java localstack lambada - how to run lambada and see logs - aws-java-sdk

Question

I am trying to run lambada using localStack and to see the log ...
so thee running class looks like :
public class LambdaLoader implements RequestHandler<Object, String> {
#Override
public String handleRequest(Object input, Context context) {
LambdaLogger logger = context.getLogger();
logger.log("\"started\"");
return "Complete";
}
I am running it
public class LambdaLoaderIT {
#Test
void handleRequest() throws InterruptedException, IOException {
AwsClientBuilder.EndpointConfiguration endpointConfiguration =
new AwsClientBuilder.EndpointConfiguration(
"http://localhost:4566", Regions.US_EAST_1.getName());
AWSLambda lambdaClient = createLambdaClient(endpointConfiguration);
createLambda(lambdaClient);
}
private AWSLambda createLambdaClient(
AwsClientBuilder.EndpointConfiguration endpointConfiguration) {
return AWSLambdaClientBuilder.standard()
.withEndpointConfiguration(endpointConfiguration)
.withCredentials(
new AWSStaticCredentialsProvider(
new BasicAWSCredentials("dummyAccessKey", "dummySecretKey")))
.build();
}
private void createLambda(AWSLambda clientLambda) throws IOException {
CreateFunctionRequest functionRequest = new CreateFunctionRequest();
functionRequest.setHandler("com.ssp.coreTeam.LambdaLoader::handleRequest");
functionRequest.setFunctionName("handleRequest");
functionRequest.setTimeout(900);
functionRequest.setRuntime("java11");
functionRequest.setRole("arn:aws:lambda:us-east-1:000000000000:function:handleRequest");
FunctionCode code = new FunctionCode();
File file = new File("target/my-lambda-0.0.0-SNAPSHOT.jar");
FileInputStream fileInputStream = new FileInputStream(file);
byte[] bytes = IoUtils.toByteArray(fileInputStream);
code.setZipFile(ByteBuffer.wrap(bytes));
functionRequest.setCode(code);
Environment environment = new Environment();
environment.setVariables(Map.of("LAMBDA_ENV","dev"));
functionRequest.setEnvironment(environment);
CreateFunctionResult function = clientLambda.createFunction(functionRequest);
System.out.println(function);
}
in addition, this is how I have configured lambada in the docker-compose file (notice LAMBDA_EXECUTOR=local ):
localstack:
image: 'localstack/localstack'
ports:
- '4566:4566'
environment:
- SERVICES=lambda,ssm
- DEBUG=1
- DATA_DIR=${DATA_DIR- }
- PORT_WEB_UI=${PORT_WEB_UI- }
- LAMBDA_EXECUTOR=local
- KINESIS_ERROR_PROBABILITY=${KINESIS_ERROR_PROBABILITY- }
- DOCKER_HOST=unix:///var/run/docker.sock
- HOST_TMP_FOLDER=${TMPDIR}
volumes:
- "${TMPDIR:-/tmp/localstack}:/tmp/localstack"
- "/var/run/docker.sock:/var/run/docker.sock"
How can I see the logs and what happened there?

Answer 1

You've already set the DEBUG to 1, so the logs are there.
To read them, use the standard Docker Compose facilities for logs. In your case it should be something like:
docker-compose logs localstack
I would also recommend you to use a small library to inject AWS clients in your tests, named aws-junit5. It would greatly simplify your tests. It supports Lambda clients for both AWS Java SDK 1.x and 2.x. The usage is pretty straightforward:
#ExtendWith(Lambda.class)
class AmazonDynamoDBInjectionTest {
#AWSClient(endpoint = Endpoint.class) // Endpoint configuration
private AWSLambda client;
#Test
void test() {
CreateFunctionRequest functionRequest = new CreateFunctionRequest();
functionRequest.setHandler("com.ssp.coreTeam.LambdaLoader::handleRequest");
functionRequest.setFunctionName("handleRequest");
functionRequest.setTimeout(900);
functionRequest.setRuntime("java11");
functionRequest.setRole("arn:aws:lambda:us-east-1:000000000000:function:handleRequest");
FunctionCode code = new FunctionCode();
File file = new File("target/my-lambda-0.0.0-SNAPSHOT.jar");
FileInputStream fileInputStream = new FileInputStream(file);
byte[] bytes = IoUtils.toByteArray(fileInputStream);
code.setZipFile(ByteBuffer.wrap(bytes));
functionRequest.setCode(code);
Environment environment = new Environment();
environment.setVariables(Map.of("LAMBDA_ENV","dev"));
functionRequest.setEnvironment(environment);
// Just use client here, it will be auto-injected!
CreateFunctionResult function = client.createFunction(functionRequest);
// Rest of your test
System.out.println(function);
}
}
There is even an example of CI/CD with GitHub, which is very similar to what you're doing.