feat: allow customization of data dir between database initialization and start

src/main/java/io/zonky/test/db/postgres/embedded/EmbeddedPostgres.java

@@ -71,6 +71,7 @@
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
+import java.util.function.Consumer;
 import java.util.stream.Stream;
 
 import static java.nio.file.StandardOpenOption.CREATE;
@@ -115,14 +116,14 @@ public class EmbeddedPostgres implements Closeable
         PgBinaryResolver pgBinaryResolver, ProcessBuilder.Redirect errorRedirector, ProcessBuilder.Redirect outputRedirector) throws IOException
     {
         this(parentDirectory, dataDirectory, cleanDataDirectory, postgresConfig, localeConfig, port, connectConfig,
-                pgBinaryResolver, errorRedirector, outputRedirector, DEFAULT_PG_STARTUP_WAIT, null);
+                pgBinaryResolver, errorRedirector, outputRedirector, DEFAULT_PG_STARTUP_WAIT, null, null);
     }
 
     EmbeddedPostgres(File parentDirectory, File dataDirectory, boolean cleanDataDirectory,
                      Map<String, String> postgresConfig, Map<String, String> localeConfig, int port, Map<String, String> connectConfig,
                      PgBinaryResolver pgBinaryResolver, ProcessBuilder.Redirect errorRedirector,
                      ProcessBuilder.Redirect outputRedirector, Duration pgStartupWait,
-                     File overrideWorkingDirectory) throws IOException
+                     File overrideWorkingDirectory, Consumer<File> dataDirectoryCustomizer) throws IOException
     {
         this.cleanDataDirectory = cleanDataDirectory;
         this.postgresConfig = new HashMap<>(postgresConfig);
@@ -159,9 +160,14 @@ public class EmbeddedPostgres implements Closeable
         }
 
         lock();
+
+        if (dataDirectoryCustomizer != null) {
+            dataDirectoryCustomizer.accept(dataDirectory);
+        }
+
         this.process = startPostmaster();
     }
-    
+
     public Process getProcess() {
     	return this.process;
     }
@@ -501,6 +507,7 @@ public static class Builder
         private final Map<String, String> connectConfig = new HashMap<>();
         private PgBinaryResolver pgBinaryResolver = DefaultPostgresBinaryResolver.INSTANCE;
         private Duration pgStartupWait = DEFAULT_PG_STARTUP_WAIT;
+        private Consumer<File> dataDirectoryCustomizer;
 
         private ProcessBuilder.Redirect errRedirector = ProcessBuilder.Redirect.PIPE;
         private ProcessBuilder.Redirect outRedirector = ProcessBuilder.Redirect.PIPE;
@@ -579,6 +586,11 @@ public Builder setPgBinaryResolver(PgBinaryResolver pgBinaryResolver) {
             return this;
         }
 
+        public Builder setDataDirectoryCustomizer(final Consumer<File> dataDirectoryCustomizer) {
+            this.dataDirectoryCustomizer = dataDirectoryCustomizer;
+            return this;
+        }
+
         public EmbeddedPostgres start() throws IOException {
             if (builderPort == 0)
             {
@@ -589,7 +601,7 @@ public EmbeddedPostgres start() throws IOException {
             }
             return new EmbeddedPostgres(parentDirectory, builderDataDirectory, builderCleanDataDirectory, config,
                     localeConfig, builderPort, connectConfig, pgBinaryResolver, errRedirector, outRedirector,
-                    pgStartupWait, overrideWorkingDirectory);
+                    pgStartupWait, overrideWorkingDirectory, dataDirectoryCustomizer);
         }
 
         @Override
@@ -611,7 +623,9 @@ public boolean equals(Object o) {
                     Objects.equals(pgBinaryResolver, builder.pgBinaryResolver) &&
                     Objects.equals(pgStartupWait, builder.pgStartupWait) &&
                     Objects.equals(errRedirector, builder.errRedirector) &&
-                    Objects.equals(outRedirector, builder.outRedirector);
+                    Objects.equals(outRedirector, builder.outRedirector) &&
+                    Objects.equals(dataDirectoryCustomizer != null ? dataDirectoryCustomizer.getClass() : null,
+                                   builder.dataDirectoryCustomizer != null ? builder.dataDirectoryCustomizer.getClass() : null);
         }
 
         @Override

src/test/java/io/zonky/test/db/postgres/embedded/EmbeddedPostgresTest.java

@@ -17,6 +17,8 @@
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.sql.Connection;
@@ -47,10 +49,28 @@ public void testEmbeddedPg() throws Exception
     @Test
     public void testEmbeddedPgCreationWithNestedDataDirectory() throws Exception
     {
+        Path dataDir = Files.createDirectories(tf.resolve("data-dir-parent").resolve("data-dir"));
         try (EmbeddedPostgres pg = EmbeddedPostgres.builder()
-                .setDataDirectory(Files.createDirectories(tf.resolve("data-dir-parent").resolve("data-dir")))
+                .setDataDirectory(dataDir)
+                .setDataDirectoryCustomizer(dd -> {
+                    assertEquals(dataDir, dd.toPath());
+                    Path pgConfigFile = dd.toPath().resolve("postgresql.conf");
+                    assertTrue(Files.isRegularFile(pgConfigFile));
+                    try {
+                        String pgConfig = new String(Files.readAllBytes(pgConfigFile), StandardCharsets.UTF_8);
+                        pgConfig = pgConfig.replaceFirst("#?listen_addresses\\s*=\\s*'localhost'", "listen_addresses = '*'");
+                        Files.write(pgConfigFile, pgConfig.getBytes(StandardCharsets.UTF_8));
+                    } catch (IOException ioe) {
+                        throw new RuntimeException(ioe);
+                    }
+                })
                 .start()) {
-            // nothing to do
+            try (Connection connection = pg.getPostgresDatabase().getConnection()) {
+                Statement statement = connection.createStatement();
+                ResultSet rs = statement.executeQuery("SHOW listen_addresses;");
+                rs.next();
+                assertEquals("*", rs.getString(1));
+            }
         }
     }
 }