@aws-cdk/aws-ecs-patterns: minScalingCapacity cannot be set to 0

[paya-cz]

Reproduction Steps

It is impossible to set minScalingCapacity on a SQS-processing Fargate task to 0, because of this check:

aws-cdk/packages/@aws-cdk/aws-ecs-patterns/lib/base/queue-processing-service-base.ts

Line 315 in 2647cf3

this.minCapacity = props.minScalingCapacity || this.desiredCount;

The operator || treats 0 as a falsy value. Use ?? instead. A workaround seems to be to set desiredTaskCount deprecated prop to 0, since that's used in the falsy branch path.

What did you expect to happen?

minScalingCapacity set to 0 should deploy autoscaling with minimum tasks: 0.

What actually happened?

minScalingCapacity set to 0 deploys ECS autoscaling with minimum tasks: 1.

Environment

• CDK CLI Version : 1.114.0 (build 7e41b6b)
• Framework Version: 1.114.0
• Node.js Version: v14.17.1
• OS : Win 10
• Language (Version): TypeScript (3.9.10)

---

This is 🐛 Bug Report

[peterwoodworth]

Hey @paya-cz, would you like to submit a pr for this?

[paya-cz]

@peterwoodworth I tried to, but it looks like getting the dev environment up and running is quite a bit more involved than I hoped for. I opened the repo in Gitpod, but the build returned error code 1 with the error message being buried somewhere deep in the log and not available in the terminal anymore.

Trying to run scripts/foreach.sh yarn build gives me error error Command "build" not found.

As a last resort, I did cd into /packages/@aws-cdk/aws-ecs-patterns and tried to yarn build, only to get a failure message with @aws-cdk/aws-ecs not being built. Attempting to build that, got another error with @aws-cdk/aws-s3-deployment. Not sure how deep that chain goes, seems like I would have to build a ton of packages by hand one by one.

Seems to me the contributing guide is either outdated, or I must have missed some step? Although I imagine the point of Gitpod is that everything should work out of the box. So I don't think I will be able to submit a PR for this.

[peterwoodworth]

I've never used the Gitpod method, so I don't think I'll be able to troubleshoot that for you. Have you tried the other method of submitting PRs? I could help you with that if you'd like. If not, I can try to get a PR up for this when I have the time

[paya-cz]

@peterwoodworth I see you already made a PR for this, thank you for handling this issue.

I use Windows VM for development, I guess I might be able to get WSL setup in order to contribute to the project, but unfortunately don't really have time to play with that at the moment. Gitpod would solve this friction beautifully though if it worked :-)

[github-actions]

⚠️COMMENT VISIBILITY WARNING⚠️

Comments on closed issues are hard for our team to see.
If you need more assistance, please either tag a team member or open a new issue that references this one.
If you wish to keep having a conversation with other community members under this issue feel free to do so.