#1577 - ENH: Add support for "dbinit" migrations (Sort of "checkpoint" or "fast forward" migrations)

src/main/java/io/ebean/config/DbMigrationConfig.java

@@ -5,7 +5,6 @@ import io.ebean.annotation.Platform;
 import io.ebean.migration.MigrationConfig;
 import io.ebean.migration.MigrationRunner;
 import io.ebean.util.StringHelper;
-
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -33,6 +32,8 @@ public class DbMigrationConfig {
    */
   protected String migrationPath = "dbmigration";
 
+  protected String migrationInitPath = "dbinit";
+
   /**
    * Subdirectory the model xml files go into.
    */
@@ -118,6 +119,15 @@ public class DbMigrationConfig {
     this.platform = platform;
   }
 
+  /**
+   * Return the path for normal migrations or dbinit migrations.
+   *
+   * @param dbinitMigration When true return the path for dbinit migrations.
+   */
+  public String getMigrationPath(boolean dbinitMigration) {
+    return dbinitMigration ? migrationInitPath : migrationPath;
+  }
+
   /**
    * Return the resource path for db migrations.
    */
@@ -419,6 +429,7 @@ public class DbMigrationConfig {
   public void loadSettings(PropertiesWrapper properties, String serverName) {
 
     migrationPath = properties.get("migration.migrationPath", migrationPath);
+    migrationInitPath = properties.get("migration.migrationInitPath", migrationInitPath);
     modelPath = properties.get("migration.modelPath", modelPath);
     applyPrefix = properties.get("migration.applyPrefix", applyPrefix);
     applySuffix = properties.get("migration.applySuffix", applySuffix);
@@ -472,6 +483,7 @@ public class DbMigrationConfig {
     runnerConfig.setMetaTable(metaTable);
     runnerConfig.setApplySuffix(applySuffix);
     runnerConfig.setMigrationPath(migrationPath);
+    runnerConfig.setMigrationInitPath(migrationInitPath);
     runnerConfig.setRunPlaceholderMap(runPlaceholderMap);
     runnerConfig.setRunPlaceholders(runPlaceholders);
     runnerConfig.setDbUsername(getDbUsername());

src/main/java/io/ebean/dbmigration/DbMigration.java

@@ -154,7 +154,7 @@ public interface DbMigration {
   List<String> getPendingDrops();
 
   /**
-   * Generate the next migration xml file and associated apply and rollback sql scripts.
+   * Generate the next migration sql script and associated model xml.
    * <p>
    * This does not run the migration or ddl scripts but just generates them.
    * </p>
@@ -186,4 +186,15 @@ public interface DbMigration {
    * @return the version of the generated migration or null
    */
   String generateMigration() throws IOException;
+
+  /**
+   * Generate an "init" migration which has all changes.
+   * <p>
+   * An "init" migration can only be executed and used on a database that has had no
+   * prior migrations run on it.
+   * </p>
+   * @return the version of the generated migration
+   */
+  String generateInitMigration() throws IOException;
+
 }

src/main/java/io/ebeaninternal/dbmigration/DefaultDbMigration.java

@@ -271,6 +271,15 @@ public class DefaultDbMigration implements DbMigration {
    */
   @Override
   public String generateMigration() throws IOException {
+    return generateMigrationFor(false);
+  }
+
+  @Override
+  public String generateInitMigration() throws IOException {
+    return generateMigrationFor(true);
+  }
+
+  private String generateMigrationFor(boolean dbinitMigration) throws IOException {
 
     // use this flag to stop other plugins like full DDL generation
     if (!online) {
@@ -286,14 +295,17 @@ public class DefaultDbMigration implements DbMigration {
       configurePlatforms();
     }
     try {
-      Request request = createRequest();
-      if (platforms.isEmpty()) {
-        generateExtraDdl(request.migrationDir, databasePlatform, request.isTablePartitioning());
-      } else {
-        for (Pair pair : platforms) {
-          PlatformDdlWriter platformWriter = createDdlWriter(pair.platform);
-          File subPath = platformWriter.subPath(request.migrationDir, pair.prefix);
-          generateExtraDdl(subPath, pair.platform, request.isTablePartitioning());
+      Request request = createRequest(dbinitMigration);
+      if (!dbinitMigration) {
+        // repeatable migrations
+        if (platforms.isEmpty()) {
+          generateExtraDdl(request.migrationDir, databasePlatform, request.isTablePartitioning());
+        } else {
+          for (Pair pair : platforms) {
+            PlatformDdlWriter platformWriter = createDdlWriter(pair.platform);
+            File subPath = platformWriter.subPath(request.migrationDir, pair.prefix);
+            generateExtraDdl(subPath, pair.platform, request.isTablePartitioning());
+          }
         }
       }
 
@@ -321,7 +333,7 @@ public class DefaultDbMigration implements DbMigration {
     }
     setDefaults();
     try {
-      return createRequest().getPendingDrops();
+      return createRequest(false).getPendingDrops();
     } finally {
       if (!online) {
         DbOffline.reset();
@@ -433,32 +445,48 @@ public class DefaultDbMigration implements DbMigration {
     return version;
   }
 
-  private Request createRequest() {
-    return new Request();
+  private Request createRequest(boolean dbinitMigration) {
+    return new Request(dbinitMigration);
   }
 
   private class Request {
 
+    final boolean dbinitMigration;
     final File migrationDir;
     final File modelDir;
-    final MigrationModel migrationModel;
     final CurrentModel currentModel;
     final ModelContainer migrated;
     final ModelContainer current;
 
-    private Request() {
-      this.migrationDir = getMigrationDirectory();
-      this.modelDir = getModelDirectory(migrationDir);
-      this.migrationModel = new MigrationModel(modelDir, migrationConfig.getModelSuffix());
-      this.migrated = migrationModel.read();
+    private Request(boolean dbinitMigration) {
+      this.dbinitMigration = dbinitMigration;
       this.currentModel = new CurrentModel(server, constraintNaming);
       this.current = currentModel.read();
+      this.migrationDir = getMigrationDirectory(dbinitMigration);
+      if (dbinitMigration) {
+        this.modelDir = null;
+        this.migrated = new ModelContainer();
+      } else {
+        this.modelDir = getModelDirectory(migrationDir);
+        MigrationModel migrationModel = new MigrationModel(modelDir, migrationConfig.getModelSuffix());
+        this.migrated = migrationModel.read(dbinitMigration);
+      }
     }
 
     boolean isTablePartitioning() {
       return current.isTablePartitioning();
     }
 
+    /**
+     * Return the next migration version (based on existing migration versions).
+     */
+    String nextVersion() {
+      // always read the next version using the main migration directory (not dbinit)
+      File migDirectory = getMigrationDirectory(false);
+      File modelDir = getModelDirectory(migDirectory);
+      return LastMigration.nextVersion(migDirectory, modelDir, dbinitMigration);
+    }
+
     /**
      * Return the migration for the pending drops for a given version.
      */
@@ -490,10 +518,10 @@ public class DefaultDbMigration implements DbMigration {
 
   private String generateMigration(Request request, Migration dbMigration, String dropsFor) throws IOException {
 
-    String fullVersion = getFullVersion(request.migrationModel, dropsFor);
+    String fullVersion = getFullVersion(request.nextVersion(), dropsFor);
 
     logger.info("generating migration:{}", fullVersion);
-    if (!writeMigrationXml(dbMigration, request.modelDir, fullVersion)) {
+    if (!request.dbinitMigration && !writeMigrationXml(dbMigration, request.modelDir, fullVersion)) {
       logger.warn("migration already exists, not generating DDL");
       return null;
     } else {
@@ -528,11 +556,11 @@ public class DefaultDbMigration implements DbMigration {
    * <p>
    * The full version can contain a comment suffix after a "__" double underscore.
    */
-  private String getFullVersion(MigrationModel migrationModel, String dropsFor) {
+  private String getFullVersion(String nextVersion, String dropsFor) {
 
     String version = getVersion();
     if (version == null) {
-      version = migrationModel.getNextVersion(initialVersion);
+      version = (nextVersion != null) ? nextVersion : initialVersion;
     }
 
     String fullVersion = migrationConfig.getApplyPrefix() + version;
@@ -672,13 +700,20 @@ public class DefaultDbMigration implements DbMigration {
   }
 
   /**
-   * Return the file path to write the xml and sql to.
+   * Return the main migration directory.
    */
   File getMigrationDirectory() {
+    return getMigrationDirectory(false);
+  }
+
+  /**
+   * Return the file path to write the xml and sql to.
+   */
+  File getMigrationDirectory(boolean dbinitMigration) {
 
     // path to src/main/resources in typical maven project
     File resourceRootDir = new File(pathToResources);
-    String resourcePath = migrationConfig.getMigrationPath();
+    String resourcePath = migrationConfig.getMigrationPath(dbinitMigration);
 
     // expect to be a path to something like - src/main/resources/dbmigration/model
     File path = new File(resourceRootDir, resourcePath);

src/main/java/io/ebeaninternal/dbmigration/LastMigration.java

@@ -0,0 +1,91 @@
+package io.ebeaninternal.dbmigration;
+
+import io.ebeaninternal.dbmigration.model.MigrationVersion;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Utility to determine the last sql migration version and next version.
+ */
+class LastMigration {
+
+  private static final String SQL = ".sql";
+
+  private static final String MODEL_XML = ".model.xml";
+
+  /**
+   * Return the next migation version given the migration directory.
+   */
+  static String nextVersion(File migDir, File modelDir, boolean dbinitMigration) {
+
+    String last = lastVersion(migDir, modelDir);
+    if (last == null) {
+      return null;
+    }
+    return (dbinitMigration) ? last : MigrationVersion.parse(last).nextVersion();
+  }
+
+  /**
+   * Return the last migation version given the migration directory.
+   */
+  static String lastVersion(File migDirectory, File modelDir) {
+
+    List<String> fileNames = new ArrayList<>();
+
+    File[] sqlFiles = migDirectory.listFiles(pathname -> includeSqlFile(pathname.getName().toLowerCase()));
+    if (sqlFiles != null) {
+      for (File file : sqlFiles) {
+        fileNames.add(trim(file.getName()));
+      }
+    }
+
+    if (modelDir != null) {
+      File[] xmlFiles = modelDir.listFiles(pathname -> includeModelFile(pathname.getName().toLowerCase()));
+      if (xmlFiles != null) {
+        for (File file : xmlFiles) {
+          fileNames.add(trim(file.getName()));
+        }
+      }
+    }
+
+    Collections.sort(fileNames);
+    if (!fileNames.isEmpty()) {
+      return fileNames.get(fileNames.size() - 1);
+    }
+    return null;
+  }
+
+  private static boolean includeSqlFile(String lowerFileName) {
+    if (lowerFileName.startsWith("r") || lowerFileName.startsWith("i") || !lowerFileName.endsWith(SQL)) {
+      return false;
+    }
+    return true;
+  }
+
+  private static boolean includeModelFile(String lowerFileName) {
+    return lowerFileName.endsWith(MODEL_XML);
+  }
+
+  private static String trim(String name) {
+    name = name.toLowerCase();
+    char c = name.charAt(0);
+    if (c == 'v') {
+      name = name.substring(1);
+    }
+    int p = name.indexOf("__");
+    if (p > -1) {
+      name = name.substring(0, p);
+    }
+    if (name.endsWith(SQL)) {
+      name = name.substring(0, name.length() - 4);
+    }
+    if (name.endsWith(MODEL_XML)) {
+      name = name.substring(0, name.length() - 10);
+    }
+    return name;
+  }
+
+}

src/main/java/io/ebeaninternal/dbmigration/model/MigrationModel.java

@@ -31,14 +31,16 @@ public class MigrationModel {
   /**
    * Read all the migrations returning the model with all
    * the migrations applied in version order.
+   *
+   * @param dbinitMigration If true we don't apply model changes, migration is from scratch.
    */
-  public ModelContainer read() {
+  public ModelContainer read(boolean dbinitMigration) {
 
-    readMigrations();
+    readMigrations(dbinitMigration);
     return model;
   }
 
-  private void readMigrations() {
+  private void readMigrations(boolean dbinitMigration) {
 
     // find all the migration xml files
     File[] xmlFiles = modelDirectory.listFiles(pathname -> pathname.getName().toLowerCase().endsWith(modelSuffix));
@@ -53,9 +55,11 @@ public class MigrationModel {
     // sort into version order before applying
     Collections.sort(resources);
 
-    for (MigrationResource migrationResource : resources) {
-      logger.debug("read {}", migrationResource);
-      model.apply(migrationResource.read(), migrationResource.getVersion());
+    if (!dbinitMigration) {
+      for (MigrationResource migrationResource : resources) {
+        logger.debug("read {}", migrationResource);
+        model.apply(migrationResource.read(), migrationResource.getVersion());
+      }
     }
 
     // remember the last version