Setup quickstart

  1. Install required software: Docker, make, and git.


    Use your package manager.


    Install Docker for Mac.

    Use homebrew to install make and git:

    $ brew install make git


    Install Docker.

    Install make.

    Install git.

  2. Clone the repository so you have a copy on your host machine.

    Instructions for cloning are on the Eliot page in GitHub.

  3. (Optional for Linux users) Set UID and GID for Docker container user.

    If you’re on Linux or you want to set the UID/GID of the app user that runs in the Docker containers, run:

    $ make .env

    Then edit the file and set the APP_UID and APP_GID variables. These will get used when creating the app user in the base image.

    If you ever want different values, change them in .env and re-run make build.

  4. Build Docker images.

    From the root of this repository, run:

    $ make build

    That will build the app Docker image required for development.

Eliot consists of a webapp and a disk cache manager.

To run Eliot, do:

$ make run

The webapp is at http://localhost:8000.

The logs its configuration at startup. You can override any of those configuration settings in your .env file.

Bugs / Issues

All bugs are tracked in Bugzilla.

Write up a new bug:

Please make sure there’s a bug for any work you want to do before you do anything. The conversations in the bug can be enlightening and flesh out issues.

Code workflow


Either find a bug to work on or write up a new one.

Assign the bug to yourself.

Work out any questions about the problem, the approach to fix it, and any additional details by posting comments in the bug comments.


Commits should be self-contained and tests should pass. If there’s outstanding work to do, note that in the commit.

Pull requests

Pull request summary should indicate the bug the pull request addresses. Use a hyphen between “bug” and the bug ID(s). For example:

bug-nnnnnnn: removed frog from tree class

For multiple bugs fixed within a single pull request, list the bugs out individually. For example:

bug-nnnnnnn, bug-nnnnnnn: removed frog from tree class

Pull request descriptions should cover at least some of the following:

  1. what is the issue the pull request is addressing?

  2. why does this pull request fix the issue?

  3. how should a reviewer review the pull request?

  4. what did you do to test the changes?

  5. any steps-to-reproduce for the reviewer to use to test the changes

After creating a pull request, attach the pull request to the relevant bugs.

We use the rob-bugson Firefox addon. If the pull request has “bug-nnnnnnn: …” or “bug-nnnnnnn, bug-nnnnnnn: …” in the summary, then rob-bugson will see that and create a “Attach this PR to bug …” link.

Then ask someone to review the pull request. If you don’t know who to ask, look at other pull requests to see who’s currently reviewing things.

Code reviews

Pull requests should be reviewed before merging.

Style nits should be covered by linting as much as possible.

Code reviews should review the changes in the context of the rest of the system.

Landing code

Once the code has been reviewed and all tasks in CI pass, the pull request author should merge the code.

This makes it easier for the author to coordinate landing the changes with other things that need to happen like landing changes in another repository, data migrations, configuration changes, and so on.

We use “Rebase and merge” in GitHub.


Git conventions

First line is a summary of the commit. It should start with the bug number. Use a hyphen between “bug” and the bug ID(s). For example:

bug-nnnnnnn: summary

For multiple bugs fixed within a single commit, list the bugs out individually. For example:

bug-nnnnnnn, bug-nnnnnnn: summary

After that, the commit should explain why the changes are being made and any notes that future readers should know for context or be aware of.

Python code conventions

All Python code files should have an MPL v2 header at the top:

# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at

We use ruff to reformat Python code.

To lint all the code, do:

$ make lint

To reformat all the code, do:

$ make lintfix

HTML/CSS conventions

2-space indentation.

Javascript code conventions

2-space indentation.

All JavaScript code files should have an MPL v2 header at the top:

 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at

Managing dependencies

Python dependencies are maintained in the file and “compiled” with hashes and dependencies of dependencies in the requirements.txt file.

To add a new dependency, add it to the file and then do:

$ make rebuildreqs

Then rebuild your docker environment:

$ make build

If there are problems, it’ll tell you.

In some cases, you might want to update the primary and all the secondary dependencies. To do this, run:

$ make updatereqs


Configuration is managed using everett.

See Configuration for Eliot configuration.


Metrics are emitted using markus.

Metrics are listed in eliot/ These can then be used anywhere in the codebase.

from eliot.libmarkus import METRICS

and then:

METRICS.histogram("eliot.symbolicate.frames_count", value=len(frames))

See Metrics for list of metrics emitted by Eliot.


Documentation for Eliot is build with Sphinx and is available on ReadTheDocs at

To build the docs, do:

$ make docs

Then view docs/_build/html/index.html in your browser.


Eliot’s tests use the pytest test framework.

To run all the tests, do:

$ make test

Tests for the Symbolication Service webapp go in tests/.

If you need to run specific tests or pass in different arguments, you can use the testshell:

$ make testshell
app@xxx:/app$ pytest

<pytest output>

app@xxx:/app$ pytest tests/

<pytest output>

How to

How to set up a development container for VS Code

The repository contains configuration files to build a development container in the .devcontainer directory. If you have the “Dev Containers” extension installed in VS Code, you should be prompted whether you want to reopen the folder in a container on startup. You can also use the “Dev containers: Reopen in container” command from the command palette. The container has all Python requirements installed. IntelliSense, type checking, code formatting with Ruff and running the tests from the test browser are all set up to work without further configuration.

VS Code should automatically start the container, but it may need to be built on first run:

$ make devcontainerbuild

Additionally on mac there is the potential that running git from inside any container that mounts the current directory to /app, such as the development container, will fail with fatal: detected dubious ownership in repository at ‘/app’. This is likely related to mozilla-services/tecken#2872, and can be treated by running the following command from inside the development container, which will probably throw exceptions on some git read-only objects that are already owned by app:app, so that’s fine:

$ chown -R app:app /app

How to change settings in your local dev environment

Edit the .env file and add/remove/change settings. These environment variables are used by make and automatically included by docker compose.

If you are using a VS Code development container for other repositories such as tecken or socorro, you may need to change the default ports exposed by docker compose to avoid conflicts with similar services, for example:


If you are using a development container for VS Code, you may need to restart the container to pick up changes:

$ make devcontainer