#1820 - ENH: For DB Migration add setLockTimeout(10); ... to add Postgres set lock_timeout = to generated migrations

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

@@ -144,6 +144,15 @@ public interface DbMigration {
    */
   void setAddForeignKeySkipCheck(boolean addForeignKeySkipCheck);
 
+  /**
+   * Set the lock timeout to be included with the DDL generation.
+   * <p>
+   * Currently this is only useful for Postgres migrations adding a <code>set lock_timeout</code>
+   * statement to the generated database migration.
+   * </p>
+   */
+  void setLockTimeout(int seconds);
+
   /**
    * Add an additional platform to write the migration DDL.
    * <p>

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

@@ -108,6 +108,7 @@ public class DefaultDbMigration implements DbMigration {
   protected String name;
   protected String generatePendingDrop;
   private boolean addForeignKeySkipCheck;
+  private int lockTimeoutSeconds;
 
   protected boolean includeBuiltInPartitioning = true;
 
@@ -187,6 +188,11 @@ public class DefaultDbMigration implements DbMigration {
     this.addForeignKeySkipCheck = addForeignKeySkipCheck;
   }
 
+  @Override
+  public void setLockTimeout(int seconds) {
+    this.lockTimeoutSeconds = seconds;
+  }
+
   @Override
   public void setGeneratePendingDrop(String generatePendingDrop) {
     this.generatePendingDrop = generatePendingDrop;
@@ -641,7 +647,7 @@ public class DefaultDbMigration implements DbMigration {
   }
 
   private PlatformDdlWriter createDdlWriter(DatabasePlatform platform) {
-    return new PlatformDdlWriter(platform, serverConfig, migrationConfig);
+    return new PlatformDdlWriter(platform, serverConfig, migrationConfig, lockTimeoutSeconds);
   }
 
   /**

src/main/java/io/ebeaninternal/dbmigration/ddlgeneration/platform/PlatformDdl.java

@@ -211,6 +211,13 @@ public class PlatformDdl {
     return inlineForeignKeys;
   }
 
+  /**
+   * By default this does nothing returning null / no lock timeout.
+   */
+  public String setLockTimeout(int lockTimeoutSeconds) {
+    return null;
+  }
+
   /**
    * Write all the table columns converting to platform types as necessary.
    */

src/main/java/io/ebeaninternal/dbmigration/ddlgeneration/platform/PostgresDdl.java

@@ -20,6 +20,10 @@ public class PostgresDdl extends PlatformDdl {
     this.addForeignKeySkipCheck = " not valid";
   }
 
+  public String setLockTimeout(int lockTimeoutSeconds) {
+    return "set lock_timeout = " + (lockTimeoutSeconds * 1000);
+  }
+
   @Override
   public boolean suppressPrimaryKeyOnPartition() {
     return true;

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

@@ -33,10 +33,13 @@ public class PlatformDdlWriter {
 
   private final PlatformDdl platformDdl;
 
-  public PlatformDdlWriter(DatabasePlatform platform, ServerConfig serverConfig, DbMigrationConfig config) {
+  private final int lockTimeoutSeconds;
+
+  public PlatformDdlWriter(DatabasePlatform platform, ServerConfig serverConfig, DbMigrationConfig config, int lockTimeoutSeconds) {
     this.platformDdl = PlatformDdlBuilder.create(platform);
     this.serverConfig = serverConfig;
     this.config = config;
+    this.lockTimeoutSeconds = lockTimeoutSeconds;
   }
 
   /**
@@ -46,6 +49,13 @@ public class PlatformDdlWriter {
 
     DdlHandler handler = handler();
     handler.generateProlog(write);
+    if (lockTimeoutSeconds > 0) {
+      String lockSql = platformDdl.setLockTimeout(lockTimeoutSeconds);
+      if (lockSql != null) {
+        write.apply().append(lockSql).endOfStatement().newLine();
+      }
+    }
+
     List<ChangeSet> changeSets = dbMigration.getChangeSet();
     for (ChangeSet changeSet : changeSets) {
       if (isApply(changeSet)) {

src/test/java/io/ebeaninternal/dbmigration/ddlgeneration/platform/PostgresDdlTest.java

@@ -0,0 +1,18 @@
+package io.ebeaninternal.dbmigration.ddlgeneration.platform;
+
+import io.ebean.config.dbplatform.postgres.PostgresPlatform;
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class PostgresDdlTest {
+
+  private PostgresDdl postgresDdl = new PostgresDdl(new PostgresPlatform());
+
+  @Test
+  public void setLockTimeout() {
+
+    final String sql = postgresDdl.setLockTimeout(5);
+    assertThat(sql).isEqualTo("set lock_timeout = 5000");
+  }
+}