Our application uses Kafka and external dependencies.
Currently, if you run the application from your terminal, you will see the following error:
./mvnw spring-boot:run
[INFO] Attaching agents: []
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v3.2.1)
2024-01-29T17:38:40.559+01:00 INFO 96159 --- [ restartedMain] org.acme.order.OrderServiceApplication : Starting OrderServiceApplication using Java 17.0.6 with PID 96159 (/Users/laurent/Development/github/microcks-testcontainers-java-spring-demo/target/classes started by laurent in /Users/laurent/Development/github/microcks-testcontainers-java-spring-demo)
2024-01-29T17:38:40.560+01:00 INFO 96159 --- [ restartedMain] org.acme.order.OrderServiceApplication : No active profile set, falling back to 1 default profile: "default"
[...]
2024-01-29T17:38:41.344+01:00 INFO 96159 --- [ restartedMain] o.a.kafka.common.utils.AppInfoParser : Kafka version: 3.6.1
2024-01-29T17:38:41.344+01:00 INFO 96159 --- [ restartedMain] o.a.kafka.common.utils.AppInfoParser : Kafka commitId: 5e3c2b738d253ff5
2024-01-29T17:38:41.344+01:00 INFO 96159 --- [ restartedMain] o.a.kafka.common.utils.AppInfoParser : Kafka startTimeMs: 1706546321343
2024-01-29T17:38:41.345+01:00 INFO 96159 --- [ restartedMain] fkaConsumerFactory$ExtendedKafkaConsumer : [Consumer clientId=consumer-order-service-1, groupId=order-service] Subscribed to topic(s): orders-reviewed
2024-01-29T17:38:41.352+01:00 INFO 96159 --- [ restartedMain] org.acme.order.OrderServiceApplication : Started OrderServiceApplication in 0.911 seconds (process running for 1.079)
2024-01-29T17:38:41.419+01:00 INFO 96159 --- [ntainer#0-0-C-1] org.apache.kafka.clients.NetworkClient : [Consumer clientId=consumer-order-service-1, groupId=order-service] Node -1 disconnected.
2024-01-29T17:38:41.420+01:00 WARN 96159 --- [ntainer#0-0-C-1] org.apache.kafka.clients.NetworkClient : [Consumer clientId=consumer-order-service-1, groupId=order-service] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available.
[...]To run the application locally, we need to have a Kafka broker up and running + the other dependencies corresponding to our Pastry API provider and reviewing system.
Instead of installing these services on our local machine, or using Docker to run these services manually, we will use Spring Boot support for Testcontainers at Development Time to provision these services automatically.
NOTE
Before Spring Boot 3.1.0, Testcontainers libraries are mainly used for testing. Spring Boot 3.1.0 introduced out-of-the-box support for Testcontainers which not only simplified testing, but we can use Testcontainers for local development as well.
To learn more, please read Spring Boot Application Testing and Development with Testcontainers
In order to see what's needed to run this, you may check the pom.xml file.
In order to specify the dependant services we need, we use a specific Spring Configuration class located into `/src/test/java``
Let's review ContainersConfiguration class under src/test/java/org/acme/order to configure the required containers.
package org.acme.order;
import io.github.microcks.testcontainers.MicrocksContainersEnsemble;
import io.github.microcks.testcontainers.connection.KafkaConnection;
import org.springframework.boot.test.context.TestConfiguration;
import org.springframework.boot.testcontainers.service.connection.ServiceConnection;
import org.springframework.context.annotation.Bean;
import org.springframework.test.context.DynamicPropertyRegistry;
import org.testcontainers.containers.KafkaContainer;
import org.testcontainers.containers.Network;
import org.testcontainers.utility.DockerImageName;
@TestConfiguration(proxyBeanMethods = false)
public class ContainersConfiguration {
private static Network network = Network.newNetwork();
private KafkaContainer kafkaContainer;
@Bean
@ServiceConnection
KafkaContainer kafkaContainer() {
kafkaContainer = new KafkaContainer(DockerImageName.parse("confluentinc/cp-kafka:7.5.0"))
.withNetwork(network)
.withNetworkAliases("kafka")
.withListener(() -> "kafka:19092");
return kafkaContainer;
}
@Bean
MicrocksContainersEnsemble microcksEnsemble(DynamicPropertyRegistry registry) {
MicrocksContainersEnsemble ensemble = new MicrocksContainersEnsemble(network, "quay.io/microcks/microcks-uber:1.10.0")
.withPostman() // We need this to do contract-testing with Postman collection
.withAsyncFeature() // We need this for async mocking and contract-testing
.withAccessToHost(true) // We need this to access our webapp while it runs
.withKafkaConnection(new KafkaConnection("kafka:19092")) // We need this to connect to Kafka
.withMainArtifacts("order-service-openapi.yaml", "order-events-asyncapi.yaml", "third-parties/apipastries-openapi.yaml")
.withSecondaryArtifacts("order-service-postman-collection.json", "third-parties/apipastries-postman-collection.json")
.withAsyncDependsOn(kafkaContainer); // We need this to be sure Kafka will be up before Microcks async minion
// We need to replace the default endpoints with those provided by Microcks.
registry.add("application.pastries-base-url",
() -> ensemble.getMicrocksContainer().getRestMockEndpoint("API Pastries", "0.0.1"));
registry.add("application.order-events-reviewed-topic",
() -> ensemble.getAsyncMinionContainer().getKafkaMockTopic("Order Events API", "0.1.0", "PUBLISH orders-reviewed"));
return ensemble;
}
}Let's understand what this configuration class does:
@TestConfigurationannotation indicates that this configuration class defines the beans that can be used for Spring Boot tests.- Spring Boot provides
ServiceConnectionsupportKafkaConnectionDetailsout-of-the-box. So, we configuredKafkaContaineras beans with@ServiceConnectionannotation. This configuration will automatically start these containers and register the Kafka connection properties automatically. - We also configure a
MicrocksContainersEnsemblethat will be responsible for providing mocks for our 3rd party systems. As REST Client URL properties are not standard ones, Microcks does not contribute anyServiceConnection. Instead, we have the ability to use theDynamicPropertyRegistryto wire our application properties corresponding to REST Client URL and Kafka Topic name. This way our application is using the endpoints that are provided by Microcks.
And that's it! 🎉 You don't need to download and install extra-things, or clone other repositories and figure out how to start your dependant services.
Next, let's create a TestOrderServiceApplication class under src/test/java to start the application with the containers configuration.
package org.acme.order;
import org.springframework.boot.SpringApplication;
/**
* A Test instance of the OrderServiceApplication.
* @author laurent
*/
class TestOrderServiceApplication {
public static void main(String[] args) {
SpringApplication.from(OrderServiceApplication::main)
.with(ContainersConfiguration.class)
.run(args);
}
}Run the TestOrderServiceApplication from our IDE and verify that the application starts successfully. 🙌
You should see the container startups messages into the logs:
[...]
18:12:37.237 [restartedMain] INFO org.testcontainers.DockerClientFactory - Checking the system...
18:12:37.237 [restartedMain] INFO org.testcontainers.DockerClientFactory - ✔︎ Docker server version should be at least 1.6.0
18:12:37.276 [restartedMain] INFO tc.quay.io/microcks/microcks-uber:1.8.1 - Creating container for image: quay.io/microcks/microcks-uber:1.8.1
18:12:37.601 [restartedMain] INFO tc.testcontainers/ryuk:0.5.1 - Creating container for image: testcontainers/ryuk:0.5.1
18:12:37.847 [restartedMain] INFO org.testcontainers.utility.RegistryAuthLocator - Credential helper/store (docker-credential-desktop) does not have credentials for https://index.docker.io/v1/
18:12:37.923 [restartedMain] INFO tc.testcontainers/ryuk:0.5.1 - Container testcontainers/ryuk:0.5.1 is starting: e9bfe5ba9c3d58ae45074c553ee774f07c012954d1f2947ea0d1c03a0129588a
18:12:38.178 [restartedMain] INFO tc.testcontainers/ryuk:0.5.1 - Container testcontainers/ryuk:0.5.1 started in PT0.577482S
18:12:38.215 [restartedMain] INFO tc.testcontainers/sshd:1.1.0 - Creating container for image: testcontainers/sshd:1.1.0
18:12:38.239 [restartedMain] INFO tc.testcontainers/sshd:1.1.0 - Container testcontainers/sshd:1.1.0 is starting: a9375373e4ccc533f7cdc3922be18c813f59317ffc16ccdfd1e5cba4ce4241bb
18:12:38.446 [restartedMain] INFO tc.testcontainers/sshd:1.1.0 - Container testcontainers/sshd:1.1.0 started in PT0.23102S
18:12:38.538 [restartedMain] INFO tc.quay.io/microcks/microcks-uber:1.8.1 - Container quay.io/microcks/microcks-uber:1.8.1 is starting: a1ba55342452f979037abab48235354003a604d566a57409d2396e9fe17c5d57
18:12:42.257 [restartedMain] INFO tc.quay.io/microcks/microcks-uber:1.8.1 - Container quay.io/microcks/microcks-uber:1.8.1 started in PT4.980663S
18:12:42.611 [restartedMain] INFO tc.quay.io/microcks/microcks-postman-runtime:latest - Creating container for image: quay.io/microcks/microcks-postman-runtime:latest
18:12:42.654 [restartedMain] INFO tc.quay.io/microcks/microcks-postman-runtime:latest - Container quay.io/microcks/microcks-postman-runtime:latest is starting: 3f9d6931537adc106ff75938ba9d42458047ad58e447ceb89e7dbe5dd25c21bd
18:12:43.378 [restartedMain] INFO tc.quay.io/microcks/microcks-postman-runtime:latest - Container quay.io/microcks/microcks-postman-runtime:latest started in PT0.766923S
18:12:43.380 [testcontainers-lifecycle-1] INFO tc.confluentinc/cp-kafka:7.5.0 - Creating container for image: confluentinc/cp-kafka:7.5.0
18:12:43.423 [testcontainers-lifecycle-1] INFO tc.confluentinc/cp-kafka:7.5.0 - Container confluentinc/cp-kafka:7.5.0 is starting: 7fa0668cbd980b82a1746a82776ec7c4f8aae7954f51051022e579a43515fbe5
18:12:46.427 [testcontainers-lifecycle-1] INFO tc.confluentinc/cp-kafka:7.5.0 - Container confluentinc/cp-kafka:7.5.0 started in PT3.04718S
18:12:46.428 [restartedMain] INFO tc.quay.io/microcks/microcks-uber-async-minion:1.8.1 - Creating container for image: quay.io/microcks/microcks-uber-async-minion:1.8.1
18:12:46.452 [restartedMain] INFO tc.quay.io/microcks/microcks-uber-async-minion:1.8.1 - Container quay.io/microcks/microcks-uber-async-minion:1.8.1 is starting: e53b149bf37d6e9a9d738fb0db328b1686d816abcb12fc0d8d87edf4513930b8
[...]Now, you can invoke the APIs using CURL or Postman or any of your favourite HTTP Client tools.
curl -XPOST localhost:8080/api/orders -H 'Content-type: application/json' \
-d '{"customerId": "lbroudoux", "productQuantities": [{"productName": "Millefeuille", "quantity": 1}], "totalPrice": 5.1}' -vYou should get a response similar to the following:
< HTTP/1.1 201
< Content-Type: application/json
< Transfer-Encoding: chunked
< Date: Mon, 29 Jan 2024 17:15:42 GMT
<
* Connection #0 to host localhost left intact
{"id":"2da3a517-9b3b-4788-81b5-b1a1aac71746","status":"CREATED","customerId":"lbroudoux","productQuantities":[{"productName":"Millefeuille","quantity":1}],"totalPrice":5.1}%Now test with something else, requesting for another Pastry:
curl -XPOST localhost:8080/api/orders -H 'Content-type: application/json' \
-d '{"customerId": "lbroudoux", "productQuantities": [{"productName": "Eclair Chocolat", "quantity": 1}], "totalPrice": 4.1}' -vThis time you get another "exception" response:
< HTTP/1.1 422
< Content-Type: application/json
< Transfer-Encoding: chunked
< Date: Mon, 29 Jan 2024 17:19:08 GMT
<
* Connection #0 to host localhost left intact
{"productName":"Eclair Chocolat","details":"Pastry Eclair Chocolat is not available"}%and this is because Microcks has created different simulations for the Pastry API 3rd party API based on API artifacts we loaded.
Check the src/test/resources/third-parties/apipastries-openapi.yaml and src/test/resources/third-parties/apipastries-postman-collection.json files to get details.