DynamicPropertyRegistry Values Not Set After Dev Tools Reload for RestartScope Containers

[shawnweeks]

When using a combination of @RestartScope Test Containers and the DynamicPropertyRegistry registry property values are not set back after Spring Dev Tools reload the project. The issue was partially resolved in #35786 but that fix does not appear to resolve the entire issue. I've linked to a small example project demonstrating the issue. See https://github.com/shawnweeks/spring_boot_testcontainers_restartscope_issue

[nosan]

I did some research regarding this bug, and frankly, it is quite a tricky one.

First run:

TestcontainersLifecycleBeanPostProcessor
  -- initializeContainers()

RestartScopeInitializer.RestartScope
  -- Restarter.getOrAddAttribute('redisContainer', ObjectFactory<?> factory)
  -- 'redisContainer' does not exist in attributes, so ObjectFactory<?> is being called.

TestcontainersPropertySourceAutoConfiguration.dynamicPropertyRegistry() is being called because it is needed for 'redisContainer'
-- Attach 'testcontainersPropertySource'
-- Register bean definition named: EventPublisherRegistrar.class.getName()

TestcontainersConfiguration.redisContainer()
  -- create RedisContainer
  -- Set RedisContainer properties to the 'dynamicPropertyRegistry'

TestcontainersLifecycleBeanPostProcessor.initializeStartables()
 -- Start containers

DemoController @Value annotations are being processed.

Restart:

TestcontainersLifecycleBeanPostProcessor
  -- initializeContainers()
RestartScopeInitializer.RestartScope
  -- Restarter.getOrAddAttribute("redisContainer", ObjectFactory<?>)
  -- "redisContainer" exists in attributes, so ObjectFactory<?> **is not being called.**

DemoController @Value annotations are not being processed due to Caused by: java.lang.IllegalArgumentException: Could not resolve placeholder 'MY_REDIS_HOST' in value "${MY_REDIS_HOST}"

There are two potential issues with this bug.

The first one TestcontainersPropertySourceAutoConfiguration.dynamicPropertyRegistry()
is being called too late if there is no direct reference to it, so TestcontainersPropertySource will not be available during @Value annotation processing.

The second one is that methods annotated @RestartScope are being called only once. That is why dynamicPropertyRegistry will not be created earlier, and container properties are ignored. (Properties are being set inside the method).

A potential fix is:

• If properties come from @RestartScope methods they should be shared across restarts.
• TestcontainersPropertySource should be registered earlier.

This branch contains an implementation of the fix that I have tried to describe above.
main...nosan:spring-boot:41552

I used this example for research: https://github.com/shawnweeks/spring_boot_testcontainers_restartscope_issue

[philwebb]

Thanks for the detailed analysis @nosan. This is indeed a complicated issue to fix and made even more difficult by the changes we're introducing in 3.4 due to #41996.

I'm not really sure if we should attempt to fix this in 3.3 since I don't really like the fact that TestcontainersPropertySource needs to know about restart scope.

The following code does appear to work with 3.4.0-SNAPSHOT:

@TestConfiguration(proxyBeanMethods = false)
class TestcontainersConfiguration {

    @Bean
    @RestartScope
    public GenericContainer<?> redisContainer() {
        GenericContainer<?> redisContainer = new GenericContainer<>("redis:7");
        redisContainer.withExposedPorts(6379);
        redisContainer.withCommand("redis-server", "--requirepass redis_user", "--save 60 1", "--loglevel debug");
        return redisContainer;
    }

    @Bean
    public DynamicPropertyRegistrar redisContainerProperties(GenericContainer<?> redisContainer) {
    	return (registry) -> {
            registry.add("MY_REDIS_HOST", () -> "localhost");
            registry.add("MY_REDIS_PORT", () -> redisContainer.getMappedPort(6379));
            registry.add("MY_REDIS_PASSWORD", () -> "redis_user");
    	};
    }

}

This split allows the container to remain in the @RestartScope whilst the properties are always recreated.

[philwebb]

The following ugly hack will work with 3.3.x:

package com.example.demo;

import java.util.List;

import org.springframework.boot.devtools.restart.RestartScope;
import org.springframework.boot.test.context.TestConfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.test.context.DynamicPropertyRegistry;
import org.testcontainers.containers.ContainerState;
import org.testcontainers.containers.GenericContainer;
import org.testcontainers.lifecycle.Startable;

import com.github.dockerjava.api.command.InspectContainerResponse;

@TestConfiguration(proxyBeanMethods = false)
class TestcontainersConfiguration {

	@Bean
	@RestartScope
	public GenericContainer<?> redisContainer(DynamicPropertyRegistry registry) {
		GenericContainer<?> redisContainer = new GenericContainer<>("redis:7");
		redisContainer.withExposedPorts(6379);
		redisContainer.withCommand("redis-server", "--requirepass redis_user", "--save 60 1", "--loglevel debug");
		return redisContainer;
	}

	@Bean
	public RedisProperties redisProperties(GenericContainer<?> redisContainer, DynamicPropertyRegistry registry) {
		redisContainer.start();
		registry.add("MY_REDIS_HOST", () -> "localhost");
		registry.add("MY_REDIS_PORT", () -> redisContainer.getMappedPort(6379));
		registry.add("MY_REDIS_PASSWORD", () -> "redis_user");
		return new RedisProperties();
	}

	static class RedisProperties implements Startable, ContainerState {

		@Override
		public void start() {
		}

		@Override
		public void stop() {
		}

		@Override
		public List<Integer> getExposedPorts() {
			return null;
		}

		@Override
		public InspectContainerResponse getContainerInfo() {
			return null;
		}

	}

}

[philwebb]

Flagging to see if the team think we should still attempt a fix in 3.2/3.3.

[nosan]

I propose adding a note to the documentation explaining that DynamicPropertyRegistry does not work with restart-scoped containers (beans), along with the reason behind this limitation.
For version 3.4.x, include a reference to DynamicPropertyRegistrar and mention that it works with restart-scoped containers (beans).

Fixing this issue in versions 3.2/3.3 would result in inconsistency with 3.4.x, as the latter will not receive a similar fix.

[nosan]

This hack works with 3.2.x, 3.3.x and 3.4.0-M3

@TestConfiguration(proxyBeanMethods = false)
class TestcontainersConfiguration {

	@Bean
	@RestartScope
	public GenericContainer<?> redisContainer() {
		GenericContainer<?> redisContainer = new GenericContainer<>("redis:7");
		redisContainer.withExposedPorts(6379);
		redisContainer.withCommand("redis-server", "--requirepass redis_user", "--save 60 1", "--loglevel debug");
		return redisContainer;
	}

	@Autowired
	void registryRedisContainerProperties(@Lazy GenericContainer<?> redisContainer, DynamicPropertyRegistry registry) {
		registry.add("MY_REDIS_HOST", () -> "localhost");
		registry.add("MY_REDIS_PORT", () -> redisContainer.getMappedPort(6379));
		registry.add("MY_REDIS_PASSWORD", () -> "redis_user");
	}

}

[wilkinsona]

It'll fail by default with 3.4.0-SNAPSHOT due to the deprecation of support for injecting DynamicPropertyRegistry.