docs: propose deprecating the global Viper instance

Signed-off-by: Mark Sagi-Kazar <mark.sagikazar@gmail.com>

.adr-dir

@@ -0,0 +1 @@
+docs/adr

.github/.editorconfig

@@ -1,2 +1,2 @@
-[*.yml]
+[{*.yml,*.yaml}]
 indent_size = 2

.github/ISSUE_TEMPLATE/bug_report.md

@@ -1,34 +0,0 @@
----
-name: 🐛 Bug report
-about: Report a bug to help us improve Viper
-labels: kind/bug
----
-<!--
-Thank you for sending a bug report! Here are some tips:
-
-1. Please fill out the template below to make it easier to debug your problem.
-2. If you are not sure if it is a bug or not, you can ask in the Gophers slack channel `#viper`.
--->
-
-**Expected behavior (what you expected to happen)**:
-
-**Actual behavior (what actually happened)**:
-
-**Repl.it link**:
-<!-- you can use the following example: https://repl.it/@sagikazarmark/Viper-example -->
-
-**Code reproducing the issue**:
-<!-- just to make sure the content of the repl doesn't get lost -->
-
-```go
-
-```
-
-<!-- include configuration file example if necessary -->
-
-**Environment**:
-- Viper version:
-- Config source: <!-- flag, env, file, etc -->
-- File format: <!-- JSON, YAML, TOML, etc -->
-
-**Anything else we should know?**:

.github/ISSUE_TEMPLATE/bug_report.yaml

@@ -0,0 +1,110 @@
+name: 🐛 Bug report
+description: Report a bug to help us improve Viper
+labels: [kind/bug]
+body:
+- type: markdown
+  attributes:
+    value: |
+      Thank you for submitting a bug report!
+
+      Please fill out the template below to make it easier to debug your problem.
+
+      If you are not sure if it is a bug or not, you can contact us via the available [support channels](https://github.com/spf13/viper/issues/new/choose).
+- type: checkboxes
+  attributes:
+    label: Preflight Checklist
+    description: Please ensure you've completed all of the following.
+    options:
+      - label: I have searched the [issue tracker](https://www.github.com/spf13/viper/issues) for an issue that matches the one I want to file, without success.
+        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
+- type: input
+  attributes:
+    label: Version
+    description: What version of Viper are you using?
+    placeholder: 1.8.1
+  validations:
+    required: true
+- type: dropdown
+  attributes:
+    label: Config Source
+    description: What sources do you load configuration from?
+    options:
+      - Manual set
+      - Flags
+      - Environment variables
+      - Files
+      - Remove K/V stores
+      - Defaults
+    multiple: true
+  validations:
+    required: true
+- type: dropdown
+  attributes:
+    label: Format
+    description: Which file formats do you use?
+    options:
+      - JSON
+      - YAML
+      - TOML
+      - Dotenv
+      - HCL
+      - Java properties
+      - INI
+      - Other (specify below)
+    multiple: true
+- type: input
+  attributes:
+    label: Repl.it link
+    description: Complete example on Repl.it reproducing the issue. [Here](https://repl.it/@sagikazarmark/Viper-example) is an example you can use.
+    placeholder: https://repl.it/@sagikazarmark/Viper-example
+- type: textarea
+  attributes:
+    label: Code reproducing the issue
+    description: Please provide a Repl.it link if possible.
+    render: go
+    placeholder: |
+      package main
+
+      import (
+        "github.com/spf13/viper"
+      )
+
+      func main() {
+        v := viper.New()
+
+        // ...
+
+        var config Config
+
+        err = v.Unmarshal(&config)
+        if err != nil {
+          panic(err)
+        }
+      }
+- type: textarea
+  attributes:
+    label: Expected Behavior
+    description: A clear and concise description of what you expected to happen.
+  validations:
+    required: true
+- type: textarea
+  attributes:
+    label: Actual Behavior
+    description: A clear description of what actually happens.
+  validations:
+    required: true
+- type: textarea
+  attributes:
+    label: Steps To Reproduce
+    description: Steps to reproduce the behavior if it is not self-explanatory.
+    placeholder: |
+      1. In this environment...
+      2. With this config...
+      3. Run '...'
+      4. See error...
+- type: textarea
+  attributes:
+    label: Additional Information
+    description: Links? References? Anything that will give us more context about the issue that you are encountering!

.github/ISSUE_TEMPLATE/feature_request.md

@@ -1,21 +0,0 @@
----
-name: 🚀 Feature request
-about: Suggest an idea for Viper
-labels: kind/enhancement
----
-<!--
- Thank you for sending a feature request!
- Please describe what you would like to change/add and why in detail by filling out the template below.
- -->
-
-**Is your feature request related to a problem? Please describe.**
-<!-- A clear and concise description of what the problem is. Ex. I'm always frustrated when [...] -->
-
-**Describe the solution you'd like to see**
-<!-- A clear and concise description of what would you like to happen. -->
-
-**Describe alternatives you've considered**
-<!-- A clear and concise description of any alternative solutions or features you've considered. -->
-
-**Additional context**
-<!-- Add any other context or screenshots about the feature request here. -->

.github/ISSUE_TEMPLATE/feature_request.yaml

@@ -0,0 +1,39 @@
+name: 🚀 Feature request
+description: Suggest an idea for Viper
+labels: [kind/enhancement]
+body:
+- type: markdown
+  attributes:
+    value: |
+      Thank you for submitting a feature request!
+
+      Please describe what you would like to change/add and why in detail by filling out the template below.
+
+      If you are not sure if your request fits into Viper, you can contact us via the available [support channels](https://github.com/spf13/viper/issues/new/choose).
+- type: checkboxes
+  attributes:
+    label: Preflight Checklist
+    description: Please ensure you've completed all of the following.
+    options:
+      - label: I have searched the [issue tracker](https://www.github.com/spf13/viper/issues) for an issue that matches the one I want to file, without success.
+        required: true
+- type: textarea
+  attributes:
+    label: Problem Description
+    description: A clear and concise description of the problem you are seeking to solve with this feature request.
+  validations:
+    required: true
+- type: textarea
+  attributes:
+    label: Proposed Solution
+    description: A clear and concise description of what would you like to happen.
+  validations:
+    required: true
+- type: textarea
+  attributes:
+    label: Alternatives Considered
+    description: A clear and concise description of any alternative solutions or features you've considered.
+- type: textarea
+  attributes:
+    label: Additional Information
+    description: Add any other context about the problem here.

.github/dependabot.yml

@@ -0,0 +1,16 @@
+version: 2
+
+updates:
+  - package-ecosystem: gomod
+    directory: /
+    labels:
+      - area/dependencies
+    schedule:
+      interval: daily
+
+  - package-ecosystem: github-actions
+    directory: /
+    labels:
+      - area/dependencies
+    schedule:
+      interval: daily

.github/workflows/feedback_issue.yml

@@ -6,7 +6,7 @@ jobs:
   comment:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/github-script@v3
+      - uses: actions/github-script@v4
         with:
           github-token: ${{secrets.GITHUB_TOKEN}}
           script: |

.github/workflows/feedback_pull_request.yml

@@ -6,7 +6,7 @@ jobs:
   comment:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/github-script@v3
+      - uses: actions/github-script@v4
         with:
           github-token: ${{secrets.GITHUB_TOKEN}}
           script: |

README.md

@@ -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: %s \n", err))
+	panic(fmt.Errorf("Fatal error config file: %w \n", err))
 }
 ```
 
@@ -778,6 +778,15 @@ if err != nil {
 
 Viper uses [github.com/mitchellh/mapstructure](https://github.com/mitchellh/mapstructure) under the hood for unmarshaling values which uses `mapstructure` tags by default.
 
+### Decoding custom formats
+
+A frequently requested feature for Viper is adding more value formats and decoders.
+For example, parsing character (dot, comma, semicolon, etc) separated strings into slices.
+
+This is already available in Viper using mapstructure decode hooks.
+
+Read more about the details in [this blog post](https://sagikazarmark.hu/blog/decoding-custom-formats-with-viper/).
+
 ### Marshalling to string
 
 You may need to marshal all the settings held in viper into a string rather than write them to a file.

docs/adr/0001-record-architecture-decisions.md

@@ -0,0 +1,19 @@
+# 1. Record architecture decisions
+
+Date: 2021-07-20
+
+## Status
+
+Proposed
+
+## Context
+
+We need to record the architectural decisions made on this project.
+
+## Decision
+
+We will use Architecture Decision Records, as [described by Michael Nygard](http://thinkrelevance.com/blog/2011/11/15/documenting-architecture-decisions).
+
+## Consequences
+
+See Michael Nygard's article, linked above. For a lightweight ADR toolset, see Nat Pryce's [adr-tools](https://github.com/npryce/adr-tools).

docs/adr/0002-prefer-making-backward-compatible-changes.md

@@ -0,0 +1,32 @@
+# 2. Prefer making backward compatible changes
+
+Date: 2021-07-20
+
+## Status
+
+Proposed
+
+Referenced by [3. Extract components with heavy dependencies from the core](0003-extract-components-with-heavy-dependencies-from-the-core.md)
+
+Referenced by [4. Use separate GitHub organization for new packages](0004-use-separate-github-organization-for-new-packages.md)
+
+Referenced by [7. Drop writing support](0007-drop-writing-support.md)
+
+## Context
+
+Architecturally speaking Viper became a giant over the years: it hides a lot of complexity behind a simple interface.
+That simple interface, however, is what makes Viper extremely popular.
+
+## Decision
+
+In order to keep the library useful to people, we should prefer making backward compatible changes to Viper, even between major releases.
+This is not a hard rule forbiding breaking changes though: when it makes sense, breaking changes are allowed,
+but keeping things backward compatible is a priority.
+
+## Consequences
+
+Although major versions allow breaking changes, a major release is no reason to break things that already work for a lot of people,
+even if it might not be the best possible solution.
+
+Instead of breaking things, introducing new interfaces should be the default way of fixing architectural problems,
+leaving old interfaces intact.

docs/adr/0003-extract-components-with-heavy-dependencies-from-the-core.md

@@ -0,0 +1,26 @@
+# 3. Extract components with heavy dependencies from the core
+
+Date: 2021-07-20
+
+## Status
+
+Proposed
+
+References [2. Prefer making backward compatible changes](0002-prefer-making-backward-compatible-changes.md)
+
+Referenced by [4. Use separate GitHub organization for new packages](0004-use-separate-github-organization-for-new-packages.md)
+
+## Context
+
+Viper (v1) currently imports a bunch of external dependencies (for encoding/decoding, remote stores, etc)
+that make the library itself quite a heavy dependency.
+
+## Decision
+
+Move components with external dependencies out of the core to separate packages.
+
+## Consequences
+
+Viper 1 will have to continue importing all of these packages to maintain backwards compatibility.
+
+Viper 2 (and future versions) on the other hand can break backwards compatibility and require users to import the required packages.

docs/adr/0004-use-separate-github-organization-for-new-packages.md

@@ -0,0 +1,24 @@
+# 4. Use separate GitHub organization for new packages
+
+Date: 2021-07-20
+
+## Status
+
+Proposed
+
+References [2. Prefer making backward compatible changes](0002-prefer-making-backward-compatible-changes.md)
+
+References [3. Extract components with heavy dependencies from the core](0003-extract-components-with-heavy-dependencies-from-the-core.md)
+
+## Context
+
+The core Viper package is under a personal GitHub account which makes collaborative development a bit difficult.
+
+## Decision
+
+Create new Go modules in the [go-viper](https://github.com/go-viper) organization.
+Keep the core library under [Steve's personal account](https://github.com/spf13/viper) for backward compatibility purposes.
+
+## Consequences
+
+It'll be easier to create new modules and to add new functionality to Viper without having to add new dependencies to the core library.

docs/adr/0005-deprecate-setters-in-favor-of-functional-options-during-initialization.md

@@ -0,0 +1,30 @@
+# 5. Deprecate setters in favor of functional options during initialization
+
+Date: 2021-07-20
+
+## Status
+
+Proposed
+
+Referenced by [8. Deprecate the global Viper instance](0008-deprecate-the-global-viper-instance.md)
+
+## Context
+
+The Viper struct currently acts as a facade for reading, writing and watching configuration for changes.
+Some of the configuration parameters can be changed runtime using setters which often lead to issues
+with concurrent activities.
+
+## Decision
+
+Deprecate setters in favor of using functional options for configuring Viper when it's initialized.
+
+Drop setters in Viper 2.
+
+## Consequences
+
+Since Viper's interface is usually invoked from a lot of places,
+moving configuration to the place where it is initialized makes using Viper safer
+(ie. someone can't just randomly call `Set` when they are only supposed to call `Get*`).
+
+This change will also clarify what roles Viper can be used in and
+makes the separation of internal components easier based on these roles.

docs/adr/0006-go-version-support.md

@@ -0,0 +1,20 @@
+# 6. Go version support
+
+Date: 2021-09-16
+
+## Status
+
+Proposed
+
+## Context
+
+From time to time new features are released in the Go language.
+Relying on those features means dropping support for older Go versions.
+
+## Decision
+
+Follow the [Go release policy](https://golang.org/doc/devel/release#policy) and support the last two major versions of Go.
+
+## Consequences
+
+Support for older Go versions will happen every 6 months according to the Go release cycle.

docs/adr/0007-drop-writing-support.md

@@ -0,0 +1,22 @@
+# 7. Drop writing support
+
+Date: 2021-09-22
+
+## Status
+
+Proposed
+
+References [2. Prefer making backward compatible changes](0002-prefer-making-backward-compatible-changes.md)
+
+## Context
+
+The number one source of issues for Viper comes from the fact that it supports both reading and writing.
+It causes concurrency issues and has lots of inconsistencies.
+
+## Decision
+
+Drop file writing support from Viper in v2.
+
+## Consequences
+
+This is going to be a major breaking change in the library, but it will make maintenance significantly easier.

docs/adr/0008-deprecate-the-global-viper-instance.md

@@ -0,0 +1,23 @@
+# 8. Deprecate the global Viper instance
+
+Date: 2021-09-23
+
+## Status
+
+Proposed
+
+References [5. Deprecate setters in favor of functional options during initialization](0005-deprecate-setters-in-favor-of-functional-options-during-initialization.md)
+
+## Context
+
+With the deprecation of setters in favor of functional options, it becomes almost impossible to get away with instantiating Viper.
+In addition to that, people should be discouraged from accessing a global Viper instance.
+
+## Decision
+
+Deprecate the global Viper instance and the global access functions.
+
+## Consequences
+
+People will still be able to create a global instance of their own,
+but instantiating a custom Viper instance will become the primary solution for using Viper.

internal/encoding/decoder.go

@@ -0,0 +1,61 @@
+package encoding
+
+import (
+	"sync"
+)
+
+// Decoder decodes the contents of b into a v representation.
+// It's primarily used for decoding contents of a file into a map[string]interface{}.
+type Decoder interface {
+	Decode(b []byte, v interface{}) error
+}
+
+const (
+	// ErrDecoderNotFound is returned when there is no decoder registered for a format.
+	ErrDecoderNotFound = encodingError("decoder not found for this format")
+
+	// ErrDecoderFormatAlreadyRegistered is returned when an decoder is already registered for a format.
+	ErrDecoderFormatAlreadyRegistered = encodingError("decoder already registered for this format")
+)
+
+// DecoderRegistry can choose an appropriate Decoder based on the provided format.
+type DecoderRegistry struct {
+	decoders map[string]Decoder
+
+	mu sync.RWMutex
+}
+
+// NewDecoderRegistry returns a new, initialized DecoderRegistry.
+func NewDecoderRegistry() *DecoderRegistry {
+	return &DecoderRegistry{
+		decoders: make(map[string]Decoder),
+	}
+}
+
+// RegisterDecoder registers a Decoder for a format.
+// Registering a Decoder for an already existing format is not supported.
+func (e *DecoderRegistry) RegisterDecoder(format string, enc Decoder) error {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	if _, ok := e.decoders[format]; ok {
+		return ErrDecoderFormatAlreadyRegistered
+	}
+
+	e.decoders[format] = enc
+
+	return nil
+}
+
+// Decode calls the underlying Decoder based on the format.
+func (e *DecoderRegistry) Decode(format string, b []byte, v interface{}) error {
+	e.mu.RLock()
+	decoder, ok := e.decoders[format]
+	e.mu.RUnlock()
+
+	if !ok {
+		return ErrDecoderNotFound
+	}
+
+	return decoder.Decode(b, v)
+}

internal/encoding/decoder_test.go

@@ -0,0 +1,77 @@
+package encoding
+
+import (
+	"testing"
+)
+
+type decoder struct {
+	v interface{}
+}
+
+func (d decoder) Decode(_ []byte, v interface{}) error {
+	rv := v.(*string)
+	*rv = d.v.(string)
+
+	return nil
+}
+
+func TestDecoderRegistry_RegisterDecoder(t *testing.T) {
+	t.Run("OK", func(t *testing.T) {
+		registry := NewDecoderRegistry()
+
+		err := registry.RegisterDecoder("myformat", decoder{})
+		if err != nil {
+			t.Fatal(err)
+		}
+	})
+
+	t.Run("AlreadyRegistered", func(t *testing.T) {
+		registry := NewDecoderRegistry()
+
+		err := registry.RegisterDecoder("myformat", decoder{})
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		err = registry.RegisterDecoder("myformat", decoder{})
+		if err != ErrDecoderFormatAlreadyRegistered {
+			t.Fatalf("expected ErrDecoderFormatAlreadyRegistered, got: %v", err)
+		}
+	})
+}
+
+func TestDecoderRegistry_Decode(t *testing.T) {
+	t.Run("OK", func(t *testing.T) {
+		registry := NewDecoderRegistry()
+		decoder := decoder{
+			v: "decoded value",
+		}
+
+		err := registry.RegisterDecoder("myformat", decoder)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		var v string
+
+		err = registry.Decode("myformat", []byte("some value"), &v)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if v != "decoded value" {
+			t.Fatalf("expected 'decoded value', got: %#v", v)
+		}
+	})
+
+	t.Run("DecoderNotFound", func(t *testing.T) {
+		registry := NewDecoderRegistry()
+
+		var v string
+
+		err := registry.Decode("myformat", []byte("some value"), &v)
+		if err != ErrDecoderNotFound {
+			t.Fatalf("expected ErrDecoderNotFound, got: %v", err)
+		}
+	})
+}

internal/encoding/encoder.go

@@ -0,0 +1,60 @@
+package encoding
+
+import (
+	"sync"
+)
+
+// 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)
+}
+
+const (
+	// ErrEncoderNotFound is returned when there is no encoder registered for a format.
+	ErrEncoderNotFound = encodingError("encoder not found for this format")
+
+	// ErrEncoderFormatAlreadyRegistered is returned when an encoder is already registered for a format.
+	ErrEncoderFormatAlreadyRegistered = encodingError("encoder already registered for this format")
+)
+
+// EncoderRegistry can choose an appropriate Encoder based on the provided format.
+type EncoderRegistry struct {
+	encoders map[string]Encoder
+
+	mu sync.RWMutex
+}
+
+// NewEncoderRegistry returns a new, initialized EncoderRegistry.
+func NewEncoderRegistry() *EncoderRegistry {
+	return &EncoderRegistry{
+		encoders: make(map[string]Encoder),
+	}
+}
+
+// RegisterEncoder registers an Encoder for a format.
+// Registering a Encoder for an already existing format is not supported.
+func (e *EncoderRegistry) RegisterEncoder(format string, enc Encoder) error {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	if _, ok := e.encoders[format]; ok {
+		return ErrEncoderFormatAlreadyRegistered
+	}
+
+	e.encoders[format] = enc
+
+	return nil
+}
+
+func (e *EncoderRegistry) Encode(format string, v interface{}) ([]byte, error) {
+	e.mu.RLock()
+	encoder, ok := e.encoders[format]
+	e.mu.RUnlock()
+
+	if !ok {
+		return nil, ErrEncoderNotFound
+	}
+
+	return encoder.Encode(v)
+}

internal/encoding/encoder_test.go

@@ -0,0 +1,70 @@
+package encoding
+
+import (
+	"testing"
+)
+
+type encoder struct {
+	b []byte
+}
+
+func (e encoder) Encode(_ interface{}) ([]byte, error) {
+	return e.b, nil
+}
+
+func TestEncoderRegistry_RegisterEncoder(t *testing.T) {
+	t.Run("OK", func(t *testing.T) {
+		registry := NewEncoderRegistry()
+
+		err := registry.RegisterEncoder("myformat", encoder{})
+		if err != nil {
+			t.Fatal(err)
+		}
+	})
+
+	t.Run("AlreadyRegistered", func(t *testing.T) {
+		registry := NewEncoderRegistry()
+
+		err := registry.RegisterEncoder("myformat", encoder{})
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		err = registry.RegisterEncoder("myformat", encoder{})
+		if err != ErrEncoderFormatAlreadyRegistered {
+			t.Fatalf("expected ErrEncoderFormatAlreadyRegistered, got: %v", err)
+		}
+	})
+}
+
+func TestEncoderRegistry_Decode(t *testing.T) {
+	t.Run("OK", func(t *testing.T) {
+		registry := NewEncoderRegistry()
+		encoder := encoder{
+			b: []byte("encoded value"),
+		}
+
+		err := registry.RegisterEncoder("myformat", encoder)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		b, err := registry.Encode("myformat", "some value")
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if string(b) != "encoded value" {
+			t.Fatalf("expected 'encoded value', got: %#v", string(b))
+		}
+	})
+
+	t.Run("EncoderNotFound", func(t *testing.T) {
+		registry := NewEncoderRegistry()
+
+		_, err := registry.Encode("myformat", "some value")
+		if err != ErrEncoderNotFound {
+			t.Fatalf("expected ErrEncoderNotFound, got: %v", err)
+		}
+	})
+}

internal/encoding/error.go

@@ -0,0 +1,7 @@
+package encoding
+
+type encodingError string
+
+func (e encodingError) Error() string {
+	return string(e)
+}

internal/encoding/hcl/codec.go

@@ -0,0 +1,40 @@
+package hcl
+
+import (
+	"bytes"
+	"encoding/json"
+
+	"github.com/hashicorp/hcl"
+	"github.com/hashicorp/hcl/hcl/printer"
+)
+
+// Codec implements the encoding.Encoder and encoding.Decoder interfaces for HCL encoding.
+// TODO: add printer config to the codec?
+type Codec struct{}
+
+func (Codec) Encode(v interface{}) ([]byte, error) {
+	b, err := json.Marshal(v)
+	if err != nil {
+		return nil, err
+	}
+
+	// TODO: use printer.Format? Is the trailing newline an issue?
+
+	ast, err := hcl.Parse(string(b))
+	if err != nil {
+		return nil, err
+	}
+
+	var buf bytes.Buffer
+
+	err = printer.Fprint(&buf, ast.Node)
+	if err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
+func (Codec) Decode(b []byte, v interface{}) error {
+	return hcl.Unmarshal(b, v)
+}

internal/encoding/json/codec.go

@@ -0,0 +1,17 @@
+package json
+
+import (
+	"encoding/json"
+)
+
+// Codec implements the encoding.Encoder and encoding.Decoder interfaces for JSON encoding.
+type Codec struct{}
+
+func (Codec) Encode(v 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)
+}

internal/encoding/toml/codec.go

@@ -0,0 +1,45 @@
+package toml
+
+import (
+	"github.com/pelletier/go-toml"
+)
+
+// 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
+	}
+
+	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)
+}

internal/encoding/yaml/codec.go

@@ -0,0 +1,14 @@
+package yaml
+
+import "gopkg.in/yaml.v2"
+
+// Codec implements the encoding.Encoder and encoding.Decoder interfaces for YAML encoding.
+type Codec struct{}
+
+func (Codec) Encode(v interface{}) ([]byte, error) {
+	return yaml.Marshal(v)
+}
+
+func (Codec) Decode(b []byte, v interface{}) error {
+	return yaml.Unmarshal(b, v)
+}

viper.go

@@ -22,7 +22,6 @@ package viper
 import (
 	"bytes"
 	"encoding/csv"
-	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
@@ -36,18 +35,20 @@ import (
 	"time"
 
 	"github.com/fsnotify/fsnotify"
-	"github.com/hashicorp/hcl"
-	"github.com/hashicorp/hcl/hcl/printer"
 	"github.com/magiconair/properties"
 	"github.com/mitchellh/mapstructure"
-	"github.com/pelletier/go-toml"
 	"github.com/spf13/afero"
 	"github.com/spf13/cast"
 	jww "github.com/spf13/jwalterweatherman"
 	"github.com/spf13/pflag"
 	"github.com/subosito/gotenv"
 	"gopkg.in/ini.v1"
-	"gopkg.in/yaml.v2"
+
+	"github.com/spf13/viper/internal/encoding"
+	"github.com/spf13/viper/internal/encoding/hcl"
+	"github.com/spf13/viper/internal/encoding/json"
+	"github.com/spf13/viper/internal/encoding/toml"
+	"github.com/spf13/viper/internal/encoding/yaml"
 )
 
 // ConfigMarshalError happens when failing to marshal the configuration.
@@ -67,8 +68,44 @@ 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)
+	}
 }
 
 type remoteConfigFactory interface {
@@ -1153,7 +1190,7 @@ func (v *Viper) find(lcaseKey string, flagDefault bool) interface{} {
 			return cast.ToInt(flag.ValueString())
 		case "bool":
 			return cast.ToBool(flag.ValueString())
-		case "stringSlice":
+		case "stringSlice", "stringArray":
 			s := strings.TrimPrefix(flag.ValueString(), "[")
 			s = strings.TrimSuffix(s, "]")
 			res, _ := readAsCSV(s)
@@ -1232,7 +1269,7 @@ func (v *Viper) find(lcaseKey string, flagDefault bool) interface{} {
 				return cast.ToInt(flag.ValueString())
 			case "bool":
 				return cast.ToBool(flag.ValueString())
-			case "stringSlice":
+			case "stringSlice", "stringArray":
 				s := strings.TrimPrefix(flag.ValueString(), "[")
 				s = strings.TrimSuffix(s, "]")
 				res, _ := readAsCSV(s)
@@ -1584,35 +1621,12 @@ func (v *Viper) unmarshalReader(in io.Reader, c map[string]interface{}) error {
 	buf := new(bytes.Buffer)
 	buf.ReadFrom(in)
 
-	switch strings.ToLower(v.getConfigType()) {
+	switch format := strings.ToLower(v.getConfigType()); format {
-	case "yaml", "yml":
+	case "yaml", "yml", "json", "toml", "hcl":
-		if err := yaml.Unmarshal(buf.Bytes(), &c); err != nil {
+		err := decoderRegistry.Decode(format, buf.Bytes(), &c)
-			return ConfigParseError{err}
-		}
-
-	case "json":
-		if err := json.Unmarshal(buf.Bytes(), &c); err != nil {
-			return ConfigParseError{err}
-		}
-
-	case "hcl":
-		obj, err := hcl.Parse(buf.String())
 		if err != nil {
 			return ConfigParseError{err}
 		}
-		if err = hcl.DecodeObject(&c, obj); err != nil {
-			return ConfigParseError{err}
-		}
-
-	case "toml":
-		tree, err := toml.LoadReader(buf)
-		if err != nil {
-			return ConfigParseError{err}
-		}
-		tmap := tree.ToMap()
-		for k, v := range tmap {
-			c[k] = v
-		}
 
 	case "dotenv", "env":
 		env, err := gotenv.StrictParse(buf)
@@ -1665,26 +1679,13 @@ 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 "json":
+	case "yaml", "yml", "json", "toml", "hcl":
-		b, err := json.MarshalIndent(c, "", "  ")
+		b, err := encoderRegistry.Encode(configType, c)
-		if err != nil {
-			return ConfigMarshalError{err}
-		}
-		_, err = f.WriteString(string(b))
 		if err != nil {
 			return ConfigMarshalError{err}
 		}
 
-	case "hcl":
+		_, err = f.WriteString(string(b))
-		b, err := json.Marshal(c)
-		if err != nil {
-			return ConfigMarshalError{err}
-		}
-		ast, err := hcl.Parse(string(b))
-		if err != nil {
-			return ConfigMarshalError{err}
-		}
-		err = printer.Fprint(f, ast.Node)
 		if err != nil {
 			return ConfigMarshalError{err}
 		}
@@ -1717,25 +1718,6 @@ func (v *Viper) marshalWriter(f afero.File, configType string) error {
 			return ConfigMarshalError{err}
 		}
 
-	case "toml":
-		t, err := toml.TreeFromMap(c)
-		if err != nil {
-			return ConfigMarshalError{err}
-		}
-		s := t.String()
-		if _, err := f.WriteString(s); err != nil {
-			return ConfigMarshalError{err}
-		}
-
-	case "yaml", "yml":
-		b, err := yaml.Marshal(c)
-		if err != nil {
-			return ConfigMarshalError{err}
-		}
-		if _, err = f.WriteString(string(b)); err != nil {
-			return ConfigMarshalError{err}
-		}
-
 	case "ini":
 		keys := v.AllKeys()
 		cfg := ini.Empty()

viper_test.go

@@ -917,6 +917,54 @@ func TestBindPFlagsStringSlice(t *testing.T) {
 	}
 }
 
+// nolint: dupl
+func TestBindPFlagsStringArray(t *testing.T) {
+	tests := []struct {
+		Expected []string
+		Value    string
+	}{
+		{[]string{}, ""},
+		{[]string{"jeden"}, "jeden"},
+		{[]string{"dwa,trzy"}, "dwa,trzy"},
+		{[]string{"cztery,\"piec , szesc\""}, "cztery,\"piec , szesc\""},
+	}
+
+	v := New() // create independent Viper object
+	defaultVal := []string{"default"}
+	v.SetDefault("stringarray", defaultVal)
+
+	for _, testValue := range tests {
+		flagSet := pflag.NewFlagSet("test", pflag.ContinueOnError)
+		flagSet.StringArray("stringarray", testValue.Expected, "test")
+
+		for _, changed := range []bool{true, false} {
+			flagSet.VisitAll(func(f *pflag.Flag) {
+				f.Value.Set(testValue.Value)
+				f.Changed = changed
+			})
+
+			err := v.BindPFlags(flagSet)
+			if err != nil {
+				t.Fatalf("error binding flag set, %v", err)
+			}
+
+			type TestStr struct {
+				StringArray []string
+			}
+			val := &TestStr{}
+			if err := v.Unmarshal(val); err != nil {
+				t.Fatalf("%+#v cannot unmarshal: %s", testValue.Value, err)
+			}
+			if changed {
+				assert.Equal(t, testValue.Expected, val.StringArray)
+				assert.Equal(t, testValue.Expected, v.Get("stringarray"))
+			} else {
+				assert.Equal(t, defaultVal, val.StringArray)
+			}
+		}
+	}
+}
+
 // nolint: dupl
 func TestBindPFlagsIntSlice(t *testing.T) {
 	tests := []struct {