The modification time of the cache archive uploaded to S3 is incorrect.

Summary

The modification time of the cache archive uploaded to S3 is incorrect.

Steps to reproduce

1. Deploy a GitLab runner with S3 cache and clear all cache (runner and S3)
2. Trigger a job with cache
3. Trigger the job again

# .gitlab-ci.yml
test:
  cache:
    key: test
    paths:
      - cache
  script:
    - mkdir -p cache
    - head -c 1M </dev/urandom > cache/random.bin

Actual behavior

The modification time of the cache archive uploaded to S3 is incorrect.

It may be a time zone issue.

After the first trigger:

• Modification time of local cache archive: 2024-12-25 22:52:32 +0800 (correct)
• Modification time of S3 cache archive: 2024-12-25 22:52:32 +0000 (incorrect)

After the second trigger:

• Modification time of local cache archive: 2024-12-26 06:52:32 +0800 (incorrect)
• Modification time of S3 cache archive: 2024-12-25 22:52:32 +0000 (incorrect)

Due to incorrect modification time, the cache was not updated properly in the second job.

Expected behavior

After the first trigger:

• Modification time of local cache archive: 2024-12-25 22:52:32 +0800 (correct)
• Modification time of S3 cache archive: 2024-12-25 14:52:32 +0000 (correct)

After the second trigger:

• Modification time of local cache archive: 2024-12-25 22:53:45 +0800 (updated)
• Modification time of S3 cache archive: 2024-12-25 14:53:45 +0000 (updated)

Relevant logs and/or screenshots

Environment description

[[runners]]
  name = ""
  url = ""
  token = ""
  executor = "shell"
  [runners.cache]
    Type = "s3"
    [runners.cache.s3]
      ServerAddress = ""
      AccessKey = ""
      SecretKey = ""
      BucketName = ""

Used GitLab Runner version

• v16.11.4
• v15.11.1

Possible fixes