Try/Catch aws cli errors in powershell script

Question

I'm trying to have a script automatically create ECR repos for projects as part of the pipeline. I want to check if it already exists first, however describe-repositories returns an error instead of "nothing", and it's not caught in a try/catch .

try{
    $ErrorActionPreference = "Stop"
    aws ecr describe-repositories --repository-names "some-project"
}
catch {
    aws ecr create-repository --repository-name "some-project"    
}

Output:

An error occurred (RepositoryNotFoundException) when calling the DescribeRepositories operation: The repository with name '...' does not exist in the registry with id '...'

Is there a way to capture the error? Edit: Setting $ErrorActionPreference = "Stop" doesn't change behaviour.

user_5039142 · Answer

You should be able to leverage $LastExitCode to tell that an error has occurred (Some minimal AWS CLI documentation on this)

aws ecr describe-repositories --repository-names "some-project"

if ($LastExitCode) {
    aws ecr create-repository --repository-name "some-project"
}

If you want the actual error message, you should be able to leverage redirection as described in How to capture error messages thrown by a command?

Really though I think there are two other improvements you can do here:

Instead of describing a specific repository, list them and see if the one you want exists:

$repositories = (aws ecr describe-repositories) | ConvertFrom-Json

if ("some-project" -notin $repositories.repositories.repositoryName) {
    aws ecr create-repository --repository-name "some-project"
}

If it's an option, use AWS Tools for PowerShell... so you can use Get-ECRRepository and things like $ErrorActionPreference work.

Try/Catch aws cli errors in powershell script

1 Answers