docker run alternative

[remal]

I'd like to execute a command like this: docker run schemaspy/schemaspy <options>. Is it possible to do it via Testcontainers?

If I understand correctly, Testcontainers requires me to start the container first and then execute a command inside a running container. However, I don't want to start the container - I'd like to execute a command in the container synchronously and get a result.

I suppose I have to "disable" ENTRYPOINT and then call execInContainer(). If it is so, could you please explain how to "disable" ENTRYPOINT? Replacing ENTRYPOINT with some dummy command, like touch is not an option, as a container can be "distroless".

[bsideup]

Hi @remal,

Have a look at OneShotStartupCheckStrategy:
https://www.testcontainers.org/features/startup_and_waits/#one-shot-startup-strategy-example

[remal]

Hi @bsideup,

Thanks for suggesting the strategy!

Is it possible to remove ENTRYPOINT at all? I'd like the container to start without any command being executed and then call execInContainer().

[kiview]

Yes, this is possible using withCreateContainerCmdModifier:
https://www.testcontainers.org/features/advanced_options/#customizing-the-container

See the docker-java API:
https://github.com/docker-java/docker-java/blob/3.2.1/docker-java-api/src/main/java/com/github/dockerjava/api/command/CreateContainerCmd.java#L106

[SimonHarmonicMinor]

@remal Have you managed to run schemaSpy with Testcontainers? If so, can you share the setup, please? I'm also trying to do it but now I'm stuck. Here is something I came up with:

private final GenericContainer<?> SCHEMA_SPY =
        new GenericContainer<>(DockerImageName.parse("schemaspy/schemaspy:6.1.0"))
            .withNetworkAliases("schemaspy")
            .withCreateContainerCmdModifier(cmd -> cmd.withEntrypoint(""))
            .withCommand("sh", "-c", "sleep 50000 && echo \"hello\"", "HELLO_TESTCONTAINERS")
            .withNetwork(NETWORK)
            .withStartupCheckStrategy(
                new IndefiniteWaitOneShotStartupCheckStrategy()
            )
            .withLogConsumer(new Slf4jLogConsumer(LoggerFactory.getLogger("SchemaSpy")));

    @Test
    @SneakyThrows
    void test() {
        Startables.deepStart(SCHEMA_SPY);
        while (!SCHEMA_SPY.isRunning()) {
            Thread.yield();
        }
        SCHEMA_SPY.execInContainer(
            "java -jar schemaspy-6.1.0.jar -t pgsql11 -db %s -host postgres -u %s -p %s -debug && tail -f /dev/null"
                .formatted(POSTGRES.getDatabaseName(), POSTGRES.getUsername(), POSTGRES.getPassword())
        );
        SCHEMA_SPY.execInContainer("tar", "-czvf", "/output/output.tar.gz", "/output");
        SCHEMA_SPY.copyFileFromContainer(
            "/output/output.tar.gz",
            Path.of(getClass().getResource("/").getPath(), "output.tar.gz")
                .toAbsolutePath()
                .toString()
        );

        SCHEMA_SPY.stop();
    }

Here is the idea:

1. I set the schemaSpy container with sleep 50000 command so the container doesn't quit immediately after start.
2. Then I run it asynchronously with Startable.deepStart and wait until it's marked as RUNNING in the while loop.
3. Finally, I run the command to generate the schema with execInContainer, archive the result folder structure into tarball, and copy it from the container to the OS.

But actually the execInContainer command fails with the message

execInContainer can only be used while the Container is running

So, the SCHEMA_SPY.isRunning() method returns true, but the container is not running actually. Any ideas about this problem?

[remal]

@SimonHarmonicMinor, yes, I have.

I wrote something like this:

try (var network = Network.newNetwork()) {
    try (var databaseContainer = new PostgreSQLContainer<>()) {
        databaseContainer.setNetwork(network);
        databaseContainer.setNetworkAliases(singletonList("postgresql"));

        databaseContainer.start();

        var dataSource = newDataSource(databaseContainer);
        executeFlywayMigrations(dataSource);


        var properties = new Properties();
        properties.setProperty("schemaspy.t", "pgsql11");
        properties.setProperty("schemaspy.host", databaseContainer.getNetworkAliases().get(0));
        properties.setProperty("schemaspy.port", String.valueOf(5432));
        properties.setProperty("schemaspy.db", databaseContainer.getDatabaseName());
        properties.setProperty("schemaspy.u", databaseContainer.getUsername());
        properties.setProperty("schemaspy.p", databaseContainer.getPassword());
        var propertiesFile = new File(tmpDir, "schemaspy.properties");
        try (var outputStream = newOutputStream(propertiesFile.toPath())) {
            properties.store(outputStream, null);
        }
        
        try (var container = new GenericContainer<>(DockerImageName.parse("schemaspy/schemaspy:latest"))) {
            container.setNetwork(databaseContainer.getNetwork());
            container.addFileSystemBind(
                    propertiesFile.getAbsolutePath(),
                    "/schemaspy.properties",
                    READ_ONLY
            );
            container.addFileSystemBind(
                    getOutputDir().getAbsolutePath(),
                    "/output",
                    READ_WRITE
            );
            if (schemaMetaFile != null) {
                container.addFileSystemBind(
                        schemaMetaFile.getAbsolutePath(),
                        "/schemameta.xml",
                        READ_ONLY
                );
            }
            container.setLogConsumers(singletonList((OutputFrame frame) ->
                    getLogger().info(frame.getUtf8String())
            ));
            container.setWaitStrategy(new LogMessageWaitStrategy().withRegEx(Stream.of(
                    "View the results by opening",
                    "Failed to connect to database URL"
            ).collect(joining("|", "(?i).*(", ").*"))));
            container.start();
        }
    }
}

[SimonHarmonicMinor]

@remal Thank you for sharing this piece. Unfortunately, it didn't work for me. The container is stuck, if I add the addFileSystemBind configuration. Anyway, I found another solution. I posted the entire explanation on this StackOverflow question, but here are the main points:

1. Start the SchemaSpy container and override the entrypoint with sleep 500000. So, it doesn't stop automatically.
2. Execute the documentation generation command with execInContainer method.
3. Execute the archiving of result folder structure in tarball inside the container.
4. Copy the tarball from the container to the OS directory.

Now you can unpack the archive and host it on GitHub/GitLab pages