[HADOOP-7368] Mechanism for providing version info of hadoop jars

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 0.23.0
• Component/s: build
• Tags: jar version providers
• Assignee: Luke Lu
• Reporter: Luke Lu
• Created: 08/Jun/11 21:22
• Updated: 22/Sep/12 09:50

Description

In 0.20.x, only one jar (hadoop-core-*.jar) really matters. The o.a.h.util.VersionInfo combined with saveVersion.sh script (generating a package level annotation) served us well. For 0.23+, due to the project split and modularization of mapreduce (currently in MR-279), a lot more essential hadoop jars are created. The potential of mixing up the jars is significantly increased as well. We need a simple way to list the version info (version, branch, source checksum etc.) for all the jars involved. This is essential for QE and tracking down various issues.

I propose that we use a VersionProvider interface (similar to the current VersionInfo util class) and ServiceLoader to enumerate the version providers in the jars.

public interface VersionProvider {
  String getJar(); 
  String getPackage();
  String getVersion();
  String getRevision();
  String getBranch();
  String getDate();
  String getUrl();
  String getSourceChecksum();
}