A hook is an executable file that runs within a snap’s confined environment when a specific action occurs.
The filename of the executable is based on the name of the hook. If this file exists, snapd will execute the file when required by that hook’s action. See Supported snap hooks for more details on which hooks are supported.
Snapcraft can integrate hooks into a snap using two methods:
snap/hooks
directoryThe hook executable can be placed in a directory called snap/hooks
relative to where the snapcraft
command is executed. This will typically mean creating a hooks directory in the same directory that contains the snapcraft.yaml file for your project. The following, for example, shows the location of a configure hook executable:
.
└── snap
├── hooks
│ └── configure
└── snapcraft.yaml
Hook executables in snap/hooks
are automatically copied into the snap during Snapcraft’s prime
step (see Parts lifecycle for details).
A part within snapcraft.yaml can also generate and install hook executables into $SNAPCRAFT_PART_INSTALL/snap/hooks/
. These are automatically copied into the snap during the prime
step.
configure-hook:
plugin: dump
source: configure-again/
organize:
configure: snap/hooks/configure
By default, hooks run with no plugs. If a hook needs more privileges, it can use the top-level hooks
attribute in snapcraft.yaml
to request plugs:
hooks: # Top-level YAML attribute, parallel to `apps`
configure: # Hook name, corresponds to executable name
plugs: [network] # Or any other plugs required by this hook
Hooks are called with no parameters. See Using the snapctl tool for details on the internal command they can use to provide and retrieve data to and from snapd.
Last updated 1 year, 3 months ago.