[DNM] refactor backup CR related logic

[dragonly]

What problem does this PR solve?

Found backup CR cleaning related logic confusing.

What is changed and how does it work?

Refactored some function with identical behavior.

Code changes

• Has Go code change
• Has CI related scripts change

Tests

• Unit test

• E2E test

• Manual test

  • test backup using following yaml (dumpling)

    apiVersion: pingcap.com/v1alpha1
    kind: Backup
    metadata:
        name: demo1-backup-s3
        namespace: default
    spec:
        from:
            host: tctest-tidb
            port: 4000
            user: root
            secretName: backup-demo1-tidb-secret
        s3:
            provider: aws
            bucket: test-lyl
            secretName: s3-secret
            region: us-west-2
            cluster: tctest
        storageClassName: standard
        storageSize: 1Gi

    backup succeeded

    NAME              STATUS     BACKUPPATH                                      BACKUPSIZE   COMMITTS             AGE
    demo1-backup-s3   Complete   s3://test-lyl/backup-2021-01-27T10:12:04Z.tgz   255 B        422508579913203714   20s
    

  • test backup using following yaml (br)

    apiVersion: pingcap.com/v1alpha1
    kind: Backup
    metadata:
        name: demo1-backup-s3
        namespace: default
    spec:
        br:
            cluster: tctest
        s3:
            provider: aws
            bucket: test-lyl
            secretName: s3-secret
            region: us-west-2
            cluster: tctest
        storageClassName: standard
        storageSize: 1Gi

    backup succeeded

    NAME              STATUS     BACKUPPATH      BACKUPSIZE   COMMITTS             AGE
    demo1-backup-s3   Complete   s3://test-lyl   16 B         422508672830144513   25s
    

  • test backup using following yaml (dumpling)

    apiVersion: pingcap.com/v1alpha1
    kind: Backup
    metadata:
        name: demo1-backup-s3
        namespace: default
    spec:
        cleanPolicy: Delete
        from:
            host: tctest-tidb
            port: 4000
            user: root
            secretName: backup-demo1-tidb-secret
        s3:
            provider: aws
            bucket: test-lyl
            secretName: s3-secret
            region: us-west-2
            cluster: tctest
        storageClassName: standard
        storageSize: 1Gi

    Backup succeeded. When backup deleted, data on s3 deleted

  • test backup schedule with cleanPolicy Retain (br)

    apiVersion: pingcap.com/v1alpha1
    kind: BackupSchedule
    metadata:
        name: demo1-backup-schedule-s3
        namespace: default
    spec:
        maxBackups: 1
        schedule: "*/1 * * * *"
        backupTemplate:
            br:
                cluster: tctest
            s3:
                provider: aws
                bucket: test-lyl
                secretName: s3-secret
                region: us-west-2
                cluster: tctest

    a new backup will be created every minute, last backup deleted

    NAME                                           STATUS     BACKUPPATH                                                 BACKUPSIZE   COMMITTS             AGE
    demo1-backup-schedule-s3-2021-01-27t10-39-00   Complete   s3://test-lyl/tctest-pd.default-2379-2021-01-27t10-39-00   16 B         422509009514790913   15s
    

• No code

Side effects

• Breaking backward compatibility
• Other side effects:

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation

Release Notes

Please refer to Release Notes Language Style Guide before writing the release note.

None

[codecov-io]

Codecov Report

Merging #3723 (cfb5478) into master (6698595) will increase coverage by 0.02%.
The diff coverage is 90.90%.

@@            Coverage Diff             @@
##           master    #3723      +/-   ##
==========================================
+ Coverage   62.32%   62.35%   +0.02%     
==========================================
  Files         165      165              
  Lines       17799    17805       +6     
==========================================
+ Hits        11093    11102       +9     
+ Misses       5631     5629       -2     
+ Partials     1075     1074       -1     

Flag	Coverage Δ
unittest	62.35% <90.90%> (?)

[DanielZhangQD]

LGTM
Please update the test result to the PR description.

[ti-chi-bot]

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• DanielZhangQD

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[dragonly]

/test pull-e2e-kind