go@v3
+        with:
+          go-version: 1.19
+
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: Lint
+        uses: golangci/golangci-lint-action@v3
+        with:
+          version: v1.50.1
@@ -1,53 +0,0 @@
-name: CI
-
-on:
-  push:
-    branches:
-      - master
-  pull_request:
-
-jobs:
-  test:
-    name: Test
-    runs-on: ${{ matrix.os }}
-    strategy:
-      # Fail fast is disabled because there are Go version specific features and tests
-      # that should be able to fail independently.
-      fail-fast: false
-      matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
-        go: ['1.14', '1.15', '1.16', '1.17']
-    env:
-      GOFLAGS: -mod=readonly
-
-    steps:
-      - name: Set up Go
-        uses: actions/setup-go@v2
-        with:
-          go-version: ${{ matrix.go }}
-
-      - name: Checkout code
-        uses: actions/checkout@v2
-
-      - name: Test
-        run: go test -race -v ./...
-
-  lint:
-    name: Lint
-    runs-on: ubuntu-latest
-    env:
-      GOFLAGS: -mod=readonly
-
-    steps:
-      - name: Set up Go
-        uses: actions/setup-go@v2
-        with:
-          go-version: 1.17
-
-      - name: Checkout code
-        uses: actions/checkout@v2
-
-      - name: Lint
-        uses: golangci/golangci-lint-action@v2
-        with:
-          version: v1.43.0
@@ -39,11 +39,11 @@ jobs:

    steps:
    - name: Checkout repository
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3

    # Initializes the CodeQL tools for scanning.
    - name: Initialize CodeQL
-      uses: github/codeql-action/init@v1
+      uses: github/codeql-action/init@v2
      with:
        languages: ${{ matrix.language }}
        # If you wish to specify custom queries, you can do so here or in a config file.
@@ -54,7 +54,7 @@ jobs:
    # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
    # If this step fails, then you should remove it and run the build manually (see below)
    - name: Autobuild
-      uses: github/codeql-action/autobuild@v1
+      uses: github/codeql-action/autobuild@v2

    # ℹ️ Command-line programs to run using the OS shell.
    # 📚 https://git.io/JvXDl
@@ -68,5 +68,5 @@ jobs:
    #   make release

    - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v1
+      uses: github/codeql-action/analyze@v2

@@ -6,7 +6,7 @@ jobs:
  comment:
    runs-on: ubuntu-latest
    steps:
-      - uses: actions/github-script@v5
+      - uses: actions/github-script@v6
        with:
          github-token: ${{secrets.GITHUB_TOKEN}}
          script: |
@@ -6,7 +6,7 @@ jobs:
  comment:
    runs-on: ubuntu-latest
    steps:
-      - uses: actions/github-script@v5
+      - uses: actions/github-script@v6
        with:
          github-token: ${{secrets.GITHUB_TOKEN}}
          script: |
@@ -1,26 +0,0 @@
-name: WASM
-
-on:
-  push:
-    branches:
-      - master
-  pull_request:
-
-jobs:
-  build:
-    name: Build
-    runs-on: ubuntu-latest
-    env:
-      GOFLAGS: -mod=readonly
-
-    steps:
-      - name: Set up Go
-        uses: actions/setup-go@v2
-        with:
-          go-version: '1.17'
-
-      - name: Checkout code
-        uses: actions/checkout@v2
-
-      - name: Ensure Viper compiles for WASM
-        run: GOOS=js GOARCH=wasm go build .
@@ -3,7 +3,10 @@ run:

 linters-settings:
    gci:
-        local-prefixes: github.com/spf13/viper
+        sections:
+            - standard
+            - default
+            - prefix(github.com/spf13/viper)
    golint:
        min-confidence: 0
    goimports:
@@ -15,8 +15,8 @@ TEST_FORMAT = short-verbose
 endif

 # Dependency versions
-GOTESTSUM_VERSION = 1.7.0
-GOLANGCI_VERSION = 1.43.0
+GOTESTSUM_VERSION = 1.8.0
+GOLANGCI_VERSION = 1.50.1

 # Add the ability to override some variables
 # Use with care
@@ -48,7 +48,7 @@ bin/golangci-lint: bin/golangci-lint-${GOLANGCI_VERSION}
 	@ln -sf golangci-lint-${GOLANGCI_VERSION} bin/golangci-lint
 bin/golangci-lint-${GOLANGCI_VERSION}:
 	@mkdir -p bin
-	curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | bash -s -- -b ./bin/ v${GOLANGCI_VERSION}
+	curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | bash -s -- -b ./bin/ v${GOLANGCI_VERSION}
 	@mv bin/golangci-lint "$@"

 .PHONY: lint
@@ -8,10 +8,10 @@
 [![Mentioned in Awesome Go](https://awesome.re/mentioned-badge-flat.svg)](https://github.com/avelino/awesome-go#configuration)
 [![run on repl.it](https://repl.it/badge/github/sagikazarmark/Viper-example)](https://repl.it/@sagikazarmark/Viper-example#main.go)

-[![GitHub Workflow Status](https://img.shields.io/github/workflow/status/spf13/viper/CI?style=flat-square)](https://github.com/spf13/viper/actions?query=workflow%3ACI)
+[![GitHub Workflow Status](https://img.shields.io/github/actions/workflow/status/spf13/viper/ci.yaml?branch=master&style=flat-square)](https://github.com/spf13/viper/actions?query=workflow%3ACI)
 [![Join the chat at https://gitter.im/spf13/viper](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/spf13/viper?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 [![Go Report Card](https://goreportcard.com/badge/github.com/spf13/viper?style=flat-square)](https://goreportcard.com/report/github.com/spf13/viper)
-![Go Version](https://img.shields.io/badge/go%20version-%3E=1.14-61CFDD.svg?style=flat-square)
+![Go Version](https://img.shields.io/badge/go%20version-%3E=1.16-61CFDD.svg?style=flat-square)
 [![PkgGoDev](https://pkg.go.dev/badge/mod/github.com/spf13/viper)](https://pkg.go.dev/mod/github.com/spf13/viper)

 **Go configuration with fangs!**
@@ -40,8 +40,8 @@ go get github.com/spf13/viper

 ## What is Viper?

-Viper is a complete configuration solution for Go applications including 12-Factor apps. It is designed
-to work within an application, and can handle all types of configuration needs
+Viper is a complete configuration solution for Go applications including [12-Factor apps](https://12factor.net/#the_twelve_factors).
+It is designed to work within an application, and can handle all types of configuration needs
 and formats. It supports:

 * setting defaults
@@ -119,7 +119,7 @@ viper.AddConfigPath("$HOME/.appname")  // call multiple times to add many search
 viper.AddConfigPath(".")               // optionally look for config in the working directory
 err := viper.ReadInConfig() // Find and read the config file
 if err != nil { // Handle errors reading the config file
-	panic(fmt.Errorf("Fatal error config file: %w \n", err))
+	panic(fmt.Errorf("fatal error config file: %w", err))
 }
 ```

@@ -447,6 +447,13 @@ viper.SetConfigType("json") // because there is no file extension in a stream of
 err := viper.ReadRemoteConfig()
 ```

+#### etcd3
+```go
+viper.AddRemoteProvider("etcd3", "http://127.0.0.1:4001","/config/hugo.json")
+viper.SetConfigType("json") // because there is no file extension in a stream of bytes, supported extensions are "json", "toml", "yaml", "yml", "properties", "props", "prop", "env", "dotenv"
+err := viper.ReadRemoteConfig()
+```
+
 #### Consul
 You need to set a key to Consul key/value storage with JSON value containing your desired config.
 For example, create a Consul key/value store key `MY_CONSUL_KEY` with value:
@@ -594,7 +601,7 @@ configuration level.

 Viper can access array indices by using numbers in the path. For example:

-```json
+```jsonc
 {
    "host": {
        "address": "localhost",
@@ -622,7 +629,7 @@ GetInt("host.ports.1") // returns 6029
 Lastly, if there exists a key that matches the delimited key path, its value
 will be returned instead. E.g.

-```json
+```jsonc
 {
    "datastore.metric.host": "0.0.0.0",
    "host": {
@@ -21,3 +21,12 @@ The solution is easy: switch to using Go Modules.
 Please refer to the [wiki](https://github.com/golang/go/wiki/Modules) on how to do that.

 **tl;dr* `export GO111MODULE=on`
+
+## Unquoted 'y' and 'n' characters get replaced with _true_ and _false_ when reading a YAML file
+
+This is a YAML 1.1 feature according to [go-yaml/yaml#740](https://github.com/go-yaml/yaml/issues/740).
+
+Potential solutions are:
+
+1. Quoting values resolved as boolean
+1. Upgrading to YAML v3 (for the time being this is possible by passing the `viper_yaml3` tag to your build)
@@ -0,0 +1,11 @@
+//go:build viper_logger
+// +build viper_logger
+
+package viper
+
+// WithLogger sets a custom logger.
+func WithLogger(l Logger) Option {
+	return optionFunc(func(v *Viper) {
+		v.logger = l
+	})
+}
@@ -3,67 +3,73 @@ module github.com/spf13/viper
 go 1.17

 require (
-	github.com/fsnotify/fsnotify v1.5.1
+	github.com/fsnotify/fsnotify v1.6.0
 	github.com/hashicorp/hcl v1.0.0
-	github.com/magiconair/properties v1.8.5
-	github.com/mitchellh/mapstructure v1.4.3
-	github.com/pelletier/go-toml v1.9.4
-	github.com/sagikazarmark/crypt v0.3.0
-	github.com/spf13/afero v1.6.0
-	github.com/spf13/cast v1.4.1
+	github.com/magiconair/properties v1.8.7
+	github.com/mitchellh/mapstructure v1.5.0
+	github.com/pelletier/go-toml/v2 v2.0.6
+	github.com/sagikazarmark/crypt v0.9.0
+	github.com/spf13/afero v1.9.3
+	github.com/spf13/cast v1.5.0
 	github.com/spf13/jwalterweatherman v1.1.0
 	github.com/spf13/pflag v1.0.5
-	github.com/stretchr/testify v1.7.0
-	github.com/subosito/gotenv v1.2.0
-	gopkg.in/ini.v1 v1.66.2
-	gopkg.in/yaml.v2 v2.4.0
+	github.com/stretchr/testify v1.8.1
+	github.com/subosito/gotenv v1.4.2
+	gopkg.in/ini.v1 v1.67.0
+	gopkg.in/yaml.v3 v3.0.1
 )

 require (
-	cloud.google.com/go v0.99.0 // indirect
-	cloud.google.com/go/firestore v1.6.1 // indirect
-	github.com/armon/go-metrics v0.3.10 // indirect
-	github.com/census-instrumentation/opencensus-proto v0.3.0 // indirect
-	github.com/cespare/xxhash/v2 v2.1.2 // indirect
-	github.com/cncf/udpa/go v0.0.0-20210930031921-04548b0d99d4 // indirect
-	github.com/cncf/xds/go v0.0.0-20211130200136-a8f946100490 // indirect
+	cloud.google.com/go v0.105.0 // indirect
+	cloud.google.com/go/compute v1.14.0 // indirect
+	cloud.google.com/go/compute/metadata v0.2.3 // indirect
+	cloud.google.com/go/firestore v1.9.0 // indirect
+	cloud.google.com/go/longrunning v0.3.0 // indirect
+	github.com/armon/go-metrics v0.4.0 // indirect
 	github.com/coreos/go-semver v0.3.0 // indirect
+	github.com/coreos/go-systemd/v22 v22.3.2 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/envoyproxy/go-control-plane v0.10.1 // indirect
-	github.com/envoyproxy/protoc-gen-validate v0.6.2 // indirect
 	github.com/fatih/color v1.13.0 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
 	github.com/golang/protobuf v1.5.2 // indirect
-	github.com/google/go-cmp v0.5.6 // indirect
-	github.com/googleapis/gax-go/v2 v2.1.1 // indirect
-	github.com/hashicorp/consul/api v1.11.0 // indirect
+	github.com/google/go-cmp v0.5.9 // indirect
+	github.com/googleapis/enterprise-certificate-proxy v0.2.1 // indirect
+	github.com/googleapis/gax-go/v2 v2.7.0 // indirect
+	github.com/hashicorp/consul/api v1.18.0 // indirect
 	github.com/hashicorp/go-cleanhttp v0.5.2 // indirect
-	github.com/hashicorp/go-hclog v1.0.0 // indirect
+	github.com/hashicorp/go-hclog v1.2.0 // indirect
 	github.com/hashicorp/go-immutable-radix v1.3.1 // indirect
 	github.com/hashicorp/go-rootcerts v1.0.2 // indirect
 	github.com/hashicorp/golang-lru v0.5.4 // indirect
-	github.com/hashicorp/serf v0.9.6 // indirect
+	github.com/hashicorp/serf v0.10.1 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/mattn/go-colorable v0.1.12 // indirect
 	github.com/mattn/go-isatty v0.0.14 // indirect
 	github.com/mitchellh/go-homedir v1.1.0 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	go.etcd.io/etcd/api/v3 v3.5.1 // indirect
-	go.etcd.io/etcd/client/pkg/v3 v3.5.1 // indirect
-	go.etcd.io/etcd/client/v2 v2.305.1 // indirect
-	go.opencensus.io v0.23.0 // indirect
-	golang.org/x/crypto v0.0.0-20210817164053-32db794688a5 // indirect
-	golang.org/x/net v0.0.0-20210813160813-60bc85c4be6d // indirect
-	golang.org/x/oauth2 v0.0.0-20211104180415-d3ed0bb246c8 // indirect
-	golang.org/x/sys v0.0.0-20211205182925-97ca703d548d // indirect
-	golang.org/x/text v0.3.7 // indirect
-	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
-	google.golang.org/api v0.62.0 // indirect
+	go.etcd.io/etcd/api/v3 v3.5.6 // indirect
+	go.etcd.io/etcd/client/pkg/v3 v3.5.6 // indirect
+	go.etcd.io/etcd/client/v2 v2.305.6 // indirect
+	go.etcd.io/etcd/client/v3 v3.5.6 // indirect
+	go.opencensus.io v0.24.0 // indirect
+	go.uber.org/atomic v1.9.0 // indirect
+	go.uber.org/multierr v1.8.0 // indirect
+	go.uber.org/zap v1.21.0 // indirect
+	golang.org/x/crypto v0.0.0-20220525230936-793ad666bf5e // indirect
+	golang.org/x/net v0.4.0 // indirect
+	golang.org/x/oauth2 v0.0.0-20221014153046-6fdb5e3db783 // indirect
+	golang.org/x/sync v0.1.0 // indirect
+	golang.org/x/sys v0.3.0 // indirect
+	golang.org/x/text v0.5.0 // indirect
+	golang.org/x/time v0.1.0 // indirect
+	golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2 // indirect
+	google.golang.org/api v0.107.0 // indirect
 	google.golang.org/appengine v1.6.7 // indirect
-	google.golang.org/genproto v0.0.0-20211208223120-3a66f561d7aa // indirect
-	google.golang.org/grpc v1.42.0 // indirect
-	google.golang.org/protobuf v1.27.1 // indirect
-	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
+	google.golang.org/genproto v0.0.0-20221227171554-f9683d7f8bef // indirect
+	google.golang.org/grpc v1.52.0 // indirect
+	google.golang.org/protobuf v1.28.1 // indirect
 )
@@ -4,10 +4,10 @@ import (
 	"sync"
 )

-// Decoder decodes the contents of b into a v representation.
+// Decoder decodes the contents of b into v.
 // It's primarily used for decoding contents of a file into a map[string]interface{}.
 type Decoder interface {
-	Decode(b []byte, v interface{}) error
+	Decode(b []byte, v map[string]interface{}) error
 }

 const (
@@ -48,7 +48,7 @@ func (e *DecoderRegistry) RegisterDecoder(format string, enc Decoder) error {
 }

 // Decode calls the underlying Decoder based on the format.
-func (e *DecoderRegistry) Decode(format string, b []byte, v interface{}) error {
+func (e *DecoderRegistry) Decode(format string, b []byte, v map[string]interface{}) error {
 	e.mu.RLock()
 	decoder, ok := e.decoders[format]
 	e.mu.RUnlock()
@@ -1,16 +1,18 @@
 package encoding

 import (
+	"reflect"
 	"testing"
 )

 type decoder struct {
-	v interface{}
+	v map[string]interface{}
 }

-func (d decoder) Decode(_ []byte, v interface{}) error {
-	rv := v.(*string)
-	*rv = d.v.(string)
+func (d decoder) Decode(_ []byte, v map[string]interface{}) error {
+	for key, value := range d.v {
+		v[key] = value
+	}

 	return nil
 }
@@ -44,7 +46,9 @@ func TestDecoderRegistry_Decode(t *testing.T) {
 	t.Run("OK", func(t *testing.T) {
 		registry := NewDecoderRegistry()
 		decoder := decoder{
-			v: "decoded value",
+			v: map[string]interface{}{
+				"key": "value",
+			},
 		}

 		err := registry.RegisterDecoder("myformat", decoder)
@@ -52,24 +56,24 @@ func TestDecoderRegistry_Decode(t *testing.T) {
 			t.Fatal(err)
 		}

-		var v string
+		v := map[string]interface{}{}

-		err = registry.Decode("myformat", []byte("some value"), &v)
+		err = registry.Decode("myformat", []byte("key: value"), v)
 		if err != nil {
 			t.Fatal(err)
 		}

-		if v != "decoded value" {
-			t.Fatalf("expected 'decoded value', got: %#v", v)
+		if !reflect.DeepEqual(decoder.v, v) {
+			t.Fatalf("decoded value does not match the expected one\nactual:   %+v\nexpected: %+v", v, decoder.v)
 		}
 	})

 	t.Run("DecoderNotFound", func(t *testing.T) {
 		registry := NewDecoderRegistry()

-		var v string
+		v := map[string]interface{}{}

-		err := registry.Decode("myformat", []byte("some value"), &v)
+		err := registry.Decode("myformat", nil, v)
 		if err != ErrDecoderNotFound {
 			t.Fatalf("expected ErrDecoderNotFound, got: %v", err)
 		}
@@ -0,0 +1,61 @@
+package dotenv
+
+import (
+	"bytes"
+	"fmt"
+	"sort"
+	"strings"
+
+	"github.com/subosito/gotenv"
+)
+
+const keyDelimiter = "_"
+
+// Codec implements the encoding.Encoder and encoding.Decoder interfaces for encoding data containing environment variables
+// (commonly called as dotenv format).
+type Codec struct{}
+
+func (Codec) Encode(v map[string]interface{}) ([]byte, error) {
+	flattened := map[string]interface{}{}
+
+	flattened = flattenAndMergeMap(flattened, v, "", keyDelimiter)
+
+	keys := make([]string, 0, len(flattened))
+
+	for key := range flattened {
+		keys = append(keys, key)
+	}
+
+	sort.Strings(keys)
+
+	var buf bytes.Buffer
+
+	for _, key := range keys {
+		_, err := buf.WriteString(fmt.Sprintf("%v=%v\n", strings.ToUpper(key), flattened[key]))
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return buf.Bytes(), nil
+}
+
+func (Codec) Decode(b []byte, v map[string]interface{}) error {
+	var buf bytes.Buffer
+
+	_, err := buf.Write(b)
+	if err != nil {
+		return err
+	}
+
+	env, err := gotenv.StrictParse(&buf)
+	if err != nil {
+		return err
+	}
+
+	for key, value := range env {
+		v[key] = value
+	}
+
+	return nil
+}
@@ -0,0 +1,63 @@
+package dotenv
+
+import (
+	"reflect"
+	"testing"
+)
+
+// original form of the data
+const original = `# key-value pair
+KEY=value
+`
+
+// encoded form of the data
+const encoded = `KEY=value
+`
+
+// Viper's internal representation
+var data = map[string]interface{}{
+	"KEY": "value",
+}
+
+func TestCodec_Encode(t *testing.T) {
+	codec := Codec{}
+
+	b, err := codec.Encode(data)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if encoded != string(b) {
+		t.Fatalf("decoded value does not match the expected one\nactual:   %#v\nexpected: %#v", string(b), encoded)
+	}
+}
+
+func TestCodec_Decode(t *testing.T) {
+	t.Run("OK", func(t *testing.T) {
+		codec := Codec{}
+
+		v := map[string]interface{}{}
+
+		err := codec.Decode([]byte(original), v)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if !reflect.DeepEqual(data, v) {
+			t.Fatalf("decoded value does not match the expected one\nactual:   %#v\nexpected: %#v", v, data)
+		}
+	})
+
+	t.Run("InvalidData", func(t *testing.T) {
+		codec := Codec{}
+
+		v := map[string]interface{}{}
+
+		err := codec.Decode([]byte(`invalid data`), v)
+		if err == nil {
+			t.Fatal("expected decoding to fail")
+		}
+
+		t.Logf("decoding failed as expected: %s", err)
+	})
+}
@@ -0,0 +1,41 @@
+package dotenv
+
+import (
+	"strings"
+
+	"github.com/spf13/cast"
+)
+
+// flattenAndMergeMap recursively flattens the given map into a new map
+// Code is based on the function with the same name in tha main package.
+// TODO: move it to a common place
+func flattenAndMergeMap(shadow map[string]interface{}, m map[string]interface{}, prefix string, delimiter string) map[string]interface{} {
+	if shadow != nil && prefix != "" && shadow[prefix] != nil {
+		// prefix is shadowed => nothing more to flatten
+		return shadow
+	}
+	if shadow == nil {
+		shadow = make(map[string]interface{})
+	}
+
+	var m2 map[string]interface{}
+	if prefix != "" {
+		prefix += delimiter
+	}
+	for k, val := range m {
+		fullKey := prefix + k
+		switch val.(type) {
+		case map[string]interface{}:
+			m2 = val.(map[string]interface{})
+		case map[interface{}]interface{}:
+			m2 = cast.ToStringMap(val)
+		default:
+			// immediate value
+			shadow[strings.ToLower(fullKey)] = val
+			continue
+		}
+		// recursively merge to shadow map
+		shadow = flattenAndMergeMap(shadow, m2, fullKey, delimiter)
+	}
+	return shadow
+}
@@ -7,7 +7,7 @@ import (
 // Encoder encodes the contents of v into a byte representation.
 // It's primarily used for encoding a map[string]interface{} into a file format.
 type Encoder interface {
-	Encode(v interface{}) ([]byte, error)
+	Encode(v map[string]interface{}) ([]byte, error)
 }

 const (
@@ -47,7 +47,7 @@ func (e *EncoderRegistry) RegisterEncoder(format string, enc Encoder) error {
 	return nil
 }

-func (e *EncoderRegistry) Encode(format string, v interface{}) ([]byte, error) {
+func (e *EncoderRegistry) Encode(format string, v map[string]interface{}) ([]byte, error) {
 	e.mu.RLock()
 	encoder, ok := e.encoders[format]
 	e.mu.RUnlock()
@@ -8,7 +8,7 @@ type encoder struct {
 	b []byte
 }

-func (e encoder) Encode(_ interface{}) ([]byte, error) {
+func (e encoder) Encode(_ map[string]interface{}) ([]byte, error) {
 	return e.b, nil
 }

@@ -41,7 +41,7 @@ func TestEncoderRegistry_Decode(t *testing.T) {
 	t.Run("OK", func(t *testing.T) {
 		registry := NewEncoderRegistry()
 		encoder := encoder{
-			b: []byte("encoded value"),
+			b: []byte("key: value"),
 		}

 		err := registry.RegisterEncoder("myformat", encoder)
@@ -49,20 +49,20 @@ func TestEncoderRegistry_Decode(t *testing.T) {
 			t.Fatal(err)
 		}

-		b, err := registry.Encode("myformat", "some value")
+		b, err := registry.Encode("myformat", map[string]interface{}{"key": "value"})
 		if err != nil {
 			t.Fatal(err)
 		}

-		if string(b) != "encoded value" {
-			t.Fatalf("expected 'encoded value', got: %#v", string(b))
+		if string(b) != "key: value" {
+			t.Fatalf("expected 'key: value', got: %#v", string(b))
 		}
 	})

 	t.Run("EncoderNotFound", func(t *testing.T) {
 		registry := NewEncoderRegistry()

-		_, err := registry.Encode("myformat", "some value")
+		_, err := registry.Encode("myformat", map[string]interface{}{"key": "value"})
 		if err != ErrEncoderNotFound {
 			t.Fatalf("expected ErrEncoderNotFound, got: %v", err)
 		}
@@ -12,7 +12,7 @@ import (
 // TODO: add printer config to the codec?
 type Codec struct{}

-func (Codec) Encode(v interface{}) ([]byte, error) {
+func (Codec) Encode(v map[string]interface{}) ([]byte, error) {
 	b, err := json.Marshal(v)
 	if err != nil {
 		return nil, err
@@ -35,6 +35,6 @@ func (Codec) Encode(v interface{}) ([]byte, error) {
 	return buf.Bytes(), nil
 }

-func (Codec) Decode(b []byte, v interface{}) error {
-	return hcl.Unmarshal(b, v)
+func (Codec) Decode(b []byte, v map[string]interface{}) error {
+	return hcl.Unmarshal(b, &v)
 }
@@ -0,0 +1,140 @@
+package hcl
+
+import (
+	"reflect"
+	"testing"
+)
+
+// original form of the data
+const original = `# key-value pair
+"key" = "value"
+
+// list
+"list" = ["item1", "item2", "item3"]
+
+/* map */
+"map" = {
+  "key" = "value"
+}
+
+/*
+nested map
+*/
+"nested_map" "map" {
+  "key" = "value"
+
+  "list" = ["item1", "item2", "item3"]
+}`
+
+// encoded form of the data
+const encoded = `"key" = "value"
+
+"list" = ["item1", "item2", "item3"]
+
+"map" = {
+  "key" = "value"
+}
+
+"nested_map" "map" {
+  "key" = "value"
+
+  "list" = ["item1", "item2", "item3"]
+}`
+
+// decoded form of the data
+//
+// in case of HCL it's slightly different from Viper's internal representation
+// (eg. map is decoded into a list of maps)
+var decoded = map[string]interface{}{
+	"key": "value",
+	"list": []interface{}{
+		"item1",
+		"item2",
+		"item3",
+	},
+	"map": []map[string]interface{}{
+		{
+			"key": "value",
+		},
+	},
+	"nested_map": []map[string]interface{}{
+		{
+			"map": []map[string]interface{}{
+				{
+					"key": "value",
+					"list": []interface{}{
+						"item1",
+						"item2",
+						"item3",
+					},
+				},
+			},
+		},
+	},
+}
+
+// Viper's internal representation
+var data = map[string]interface{}{
+	"key": "value",
+	"list": []interface{}{
+		"item1",
+		"item2",
+		"item3",
+	},
+	"map": map[string]interface{}{
+		"key": "value",
+	},
+	"nested_map": map[string]interface{}{
+		"map": map[string]interface{}{
+			"key": "value",
+			"list": []interface{}{
+				"item1",
+				"item2",
+				"item3",
+			},
+		},
+	},
+}
+
+func TestCodec_Encode(t *testing.T) {
+	codec := Codec{}
+
+	b, err := codec.Encode(data)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if encoded != string(b) {
+		t.Fatalf("decoded value does not match the expected one\nactual:   %#v\nexpected: %#v", string(b), encoded)
+	}
+}
+
+func TestCodec_Decode(t *testing.T) {
+	t.Run("OK", func(t *testing.T) {
+		codec := Codec{}
+
+		v := map[string]interface{}{}
+
+		err := codec.Decode([]byte(original), v)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if !reflect.DeepEqual(decoded, v) {
+			t.Fatalf("decoded value does not match the expected one\nactual:   %#v\nexpected: %#v", v, decoded)
+		}
+	})
+
+	t.Run("InvalidData", func(t *testing.T) {
+		codec := Codec{}
+
+		v := map[string]interface{}{}
+
+		err := codec.Decode([]byte(`invalid data`), v)
+		if err == nil {
+			t.Fatal("expected decoding to fail")
+		}
+
+		t.Logf("decoding failed as expected: %s", err)
+	})
+}
@@ -0,0 +1,99 @@
+package ini
+
+import (
+	"bytes"
+	"sort"
+	"strings"
+
+	"github.com/spf13/cast"
+	"gopkg.in/ini.v1"
+)
+
+// LoadOptions contains all customized options used for load data source(s).
+// This type is added here for convenience: this way consumers can import a single package called "ini".
+type LoadOptions = ini.LoadOptions
+
+// Codec implements the encoding.Encoder and encoding.Decoder interfaces for INI encoding.
+type Codec struct {
+	KeyDelimiter string
+	LoadOptions  LoadOptions
+}
+
+func (c Codec) Encode(v map[string]interface{}) ([]byte, error) {
+	cfg := ini.Empty()
+	ini.PrettyFormat = false
+
+	flattened := map[string]interface{}{}
+
+	flattened = flattenAndMergeMap(flattened, v, "", c.keyDelimiter())
+
+	keys := make([]string, 0, len(flattened))
+
+	for key := range flattened {
+		keys = append(keys, key)
+	}
+
+	sort.Strings(keys)
+
+	for _, key := range keys {
+		sectionName, keyName := "", key
+
+		lastSep := strings.LastIndex(key, ".")
+		if lastSep != -1 {
+			sectionName = key[:(lastSep)]
+			keyName = key[(lastSep + 1):]
+		}
+
+		// TODO: is this a good idea?
+		if sectionName == "default" {
+			sectionName = ""
+		}
+
+		cfg.Section(sectionName).Key(keyName).SetValue(cast.ToString(flattened[key]))
+	}
+
+	var buf bytes.Buffer
+
+	_, err := cfg.WriteTo(&buf)
+	if err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
+func (c Codec) Decode(b []byte, v map[string]interface{}) error {
+	cfg := ini.Empty(c.LoadOptions)
+
+	err := cfg.Append(b)
+	if err != nil {
+		return err
+	}
+
+	sections := cfg.Sections()
+
+	for i := 0; i < len(sections); i++ {
+		section := sections[i]
+		keys := section.Keys()
+
+		for j := 0; j < len(keys); j++ {
+			key := keys[j]
+			value := cfg.Section(section.Name()).Key(key.Name()).String()
+
+			deepestMap := deepSearch(v, strings.Split(section.Name(), c.keyDelimiter()))
+
+			// set innermost value
+			deepestMap[key.Name()] = value
+		}
+	}
+
+	return nil
+}
+
+func (c Codec) keyDelimiter() string {
+	if c.KeyDelimiter == "" {
+		return "."
+	}
+
+	return c.KeyDelimiter
+}
@@ -0,0 +1,111 @@
+package ini
+
+import (
+	"reflect"
+	"testing"
+)
+
+// original form of the data
+const original = `; key-value pair
+key=value ; key-value pair
+
+# map
+[map] # map
+key=%(key)s
+
+`
+
+// encoded form of the data
+const encoded = `key=value
+
+[map]
+key=value
+`
+
+// decoded form of the data
+//
+// in case of INI it's slightly different from Viper's internal representation
+// (eg. top level keys land in a section called default)
+var decoded = map[string]interface{}{
+	"DEFAULT": map[string]interface{}{
+		"key": "value",
+	},
+	"map": map[string]interface{}{
+		"key": "value",
+	},
+}
+
+// Viper's internal representation
+var data = map[string]interface{}{
+	"key": "value",
+	"map": map[string]interface{}{
+		"key": "value",
+	},
+}
+
+func TestCodec_Encode(t *testing.T) {
+	t.Run("OK", func(t *testing.T) {
+		codec := Codec{}
+
+		b, err := codec.Encode(data)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if encoded != string(b) {
+			t.Fatalf("decoded value does not match the expected one\nactual:   %#v\nexpected: %#v", string(b), encoded)
+		}
+	})
+
+	t.Run("Default", func(t *testing.T) {
+		codec := Codec{}
+
+		data := map[string]interface{}{
+			"default": map[string]interface{}{
+				"key": "value",
+			},
+			"map": map[string]interface{}{
+				"key": "value",
+			},
+		}
+
+		b, err := codec.Encode(data)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if encoded != string(b) {
+			t.Fatalf("decoded value does not match the expected one\nactual:   %#v\nexpected: %#v", string(b), encoded)
+		}
+	})
+}
+
+func TestCodec_Decode(t *testing.T) {
+	t.Run("OK", func(t *testing.T) {
+		codec := Codec{}
+
+		v := map[string]interface{}{}
+
+		err := codec.Decode([]byte(original), v)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if !reflect.DeepEqual(decoded, v) {
+			t.Fatalf("decoded value does not match the expected one\nactual:   %#v\nexpected: %#v", v, decoded)
+		}
+	})
+
+	t.Run("InvalidData", func(t *testing.T) {
+		codec := Codec{}
+
+		v := map[string]interface{}{}
+
+		err := codec.Decode([]byte(`invalid data`), v)
+		if err == nil {
+			t.Fatal("expected decoding to fail")
+		}
+
+		t.Logf("decoding failed as expected: %s", err)
+	})
+}
@@ -0,0 +1,74 @@
+package ini
+
+import (
+	"strings"
+
+	"github.com/spf13/cast"
+)
+
+// THIS CODE IS COPIED HERE: IT SHOULD NOT BE MODIFIED
+// AT SOME POINT IT WILL BE MOVED TO A COMMON PLACE
+// deepSearch scans deep maps, following the key indexes listed in the
+// sequence "path".
+// The last value is expected to be another map, and is returned.
+//
+// In case intermediate keys do not exist, or map to a non-map value,
+// a new map is created and inserted, and the search continues from there:
+// the initial map "m" may be modified!
+func deepSearch(m map[string]interface{}, path []string) map[string]interface{} {
+	for _, k := range path {
+		m2, ok := m[k]
+		if !ok {
+			// intermediate key does not exist
+			// => create it and continue from there
+			m3 := make(map[string]interface{})
+			m[k] = m3
+			m = m3
+			continue
+		}
+		m3, ok := m2.(map[string]interface{})
+		if !ok {
+			// intermediate key is a value
+			// => replace with a new map
+			m3 = make(map[string]interface{})
+			m[k] = m3
+		}
+		// continue search from here
+		m = m3
+	}
+	return m
+}
+
+// flattenAndMergeMap recursively flattens the given map into a new map
+// Code is based on the function with the same name in tha main package.
+// TODO: move it to a common place
+func flattenAndMergeMap(shadow map[string]interface{}, m map[string]interface{}, prefix string, delimiter string) map[string]interface{} {
+	if shadow != nil && prefix != "" && shadow[prefix] != nil {
+		// prefix is shadowed => nothing more to flatten
+		return shadow
+	}
+	if shadow == nil {
+		shadow = make(map[string]interface{})
+	}
+
+	var m2 map[string]interface{}
+	if prefix != "" {
+		prefix += delimiter
+	}
+	for k, val := range m {
+		fullKey := prefix + k
+		switch val.(type) {
+		case map[string]interface{}:
+			m2 = val.(map[string]interface{})
+		case map[interface{}]interface{}:
+			m2 = cast.ToStringMap(val)
+		default:
+			// immediate value
+			shadow[strings.ToLower(fullKey)] = val
+			continue
+		}
+		// recursively merge to shadow map
+		shadow = flattenAndMergeMap(shadow, m2, fullKey, delimiter)
+	}
+	return shadow
+}
@@ -0,0 +1,86 @@
+package javaproperties
+
+import (
+	"bytes"
+	"sort"
+	"strings"
+
+	"github.com/magiconair/properties"
+	"github.com/spf13/cast"
+)
+
+// Codec implements the encoding.Encoder and encoding.Decoder interfaces for Java properties encoding.
+type Codec struct {
+	KeyDelimiter string
+
+	// Store read properties on the object so that we can write back in order with comments.
+	// This will only be used if the configuration read is a properties file.
+	// TODO: drop this feature in v2
+	// TODO: make use of the global properties object optional
+	Properties *properties.Properties
+}
+
+func (c *Codec) Encode(v map[string]interface{}) ([]byte, error) {
+	if c.Properties == nil {
+		c.Properties = properties.NewProperties()
+	}
+
+	flattened := map[string]interface{}{}
+
+	flattened = flattenAndMergeMap(flattened, v, "", c.keyDelimiter())
+
+	keys := make([]string, 0, len(flattened))
+
+	for key := range flattened {
+		keys = append(keys, key)
+	}
+
+	sort.Strings(keys)
+
+	for _, key := range keys {
+		_, _, err := c.Properties.Set(key, cast.ToString(flattened[key]))
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	var buf bytes.Buffer
+
+	_, err := c.Properties.WriteComment(&buf, "#", properties.UTF8)
+	if err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
+func (c *Codec) Decode(b []byte, v map[string]interface{}) error {
+	var err error
+	c.Properties, err = properties.Load(b, properties.UTF8)
+	if err != nil {
+		return err
+	}
+
+	for _, key := range c.Properties.Keys() {
+		// ignore existence check: we know it's there
+		value, _ := c.Properties.Get(key)
+
+		// recursively build nested maps
+		path := strings.Split(key, c.keyDelimiter())
+		lastKey := strings.ToLower(path[len(path)-1])
+		deepestMap := deepSearch(v, path[0:len(path)-1])
+
+		// set innermost value
+		deepestMap[lastKey] = value
+	}
+
+	return nil
+}
+
+func (c Codec) keyDelimiter() string {
+	if c.KeyDelimiter == "" {
+		return "."
+	}
+
+	return c.KeyDelimiter
+}
@@ -0,0 +1,89 @@
+package javaproperties
+
+import (
+	"reflect"
+	"testing"
+)
+
+// original form of the data
+const original = `#key-value pair
+key = value
+map.key = value
+`
+
+// encoded form of the data
+const encoded = `key = value
+map.key = value
+`
+
+// Viper's internal representation
+var data = map[string]interface{}{
+	"key": "value",
+	"map": map[string]interface{}{
+		"key": "value",
+	},
+}
+
+func TestCodec_Encode(t *testing.T) {
+	codec := Codec{}
+
+	b, err := codec.Encode(data)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if encoded != string(b) {
+		t.Fatalf("decoded value does not match the expected one\nactual:   %#v\nexpected: %#v", string(b), encoded)
+	}
+}
+
+func TestCodec_Decode(t *testing.T) {
+	t.Run("OK", func(t *testing.T) {
+		codec := Codec{}
+
+		v := map[string]interface{}{}
+
+		err := codec.Decode([]byte(original), v)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if !reflect.DeepEqual(data, v) {
+			t.Fatalf("decoded value does not match the expected one\nactual:   %#v\nexpected: %#v", v, data)
+		}
+	})
+
+	t.Run("InvalidData", func(t *testing.T) {
+		t.Skip("TODO: needs invalid data example")
+
+		codec := Codec{}
+
+		v := map[string]interface{}{}
+
+		codec.Decode([]byte(``), v)
+
+		if len(v) > 0 {
+			t.Fatalf("expected map to be empty when data is invalid\nactual: %#v", v)
+		}
+	})
+}
+
+func TestCodec_DecodeEncode(t *testing.T) {
+	codec := Codec{}
+
+	v := map[string]interface{}{}
+
+	err := codec.Decode([]byte(original), v)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	b, err := codec.Encode(data)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if original != string(b) {
+		t.Fatalf("encoded value does not match the original\nactual:   %#v\nexpected: %#v", string(b), original)
+	}
+}
@@ -0,0 +1,74 @@
+package javaproperties
+
+import (
+	"strings"
+
+	"github.com/spf13/cast"
+)
+
+// THIS CODE IS COPIED HERE: IT SHOULD NOT BE MODIFIED
+// AT SOME POINT IT WILL BE MOVED TO A COMMON PLACE
+// deepSearch scans deep maps, following the key indexes listed in the
+// sequence "path".
+// The last value is expected to be another map, and is returned.
+//
+// In case intermediate keys do not exist, or map to a non-map value,
+// a new map is created and inserted, and the search continues from there:
+// the initial map "m" may be modified!
+func deepSearch(m map[string]interface{}, path []string) map[string]interface{} {
+	for _, k := range path {
+		m2, ok := m[k]
+		if !ok {
+			// intermediate key does not exist
+			// => create it and continue from there
+			m3 := make(map[string]interface{})
+			m[k] = m3
+			m = m3
+			continue
+		}
+		m3, ok := m2.(map[string]interface{})
+		if !ok {
+			// intermediate key is a value
+			// => replace with a new map
+			m3 = make(map[string]interface{})
+			m[k] = m3
+		}
+		// continue search from here
+		m = m3
+	}
+	return m
+}
+
+// flattenAndMergeMap recursively flattens the given map into a new map
+// Code is based on the function with the same name in tha main package.
+// TODO: move it to a common place
+func flattenAndMergeMap(shadow map[string]interface{}, m map[string]interface{}, prefix string, delimiter string) map[string]interface{} {
+	if shadow != nil && prefix != "" && shadow[prefix] != nil {
+		// prefix is shadowed => nothing more to flatten
+		return shadow
+	}
+	if shadow == nil {
+		shadow = make(map[string]interface{})
+	}
+
+	var m2 map[string]interface{}
+	if prefix != "" {
+		prefix += delimiter
+	}
+	for k, val := range m {
+		fullKey := prefix + k
+		switch val.(type) {
+		case map[string]interface{}:
+			m2 = val.(map[string]interface{})
+		case map[interface{}]interface{}:
+			m2 = cast.ToStringMap(val)
+		default:
+			// immediate value
+			shadow[strings.ToLower(fullKey)] = val
+			continue
+		}
+		// recursively merge to shadow map
+		shadow = flattenAndMergeMap(shadow, m2, fullKey, delimiter)
+	}
+	return shadow
+}
@@ -7,11 +7,11 @@ import (
 // Codec implements the encoding.Encoder and encoding.Decoder interfaces for JSON encoding.
 type Codec struct{}

-func (Codec) Encode(v interface{}) ([]byte, error) {
+func (Codec) Encode(v map[string]interface{}) ([]byte, error) {
 	// TODO: expose prefix and indent in the Codec as setting?
 	return json.MarshalIndent(v, "", "  ")
 }

-func (Codec) Decode(b []byte, v interface{}) error {
-	return json.Unmarshal(b, v)
+func (Codec) Decode(b []byte, v map[string]interface{}) error {
+	return json.Unmarshal(b, &v)
 }
@@ -0,0 +1,95 @@
+package json
+
+import (
+	"reflect"
+	"testing"
+)
+
+// encoded form of the data
+const encoded = `{
+  "key": "value",
+  "list": [
+    "item1",
+    "item2",
+    "item3"
+  ],
+  "map": {
+    "key": "value"
+  },
+  "nested_map": {
+    "map": {
+      "key": "value",
+      "list": [
+        "item1",
+        "item2",
+        "item3"
+      ]
+    }
+  }
+}`
+
+// Viper's internal representation
+var data = map[string]interface{}{
+	"key": "value",
+	"list": []interface{}{
+		"item1",
+		"item2",
+		"item3",
+	},
+	"map": map[string]interface{}{
+		"key": "value",
+	},
+	"nested_map": map[string]interface{}{
+		"map": map[string]interface{}{
+			"key": "value",
+			"list": []interface{}{
+				"item1",
+				"item2",
+				"item3",
+			},
+		},
+	},
+}
+
+func TestCodec_Encode(t *testing.T) {
+	codec := Codec{}
+
+	b, err := codec.Encode(data)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if encoded != string(b) {
+		t.Fatalf("decoded value does not match the expected one\nactual:   %#v\nexpected: %#v", string(b), encoded)
+	}
+}
+
+func TestCodec_Decode(t *testing.T) {
+	t.Run("OK", func(t *testing.T) {
+		codec := Codec{}
+
+		v := map[string]interface{}{}
+
+		err := codec.Decode([]byte(encoded), v)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if !reflect.DeepEqual(data, v) {
+			t.Fatalf("decoded value does not match the expected one\nactual:   %#v\nexpected: %#v", v, data)
+		}
+	})
+
+	t.Run("InvalidData", func(t *testing.T) {
+		codec := Codec{}
+
+		v := map[string]interface{}{}
+
+		err := codec.Decode([]byte(`invalid data`), v)
+		if err == nil {
+			t.Fatal("expected decoding to fail")
+		}
+
+		t.Logf("decoding failed as expected: %s", err)
+	})
+}
@@ -1,45 +1,16 @@
 package toml

 import (
-	"github.com/pelletier/go-toml"
+	"github.com/pelletier/go-toml/v2"
 )

 // Codec implements the encoding.Encoder and encoding.Decoder interfaces for TOML encoding.
 type Codec struct{}

-func (Codec) Encode(v interface{}) ([]byte, error) {
-	if m, ok := v.(map[string]interface{}); ok {
-		t, err := toml.TreeFromMap(m)
-		if err != nil {
-			return nil, err
-		}
-
-		s, err := t.ToTomlString()
-		if err != nil {
-			return nil, err
-		}
-
-		return []byte(s), nil
-	}
-
+func (Codec) Encode(v map[string]interface{}) ([]byte, error) {
 	return toml.Marshal(v)
 }

-func (Codec) Decode(b []byte, v interface{}) error {
-	tree, err := toml.LoadBytes(b)
-	if err != nil {
-		return err
-	}
-
-	if m, ok := v.(*map[string]interface{}); ok {
-		vmap := *m
-		tmap := tree.ToMap()
-		for k, v := range tmap {
-			vmap[k] = v
-		}
-
-		return nil
-	}
-
-	return tree.Unmarshal(v)
+func (Codec) Decode(b []byte, v map[string]interface{}) error {
+	return toml.Unmarshal(b, &v)
 }
@@ -0,0 +1,105 @@
+package toml
+
+import (
+	"reflect"
+	"testing"
+)
+
+// original form of the data
+const original = `# key-value pair
+key = "value"
+list = ["item1", "item2", "item3"]
+
+[map]
+key = "value"
+
+# nested
+# map
+[nested_map]
+[nested_map.map]
+key = "value"
+list = [
+  "item1",
+  "item2",
+  "item3",
+]
+`
+
+// encoded form of the data
+const encoded = `key = 'value'
+list = ['item1', 'item2', 'item3']
+
+[map]
+key = 'value'
+
+[nested_map]
+[nested_map.map]
+key = 'value'
+list = ['item1', 'item2', 'item3']
+`
+
+// Viper's internal representation
+var data = map[string]interface{}{
+	"key": "value",
+	"list": []interface{}{
+		"item1",
+		"item2",
+		"item3",
+	},
+	"map": map[string]interface{}{
+		"key": "value",
+	},
+	"nested_map": map[string]interface{}{
+		"map": map[string]interface{}{
+			"key": "value",
+			"list": []interface{}{
+				"item1",
+				"item2",
+				"item3",
+			},
+		},
+	},
+}
+
+func TestCodec_Encode(t *testing.T) {
+	codec := Codec{}
+
+	b, err := codec.Encode(data)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if encoded != string(b) {
+		t.Fatalf("decoded value does not match the expected one\nactual:   %#v\nexpected: %#v", string(b), encoded)
+	}
+}
+
+func TestCodec_Decode(t *testing.T) {
+	t.Run("OK", func(t *testing.T) {
+		codec := Codec{}
+
+		v := map[string]interface{}{}
+
+		err := codec.Decode([]byte(original), v)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if !reflect.DeepEqual(data, v) {
+			t.Fatalf("decoded value does not match the expected one\nactual:   %#v\nexpected: %#v", v, data)
+		}
+	})
+
+	t.Run("InvalidData", func(t *testing.T) {
+		codec := Codec{}
+
+		v := map[string]interface{}{}
+
+		err := codec.Decode([]byte(`invalid data`), v)
+		if err == nil {
+			t.Fatal("expected decoding to fail")
+		}
+
+		t.Logf("decoding failed as expected: %s", err)
+	})
+}
@@ -1,14 +1,14 @@
 package yaml

-import "gopkg.in/yaml.v2"
+import "gopkg.in/yaml.v3"

 // Codec implements the encoding.Encoder and encoding.Decoder interfaces for YAML encoding.
 type Codec struct{}

-func (Codec) Encode(v interface{}) ([]byte, error) {
+func (Codec) Encode(v map[string]interface{}) ([]byte, error) {
 	return yaml.Marshal(v)
 }

-func (Codec) Decode(b []byte, v interface{}) error {
-	return yaml.Unmarshal(b, v)
+func (Codec) Decode(b []byte, v map[string]interface{}) error {
+	return yaml.Unmarshal(b, &v)
 }
@@ -0,0 +1,136 @@
+package yaml
+
+import (
+	"reflect"
+	"testing"
+)
+
+// original form of the data
+const original = `# key-value pair
+key: value
+list:
+    - item1
+    - item2
+    - item3
+map:
+    key: value
+
+# nested
+# map
+nested_map:
+    map:
+        key: value
+        list:
+            - item1
+            - item2
+            - item3
+`
+
+// encoded form of the data
+const encoded = `key: value
+list:
+    - item1
+    - item2
+    - item3
+map:
+    key: value
+nested_map:
+    map:
+        key: value
+        list:
+            - item1
+            - item2
+            - item3
+`
+
+// decoded form of the data
+//
+// in case of YAML it's slightly different from Viper's internal representation
+// (eg. map is decoded into a map with interface key)
+var decoded = map[string]interface{}{
+	"key": "value",
+	"list": []interface{}{
+		"item1",
+		"item2",
+		"item3",
+	},
+	"map": map[string]interface{}{
+		"key": "value",
+	},
+	"nested_map": map[string]interface{}{
+		"map": map[string]interface{}{
+			"key": "value",
+			"list": []interface{}{
+				"item1",
+				"item2",
+				"item3",
+			},
+		},
+	},
+}
+
+// Viper's internal representation
+var data = map[string]interface{}{
+	"key": "value",
+	"list": []interface{}{
+		"item1",
+		"item2",
+		"item3",
+	},
+	"map": map[string]interface{}{
+		"key": "value",
+	},
+	"nested_map": map[string]interface{}{
+		"map": map[string]interface{}{
+			"key": "value",
+			"list": []interface{}{
+				"item1",
+				"item2",
+				"item3",
+			},
+		},
+	},
+}
+
+func TestCodec_Encode(t *testing.T) {
+	codec := Codec{}
+
+	b, err := codec.Encode(data)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if encoded != string(b) {
+		t.Fatalf("decoded value does not match the expected one\nactual:   %#v\nexpected: %#v", string(b), encoded)
+	}
+}
+
+func TestCodec_Decode(t *testing.T) {
+	t.Run("OK", func(t *testing.T) {
+		codec := Codec{}
+
+		v := map[string]interface{}{}
+
+		err := codec.Decode([]byte(original), v)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if !reflect.DeepEqual(decoded, v) {
+			t.Fatalf("decoded value does not match the expected one\nactual:   %#v\nexpected: %#v", v, decoded)
+		}
+	})
+
+	t.Run("InvalidData", func(t *testing.T) {
+		codec := Codec{}
+
+		v := map[string]interface{}{}
+
+		err := codec.Decode([]byte(`invalid data`), v)
+		if err == nil {
+			t.Fatal("expected decoding to fail")
+		}
+
+		t.Logf("decoding failed as expected: %s", err)
+	})
+}
@@ -7,8 +7,8 @@ import (
 )

 // Logger is a unified interface for various logging use cases and practices, including:
-// 		- leveled logging
-// 		- structured logging
+//   - leveled logging
+//   - structured logging
 type Logger interface {
 	// Trace logs a Trace event.
 	//
@@ -10,6 +10,7 @@ import (
 	"bytes"
 	"io"
 	"os"
+	"strings"

 	crypt "github.com/sagikazarmark/crypt/config"

@@ -75,6 +76,7 @@ func getConfigManager(rp viper.RemoteProvider) (crypt.ConfigManager, error) {
 	var cm crypt.ConfigManager
 	var err error

+	endpoints := strings.Split(rp.Endpoint(), ";")
 	if rp.SecretKeyring() != "" {
 		var kr *os.File
 		kr, err = os.Open(rp.SecretKeyring())
@@ -84,20 +86,24 @@ func getConfigManager(rp viper.RemoteProvider) (crypt.ConfigManager, error) {
 		defer kr.Close()
 		switch rp.Provider() {
 		case "etcd":
-			cm, err = crypt.NewEtcdConfigManager([]string{rp.Endpoint()}, kr)
+			cm, err = crypt.NewEtcdConfigManager(endpoints, kr)
+		case "etcd3":
+			cm, err = crypt.NewEtcdV3ConfigManager(endpoints, kr)
 		case "firestore":
-			cm, err = crypt.NewFirestoreConfigManager([]string{rp.Endpoint()}, kr)
+			cm, err = crypt.NewFirestoreConfigManager(endpoints, kr)
 		default:
-			cm, err = crypt.NewConsulConfigManager([]string{rp.Endpoint()}, kr)
+			cm, err = crypt.NewConsulConfigManager(endpoints, kr)
 		}
 	} else {
 		switch rp.Provider() {
 		case "etcd":
-			cm, err = crypt.NewStandardEtcdConfigManager([]string{rp.Endpoint()})
+			cm, err = crypt.NewStandardEtcdConfigManager(endpoints)
+		case "etcd3":
+			cm, err = crypt.NewStandardEtcdV3ConfigManager(endpoints)
 		case "firestore":
-			cm, err = crypt.NewStandardFirestoreConfigManager([]string{rp.Endpoint()})
+			cm, err = crypt.NewStandardFirestoreConfigManager(endpoints)
 		default:
-			cm, err = crypt.NewStandardConsulConfigManager([]string{rp.Endpoint()})
+			cm, err = crypt.NewStandardConsulConfigManager(endpoints)
 		}
 	}
 	if err != nil {
@@ -64,18 +64,25 @@ func copyAndInsensitiviseMap(m map[string]interface{}) map[string]interface{} {
 	return nm
 }

+func insensitiviseVal(val interface{}) interface{} {
+	switch val.(type) {
+	case map[interface{}]interface{}:
+		// nested map: cast and recursively insensitivise
+		val = cast.ToStringMap(val)
+		insensitiviseMap(val.(map[string]interface{}))
+	case map[string]interface{}:
+		// nested map: recursively insensitivise
+		insensitiviseMap(val.(map[string]interface{}))
+	case []interface{}:
+		// nested array: recursively insensitivise
+		insensitiveArray(val.([]interface{}))
+	}
+	return val
+}
+
 func insensitiviseMap(m map[string]interface{}) {
 	for key, val := range m {
-		switch val.(type) {
-		case map[interface{}]interface{}:
-			// nested map: cast and recursively insensitivise
-			val = cast.ToStringMap(val)
-			insensitiviseMap(val.(map[string]interface{}))
-		case map[string]interface{}:
-			// nested map: recursively insensitivise
-			insensitiviseMap(val.(map[string]interface{}))
-		}
-
+		val = insensitiviseVal(val)
 		lower := strings.ToLower(key)
 		if key != lower {
 			// remove old key (not lower-cased)
@@ -86,6 +93,12 @@ func insensitiviseMap(m map[string]interface{}) {
 	}
 }

+func insensitiveArray(a []interface{}) {
+	for i, val := range a {
+		a[i] = insensitiviseVal(val)
+	}
+}
+
 func absPathify(logger Logger, inPath string) string {
 	logger.Info("trying to resolve absolute path", "path", inPath)

@@ -35,16 +35,16 @@ import (
 	"time"

 	"github.com/fsnotify/fsnotify"
-	"github.com/magiconair/properties"
 	"github.com/mitchellh/mapstructure"
 	"github.com/spf13/afero"
 	"github.com/spf13/cast"
 	"github.com/spf13/pflag"
-	"github.com/subosito/gotenv"
-	"gopkg.in/ini.v1"

 	"github.com/spf13/viper/internal/encoding"
+	"github.com/spf13/viper/internal/encoding/dotenv"
 	"github.com/spf13/viper/internal/encoding/hcl"
+	"github.com/spf13/viper/internal/encoding/ini"
+	"github.com/spf13/viper/internal/encoding/javaproperties"
 	"github.com/spf13/viper/internal/encoding/json"
 	"github.com/spf13/viper/internal/encoding/toml"
 	"github.com/spf13/viper/internal/encoding/yaml"
@@ -67,47 +67,8 @@ type RemoteResponse struct {
 	Error error
 }

-var (
-	encoderRegistry = encoding.NewEncoderRegistry()
-	decoderRegistry = encoding.NewDecoderRegistry()
-)
-
 func init() {
 	v = New()
-
-	{
-		codec := yaml.Codec{}
-
-		encoderRegistry.RegisterEncoder("yaml", codec)
-		decoderRegistry.RegisterDecoder("yaml", codec)
-
-		encoderRegistry.RegisterEncoder("yml", codec)
-		decoderRegistry.RegisterDecoder("yml", codec)
-	}
-
-	{
-		codec := json.Codec{}
-
-		encoderRegistry.RegisterEncoder("json", codec)
-		decoderRegistry.RegisterDecoder("json", codec)
-	}
-
-	{
-		codec := toml.Codec{}
-
-		encoderRegistry.RegisterEncoder("toml", codec)
-		decoderRegistry.RegisterDecoder("toml", codec)
-	}
-
-	{
-		codec := hcl.Codec{}
-
-		encoderRegistry.RegisterEncoder("hcl", codec)
-		decoderRegistry.RegisterDecoder("hcl", codec)
-
-		encoderRegistry.RegisterEncoder("tfvars", codec)
-		decoderRegistry.RegisterDecoder("tfvars", codec)
-	}
 }

 type remoteConfigFactory interface {
@@ -171,10 +132,10 @@ type DecoderConfigOption func(*mapstructure.DecoderConfig)
 // DecodeHook returns a DecoderConfigOption which overrides the default
 // DecoderConfig.DecodeHook value, the default is:
 //
-//  mapstructure.ComposeDecodeHookFunc(
-//		mapstructure.StringToTimeDurationHookFunc(),
-//		mapstructure.StringToSliceHookFunc(","),
-//	)
+//	 mapstructure.ComposeDecodeHookFunc(
+//			mapstructure.StringToTimeDurationHookFunc(),
+//			mapstructure.StringToSliceHookFunc(","),
+//		)
 func DecodeHook(hook mapstructure.DecodeHookFunc) DecoderConfigOption {
 	return func(c *mapstructure.DecoderConfig) {
 		c.DecodeHook = hook
@@ -195,18 +156,18 @@ func DecodeHook(hook mapstructure.DecodeHookFunc) DecoderConfigOption {
 //
 // For example, if values from the following sources were loaded:
 //
-//  Defaults : {
-//  	"secret": "",
-//  	"user": "default",
-//  	"endpoint": "https://localhost"
-//  }
-//  Config : {
-//  	"user": "root"
-//  	"secret": "defaultsecret"
-//  }
-//  Env : {
-//  	"secret": "somesecretkey"
-//  }
+//	Defaults : {
+//		"secret": "",
+//		"user": "default",
+//		"endpoint": "https://localhost"
+//	}
+//	Config : {
+//		"user": "root"
+//		"secret": "defaultsecret"
+//	}
+//	Env : {
+//		"secret": "somesecretkey"
+//	}
 //
 // The resulting config will have the following values:
 //
@@ -254,13 +215,13 @@ type Viper struct {
 	aliases        map[string]string
 	typeByDefValue bool

-	// Store read properties on the object so that we can write back in order with comments.
-	// This will only be used if the configuration read is a properties file.
-	properties *properties.Properties
-
 	onConfigChange func(fsnotify.Event)

 	logger Logger
+
+	// TODO: should probably be protected with a mutex
+	encoderRegistry *encoding.EncoderRegistry
+	decoderRegistry *encoding.DecoderRegistry
 }

 // New returns an initialized Viper instance.
@@ -280,6 +241,8 @@ func New() *Viper {
 	v.typeByDefValue = false
 	v.logger = jwwLogger{}

+	v.resetEncoding()
+
 	return v
 }

@@ -326,6 +289,8 @@ func NewWithOptions(opts ...Option) *Viper {
 		opt.apply(v)
 	}

+	v.resetEncoding()
+
 	return v
 }

@@ -335,7 +300,85 @@ func NewWithOptions(opts ...Option) *Viper {
 func Reset() {
 	v = New()
 	SupportedExts = []string{"json", "toml", "yaml", "yml", "properties", "props", "prop", "hcl", "tfvars", "dotenv", "env", "ini"}
-	SupportedRemoteProviders = []string{"etcd", "consul", "firestore"}
+	SupportedRemoteProviders = []string{"etcd", "etcd3", "consul", "firestore"}
+}
+
+// TODO: make this lazy initialization instead
+func (v *Viper) resetEncoding() {
+	encoderRegistry := encoding.NewEncoderRegistry()
+	decoderRegistry := encoding.NewDecoderRegistry()
+
+	{
+		codec := yaml.Codec{}
+
+		encoderRegistry.RegisterEncoder("yaml", codec)
+		decoderRegistry.RegisterDecoder("yaml", codec)
+
+		encoderRegistry.RegisterEncoder("yml", codec)
+		decoderRegistry.RegisterDecoder("yml", codec)
+	}
+
+	{
+		codec := json.Codec{}
+
+		encoderRegistry.RegisterEncoder("json", codec)
+		decoderRegistry.RegisterDecoder("json", codec)
+	}
+
+	{
+		codec := toml.Codec{}
+
+		encoderRegistry.RegisterEncoder("toml", codec)
+		decoderRegistry.RegisterDecoder("toml", codec)
+	}
+
+	{
+		codec := hcl.Codec{}
+
+		encoderRegistry.RegisterEncoder("hcl", codec)
+		decoderRegistry.RegisterDecoder("hcl", codec)
+
+		encoderRegistry.RegisterEncoder("tfvars", codec)
+		decoderRegistry.RegisterDecoder("tfvars", codec)
+	}
+
+	{
+		codec := ini.Codec{
+			KeyDelimiter: v.keyDelim,
+			LoadOptions:  v.iniLoadOptions,
+		}
+
+		encoderRegistry.RegisterEncoder("ini", codec)
+		decoderRegistry.RegisterDecoder("ini", codec)
+	}
+
+	{
+		codec := &javaproperties.Codec{
+			KeyDelimiter: v.keyDelim,
+		}
+
+		encoderRegistry.RegisterEncoder("properties", codec)
+		decoderRegistry.RegisterDecoder("properties", codec)
+
+		encoderRegistry.RegisterEncoder("props", codec)
+		decoderRegistry.RegisterDecoder("props", codec)
+
+		encoderRegistry.RegisterEncoder("prop", codec)
+		decoderRegistry.RegisterDecoder("prop", codec)
+	}
+
+	{
+		codec := &dotenv.Codec{}
+
+		encoderRegistry.RegisterEncoder("dotenv", codec)
+		decoderRegistry.RegisterDecoder("dotenv", codec)
+
+		encoderRegistry.RegisterEncoder("env", codec)
+		decoderRegistry.RegisterDecoder("env", codec)
+	}
+
+	v.encoderRegistry = encoderRegistry
+	v.decoderRegistry = decoderRegistry
 }

 type defaultRemoteProvider struct {
@@ -376,15 +419,20 @@ type RemoteProvider interface {
 var SupportedExts = []string{"json", "toml", "yaml", "yml", "properties", "props", "prop", "hcl", "tfvars", "dotenv", "env", "ini"}

 // SupportedRemoteProviders are universally supported remote providers.
-var SupportedRemoteProviders = []string{"etcd", "consul", "firestore"}
+var SupportedRemoteProviders = []string{"etcd", "etcd3", "consul", "firestore"}

+// OnConfigChange sets the event handler that is called when a config file changes.
 func OnConfigChange(run func(in fsnotify.Event)) { v.OnConfigChange(run) }
+
+// OnConfigChange sets the event handler that is called when a config file changes.
 func (v *Viper) OnConfigChange(run func(in fsnotify.Event)) {
 	v.onConfigChange = run
 }

+// WatchConfig starts watching a config file for changes.
 func WatchConfig() { v.WatchConfig() }

+// WatchConfig starts watching a config file for changes.
 func (v *Viper) WatchConfig() {
 	initWG := sync.WaitGroup{}
 	initWG.Add(1)
@@ -420,9 +468,8 @@ func (v *Viper) WatchConfig() {
 					// we only care about the config file with the following cases:
 					// 1 - if the config file was modified or created
 					// 2 - if the real path to the config file changed (eg: k8s ConfigMap replacement)
-					const writeOrCreateMask = fsnotify.Write | fsnotify.Create
 					if (filepath.Clean(event.Name) == configFile &&
-						event.Op&writeOrCreateMask != 0) ||
+						(event.Has(fsnotify.Write) || event.Has(fsnotify.Create))) ||
 						(currentConfigFile != "" && currentConfigFile != realConfigFile) {
 						realConfigFile = currentConfigFile
 						err := v.ReadInConfig()
@@ -432,8 +479,7 @@ func (v *Viper) WatchConfig() {
 						if v.onConfigChange != nil {
 							v.onConfigChange(event)
 						}
-					} else if filepath.Clean(event.Name) == configFile &&
-						event.Op&fsnotify.Remove&fsnotify.Remove != 0 {
+					} else if filepath.Clean(event.Name) == configFile && event.Has(fsnotify.Remove) {
 						eventsWG.Done()
 						return
 					}
@@ -530,7 +576,7 @@ func (v *Viper) AddConfigPath(in string) {

 // AddRemoteProvider adds a remote configuration source.
 // Remote Providers are searched in the order they are added.
-// provider is a string value: "etcd", "consul" or "firestore" are currently supported.
+// provider is a string value: "etcd", "etcd3", "consul" or "firestore" are currently supported.
 // endpoint is the url.  etcd requires http://ip:port  consul requires ip:port
 // path is the path in the k/v store to retrieve configuration
 // To retrieve a config file called myapp.json from /configs/myapp.json
@@ -561,7 +607,7 @@ func (v *Viper) AddRemoteProvider(provider, endpoint, path string) error {

 // AddSecureRemoteProvider adds a remote configuration source.
 // Secure Remote Providers are searched in the order they are added.
-// provider is a string value: "etcd", "consul" or "firestore" are currently supported.
+// provider is a string value: "etcd", "etcd3", "consul" or "firestore" are currently supported.
 // endpoint is the url.  etcd requires http://ip:port  consul requires ip:port
 // secretkeyring is the filepath to your openpgp secret keyring.  e.g. /etc/secrets/myring.gpg
 // path is the path in the k/v store to retrieve configuration
@@ -742,7 +788,8 @@ func (v *Viper) searchMapWithPathPrefixes(
 // isPathShadowedInDeepMap makes sure the given path is not shadowed somewhere
 // on its path in the map.
 // e.g., if "foo.bar" has a value in the given map, it “shadows”
-//       "foo.bar.baz" in a lower-priority map
+//
+//	"foo.bar.baz" in a lower-priority map
 func (v *Viper) isPathShadowedInDeepMap(path []string, m map[string]interface{}) string {
 	var parentVal interface{}
 	for i := 1; i < len(path); i++ {
@@ -767,7 +814,8 @@ func (v *Viper) isPathShadowedInDeepMap(path []string, m map[string]interface{})
 // isPathShadowedInFlatMap makes sure the given path is not shadowed somewhere
 // in a sub-path of the map.
 // e.g., if "foo.bar" has a value in the given map, it “shadows”
-//       "foo.bar.baz" in a lower-priority map
+//
+//	"foo.bar.baz" in a lower-priority map
 func (v *Viper) isPathShadowedInFlatMap(path []string, mi interface{}) string {
 	// unify input map
 	var m map[string]interface{}
@@ -792,7 +840,8 @@ func (v *Viper) isPathShadowedInFlatMap(path []string, mi interface{}) string {
 // isPathShadowedInAutoEnv makes sure the given path is not shadowed somewhere
 // in the environment, when automatic env is on.
 // e.g., if "foo.bar" has a value in the environment, it “shadows”
-//       "foo.bar.baz" in a lower-priority map
+//
+//	"foo.bar.baz" in a lower-priority map
 func (v *Viper) isPathShadowedInAutoEnv(path []string) string {
 	var parentKey string
 	for i := 1; i < len(path); i++ {
@@ -813,11 +862,11 @@ func (v *Viper) isPathShadowedInAutoEnv(path []string) string {
 // would return a string slice for the key if the key's type is inferred by
 // the default value and the Get function would return:
 //
-//   []string {"a", "b", "c"}
+//	[]string {"a", "b", "c"}
 //
 // Otherwise the Get function would return:
 //
-//   "a b c"
+//	"a b c"
 func SetTypeByDefaultValue(enable bool) { v.SetTypeByDefaultValue(enable) }

 func (v *Viper) SetTypeByDefaultValue(enable bool) {
@@ -945,6 +994,13 @@ func (v *Viper) GetUint(key string) uint {
 	return cast.ToUint(v.Get(key))
 }

+// GetUint16 returns the value associated with the key as an unsigned integer.
+func GetUint16(key string) uint16 { return v.GetUint16(key) }
+
+func (v *Viper) GetUint16(key string) uint16 {
+	return cast.ToUint16(v.Get(key))
+}
+
 // GetUint32 returns the value associated with the key as an unsigned integer.
 func GetUint32(key string) uint32 { return v.GetUint32(key) }

@@ -1094,9 +1150,8 @@ func (v *Viper) BindPFlags(flags *pflag.FlagSet) error {
 // BindPFlag binds a specific key to a pflag (as used by cobra).
 // Example (where serverCmd is a Cobra instance):
 //
-//	 serverCmd.Flags().Int("port", 1138, "Port to run Application server on")
-//	 Viper.BindPFlag("port", serverCmd.Flags().Lookup("port"))
-//
+//	serverCmd.Flags().Int("port", 1138, "Port to run Application server on")
+//	Viper.BindPFlag("port", serverCmd.Flags().Lookup("port"))
 func BindPFlag(key string, flag *pflag.Flag) error { return v.BindPFlag(key, flag) }

 func (v *Viper) BindPFlag(key string, flag *pflag.Flag) error {
@@ -1154,6 +1209,17 @@ func (v *Viper) BindEnv(input ...string) error {
 	return nil
 }

+// MustBindEnv wraps BindEnv in a panic.
+// If there is an error binding an environment variable, MustBindEnv will
+// panic.
+func MustBindEnv(input ...string) { v.MustBindEnv(input...) }
+
+func (v *Viper) MustBindEnv(input ...string) {
+	if err := v.BindEnv(input...); err != nil {
+		panic(fmt.Sprintf("error while binding environment variable: %v", err))
+	}
+}
+
 // Given a key, find the value.
 //
 // Viper will check to see if an alias exists first.
@@ -1634,53 +1700,11 @@ func (v *Viper) unmarshalReader(in io.Reader, c map[string]interface{}) error {
 	buf.ReadFrom(in)

 	switch format := strings.ToLower(v.getConfigType()); format {
-	case "yaml", "yml", "json", "toml", "hcl", "tfvars":
-		err := decoderRegistry.Decode(format, buf.Bytes(), &c)
+	case "yaml", "yml", "json", "toml", "hcl", "tfvars", "ini", "properties", "props", "prop", "dotenv", "env":
+		err := v.decoderRegistry.Decode(format, buf.Bytes(), c)
 		if err != nil {
 			return ConfigParseError{err}
 		}
-
-	case "dotenv", "env":
-		env, err := gotenv.StrictParse(buf)
-		if err != nil {
-			return ConfigParseError{err}
-		}
-		for k, v := range env {
-			c[k] = v
-		}
-
-	case "properties", "props", "prop":
-		v.properties = properties.NewProperties()
-		var err error
-		if v.properties, err = properties.Load(buf.Bytes(), properties.UTF8); err != nil {
-			return ConfigParseError{err}
-		}
-		for _, key := range v.properties.Keys() {
-			value, _ := v.properties.Get(key)
-			// recursively build nested maps
-			path := strings.Split(key, ".")
-			lastKey := strings.ToLower(path[len(path)-1])
-			deepestMap := deepSearch(c, path[0:len(path)-1])
-			// set innermost value
-			deepestMap[lastKey] = value
-		}
-
-	case "ini":
-		cfg := ini.Empty(v.iniLoadOptions)
-		err := cfg.Append(buf.Bytes())
-		if err != nil {
-			return ConfigParseError{err}
-		}
-		sections := cfg.Sections()
-		for i := 0; i < len(sections); i++ {
-			section := sections[i]
-			keys := section.Keys()
-			for j := 0; j < len(keys); j++ {
-				key := keys[j]
-				value := cfg.Section(section.Name()).Key(key.Name()).String()
-				c[section.Name()+"."+key.Name()] = value
-			}
-		}
 	}

 	insensitiviseMap(c)
@@ -1691,8 +1715,8 @@ func (v *Viper) unmarshalReader(in io.Reader, c map[string]interface{}) error {
 func (v *Viper) marshalWriter(f afero.File, configType string) error {
 	c := v.AllSettings()
 	switch configType {
-	case "yaml", "yml", "json", "toml", "hcl", "tfvars":
-		b, err := encoderRegistry.Encode(configType, c)
+	case "yaml", "yml", "json", "toml", "hcl", "tfvars", "ini", "prop", "props", "properties", "dotenv", "env":
+		b, err := v.encoderRegistry.Encode(configType, c)
 		if err != nil {
 			return ConfigMarshalError{err}
 		}
@@ -1701,50 +1725,6 @@ func (v *Viper) marshalWriter(f afero.File, configType string) error {
 		if err != nil {
 			return ConfigMarshalError{err}
 		}
-
-	case "prop", "props", "properties":
-		if v.properties == nil {
-			v.properties = properties.NewProperties()
-		}
-		p := v.properties
-		for _, key := range v.AllKeys() {
-			_, _, err := p.Set(key, v.GetString(key))
-			if err != nil {
-				return ConfigMarshalError{err}
-			}
-		}
-		_, err := p.WriteComment(f, "#", properties.UTF8)
-		if err != nil {
-			return ConfigMarshalError{err}
-		}
-
-	case "dotenv", "env":
-		lines := []string{}
-		for _, key := range v.AllKeys() {
-			envName := strings.ToUpper(strings.Replace(key, ".", "_", -1))
-			val := v.Get(key)
-			lines = append(lines, fmt.Sprintf("%v=%v", envName, val))
-		}
-		s := strings.Join(lines, "\n")
-		if _, err := f.WriteString(s); err != nil {
-			return ConfigMarshalError{err}
-		}
-
-	case "ini":
-		keys := v.AllKeys()
-		cfg := ini.Empty()
-		ini.PrettyFormat = false
-		for i := 0; i < len(keys); i++ {
-			key := keys[i]
-			lastSep := strings.LastIndex(key, ".")
-			sectionName := key[:(lastSep)]
-			keyName := key[(lastSep + 1):]
-			if sectionName == "default" {
-				sectionName = ""
-			}
-			cfg.Section(sectionName).Key(keyName).SetValue(v.GetString(key))
-		}
-		cfg.WriteTo(f)
 	}
 	return nil
 }
@@ -1761,7 +1741,8 @@ func keyExists(k string, m map[string]interface{}) string {
 }

 func castToMapStringInterface(
-	src map[interface{}]interface{}) map[string]interface{} {
+	src map[interface{}]interface{},
+) map[string]interface{} {
 	tgt := map[string]interface{}{}
 	for k, v := range src {
 		tgt[fmt.Sprintf("%v", k)] = v
@@ -1799,7 +1780,8 @@ func castMapFlagToMapInterface(src map[string]FlagValue) map[string]interface{}
 // deep. Both map types are supported as there is a go-yaml fork that uses
 // `map[string]interface{}` instead.
 func mergeMaps(
-	src, tgt map[string]interface{}, itgt map[interface{}]interface{}) {
+	src, tgt map[string]interface{}, itgt map[interface{}]interface{},
+) {
 	for sk, sv := range src {
 		tk := keyExists(sk, tgt)
 		if tk == "" {
@@ -1823,17 +1805,6 @@ func mergeMaps(

 		svType := reflect.TypeOf(sv)
 		tvType := reflect.TypeOf(tv)
-		if tvType != nil && svType != tvType { // Allow for the target to be nil
-			v.logger.Error(
-				"svType != tvType",
-				"key", sk,
-				"st", svType,
-				"tt", tvType,
-				"sv", sv,
-				"tv", tv,
-			)
-			continue
-		}

 		v.logger.Trace(
 			"processing",
@@ -1847,13 +1818,37 @@ func mergeMaps(
 		switch ttv := tv.(type) {
 		case map[interface{}]interface{}:
 			v.logger.Trace("merging maps (must convert)")
-			tsv := sv.(map[interface{}]interface{})
+			tsv, ok := sv.(map[interface{}]interface{})
+			if !ok {
+				v.logger.Error(
+					"Could not cast sv to map[interface{}]interface{}",
+					"key", sk,
+					"st", svType,
+					"tt", tvType,
+					"sv", sv,
+					"tv", tv,
+				)
+				continue
+			}
+
 			ssv := castToMapStringInterface(tsv)
 			stv := castToMapStringInterface(ttv)
 			mergeMaps(ssv, stv, ttv)
 		case map[string]interface{}:
 			v.logger.Trace("merging maps")
-			mergeMaps(sv.(map[string]interface{}), ttv, nil)
+			tsv, ok := sv.(map[string]interface{})
+			if !ok {
+				v.logger.Error(
+					"Could not cast sv to map[string]interface{}",
+					"key", sk,
+					"st", svType,
+					"tt", tvType,
+					"sv", sv,
+					"tv", tv,
+				)
+				continue
+			}
+			mergeMaps(tsv, ttv, nil)
 		default:
 			v.logger.Trace("setting value")
 			tgt[tk] = sv
@@ -1887,6 +1882,10 @@ func (v *Viper) getKeyValueConfig() error {
 		return RemoteConfigError("Enable the remote features by doing a blank import of the viper/remote package: '_ github.com/spf13/viper/remote'")
 	}

+	if len(v.remoteProviders) == 0 {
+		return RemoteConfigError("No Remote Providers")
+	}
+
 	for _, rp := range v.remoteProviders {
 		val, err := v.getRemoteConfig(rp)
 		if err != nil {
@@ -1913,6 +1912,10 @@ func (v *Viper) getRemoteConfig(provider RemoteProvider) (map[string]interface{}

 // Retrieve the first found remote configuration.
 func (v *Viper) watchKeyValueConfigOnChannel() error {
+	if len(v.remoteProviders) == 0 {
+		return RemoteConfigError("No Remote Providers")
+	}
+
 	for _, rp := range v.remoteProviders {
 		respc, _ := RemoteConfig.WatchChannel(rp)
 		// Todo: Add quit channel
@@ -1930,9 +1933,15 @@ func (v *Viper) watchKeyValueConfigOnChannel() error {

 // Retrieve the first found remote configuration.
 func (v *Viper) watchKeyValueConfig() error {
+	if len(v.remoteProviders) == 0 {
+		return RemoteConfigError("No Remote Providers")
+	}
+
 	for _, rp := range v.remoteProviders {
 		val, err := v.watchRemoteConfig(rp)
 		if err != nil {
+			v.logger.Error(fmt.Errorf("watch remote config: %w", err).Error())
+
 			continue
 		}
 		v.kvstore = val
@@ -1975,9 +1984,10 @@ func (v *Viper) AllKeys() []string {

 // flattenAndMergeMap recursively flattens the given map into a map[string]bool
 // of key paths (used as a set, easier to manipulate than a []string):
-// - each path is merged into a single key string, delimited with v.keyDelim
-// - if a path is shadowed by an earlier value in the initial shadow map,
-//   it is skipped.
+//   - each path is merged into a single key string, delimited with v.keyDelim
+//   - if a path is shadowed by an earlier value in the initial shadow map,
+//     it is skipped.
+//
 // The resulting set of paths is merged to the given shadow set at the same time.
 func (v *Viper) flattenAndMergeMap(shadow map[string]bool, m map[string]interface{}, prefix string) map[string]bool {
 	if shadow != nil && prefix != "" && shadow[prefix] {
@@ -2128,14 +2138,17 @@ func (v *Viper) getConfigFile() (string, error) {

 // Debug prints all configuration registries for debugging
 // purposes.
-func Debug() { v.Debug() }
+func Debug()              { v.Debug() }
+func DebugTo(w io.Writer) { v.DebugTo(w) }

-func (v *Viper) Debug() {
-	fmt.Printf("Aliases:\n%#v\n", v.aliases)
-	fmt.Printf("Override:\n%#v\n", v.override)
-	fmt.Printf("PFlags:\n%#v\n", v.pflags)
-	fmt.Printf("Env:\n%#v\n", v.env)
-	fmt.Printf("Key/Value Store:\n%#v\n", v.kvstore)
-	fmt.Printf("Config:\n%#v\n", v.config)
-	fmt.Printf("Defaults:\n%#v\n", v.defaults)
+func (v *Viper) Debug() { v.DebugTo(os.Stdout) }
+
+func (v *Viper) DebugTo(w io.Writer) {
+	fmt.Fprintf(w, "Aliases:\n%#v\n", v.aliases)
+	fmt.Fprintf(w, "Override:\n%#v\n", v.override)
+	fmt.Fprintf(w, "PFlags:\n%#v\n", v.pflags)
+	fmt.Fprintf(w, "Env:\n%#v\n", v.env)
+	fmt.Fprintf(w, "Key/Value Store:\n%#v\n", v.kvstore)
+	fmt.Fprintf(w, "Config:\n%#v\n", v.config)
+	fmt.Fprintf(w, "Defaults:\n%#v\n", v.defaults)
 }
@@ -9,7 +9,7 @@ import (
 	"bytes"
 	"encoding/json"
 	"io"
-	"io/ioutil"
+	"io/ioutil" //nolint:staticcheck
 	"os"
 	"os/exec"
 	"path"
@@ -33,21 +33,21 @@ import (
 	"github.com/spf13/viper/internal/testutil"
 )

-var yamlExample = []byte(`Hacker: true
-name: steve
-hobbies:
- skateboarding
- snowboarding
- go
-clothing:
-  jacket: leather
-  trousers: denim
-  pants:
-    size: large
-age: 35
-eyes : brown
-beard: true
-`)
+// var yamlExample = []byte(`Hacker: true
+// name: steve
+// hobbies:
+//     - skateboarding
+//     - snowboarding
+//     - go
+// clothing:
+//     jacket: leather
+//     trousers: denim
+//     pants:
+//         size: large
+// age: 35
+// eyes : brown
+// beard: true
+// `)

 var yamlExampleWithExtras = []byte(`Existing: true
 Bogus: true
@@ -998,7 +998,7 @@ func TestBindPFlags(t *testing.T) {
 	}
 }

-// nolint: dupl
+//nolint:dupl
 func TestBindPFlagsStringSlice(t *testing.T) {
 	tests := []struct {
 		Expected []string
@@ -1046,7 +1046,7 @@ func TestBindPFlagsStringSlice(t *testing.T) {
 	}
 }

-// nolint: dupl
+//nolint:dupl
 func TestBindPFlagsStringArray(t *testing.T) {
 	tests := []struct {
 		Expected []string
@@ -1094,7 +1094,7 @@ func TestBindPFlagsStringArray(t *testing.T) {
 	}
 }

-// nolint: dupl
+//nolint:dupl
 func TestBindPFlagsIntSlice(t *testing.T) {
 	tests := []struct {
 		Expected []int
@@ -1558,21 +1558,21 @@ p_ppu = 0.55
 p_batters.batter.type = Regular
 `)

-var yamlWriteExpected = []byte(`age: 35
-beard: true
-clothing:
-  jacket: leather
-  pants:
-    size: large
-  trousers: denim
-eyes: brown
-hacker: true
-hobbies:
- skateboarding
- snowboarding
- go
-name: steve
-`)
+// var yamlWriteExpected = []byte(`age: 35
+// beard: true
+// clothing:
+//     jacket: leather
+//     pants:
+//         size: large
+//     trousers: denim
+// eyes: brown
+// hacker: true
+// hobbies:
+//     - skateboarding
+//     - snowboarding
+//     - go
+// name: steve
+// `)

 func TestWriteConfig(t *testing.T) {
 	fs := afero.NewMemMapFs()
@@ -1912,6 +1912,24 @@ hello:
 fu: bar
 `)

+var jsonMergeExampleTgt = []byte(`
+{
+	"hello": {
+		"foo": null,
+		"pop": 123456
+	}
+}
+`)
+
+var jsonMergeExampleSrc = []byte(`
+{
+	"hello": {
+		"foo": "foo str",
+		"pop": "pop str"
+	}
+}
+`)
+
 func TestMergeConfig(t *testing.T) {
 	v := New()
 	v.SetConfigType("yml")
@@ -1935,6 +1953,10 @@ func TestMergeConfig(t *testing.T) {
 		t.Fatalf("uint pop != 37890, = %d", pop)
 	}

+	if pop := v.GetUint16("hello.pop"); pop != uint16(37890) {
+		t.Fatalf("uint pop != 37890, = %d", pop)
+	}
+
 	if pop := v.GetUint32("hello.pop"); pop != 37890 {
 		t.Fatalf("uint32 pop != 37890, = %d", pop)
 	}
@@ -1984,6 +2006,26 @@ func TestMergeConfig(t *testing.T) {
 	}
 }

+func TestMergeConfigOverrideType(t *testing.T) {
+	v := New()
+	v.SetConfigType("json")
+	if err := v.ReadConfig(bytes.NewBuffer(jsonMergeExampleTgt)); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := v.MergeConfig(bytes.NewBuffer(jsonMergeExampleSrc)); err != nil {
+		t.Fatal(err)
+	}
+
+	if pop := v.GetString("hello.pop"); pop != "pop str" {
+		t.Fatalf("pop != \"pop str\", = %s", pop)
+	}
+
+	if foo := v.GetString("hello.foo"); foo != "foo str" {
+		t.Fatalf("foo != \"foo str\", = %s", foo)
+	}
+}
+
 func TestMergeConfigNoMerge(t *testing.T) {
 	v := New()
 	v.SetConfigType("yml")
@@ -2410,25 +2452,25 @@ func TestUnmarshal_DotSeparatorBackwardCompatibility(t *testing.T) {
 	assert.Equal(t, "cobra_flag", config.Foo.Bar)
 }

-var yamlExampleWithDot = []byte(`Hacker: true
-name: steve
-hobbies:
-  - skateboarding
-  - snowboarding
-  - go
-clothing:
-  jacket: leather
-  trousers: denim
-  pants:
-    size: large
-age: 35
-eyes : brown
-beard: true
-emails:
-  steve@hacker.com:
-    created: 01/02/03
-    active: true
-`)
+// var yamlExampleWithDot = []byte(`Hacker: true
+// name: steve
+// hobbies:
+//     - skateboarding
+//     - snowboarding
+//     - go
+// clothing:
+//     jacket: leather
+//     trousers: denim
+//     pants:
+//         size: large
+// age: 35
+// eyes : brown
+// beard: true
+// emails:
+//     steve@hacker.com:
+//         created: 01/02/03
+//         active: true
+// `)

 func TestKeyDelimiter(t *testing.T) {
 	v := NewWithOptions(KeyDelimiter("::"))
@@ -2478,7 +2520,10 @@ func TestKeyDelimiter(t *testing.T) {
 }

 var yamlDeepNestedSlices = []byte(`TV:
- title: "The expanse"
+- title: "The Expanse"
+  title_i18n:
+    USA: "The Expanse"
+    Japan: "エクスパンス -巨獣めざめる-"
  seasons:
  - first_released: "December 14, 2015"
    episodes:
@@ -2508,11 +2553,15 @@ func TestSliceIndexAccess(t *testing.T) {
 	err := v.unmarshalReader(r, v.config)
 	require.NoError(t, err)

-	assert.Equal(t, "The expanse", v.GetString("tv.0.title"))
+	assert.Equal(t, "The Expanse", v.GetString("tv.0.title"))
 	assert.Equal(t, "February 1, 2017", v.GetString("tv.0.seasons.1.first_released"))
 	assert.Equal(t, "Static", v.GetString("tv.0.seasons.1.episodes.2.title"))
 	assert.Equal(t, "December 15, 2015", v.GetString("tv.0.seasons.0.episodes.1.air_date"))

+	// Test nested keys with capital letters
+	assert.Equal(t, "The Expanse", v.GetString("tv.0.title_i18n.USA"))
+	assert.Equal(t, "エクスパンス -巨獣めざめる-", v.GetString("tv.0.title_i18n.Japan"))
+
 	// Test for index out of bounds
 	assert.Equal(t, "", v.GetString("tv.0.seasons.2.first_released"))

@@ -0,0 +1,53 @@
+package viper
+
+var yamlExample = []byte(`Hacker: true
+name: steve
+hobbies:
+    - skateboarding
+    - snowboarding
+    - go
+clothing:
+    jacket: leather
+    trousers: denim
+    pants:
+        size: large
+age: 35
+eyes : brown
+beard: true
+`)
+
+var yamlWriteExpected = []byte(`age: 35
+beard: true
+clothing:
+    jacket: leather
+    pants:
+        size: large
+    trousers: denim
+eyes: brown
+hacker: true
+hobbies:
+    - skateboarding
+    - snowboarding
+    - go
+name: steve
+`)
+
+var yamlExampleWithDot = []byte(`Hacker: true
+name: steve
+hobbies:
+    - skateboarding
+    - snowboarding
+    - go
+clothing:
+    jacket: leather
+    trousers: denim
+    pants:
+        size: large
+age: 35
+eyes : brown
+beard: true
+emails:
+    steve@hacker.com:
+        created: 01/02/03
+        active: true
+`)
@@ -1,5 +1,5 @@
-//go:build !js
-// +build !js
+//go:build darwin || dragonfly || freebsd || openbsd || linux || netbsd || solaris || windows
+// +build darwin dragonfly freebsd openbsd linux netbsd solaris windows

 package viper

@@ -1,13 +1,19 @@
-// +build js,wasm
+//go:build appengine || (!darwin && !dragonfly && !freebsd && !openbsd && !linux && !netbsd && !solaris && !windows)
+// +build appengine !darwin,!dragonfly,!freebsd,!openbsd,!linux,!netbsd,!solaris,!windows

 package viper

 import (
-	"errors"
+	"fmt"
+	"runtime"

 	"github.com/fsnotify/fsnotify"
 )

+func newWatcher() (*watcher, error) {
+	return &watcher{}, fmt.Errorf("fsnotify not supported on %s", runtime.GOOS)
+}
+
 type watcher struct {
 	Events chan fsnotify.Event
 	Errors chan error
@@ -24,7 +30,3 @@ func (*watcher) Add(name string) error {
 func (*watcher) Remove(name string) error {
 	return nil
 }
-
-func newWatcher() (*watcher, error) {
-	return &watcher{}, errors.New("fsnotify is not supported on WASM")
-}