Error message Unknown host gcr.io

Description of the issue: I’m trying to use jib in a maven project. However, during building with jib:dockerBuild, I get the error message Build to Docker daemon failed, perhaps you should make sure that the registry you configured exists/is spelled properly: Unknown host gcr.io. This is usually a sign for a program not using our corporate proxy, but maven is configured to use the proxy and can download the plugin just fine.

Expected behavior: Have the build work when running mvn jib:dockerBuild.

Steps to reproduce: Run mvn jib:dockerBuild. I assume a corporate proxy is involved in the error.

Environment:

• Windows 7
• Maven 3.3.9

jib-maven-plugin Configuration:

            <plugin>
                <groupId>com.google.cloud.tools</groupId>
                <artifactId>jib-maven-plugin</artifactId>
                <version>0.9.2</version>
                <configuration>
                    <to>
                        <image>phycus</image>
                    </to>
                </configuration>
            </plugin>

Log output:

[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building service-haplotype-frequency-curation 0.0.1
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- jib-maven-plugin:0.9.2:dockerBuild (default-cli) @ service-haplotype-frequency-curation ---
[WARNING] Base image 'gcr.io/distroless/java' does not use a specific image digest - build may not be reproducible
[INFO] 
[INFO] Containerizing application to Docker daemon as phycus...
[INFO] 
[INFO] Getting base image gcr.io/distroless/java...
[INFO] Building dependencies layer...
[INFO] Building resources layer...
[INFO] Building classes layer...
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 4.368 s
[INFO] Finished at: 2018-07-10T15:42:26+02:00
[INFO] Final Memory: 21M/264M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal com.google.cloud.tools:jib-maven-plugin:0.9.2:dockerBuild (default-cli) on project service-haplotype-frequency-curation: Build to Docker daemon failed, perhaps you should make sure that the registry you configured exists/is spelled properly: Unknown host gcr.io -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

[chanseokoh]

Not sure, but I guess we can add proxy support? https://maven.apache.org/guides/mini/guide-proxies.html

That is, read the proxy settings Maven is using and set it properly with our connection factory.

[chanseokoh]

@fscheel also, can you try the following properties on mvn execution to see if the workaround works?

https://docs.oracle.com/javase/7/docs/api/java/net/doc-files/net-properties.html

For example, mvn -Dhttps.proxyHost=... -Dhttps.proxyPort-... -Dhttp.proxyHost=... -Dhttp.proxyPort=...

Sometimes it seems possible to use http(s).proxyUser and http(s).proxyPassword if the server requires auth.