The Shell executor
The Shell executor is a simple executor that you use to execute builds locally on the machine where GitLab Runner is installed. It supports all systems on which the Runner can be installed. That means that it’s possible to use scripts generated for Bash, PowerShell Core, Windows PowerShell, and Windows Batch (deprecated).
NOTE:
Always use the latest version of Git available. Additionally, GitLab Runner will use
the git lfs
command if Git LFS is installed on the machine,
so ensure Git LFS is up-to-date when GitLab Runner will run using the shell executor.
Overview
The scripts can be run as unprivileged user if the --user
is added to the
gitlab-runner run
command. This feature is only supported by Bash.
The source project is checked out to:
<working-directory>/builds/<short-token>/<concurrent-id>/<namespace>/<project-name>
.
The caches for project are stored in
<working-directory>/cache/<namespace>/<project-name>
.
Where:
<working-directory>
is the value of--working-directory
as passed to thegitlab-runner run
command or the current directory where the Runner is running<short-token>
is a shortened version of the Runner’s token (first 8 letters)<concurrent-id>
is a unique number, identifying the local job ID on the particular Runner in context of the project<namespace>
is the namespace where the project is stored on GitLab<project-name>
is the name of the project as it is stored on GitLab
To overwrite the <working-directory>/builds
and <working-directory/cache
specify the builds_dir
and cache_dir
options under the [[runners]]
section
in config.toml
.
Running as unprivileged user
If GitLab Runner is installed on Linux from the official .deb
or .rpm
packages, the installer will try to use the gitlab_ci_multi_runner
user if found. If it is not found, it will create a gitlab-runner
user and use
this instead.
All shell builds will be then executed as either the gitlab-runner
or
gitlab_ci_multi_runner
user.
In some testing scenarios, your builds may need to access some privileged
resources, like Docker Engine or VirtualBox. In that case you need to add the
gitlab-runner
user to the respective group:
usermod -aG docker gitlab-runner
usermod -aG vboxusers gitlab-runner
Selecting your shell
GitLab Runner supports certain shells. To select a shell, specify it in your config.toml
file. For example:
...
[[runners]]
name = "shell executor runner"
executor = "shell"
shell = "powershell"
...
Security
Generally it’s unsafe to run tests with shell executors. The jobs are run with
the user’s permissions (gitlab-runner
) and can “steal” code from other
projects that are run on this server. Use it only for running builds on a
server you trust and own.
Terminating and killing processes
The shell executor starts the script for each job in a new process. On UNIX systems, it sets the main process as a process group.
GitLab Runner terminates processes when:
- A job times out.
- A job is canceled.
GitLab 13.0 and earlier
On UNIX systems gitlab-runner
sends a SIGKILL
to the process to
terminate it, because the child processes belong to the same process
group the signal is also sent to them. Windows sends a taskkill /F /T
.
GitLab 13.1 and later
On UNIX system gitlab-runner
sends SIGTERM
to the process and its
child processes, and after 10 minutes sends SIGKILL
. This allows for
graceful termination for the process. Windows don’t have a SIGTERM
equivalent, so the kill process is sent twice. The second is sent after
10 minutes.