gitlab-org--gitlab-foss/workhorse/doc/operations/configuration.md

Workhorse configuration

For historical reasons Workhorse uses both command line flags, a configuration file and environment variables.

All new configuration options that get added to Workhorse should go 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/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 events (currently only builds/register for runners). This requires you to pass a valid TOML config file via -config flag. For regular setups 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. This is configured via two things:

• Redis settings in the TOML config file
• The -apiCiLongPollingDuration command line flag to control polling behavior for CI build requests

It is OK to enable Redis in the config file but to leave CI polling disabled; this just results in an idle Redis pubsub connection. The opposite is not possible: CI long polling requires a correct Redis configuration.

Below we discuss the options for the [redis] section in the config file.

[redis]
URL = "unix:///var/run/gitlab/redis.sock"
Password = "my_awesome_password"
Sentinel = [ "tcp://sentinel1:23456", "tcp://sentinel2:23456" ]
SentinelMaster = "mymaster"

• URL takes a string in the format unix://path/to/redis.sock or tcp://host:port.
• Password is only required if your redis instance is password-protected
• Sentinel is used if you are using Sentinel. NOTE that if both Sentinel and URL are given, only Sentinel will be used

Optional fields are as follows:

[redis]
DB = 0
MaxIdle = 1
MaxActive = 1

• DB is the Database to connect to. Defaults to 0
• MaxIdle is how many idle connections can be in the redis-pool at once. Defaults to 1
• MaxActive is how many connections the pool can keep. Defaults to 1

Relative URL support

If you are mounting GitLab at a relative URL, e.g. example.com/gitlab, then you should also 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 a bit confusing. It comes down to: if authSocket is set it overrides the host part 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 functionality to separate staging, production and development.

Omnibus (/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, but different OpenTracing providers can be linked in using build tags/build constraints. This can be done by setting the BUILD_TAGS make variable.

For more details of the supported providers, see LabKit, but as an example, for Jaeger tracing support, include the tags: BUILD_TAGS="tracer_static tracer_static_jaeger".

make BUILD_TAGS="tracer_static tracer_static_jaeger"

Once Workhorse is compiled with an opentracing provider, the tracing configuration is configured via the GITLAB_TRACING environment variable.

For example:

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=""

Once Workhorse is compiled with Continuous Profiling, the profiler configuration can be set via GITLAB_CONTINUOUS_PROFILING environment variable.

For example:

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

More information about see the LabKit monitoring docs.