Can't get proper DBCluster port

[dekoza]

This look like regression - there was already similar bug: #2711

I try to configure RDS using CDK in Python and then pass port number to ECS.

This is how the DBCluster is created:

    cluster = rds.DatabaseCluster(
        stack,
        "MyDBCluster",
        #master_user=...
        default_database_name=DATABASE_NAME,
        engine=rds.DatabaseClusterEngine.AURORA_POSTGRESQL,
        engine_version="11.6",
        instances=1,
        parameter_group=rds.ClusterParameterGroup.from_parameter_group_name(
            stack, "MyParamGroup", "default.aurora-postgresql11"
        ),
        instance_props=rds.InstanceProps(
            instance_type=ec2.InstanceType.of(
                ec2.InstanceClass.BURSTABLE3, ec2.InstanceSize.MEDIUM,
            ),
            vpc=vpc,
        ),
        removal_policy=core.RemovalPolicy.RETAIN,
    )

and here is the ECS pattern:

ecs_patterns.ApplicationLoadBalancedFargateService(
        stack,
        "BackendService",
        # cluster= previously created ECS cluster...
        desired_count=1,
        task_image_options=ecs_patterns.ApplicationLoadBalancedTaskImageOptions(
            image=ecs.ContainerImage.from_ecr_repository(
                # repo and tag passed from previously created objects
            ),
            environment={
                "POSTGRES_DB": DATABASE_NAME,
                "POSTGRES_HOST": database.cluster_endpoint.hostname,
                "POSTGRES_PORT": str(database.cluster_endpoint.port),
                "POSTGRES_USER": DB_USER,
                "POSTGRES_PASSWORD": DB_PASS,
            },
        ),
)

After that POSTGRES_PORT has value "-1.8881545897087736e+289".

Expected result

POSTGRES_PORT should have value "3306".

Environment

• CLI Version :aws-cli/2.0.16 Python/3.7.3 Linux/5.6.15-1-MANJARO botocore/2.0.0dev20
• Framework Version: 1.45.0
• Node.js Version: v14.3.0
• OS : Manjaro Linux
• Language (Version): Python 3.7/3.8

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This is 🐛 Bug Report

[jogold]

You should be able to do something like this: core.Token.as_string(database.cluster_endpoint.port)

(database.cluster_endpoint.port is a deploy time value and it is encoded as a large negative number in the framework)

[nija-at]

@jogold is right. Because the value of the port is returned by CloudFormation after the resource is created (see Endpoint.Port here), the CDK does not know what this will be and hence holds a placeholder value.

If you need the string version of this number, you need to use the Token.asString() method mentioned above.

Let us know if that doesn't work.