If you haven’t set up your developer environment, please do so before continuing with this section.
Join the Developers community channel to ask questions from community members and the Mattermost core team.
Here’s a general workflow for a Mattermost developer working on the mattermost repository:
Review the repository structure to familiarize yourself with the project:
On your fork, create a feature branch for your changes. Name it
$NUMBER is the Jira ticket number you are working on and
$DESCRIPTION is a short description of your changes. Example branch names are
Make the code changes required to complete your ticket.
Ensure that unit tests are written or modified where appropriate. For the server repository in general, Mattermost follows the opinionated way of testing in Go. You can learn more about this process in DigitalOcean's How To Write Unit Tests in Go tutorial. Test files must always end with
_test.go, and should be located in the same folder where the code they are checking lives. For example, check out download.go and download_test.go, which are both located in the
app folder. Please also use testify for new tests.
If you made changes to the store, run
make store-mocks and
make store-layers to update test mocks and timing layer.
To test your changes, run
make run-server from the root directory of the server repository. This will start up the server at
http://localhost:8065. To get changes to the server it must be restarted with
make restart-server. If you want to test with the web app, you may also run
make run which will start the server and a watcher for changes to the web app.
Once everything works to meet the ticket requirements, stop Mattermost by running
make stop in the server repository, then run
make check-style to check your syntax.
Run the tests using one or more of the following options:
make testto run all the tests in the project. This may take a long time and provides very little feedback while it’s running.
go test -run "TestName" ./<directory>.
go test app.
Running every single unit test takes a lot of time while making changes, so you can run a subset of the server-side unit tests by using the following:
go test -v -run='<test name or regex>' ./<package containing test>
For example, if you want to run
app/post_test.go, you would execute the following:
go test -v -run='TestUpdatePost' ./app
If you added or changed any localization strings you will need to run
make i18n-extract to generate the new/updated strings.
make commands include:
make runruns the server, creates a symlink for your mattermost-webapp folder, and starts a watcher for the web app.
make stopstops the server and the web app watcher.
make run-serverruns only the server and not the client.
make debug-serverwill run the server in the
make stop-serverstops only the server.
make update-dockerstops and updates your Docker images. This is needed if any changes are made to
make clean-dockerstops and removes your Docker images and is a good way to wipe your database.
make cleancleans your local environment of temporary files.
make config-resetresets the
config/config.jsonfile to the default.
make nukewipes your local environment back to a completely fresh start.
make packagecreates packages for distributing your builds and puts them in the
./distdirectory. You will first need to run
If you would like to run the development environment without Docker you can set the
MM_NO_DOCKER environment variable. If you do this, you will need to set up your own database and any of the other services needed to run Mattermost.
During development you may want to reset the database and generate random data for testing your changes. For this purpose, Mattermost has the following commands in the Mattermost CLI:
First, install the server with
go install ./cmd/mattermost in the server repository.
You can reset your database to the initial state using:
mattermost db reset
The following commands need to be run via the mmctl tool.
You can generate random data to populate the Mattermost database using:
Create an account using the following command:
mmctl user create --email email@example.com --username test1 --password mypassword
Optionally, you can assign that account System Admin rights with the following command:
mmctl user create --email firstname.lastname@example.org --username test1 --password mypassword --system_admin
You can customize variables of the Makefile by creating a
config.override.mk file or setting environment variables. To get started, you can copy the
config.mk file to
config.override.mk and change the values in your newly copied file.
If you create a
docker-compose.override.yaml file at the root of the project, it will be automatically loaded by all the
Makefile tasks using
docker-compose, allowing you to define your own services or change the configuration of the ones Mattermost provides.