s3: add storage_class option

[linxside]

I want to be able to set the storage class in lightningstream for S3. For this reason I've added the class in the "doStoreReader" method. It should be fine to set it for every call in simpleblob, as the minio-go client takes care of handling an empty string (according to https://github.com/minio/minio-go/blob/master/api-put-object.go#L200).

[Copilot]

Pull request overview

This PR adds support for configuring the S3 storage class in the S3 backend. This allows users to specify storage classes like STANDARD_IA, GLACIER, etc., when storing objects to optimize costs based on access patterns.

• Added StorageClass field to the Options struct with YAML configuration support
• The storage class is now passed to the minio client's PutObjectOptions when storing objects

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[ahouene]

Thanks for the contribution, it looks good! Could you provide more information about how the test suite fails?

[linxside]

Thank you for the review :)

I've taken a deeper look into the test issue. The failed tests are related to the minio test container. The testcontainers library creates the minio container in my rootless podman instance, but doesn't start it.

--- FAIL: TestMetrics (29.86s)
    s3_test.go:90: 
                Error Trace:   ~/simpleblob/backends/s3/s3_test.go:90
                Error:          Received unexpected error:
                                 # HELP storage_s3_call_error_by_type_total S3 API call errors by method and error type
                                 # TYPE storage_s3_call_error_by_type_total counter
                                +storage_s3_call_error_by_type_total{error="NotFound",method="load"} 3
                                 storage_s3_call_error_by_type_total{error="Timeout",method="list"} 1
                                 
                Test:           TestMetrics
    s3_test.go:100: 
                Error Trace:   ~/simpleblob/backends/s3/s3_test.go:100
                Error:          Received unexpected error:
                                 # HELP storage_s3_call_error_by_type_total S3 API call errors by method and error type
                                 # TYPE storage_s3_call_error_by_type_total counter
                                -storage_s3_call_error_by_type_total{error="Timeout",method="list"} 2
                                +storage_s3_call_error_by_type_total{error="DNSError",method="list"} 1
                                +storage_s3_call_error_by_type_total{error="NotFound",method="load"} 3
                                +storage_s3_call_error_by_type_total{error="Timeout",method="list"} 1
                                 
                Test:           TestMetrics

[ahouene]

Hey @linxside, sorry for the delay and thanks again for the contribution! I'm merging it, tagging a release soon.

The issues you had with the tests were fixed in #118, and #119 allows using Podman if a backend is running!