Gitlab-runner maven build fails with Permission denied message BUT succeeds with debug option on

When using GitLab Runner to build a Maven project, you may encounter an issue where the build fails with a "Permission denied" message. However, the build succeeds when you use the debug option. This article will explain why this issue occurs and how to resolve it.

Understanding the Issue

The "Permission denied" error typically occurs when the GitLab Runner does not have the necessary permissions to access certain files or directories required for the Maven build process. This can happen due to various reasons, such as incorrect file permissions or ownership.

When you enable the debug option, GitLab Runner provides more detailed information about the build process. This additional information can help identify the specific file or directory causing the permission issue.

Resolving the Issue

To resolve the "Permission denied" issue, follow these steps:

Step 1: Identify the Problematic File or Directory

First, you need to identify the file or directory causing the permission issue. To do this, enable the debug option in the GitLab Runner configuration file. Open the file /etc/gitlab-runner/config.toml using a text editor.

Look for the section that starts with [[runners]] and locate the line that says debug = false. Change it to debug = true and save the file.

Step 2: Run the Build with Debug Option

Now, run the Maven build command again using the GitLab Runner. This time, the build process will provide more detailed information about each step.

Look for the specific error message that indicates a "Permission denied" issue. Note down the file or directory mentioned in the error message.

Step 3: Check File Permissions

Once you have identified the problematic file or directory, you need to check its permissions. Open a terminal and navigate to the location of the file or directory.

Use the ls -l command to view the permissions of the file or directory. The output will display something like this:

drwxr-xr-x  2 user group 4096 Sep  1 10:00 my-directory
-rw-r--r--  1 user group 1024 Sep  1 10:00 my-file.txt

The permissions are displayed in the first column. The letters r, w, and x represent read, write, and execute permissions, respectively. The first character indicates the file type (e.g., d for directory, - for regular file).

If the permissions are not set correctly, you can use the chmod command to modify them. For example, to grant read, write, and execute permissions to the owner, and read and execute permissions to the group and others, you can use the following command:

chmod 755 my-directory
chmod 644 my-file.txt

Make sure to replace my-directory and my-file.txt with the actual names of your file or directory.

Step 4: Retry the Build

After adjusting the file permissions, retry the Maven build using the GitLab Runner. This time, the build should succeed without any "Permission denied" errors.

When encountering a "Permission denied" error during a GitLab Runner Maven build, enabling the debug option can help identify the problematic file or directory causing the issue. By checking and adjusting the file permissions, you can resolve this error and successfully build your Maven project.

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