Environment variables¶
Applications built on craft-application have several environment variables that can configure their behaviour. They and the behaviour they modify are listed below.
Variables passed to managed builders¶
Several environment variables from the host environment are passed to the
managed build environment. While an application may adjust these by adjusting
the environment dictionary attached to the ProviderService,
craft-application will by default forward the http_proxy, https_proxy
and no_proxy environment variables from the host.
Supported variables¶
These variables are explicitly supported for user configuration.
CRAFT_BUILD_ENVIRONMENT¶
If the value is host, allows an environment to tell a craft application
to run directly on the host rather than in managed mode. This method is
roughly equivalent to using --destructive-mode, but is designed for
configurations where the application is already being run in an appropriate
container or VM, such as
Snapcraft rocks or
when controlled by a CI system such as Launchpad.
CAUTION: Setting the build environment is only recommended if you are aware of the exact packages needed to reproduce the build containers created by the app.
CRAFT_BUILD_FOR¶
Sets the default architecture to build for. Overridden by --build-for in
lifecycle commands.
CRAFT_PLATFORM¶
Sets the default platform to build. Overridden by --platform in lifecycle
commands.
CRAFT_SNAP_CHANNEL¶
Overrides the default channel that a craft application’s snap is installed from
if the manager instance is not running as a snap. If unset, the application
will be installed from the latest/stable channel. If the application is
running from a snap, this variable is ignored and the same snap used on
the host system is injected into the managed builder.
CRAFT_VERBOSITY_LEVEL¶
Set the verbosity level for the application. Valid values are: quiet,
brief, verbose, debug and trace. This is overridden by the
--quiet, --verbose or --verbosity={value} global command options.
Development variables¶
The following variables exist to help developers writing applications using craft-application more easily debug their code:
CRAFT_DEBUG¶
Controls whether the application is in debug mode. If this variable is set to
1, general exceptions will not be caught, instead showing a traceback on
the command line. This is normally only useful for developers working on
craft-application or an app that uses the framework, as a traceback is always
written to the log file as well.
CRAFT_LAUNCHPAD_INSTANCE¶
For remote builds, allows the user to set an alternative launchpad instance.
Accepts any string that can be used as the service_root value in
Launchpadlib.
Unsupported variables¶
The following variables cause behaviour changes in craft-application, but should not be set except by craft-application itself.
CRAFT_LXD_REMOTE¶
If using LXD, the application will start containers in the configured remote
rather than local.
CAUTION: Using non-default remotes is experimental and not recommended at this time.
CRAFT_MANAGED_MODE¶
Alerts the application that it is running in managed mode. This should only be set by craft-application when creating a provider. Systems designed to wrap craft applications may use the CRAFT_BUILD_ENVIRONMENT environment variable to make the app run on the host.