Enabling profiling also causes snapshot test instability

[mbonig]

Expected Behavior

When snapshot testing a stack with a DD-enabled Lambda function, I'd expect the snapshot tests to remain stable. This is not currently possible without injecting the following code before any constructs are loaded:

jest.spyOn(require('child_process'), 'execSync').mockImplementation((_command) => {
  return 'ABCDEFG0123456';
});

(and is horribly fragile)

Ideally, a context variable should be available that would allow me to choose, during tests, to mock the hash value to create stability. This has been done with good success in other projects, like:

https://github.com/wheatstalk/cdk-intrinsic-validator?tab=readme-ov-file#tips

Actual Behavior

When enabling profiling on Lambda functions, a DD_TAG environment variable is added which includes the commit hash. This causes a constant churn if using snapshot tests.

Steps to Reproduce the Problem

1. Create a stack with a lambda function and the DD construct with profiling enabled
2. Create a snapshot test like:

test('Snapshot', () => {
  const app = new App();
  const stack = new SomeStack(app, 'test', {
    env: {
      account: '0123456789012',
      region: 'us-east-1',
    },
  });

  const template = Template.fromStack(stack);
  expect(template.toJSON()).toMatchSnapshot();
});

1. Commit the code change and updated snapshot
2. re-run the snapshot, test, it will now fail as the commit hash has changed.

Specifications

• Datadog Lambda Layer version: nodeLayerVersion: 118, extensionLayerVersion: 68,
• Node version: 22

Stacktrace

none...

[clifordshelton]

Hi Matthew! Thanks for reporting this issue. That sounds like a very useful suggestion. We'll prioritize this and keep you updated here

[avangelillo]

Hi @mbonig, as of 1.24.0 you can now override the git metadata from your test by calling the overrideGitMetadata function on the DatadogLambda object.

test('Snapshot', () => {
  const app = new App();
  const stack = new SomeStack(app, 'test', {
    env: {
      account: '0123456789012',
      region: 'us-east-1',
    },
  });

  // New line
  stack.datadogLambda.overrideGitMetadata("fake-sha");

  const template = Template.fromStack(stack);
  expect(template.toJSON()).toMatchSnapshot();
});

[mbonig]

Hi @mbonig, as of 1.24.0 you can now override the git metadata from your test by calling the overrideGitMetadata function on the DatadogLambda object.

test('Snapshot', () => {
  const app = new App();
  const stack = new SomeStack(app, 'test', {
    env: {
      account: '0123456789012',
      region: 'us-east-1',
    },
  });

  // New line
  stack.datadogLambda.overrideGitMetadata("fake-sha");

  const template = Template.fromStack(stack);
  expect(template.toJSON()).toMatchSnapshot();
});

This is slightly annoying, as it requires me to expose the underlying lambda and I'd prefer not to do that.

Could this be a context variable instead? Something like:

 const app = new App({
    context: {
      'DataDog:DisableGitSha': true,
    },
  });

See a similar scenario here:
https://github.com/wheatstalk/cdk-intrinsic-validator?tab=readme-ov-file#tips