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.. _snap:
Firefox Snap Packaging
This page explains interactions between Firefox and Snap packaging format.
Where is the upstream
The code reference itself is mozilla-central, but the packaging is being worked
within the `Canonical's firefox-snap repository <>`_.
This packaging includes a few more bits and dependencies, including compiler.
It will also re-download the mercurial repository: this is on purpose.
Where to report bugs
All bugs should be reported to Bugzilla's ``Third Party Packaging`` component,
and marked as blocking ``snap`` meta-bug.
Build process
While there is an existing ``repackage`` `task
is currently is no up-to-date and it is not usable from ``mach`` (work is being
so unfortunately the only way to work right now is a full rebuild using
upstream tooling.
The following steps should be enough, assuming you have properly setup:
- ``snapcraft`` (see `quickstart doc <>`_)
- ``LXD`` (see `providers doc <>`_)
While the documentation still refers to `Multipass`, the Firefox Snap and its
dependency had some requirements that made it better suited to use `LXD`.
When performing the checkout, please keep in mind the branch mapping:
- `edge` is our `nightly`
- `beta` is our `beta`
- `stable` is our `release`
- `esr` is our `esr`
.. code-block:: shell
$ git clone --branch BRANCH
$ snap run snapcraft
You should end up after some time with two files: ``firefox-XXX.snap`` and
``firefox-XXX.debug``. The first one is the package you will want to ``snap
install`` while the second one holds your debugging symbols.
You can then install the package:
.. code-block:: shell
$ sudo snap install --name firefox --dangerous ./path/to/firefox-XXX.snap
If you want to have parallel installs, then you can change the `--name firefox`
to something else. This will be the name you use for ``snap run
installed-name``, e.g., ``--name firefox_nightly`` will require you to run
``snap run firefox_nightly``.
`Snap` has a notion of plugs and slots, and some gets automatically connected
in various ways, including depending on the ``Snap Sore`` itself, and if you
manually install as ``firefox`` it should reuse them (but you might do bad
things with your profile). If you install using another name, then the ``Snap
Store`` automatic connection will not happen and this can result in a broken
state. Inspecting ``snap connections firefox`` using a store-installed snap
should get your an accurate list that you can replicate.
What CI coverage
Currently, there are upstream-like builds on treeherder. They are scheduled as
a cron task daily and includes:
- building opt/debug versions of the snap
- building them on all branches
- running a few selenium-based tests
It should be noted that for the moment, all tasks needs to run under docker.
However, this setup is not working for `Snap` since it interacts with `SystemD`
which does not work under `Docker`. This is why the installation is handled by
`the install-snap script
rather than plain `sudo snap install`, and also why we need to run `snap` in
`destructive mode` (which is fine since we are within a docker container). This
does not apply to the tests case which relies on newly-available wayland
virtual machines.
Outside the build oddities because of the setup, it should be noted that those
builds are as close as possible to upstream. This means:
- the mozilla-central hash they run against is not matching the source code it
builds from, and one should inspect the build log to see the mercurial clone
- it builds using the clang build within the snap definition
The tests are defined `within the docker subdirectory
They are using Selenium because this is what was used by pre-existing tests ran
on GitHub Actions from upstream.
Their coverage is ensuring that we get a basic working browser out of builds.
It includes some tests that previously were manually ran by QA.
How to hack on try
Build and test tasks can be explored via ``mach try fuzzy --full`` by searching
for ``'snap 'upstream``. There is a bit of hacking for try to make sure we
actually don't re-download the mercurial repo and directly reuse the clone
generated by `run-task`, handled in the ` script
So pushing to try is basically just:
.. code-block:: shell
$ mach try fuzzy --full -q "'snap 'upstream 'try"
Because of the build process, a full opt build will take around 1h45-2h while a
debug build will be around 60 minutes, the difference coming from the use of
PGO on opt builds.
If you need to reuse a package from the Snap Store or from the latest
mozilla-central or a specific successful build, you can use ``USE_SNAP_FROM_STORE_OR_MC`` en
variable ; setting it to ``store`` will download from the Snap Store (warning:
no debug builds on the Snap Store, so whatever ``debug`` variants we have will
be an ``opt`` build in fact), and setting to a TaskCluster index value will
download from the index. Set it to ``latest`` if you want latest, or explore
the TaskCluster index for others. Any ``try`` will be pulled from latest
``nightly`` while others will be fetched from their respective branches.