S3 cache is not properly cleaned up within the configured time frame

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 7.0.X, 7.1.X, 7.2.X, Master
• Fix Version/s: 7.0.0 DXP FP86, 7.0.X, 7.1.10 DXP FP14, 7.1.X, 7.2.10 DXP FP1, 7.2.X, 7.2.1 CE GA2, Master
• Component/s: External Document Repositories
• Labels:
  • ee-ts
  • liferay-fixpack-de-86-7010
  • liferay-fixpack-dxp-1-7210
  • liferay-fixpack-dxp-14-7110
• Branch Version/s:
  7.2.x, 7.1.x, 7.0.x
• Backported to Branch:
  Committed
• Story Points: 1
• Fix Priority: 2
• Sprint: 031 - Nidoqueen
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/76606

Background
When using S3, uploaded documents and generated previews are stored as cache in <tomcat_home>/temp/liferay/s3 directory.

• generated previews are stored in a sub-folder:
  • master/72x: adaptive/
  • 71x: document_thumbnail/

Cache files are cleaned, based on the "Cache Directory Clean Up Expunge" and "Cache Directory Clean Up Frequency" configuration options, in System Settings.

See this KB for more details:
https://help.liferay.com/hc/ja/articles/360017899351-Optimizing-S3Store-Cache-Settings

Issue
Cache files that are expected to be expired, are not getting removed.

Steps to Reproduce

1. Start Liferay
2. Configure Liferay to use S3 Store
   • Reference: Liferay Help Center - Using Amazon Simple Storage Service
3. Configure S3 Store Cache properties in System Settings:
   • Cache Directory Clean Up Expunge = 1
   • Cache Directory Clean Up Frequency = 1 
   • Reference: Liferay Help Center - Optimizing S3Store Cache Settings
4. Note that <tomcat_home>/temp/liferay/s3 does not exist
5. Go to Documents and Media 
   1. Upload a new image
   2. Click Save
6. Refresh Documents and Media page
7. Notice that the following folders and files are created, based on the current date (e.g. 07-17-2019)
   1. Cache File:
      • <tomcat_home>/temp/liferay/s3/2019/07/17/07/1021563349685000
   2. Thumbnail Folder:
      • <tomcat_home>/temp/liferay/s3/2019/07/17/07/adaptive/Preview-1000x0/
   3. Thumbnail File:
      • <tomcat_home>/temp/liferay/s3/2019/07/17/07/adaptive/Preview-1000x0/20142/206/30926/30927.png1563349712000
8. Logout
9. Change the OS date to fast-forward time to 2 days ahead (e.g. 7/17 to 7/19)
10. Log back in
11. Go to Documents and Media page again
12. Notice the following observations:
    1. A New thumbnail cache file is created for the different "day" and with the same name:
       • Thumbnail File:
         <tomcat_home>/temp/liferay/s3/2019/07/19/07/adaptive/Preview-1000x0/20142/206/30926/30927.png1563349712000
    2. The Old thumbnail cache folder/file(s) from the previous day has been removed:
       • Thumbnail Folder:
         • <tomcat_home>/temp/liferay/s3/2019/07/17/07/adaptive/Preview-1000x0/
       • Thumbnail File:
         • <tomcat_home>/temp/liferay/s3/2019/07/17/07/adaptive/Preview-1000x0/20142/206/30926/30927.png1563349712000
    3. The Old Cache File has not been removed:
       • Cache File:
         • <tomcat_home>/temp/liferay/s3/2019/07/17/07/1021563349685000

Actual behavior
The Original Cache File is not removed (only the Original Thumbnail Folder/File(s) have been removed)

Expected behavior
Both the Old Cache File and Old Thumbnail Folder/File(s) are removed