Allow to add single file to a container (with setting rights)

[tomikmar]

Environment:

• Jib version: 2.4.0
• Build tool: maven:3.6.3-amazoncorretto-11
• OS: Amazon Linux 2

Description of the issue:

It would be useful if it was possible to add single file to a container (with setting rights). I am currently migrating from one system to the other and for some time I need to keep things compatible between both of them. Currently it is not possible (without workaround) to move the following Dockerfile command to jib-maven-plugin (it's possible only for directories):

COPY ./ssh/id_rsa /home/myuser/.ssh/id_rsa

Steps to reproduce:

<extraDirectories>
    <paths>
        <path>
            <from>./ssh/id_rsa</from>
            <into>/home/myuser/.ssh/id_rsa</into>
         </path>
    </paths>
</extraDirectories>

Failed to execute goal com.google.cloud.tools:jib-maven-plugin:2.4.0:build (default-cli) on project config: /home/builder/src/config/ssh/id_rsa is not a directory -> [Help 1]

[loosebazooka]

Yeah it's a limitation of our system, it only works for directories. You probably need to make sure the ssh directory only has the id_rsa file, and copy that directory over.

<from>./ssh</from>
<into>/home/myuser/.ssh</into>

[chanseokoh]

Copying the following comment from #3164, as this issue was opened far earlier and has many thumbs-ups.

---

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]

@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.