Workhorse configuration

For historical reasons, Workhorse uses:

  • Command line flags.
  • A configuration file.
  • Environment variables.

Add any new Workhorse configuration options into the configuration file.

CLI options 

  gitlab-workhorse [OPTIONS]

Options:
  -apiCiLongPollingDuration duration
      Long polling duration for job requesting for runners (default 50ns)
  -apiLimit uint
      Number of API requests allowed at single time
  -apiQueueDuration duration
      Maximum queueing duration of requests (default 30s)
  -apiQueueLimit uint
      Number of API requests allowed to be queued
  -authBackend string
      Authentication/authorization backend (default "http://localhost:8080")
  -authSocket string
      Optional: Unix domain socket to dial authBackend at
  -cableBackend string
      Optional: ActionCable backend (default authBackend)
  -cableSocket string
      Optional: Unix domain socket to dial cableBackend at (default authSocket)
  -config string
      TOML file to load config from
  -developmentMode
      Allow the assets to be served from Rails app
  -documentRoot string
      Path to static files content (default "public")
  -listenAddr string
      Listen address for HTTP server (default "localhost:8181")
  -listenNetwork string
      Listen 'network' (tcp, tcp4, tcp6, unix) (default "tcp")
  -listenUmask int
      Umask for Unix socket
  -logFile string
      Log file location
  -logFormat string
      Log format to use defaults to text (text, json, structured, none) (default "text")
  -pprofListenAddr string
      pprof listening address, e.g. 'localhost:6060'
  -prometheusListenAddr string
      Prometheus listening address, e.g. 'localhost:9229'
  -proxyHeadersTimeout duration
      How long to wait for response headers when proxying the request (default 5m0s)
  -secretPath string
      File with secret key to authenticate with authBackend (default "./.gitlab_workhorse_secret")
  -version
      Print version and exit

The ‘auth backend’ refers to the GitLab Rails application. The name is a holdover from when GitLab Workhorse only handled git push and git pull over HTTP.

GitLab Workhorse can listen on either a TCP or a Unix domain socket. It can also open a second listening TCP listening socket with the Go net/http/pprof profiler server.

GitLab Workhorse can listen on Redis build and runner registration events if you pass a valid TOML configuration file through the -config flag. A regular setup it only requires the following (replacing the string with the actual socket)

Redis

GitLab Workhorse integrates with Redis to do long polling for CI build requests. To configure it:

  • Configure Redis settings in the TOML configuration file.
  • Control polling behavior for CI build requests with the -apiCiLongPollingDuration command-line flag.

You can enable Redis in the configuration file while leaving CI polling disabled. This configuration results in an idle Redis Pub/Sub connection. The opposite is not possible: CI long polling requires a correct Redis configuration.

For example, the [redis] section in the configuration file could contain: 

[redis]
URL = "unix:///var/run/gitlab/redis.sock"
Password = "my_awesome_password"
Sentinel = [ "tcp://sentinel1:23456", "tcp://sentinel2:23456" ]
SentinelMaster = "mymaster"
  • URL - A string in the format unix://path/to/redis.sock or tcp://host:port.
  • Password - Required only if your Redis instance is password-protected.
  • Sentinel - Required if you use Sentinel.

If both Sentinel and URL are given, only Sentinel is used.

Optional fields: 

[redis]
DB = 0
MaxIdle = 1
MaxActive = 1
  • DB - The database to connect to. Defaults to 0.
  • MaxIdle - How many idle connections can be in the Redis pool at once. Defaults to 1.
  • MaxActive - How many connections the pool can keep. Defaults to 1.

Relative URL support

If you mount GitLab at a relative URL, like example.com/gitlab), use this relative URL in the authBackend setting: 

gitlab-workhorse -authBackend http://localhost:8080/gitlab

Interaction of authBackend and authSocket

The interaction between authBackend and authSocket can be confusing. If authSocket is set, it overrides the host portion of authBackend, but not the relative path.

In table form:

authBackend authSocket Workhorse connects to Rails relative URL
unset unset localhost:8080 /
http://localhost:3000 unset localhost:3000 /
http://localhost:3000/gitlab unset localhost:3000 /gitlab
unset /path/to/socket /path/to/socket /
http://localhost:3000 /path/to/socket /path/to/socket /
http://localhost:3000/gitlab /path/to/socket /path/to/socket /gitlab

The same applies to cableBackend and cableSocket.

Error tracking

GitLab-Workhorse supports remote error tracking with Sentry. To enable this feature, set the GITLAB_WORKHORSE_SENTRY_DSN environment variable. You can also set the GITLAB_WORKHORSE_SENTRY_ENVIRONMENT environment variable to use the Sentry environment feature to separate staging, production and development.

Omnibus GitLab (/etc/gitlab/gitlab.rb): 

gitlab_workhorse['env'] = {
    'GITLAB_WORKHORSE_SENTRY_DSN' => 'https://foobar'
    'GITLAB_WORKHORSE_SENTRY_ENVIRONMENT' => 'production'
}

Source installations (/etc/default/gitlab): 

export GITLAB_WORKHORSE_SENTRY_DSN='https://foobar'
export GITLAB_WORKHORSE_SENTRY_ENVIRONMENT='production'

Distributed tracing

Workhorse supports distributed tracing through LabKit using OpenTracing APIs.

By default, no tracing implementation is linked into the binary. You can link in different OpenTracing providers with build tags or build constraints by setting the BUILD_TAGS make variable.

For more details of the supported providers, refer to LabKit. For an example of Jaeger tracing support, include the tags: BUILD_TAGS="tracer_static tracer_static_jaeger" like this: 

make BUILD_TAGS="tracer_static tracer_static_jaeger"

After you compile Workhorse with an OpenTracing provider, configure the tracing configuration with the GITLAB_TRACING environment variable, like this: 

GITLAB_TRACING=opentracing://jaeger ./gitlab-workhorse

Continuous profiling

Workhorse supports continuous profiling through LabKit using Stackdriver Profiler. By default, the Stackdriver Profiler implementation is linked in the binary using build tags, though it’s not required and can be skipped. For example: 

make BUILD_TAGS=""

After you compile Workhorse with continuous profiling, set the profiler configuration with the GITLAB_CONTINUOUS_PROFILING environment variable. For example: 

GITLAB_CONTINUOUS_PROFILING="stackdriver?service=workhorse&service_version=1.0.1&project_id=test-123 ./gitlab-workhorse"