fix(backend): Caching should not be wrongly shown as successful if the artifacts have been deleted from S3

[juliusvonkohout]

Description of your changes:

Fixes #7939

Checklist:

• The title for your pull request (PR) should follow our title convention. Learn more about the pull request title convention used in this repository.

[juliusvonkohout]

Maybe we should remove minio entirely to get rid of any possible licence issues. We could fetch the artifact as the persistenceagent does

pipelines/backend/src/agent/persistence/worker/metrics_reporter.go

Lines 144 to 160 in a294e75

	artifactRequest := &api.ReadArtifactRequest{
	RunId: runID,
	NodeId: nodeStatus.ID,
	ArtifactName: metricsArtifactName,
	}
	artifactResponse, err := r.pipelineClient.ReadArtifact(artifactRequest)
	if err != nil {
	return "", err
	}
	if artifactResponse == nil || artifactResponse.GetData() == nil || len(artifactResponse.GetData()) == 0 {
	// If artifact is not found or empty content, skip the reporting.
	return "", nil
	}
	archivedFiles, err := util.ExtractTgz(string(artifactResponse.GetData()))
	if err != nil {
	// Invalid tgz file. This should never happen unless there is a bug in the system and
	// it is a unrecoverable error.

with a readartifact call instead. Then we would save a lot of S3 configuration too.

The apiserver S3 is configurable via environment variables

pipelines/backend/src/apiserver/client_manager.go

Lines 37 to 45 in a294e75

	const (
	minioServiceHost = "MINIO_SERVICE_SERVICE_HOST"
	minioServicePort = "MINIO_SERVICE_SERVICE_PORT"
	minioServiceRegion = "MINIO_SERVICE_REGION"
	minioServiceSecure = "MINIO_SERVICE_SECURE"
	pipelineBucketName = "MINIO_PIPELINE_BUCKET_NAME"
	pipelinePath = "MINIO_PIPELINE_PATH"
	mysqlServiceHost = "DBConfig.Host"
	mysqlServicePort = "DBConfig.Port"

and since even the persistenceagent uses readArtifact we are anyway limited to use the S3 configuration of the apiserver. Trying to get caching work with another S3 configuration would be nonsense then.

I created a new PR for that #7958 but sadly there is not enough data in the cachedb to get the parameters for the readartifact call. Therefore we have to stick with this approach, if we do not want to change the database entries.

[juliusvonkohout]

/assign @Linchin @zijianjoy

[google-oss-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
To complete the pull request process, please ask for approval from zijianjoy after the PR has been reviewed.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• backend/OWNERS
• manifests/kustomize/OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[juliusvonkohout]

Sadly we have to be agnostic of the backend until the new unified storage architecture from #7725 (comment) is there. So i got #8270 in instead. V2 pipelines are not yet covered.