Enhancement: Have an <extraFiles> option to add individual files instead of a whole directory

[MiellyEllen]

Environment:

• *Jib version:*2.8.0
• Build tool: mvn
• OS: Windows

Description of the issue:
If this does not exist already, could there be an enhancement to add individual files into an image layer, rather than selecting all the files in a directory.

Expected behavior:

<extraFiles>
   <extraFile><from>../folder1/context1.xml</from><to>/app/contexts</to></extrafile>
<extraFiles>

Additional Information: If this is not available, is there an expected version where this might be added?

[chanseokoh]

Thanks for the feedback! Yeah, unfortunately <extraDirectories> requires preparing a directory. If you can just put the file at src/main/jib/app/contexts/context1.xml, the file will be copied into the image (as /src/main/jib is the default extra directory).

If you can't put it in src/main/jib (e.g., you don't want to duplicate the file, or you only want to filter out a single file in a directory), it's still easy to prepare a directory in Maven. Here's an example using maven-resources-plugin, which prepares the directory target/jib-extras to be used for <extraDirectories>:

      <plugin>
        <artifactId>maven-resources-plugin</artifactId>
        <version>3.2.0</version>
        <executions>
          <execution>
            <id>copy-extras</id>
            <phase>process-resources</phase>
            <goals>
              <goal>copy-resources</goal>
            </goals>
            <configuration>
              <outputDirectory>target/jib-extras</outputDirectory>
              <resources>
                <resource>
                  <directory>target/some-files</directory>
                  <includes>**/*.txt,**/*.rtf</includes>
                </resource>
              </resources>
            </configuration>
          </execution>
        </executions>
      </plugin>

Then for the Jib configuration,

          <extraDirectories>
            <paths>
              <path>
                <from>target/jib-extras</from>
                <into>/dest-dir</into>
              </path>
            </paths>
          </extraDirectories>

I'm not saying that adding the <extraFiles> feature doesn't provide a value; I think it's useful in many situations. It's just that it will be a low priority for us, and there's a workaround.

But probably, instead of adding the new config <extraFiles>, what we could do is to add a filtering mechanism similar to maven-resources-plugin. For example,

          <extraDirectories>
            <paths>
              <path>
                <from>../folder1/</from>
                <into>/app/contexts</into>
                <includes>context1.xml</includes>
              </path>
            </paths>
          </extraDirectories>

That way, we can have the same effect of copying a single file without adding <extraFiles>. What's even better is that it's more general and flexible and enables copying multiple files.

[chanseokoh]

Actually, we have an open issue. Closing this as a dup of #2564. Please follow #2564.

[MiellyEllen]

Thanks so much for the very helpful feedback as well as the priority insight.
Cheers!

[chanseokoh]

@tomikmar @labmonkey @andritch @daanschipper @cpvandehey @Nemesys @MiellyEllen

We released Jib plugins 3.0 that implemented a inclusion/exclusion feature to <extraDirectories>, which not only makes it super easy to add a single file but is very flexible in copying a subset of files. Check out the docs (Gradle / Maven) for example usage.