ServerlessSpy

Marko (ServerlessLife)

ServerlessSpy

CDK-based library for writing elegant, fast-executing integration tests on AWS serverless architecture and an additional web console to monitor events in real time.

How it works

ServerlessSpy CDK construct creates infrastructure to intercept events in Lambda, SNS, SQS, EventBridge, DynamoDB, S3… and sends it to a testing library or your local web console via AWS IoT WebSockets. The testing library subscribes to events so tests can be executed fast without checking/retrying if the process has finished. The testing library is integrated with Jest but can also be used with any other testing library. The web console can be used to see and inspect events in real time.

Concept

Your test for the example above would look something like this:

(
  await serverlessSpyListener.waitForEventBridgeMyEventBus<TestData>({
    condition: (d) => d.detail.id === id,
  })
).toMatchObject(...);

(
  await serverlessSpyListener.waitForSnsTopicMyTopic<TestData>({
    condition: (d) => d.message.id === id,
  })
).toMatchObject(...);

(
  await serverlessSpyListener.waitForSqsMyQueue<TestData>({
    condition: (d) => d.body.id === id,
  })
).toMatchObject(...);

(
  await (
    await serverlessSpyListener.waitForFunctionMyLambdaRequest<TestData>({
      condition: (d) => d.request.id === id,
    })
  ).followedByResponse();
).toMatchObject(...);

(
  await serverlessSpyListener.waitForDynamoDBMyTable<TestData>({
    condition: (d) => d.keys.pk === id,
  })
).toMatchObject({
  eventName: 'INSERT',
  newImage: ...,
});

You can see all the events in the local web console: Web console

Key benefits

  • Easy to write tests that are strongly typed thanks to TypeScript ❤️.
  • Tests are executed much FASTER 🏎️💨 No need to write tests in a way to periodically check if the process has finished because all events are pushed to the testing library.
  • Tests can run in parallel if you use conditions and filter events specific to your test. This drastically reduces the execution time of the CI/CD process.
  • Web console enables you to see all events in real time. Debugging 🕵 has never been easier. Search is supported (with regular expression).

What ServerlessSpy is not

  • ServerlessSpy can not be used if your infrastructure is not created with CDK.
  • The solution is meant only for the development and (automatic) testing environment. You should EXCLUDE ServerlessSpy CDK construct in any other environment, especially a production or a high-load environment. ServerlessSpy is not meant for those; it just induces costs and could contribute to hitting AWS quotas (Lambda concurrent executions, …).
  • Node.js and Python stacks are supported. There are no plans to support any other but feel free to contribute. Use of TypeScript is deeply encouraged.
  • Web console only runs on your local computer. No cloud hosting of any kind (for now).

Troubleshooting

When first setting up ServerlessSpy for a new account it can take a couple of minutes before AWS has fully activated AWS IoT. You can tell if it’s not activated if you cannot connect using the MQTT Test Client in the AWS IoT console.

Documentation

Co-authors

Contributors (alphabetical)