Extend PostgresDumpTest: connect via an IP address of a container

Author: bwaldvogel

data/test/validation/PostgresDumpTest/testConnectViaDockerContainerIpAddress.txt

@@ -0,0 +1,22 @@
+--
+-- PostgreSQL database dump
+--
+
+-- Dumped from database version 17.0 (Debian 17.0-1.pgdg120+1)
+-- Dumped by pg_dump version 17.0 (Debian 17.0-1.pgdg120+1)
+
+SET statement_timeout = 0;
+SET lock_timeout = 0;
+SET idle_in_transaction_session_timeout = 0;
+SET transaction_timeout = 0;
+SET client_encoding = 'UTF8';
+SET standard_conforming_strings = on;
+SELECT pg_catalog.set_config('search_path', '', false);
+SET check_function_bodies = false;
+SET xmloption = content;
+SET client_min_messages = warning;
+SET row_security = off;
+
+--
+-- PostgreSQL database dump complete
+--

src/test/java/de/cronn/postgres/snapshot/util/PostgresDumpTest.java

@@ -8,14 +8,19 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 import org.testcontainers.containers.ContainerLaunchException;
+import org.testcontainers.containers.GenericContainer;
+import org.testcontainers.containers.Network;
 import org.testcontainers.containers.PostgreSQLContainer;
+import org.testcontainers.containers.startupcheck.OneShotStartupCheckStrategy;
 import org.testcontainers.utility.DockerImageName;
 
 import de.cronn.assertions.validationfile.normalization.SimpleRegexReplacement;
@@ -173,4 +178,34 @@ void testOtherPostgresVersion() {
 			compareActualWithValidationFile(schema);
 		}
 	}
+
+	@Test
+	void testConnectViaDockerContainerIpAddress() {
+		String networkAlias = "postgres-db";
+		try (Network network = Network.newNetwork();
+			 PostgreSQLContainer<?> postgresInNetworkContainer = createPostgresContainer(DockerImageName.parse("postgres:17.0"))
+				 .withNetwork(network)
+				 .withNetworkAliases(networkAlias)) {
+			postgresInNetworkContainer.start();
+
+			String ipAddress = resolveHostname(network, networkAlias);
+
+			String jdbcUrl = "jdbc:postgresql://%s/test-db".formatted(ipAddress);
+			String schema = PostgresDump.dumpToString(jdbcUrl, USERNAME, PASSWORD);
+			compareActualWithValidationFile(schema);
+		}
+	}
+
+	private String resolveHostname(Network network, String hostname) {
+		try (GenericContainer<?> dnsContainer = new GenericContainer<>("alpine:3.20.3")
+			.withNetwork(network)
+			.withCommand("getent hosts " + hostname)
+			.withStartupCheckStrategy(new OneShotStartupCheckStrategy())) {
+			dnsContainer.start();
+			String logs = dnsContainer.getLogs();
+			Matcher matcher = Pattern.compile("(\\d+\\.\\d+\\.\\d+\\.\\d+)\\s+" + hostname + "\\s+" + hostname + "\\n").matcher(logs);
+			assertThat(matcher.matches()).describedAs("Failed to parse '%s'", logs).isTrue();
+			return matcher.group(1);
+		}
+	}
 }