[aws-codepipeline-actions] Not able to use EVENTS based S3 trigger when bucketKey contains a CDK token

[jimistry123]

❓ General Issue

The Question

I am trying to use S3SourceAction class to define a bunch of S3 sources for a Pipeline. The bucket key for the source action is determined during deployment time using a CFN custom resource. This is how I am building an object for S3SourceAction:

public S3SourceAction createS3SourceAction(String projectName, Artifact outputArtifact) {
        // The getFileName() method will create a custom resource which will determine the filename.
        String bucketKey = "rpms/" + projectName + "/" + getFileName(projectName, artifactsBucketName);
        return S3SourceAction.Builder.create()
                .actionName(projectName)
                .bucket(artifactsBucket)
                .bucketKey(bucketKey)
                .output(outputArtifact)
                .trigger(S3Trigger.EVENTS)
                .build();
    }

Now, because the S3 trigger is set to EVENTS, CDK will automatically create a corresponding CloudWatch Events rule as a dependency. I noticed that the logical ID of the CW rule will include the bucket key in it. And because of the way I am setting bucket key, the bucket key contains a CDK token during stack synthesis.

So when I try to synthesize my stack, it throws the following error:

Exception in thread "main" software.amazon.jsii.JsiiException: Cannot use tokens in construct ID: <dynamically-generated-logical-ID>/rpms/${Token[Default.Response.4408]}

I came across #1374 which explains why CDK does not allow to use tokens in construct ID.

So my question is - Since I have no control over the logical ID of the dependent CloudWatch Events rule, is it possible to set an event based trigger on a dynamically generated bucket key? If there is a workaround or a better way to this then that would be great.

Environment

• CDK CLI Version: 1.42.0 (build 3b64241)
• Module Version: Same as CDK version (1.42.0)
• Node.js Version: v12.16.3
• OS: macOS Mojave
• Language (Version): Java 8

Other information

[skinny85]

Hey @jimistry123 ,

you're right, this is probably a miss in the construct library for codepipeline.

To unblock yourself, you can set the trigger property to S3Trigger.NONE, and create the Event yourself:

var action = S3SourceAction.Builder.create()
                .actionName(projectName)
                .bucket(artifactsBucket)
                .bucketKey(bucketKey)
                .output(outputArtifact)
                .trigger(S3Trigger.NONE)
                .build();

        artifactsBucket.onCloudTrailPutObject("some-id", OnCloudTrailBucketEventOptions.builder()
                .target(new CodePipeline(pipeline))
                .paths(Collections.singletonList(bucketKey))
                .build()
        );

[skinny85]

I'll work on a fix for this in the meantime.