Customizations to the Mattermost Web App can be performed in cases where you need to customize branding, alter localization strings, or fulfill security requirements that are not immediately offered out-of-the-box.
With that in mind, customizing and deploying your Mattermost Web App can be done in a few steps:
Fork the mattermost repository and then clone your fork in your local environment.
git clone https://github.com/<yourgithubusername>/mattermost
Create a separate branch for your customized version, as it’s not recommended to perform them in the master branch (more details about that in the next section regarding rebasing).
git checkout -b custom_branch
Perform customization tasks by replacing image assets, changing strings, altering the UI, and whatever else may be necessary. Be mindful not to violate any of the guidelines on trademark use during this process.
Once customization has been completed, build the files that will be used in your deployment and generate mattermost-webapp.tar.gz containing them.
make dist
In a Mattermost deployment, rename client (assuming Mattermost was deployed in the $HOME directory).
cd ~/mattermost
mv client client-original
Transfer compressed dist files inside Mattermost’s client directory, and decompress it.
tar -xvf mattermost-webapp.tar.gz
Copy the products subdirectory from the original deployment into the customized one.
cp -R client-original/products client/products
Challenges arise when creating a separate custom branch from an active open-source project like mattermost. As the project gets new commits and pull requests on a daily basis, your custom webapp can quickly become outdated.
To deal with that, you’ll need to leverage Git’s interactive rebasing functionality in the following way:
Add an upstream with the original mattermost repository.
git remote add upstream https://github.com/mattermost/mattermost.git
Update master branch to latest upstream commit.
git checkout master
git pull upstream master
Perform interactive rebase.
git checkout custom_branch
git rebase -i master
Use git rebase --continue after resolving any conflicts that arise during rebase process
Push new version back to remote (Note: Rebasing requires that you override previous remote version with a force push. Be sure you’ve tested that your rebase was successful before completing this last command).
git push -f origin custom_branch