snap-helpers

Helpers for interacting with the Snap system within a Snap

These details have not been verified by PyPI

Project links

Project description

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
'testapp'
>>> snap.instance_name
'testapp'
>>> snap.version
'0+git.fdf80cd'
>>> snap.revision
'x1'

paths:

>>> snap.paths.common
PosixPath('/var/snap/testapp/common')
>>> snap.paths.data
PosixPath('/var/snap/testapp/x1')
>>> snap.paths.snap
PosixPath('/snap/testapp/x1')
>>> snap.paths.user_common
PosixPath('/home/ack/snap/testapp/common')
>>> snap.paths.user_data
PosixPath('/home/ack/snap/testapp/x1')

snap-related environment variables:

>>> pprint.pprint(dict(snap.environ))
{'ARCH': 'amd64',
 'COMMON': '/var/snap/testapp/common',
 'CONTEXT': 'ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890',
 'COOKIE': 'ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890',
 'DATA': '/var/snap/testapp/x1',
 'INSTANCE_KEY': '',
 'INSTANCE_NAME': 'testapp',
 'LIBRARY_PATH': '/var/lib/snapd/lib/gl:/var/lib/snapd/lib/gl32:/var/lib/snapd/void',
 'NAME': 'testapp',
 'REEXEC': '',
 'REVISION': 'x1',
 'SNAP': '/snap/testapp/x1',
 'USER_COMMON': '/home/ack/snap/testapp/common',
 'USER_DATA': '/home/ack/snap/testapp/x1',
 'VERSION': '0+git.fdf80cd'}
>>> 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'}}

Hook helpers

The library provides helpers to reduce boilerplate when setting up hooks for the snap.

Hooks can be defined by simply registering functions to be called as hooks via entry_points in the application setup.py:

setup(
    # ...
    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).

Testing with the snap

The snap-helpers snap provides a way to easily test code using the library in a real snap environment with strict confinement.

It provides the python and ipython commands:

$ snap-helpers.python -c 'from pprint import pprint; import snaphelpers; pprint(dict(snaphelpers.SnapEnviron()))'
{'ARCH': 'amd64',
 'COMMON': '/var/snap/snap-helpers/common',
 'CONTEXT': 'ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890',
 'COOKIE': 'ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890',
 'DATA': '/var/snap/snap-helpers/x1',
 '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',
 'REEXEC': '',
 'REVISION': 'x1',
 'SNAP': '/snap/snap-helpers/x1',
 'USER_COMMON': '/home/ack/snap/snap-helpers/common',
 'USER_DATA': '/home/ack/snap/snap-helpers/x1',
 'VERSION': '0+git.26e1e9d'}

The snap can be built and installed as follows:

$ snapcraft
$ sudo snap install --dangerous snap-helpers_*.snap

Installation

snap-helpers can be installed from PyPI.

Run:

$ pip install snap-helpers

Documentation

Full documentation is available on ReadTheDocs.

Project details

These details have not been verified by PyPI

Project links

Release history Release notifications | RSS feed

0.4.2

Aug 6, 2023

0.4.1

Aug 6, 2023

0.4.0

Jul 16, 2023

0.3.2

Jan 14, 2023

0.3.1

Dec 3, 2022

0.3.0

Nov 19, 2022

0.2.0

Nov 20, 2019

0.1.6

Sep 18, 2019

0.1.5

Apr 29, 2019

0.1.4

Apr 29, 2019

0.1.3

Apr 29, 2019

0.1.2

Mar 14, 2019

This version

0.1.1

Mar 12, 2019

0.1.0

Mar 10, 2019

0.0.1

Mar 9, 2019

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