A Python library to interact with snap configuration and properties from inside a snap.
It exposes a top-level snaphelpers.Snap
object which provides access to:
snap details:
>>> snap = snaphelpers.Snap() >>> snap.name 'snap-helpers' >>> snap.instance_name 'snap-helpers' >>> snap.version '0.3.0+git5.5794660' >>> snap.revision '138'
paths:
>>> snap.paths.common PosixPath('/var/snap/snap-helpers/common') >>> snap.paths.data PosixPath('/var/snap/snap-helpers/138') >>> snap.paths.real_home PosixPath('/home/ack') >>> snap.paths.snap PosixPath('/snap/snap-helpers/138') >>> snap.paths.user_common PosixPath('/home/ack/snap/snap-helpers/common') >>> snap.paths.user_data PosixPath('/home/ack/snap/snap-helpers/138')
snap-related environment variables:
>>> pprint.pprint(dict(snap.environ)) {'ARCH': 'amd64', 'COMMON': '/var/snap/snap-helpers/common', 'CONTEXT': 'XbhAD8QBMDwJiEi5LcN-5fCrVeAG7qBGojWiWA0vXkx0hX-JxyqX', 'COOKIE': 'XbhAD8QBMDwJiEi5LcN-5fCrVeAG7qBGojWiWA0vXkx0hX-JxyqX', 'DATA': '/var/snap/snap-helpers/138', 'INSTANCE_KEY': '', 'INSTANCE_NAME': 'snap-helpers', 'LIBRARY_PATH': '/var/lib/snapd/lib/gl:/var/lib/snapd/lib/gl32:/var/lib/snapd/void', 'NAME': 'snap-helpers', 'REAL_HOME': '/home/ack', 'REEXEC': '', 'REVISION': '138', 'SNAP': '/snap/snap-helpers/138', 'USER_COMMON': '/home/ack/snap/snap-helpers/common', 'USER_DATA': '/home/ack/snap/snap-helpers/138', 'VERSION': '0.3.0+git5.5794660'} >>> snap.environ.ARCH 'amd64'
configuration options:
>>> snap.config.set({'foo.bar': 'baz', 'asdf': 3}) # this needs to be run as root >>> options = snap.config.get_options('foo', 'asdf') >>> options['foo'] {'bar': 'baz'} >>> options['foo.bar'] 'baz' >>> options['asdf'] 3 >>> options.as_dict() {'asdf': 3, 'foo': {'bar': 'baz'}}
setting snap health status, along with message and optional status code:
>>> snap.health.okay() >>> snap.health.waiting('foo must happen first', code='wait-foo')
Health status (when different from
okay
) is visible from thesnap
CLI:$ snap info snap-helpers name: snap-helpers summary: Test snap for snap-helpers health: status: waiting message: foo must happen first code: wait-foo checked: today at 16:23 CEST
content of snap metadata files such as:
snap/metadata.yaml
meta/snap.yaml
snap/snapcraft.yaml
These can be accessed as follows:
>>> snap.metadata_files.snap SnapMetadataFile('/snap/snap-helpers/138/meta/snap.yaml') >>> snap.metadata_files.snap.path PosixPath('/snap/snap-helpers/138/meta/snap.yaml') >>> snap.metadata_files.snap["name"] 'snap-helpers' >>> snap.metadata_files.snap["base"] 'core22' >>> pprint.pprint(dict(snap.metadata_files.snap)) {'apps': {'python': {'command': 'bin/python3', 'plugs': ['home', 'network', 'network-bind']}, 'snap-helpers': {'command': 'bin/snap-helpers-shell', 'plugs': ['home', 'network', 'network-bind']}}, 'architectures': ['amd64'], 'base': 'core22', 'confinement': 'strict', 'description': 'Test snap for the snap-helpers Python library.\n' '\n' 'It provides python and ipython shells to interact and test ' 'the `snaphelpers`\n' 'library.\n' '\n' 'See the https://github.com/albertodonato/snap-helpers for ' 'more details.\n', 'environment': {'LD_LIBRARY_PATH': '${SNAP_LIBRARY_PATH}${LD_LIBRARY_PATH:+:$LD_LIBRARY_PATH}:$SNAP/lib', 'PATH': '$SNAP/usr/sbin:$SNAP/usr/bin:$SNAP/sbin:$SNAP/bin:$PATH'}, 'grade': 'stable', 'license': 'LGPL-3.0', 'name': 'snap-helpers', 'slots': {'snap-helpers-lib': {'content': 'snap-helpers-lib', 'interface': 'content', 'read': ['$SNAP/lib/python3.10/site-packages/snaphelpers']}}, 'summary': 'Test snap for the snap-helpers Python library.', 'version': '0.3.0+git5.5794660'}
The library provides helpers to reduce boilerplate when setting up hooks for
the snap, by using entry-points
in the package metadata.
This can be done in setup.py
:
setup(
# ...
entry_points={
"snaphelpers.hooks": [
"configure = testapp:configure_hook",
"install = testapp:install_hook",
]
}
)
or in setup.cfg
:
[options.entry_points]
snaphelpers.hooks =
configure = testapp:configure_hook
install = testapp:install_hook
or in pyproject.toml
:
[project.entry-points."snaphelpers.hooks"]
configure = "testapp:configure_hook"
install = "testapp:install_hook"
Hook functions are called with a Snap
object as argument:
def install_hook(snap: snaphelpers.Snap):
# ...
def configure_hook(snap: snaphelpers.Snap):
# ...
snap-helpers
will take care of the hooks plumbing (i.e. creating hook files
in $SNAP/snap/hooks
).
Currently supported snap bases are:
core20
(Python 3.8)core22
(Python 3.10)
The core18
base (with Python 3.6) is supported until the 0.3.2
release.
The snap-helpers
snap provides a way to easily test code using the library
in a real snap environment with strict confinement.
It provides an IPython shell which automatically imports the snaphelpers
module and provides a Snap
instance for the current snap.
$ snap-helpers Python 3.10.4 (main, Jun 29 2022, 12:14:53) [GCC 11.2.0] Type 'copyright', 'credits' or 'license' for more information IPython 8.7.0 -- An enhanced Interactive Python. Type '?' for help. Use the "snap" variable for an instance for the current snap. In [1]: import pprint In [2]: pprint.pprint(dict(snap.environ)) {'ARCH': 'amd64', 'COMMON': '/var/snap/snap-helpers/common', 'CONTEXT': 'XbhAD8QBMDwJiEi5LcN-5fCrVeAG7qBGojWiWA0vXkx0hX-JxyqX', 'COOKIE': 'XbhAD8QBMDwJiEi5LcN-5fCrVeAG7qBGojWiWA0vXkx0hX-JxyqX', 'DATA': '/var/snap/snap-helpers/138', 'INSTANCE_KEY': '', 'INSTANCE_NAME': 'snap-helpers', 'LIBRARY_PATH': '/var/lib/snapd/lib/gl:/var/lib/snapd/lib/gl32:/var/lib/snapd/void', 'NAME': 'snap-helpers', 'REAL_HOME': '/home/ack', 'REEXEC': '', 'REVISION': '138', 'SNAP': '/snap/snap-helpers/138', 'USER_COMMON': '/home/ack/snap/snap-helpers/common', 'USER_DATA': '/home/ack/snap/snap-helpers/138', 'VERSION': '0.3.0+git5.5794660'}
The snap can be built and installed as follows:
$ snapcraft -v
$ sudo snap install --dangerous snap-helpers_*.snap
snap-helpers
can be installed from PyPI.
Run:
$ pip install snap-helpers
Full documentation is available on ReadTheDocs.