How to Contribute

Step 1: Fork in the Cloud

  1. Visit
  2. Click Fork button (top right) to establish a cloud-based fork.

Step 2: Clone Fork to Local Storage

Define a local working directory:

# Define your working directory

Set user to match your Github profile name:

user={your Github profile name}

Create your clone:

mkdir -p $working_dir
cd $working_dir
git clone$user/nebula.git
# the following is recommended
# or: git clone$user/nebula.git

cd $working_dir/nebula
git remote add upstream
# or: git remote add upstream

# Never push to upstream master since you do not have write access.
git remote set-url --push upstream no_push

# Confirm that your remotes make sense:
# It should look like:
# origin$(user)/nebula.git (fetch)
# origin$(user)/nebula.git (push)
# upstream (fetch)
# upstream  no_push (push)
git remote -v

Define a Pre-Commit Hook

Please link the Nebula Graph pre-commit hook into your .git directory.

This hook checks your commits for formatting, building, doc generation, etc.

cd $working_dir/nebula/.git/hooks
ln -s ../../.linters/cpp/hooks/ .

Sometimes, pre-commit hook can not be executable. In such case, you have to make it executable manually.

cd $working_dir/nebula/.git/hooks
chmod +x pre-commit

Step 3: Branch

Get your local master up to date:

cd $working_dir/nebula
git fetch upstream
git checkout master
git rebase upstream/master

Checkout a new branch from master:

git checkout -b myfeature

NOTE: Because your PR often consists of several commits, which might be squashed while being merged into upstream, we strongly suggest you open a separate topic branch to make your changes on. After merged, this topic branch could be just abandoned, thus you could synchronize your master branch with upstream easily with a rebase like above. Otherwise, if you commit your changes directly into master, maybe you must use a hard reset on the master branch, like:

git fetch upstream
git checkout master
git reset --hard upstream/master
git push --force origin master

Step 4: Develop

Edit the Code

You can now edit the code on myfeature branch. Please be noted that we are following Google C++ Style Guide.

Verifying Your Code

Compiling the Source Code

Please refer to the build source code documentation to compile.

Code Verification

  • Replace the binary files

    The compiled binary files of the three services are in nebula/build/src/daemon/_build/ directory. The compiled console is in nebula/build/src/console/_build directory. You can replace the binary files in the bin directory, restart the services and verify. - Add unit tests

    There is a test directory in the modified code module. You can add unit tests in it, then compile and run the unit tests. Please make sure your submitted codes pass all the unit tests. - Run all the unit tests

    bash cd nebula/build ctest -j$(nproc)

Step 5: Keep Your Branch in Sync

# While on your myfeature branch.
git fetch upstream
git rebase upstream/master

Step 6: Commit

Commit your changes.

git commit

Likely you'll go back and edit/build/test some more than commit --amend in a few cycles.

Step 7: Push

When ready to review (or just to establish an offsite backup or your work), push your branch to your fork on

git push -f origin myfeature

Step 8: Create a Pull Request

  1. Visit your fork at$user/nebula (replace $user obviously).
  2. Click the Compare & pull request button next to your myfeature branch.

Step 9: Get a Code Review

Once your pull request has been opened, it will be assigned to at least two reviewers. Those reviewers will do a thorough code review to ensure the changes meet the repository's contributing guidelines and other quality standards.