fix(auth): #22827 missing region error when using AWS credentials file auth

[cahartma]

Summary

Resolves newly created bug #22827, adding region to the credentials_file authentication method for aws services.

Before this fix, when using auth.credentials_file, and the file contained role_arn, and web_identity_token keys, the resulting sts calls produced a "Invalid Configuration" error in the log, and prevented the cloudwatch logs sink from authenticating. This fix adds 'auth.region' to the valid spec, and sets the value to the service_region if not provided.

Change Type

• Bug fix
• New feature
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

How did you test this PR?

[sinks.output_my_cw]
type = "aws_cloudwatch_logs"
inputs = ["in"]
region = "us-east-2"
group_name = "group-test"
stream_name = "my-stream"
auth.credentials_file = "/root/.aws/credentials"
#auth.profile = "default"
encoding.codec = "json"

--------------------------
#Sample aws credentials file:
[default]
web_identity_token_file=/var/run/secrets/serviceaccount/token
role_arn=arn:aws:iam::123456789012:role/logging-role-for-sts

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on our guidelines.
• No. A maintainer will apply the "no-changelog" label to this PR.

Checklist

• Please read our Vector contributor resources.
• If this PR introduces changes Vector dependencies (modifies Cargo.lock), please
  run dd-rust-license-tool write to regenerate the license inventory and commit the changes (if any). More details here.

References

• Closes: AWS Cloudwatch sink missing region error when role_arn is used with Credentials File Authentication #22827

[bits-bot]

All committers have signed the CLA.

[pront]

Hi @cahartma, thank you for the fix!

Please run generate-component-docs

[cahartma]

Hey @pront, I've run make generate-component-docs as well as make docs with no changes.

[pront]

Hey @pront, I've run make generate-component-docs as well as make docs with no changes.

Oh I see. I was expecting changes but region already exists in another variant and (unfortunately) the AwsAuthentication is marked as untagged.

There are a few checks that are failing. We need a changelog and fmt.