Embedding build time into JAR Manifest using Ant

Question

If I want to embed the current time in JAR manifest using ant is there an ant property I can use for "now" and which manifest attribute is the best to put this information?

I currently have the following

  <manifest>
    <attribute name="Signature-Title" value="${project.name}"/>
    <attribute name="Signature-Version" value="${release.version}"/>
    <attribute name="Signature-Vendor" value="XXX"/>
    <attribute name="Built-By" value="${user.name}"/>
  </manifest>

Masinissa

Answer 1

You can use the tstamp task for this.

 <tstamp>
    <format property="TODAY" pattern="yyyy-MM-dd HH:mm:ss" />
  </tstamp>

  <manifest>
    <attribute name="Signature-Title" value="${project.name}"/>
    <attribute name="Signature-Version" value="${release.version}"/>
    <attribute name="Signature-Vendor" value="XXX"/>
    <attribute name="Built-By" value="${user.name}"/>
    <attribute name="Built-Date" value="${TODAY}"/>
  </manifest>

This task set three properties (DSTAMP, TSTAMP, and TODAY) with the current timestamp, each in a different default format (check the link). With the nested format node, you can define a custom format for any of them.

Jessie

It's worth noting that embedding the built time in the MANIFEST will cause the WAR to be rebuilt every time even if nothing at all has changed; not very clean IMO. – Cipolin

Answer 2

Use UTC format only in jaror war META-INF/MANIFEST.MF (don't use localized date/time without TZ because you will lost TimeZone information).

See How to have Maven show local timezone in maven.build.timestamp?

Pardo