add github-workflow doc

Signed-off-by: carlory <[email protected]>

docs/contributors/devel/github-workflow.md

@@ -0,0 +1,279 @@
+---
+title: "GitHub Workflow"
+weight: 6
+description: |
+  An overview of the GitHub workflow used by the Karmada project. It includes
+  some tips and suggestions on things such as keeping your local environment in
+  sync with upstream and commit hygiene.
+---
+
+> This doc is lifted from [Kubernetes github-workflow](https://github.com/kubernetes/community/blob/master/contributors/guide/github-workflow.md).
+
+![Git workflow](git_workflow.png)
+
+### 1 Fork in the cloud
+
+1. Visit https://github.com/karmada-io/karmada
+2. Click `Fork` button (top right) to establish a cloud-based fork.
+
+### 2 Clone fork to local storage
+
+Per Go's [workspace instructions][go-workspace], place Karmada' code on your
+`GOPATH` using the following cloning procedure.
+
+[go-workspace]: https://golang.org/doc/code.html#Workspaces
+
+Define a local working directory:
+
+```sh
+# If your GOPATH has multiple paths, pick
+# just one and use it instead of $GOPATH here.
+# You must follow exactly this pattern,
+# neither `$GOPATH/src/github.com/${your github profile name/`
+# nor any other pattern will work.
+export working_dir="$(go env GOPATH)/src/github.com/karmada-io"
+```
+
+Set `user` to match your github profile name:
+
+```sh
+export user={your github profile name}
+```
+
+Both `$working_dir` and `$user` are mentioned in the figure above.
+
+Create your clone:
+
+```sh
+mkdir -p $working_dir
+cd $working_dir
+git clone https://github.com/$user/karmada.git
+# or: git clone [email protected]:$user/karmada.git
+
+cd $working_dir/karmada
+git remote add upstream https://github.com/karmada-io/karmada.git
+# or: git remote add upstream [email protected]:karmada-io/karmada.git
+
+# Never push to upstream master
+git remote set-url --push upstream no_push
+
+# Confirm that your remotes make sense:
+git remote -v
+```
+
+### 3 Branch
+
+Get your local master up to date:
+
+```sh
+# Depending on which repository you are working from,
+# the default branch may be called 'main' instead of 'master'.
+
+cd $working_dir/karmada
+git fetch upstream
+git checkout master
+git rebase upstream/master
+```
+
+Branch from it:
+```sh
+git checkout -b myfeature
+```
+
+Then edit code on the `myfeature` branch.
+
+### 4 Keep your branch in sync
+
+```sh
+# Depending on which repository you are working from,
+# the default branch may be called 'main' instead of 'master'.
+
+# While on your myfeature branch
+git fetch upstream
+git rebase upstream/master
+```
+
+Please don't use `git pull` instead of the above `fetch` / `rebase`. `git pull`
+does a merge, which leaves merge commits. These make the commit history messy
+and violate the principle that commits ought to be individually understandable
+and useful (see below). You can also consider changing your `.git/config` file via
+`git config branch.autoSetupRebase always` to change the behavior of `git pull`, or another non-merge option such as `git pull --rebase`.
+
+### 5 Commit
+
+Commit your changes.
+
+```sh
+git commit --signoff
+```
+Likely you go back and edit/build/test some more then `commit --amend`
+in a few cycles.
+
+### 6 Push
+
+When ready to review (or just to establish an offsite backup of your work),
+push your branch to your fork on `github.com`:
+
+```sh
+git push -f ${your_remote_name} myfeature
+```
+
+### 7 Create a pull request
+
+1. Visit your fork at `https://github.com/$user/karmada`
+2. Click the `Compare & Pull Request` button next to your `myfeature` branch.
+
+_If you have upstream write access_, please refrain from using the GitHub UI for
+creating PRs, because GitHub will create the PR branch inside the main
+repository rather than inside your fork.
+
+#### Get a code review
+
+Once your pull request has been opened it will be assigned to one or more
+reviewers.  Those reviewers will do a thorough code review, looking for
+correctness, bugs, opportunities for improvement, documentation and comments,
+and style.
+
+Commit changes made in response to review comments to the same branch on your
+fork.
+
+Very small PRs are easy to review.  Very large PRs are very difficult to review.
+
+#### Squash commits
+
+After a review, prepare your PR for merging by squashing your commits.
+
+All commits left on your branch after a review should represent meaningful milestones or units of work. Use commits to add clarity to the development and review process.
+
+Before merging a PR, squash the following kinds of commits:
+
+- Fixes/review feedback
+- Typos
+- Merges and rebases
+- Work in progress
+
+Aim to have every commit in a PR compile and pass tests independently if you can, but it's not a requirement. In particular, `merge` commits must be removed, as they will not pass tests.
+
+To squash your commits, perform an [interactive
+rebase](https://git-scm.com/book/en/v2/Git-Tools-Rewriting-History):
+
+1. Check your git branch:
+
+  ```
+  git status
+  ```
+
+  Output is similar to:
+
+  ```
+  On branch your-contribution
+  Your branch is up to date with 'origin/your-contribution'.
+  ```
+
+2. Start an interactive rebase using a specific commit hash, or count backwards from your last commit using `HEAD~<n>`, where `<n>` represents the number of commits to include in the rebase.
+
+  ```
+  git rebase -i HEAD~3
+  ```
+
+  Output is similar to:
+
+  ```
+  pick 2ebe926 Original commit
+  pick 31f33e9 Address feedback
+  pick b0315fe Second unit of work
+
+  # Rebase 7c34fc9..b0315ff onto 7c34fc9 (3 commands)
+  #
+  # Commands:
+  # p, pick <commit> = use commit
+  # r, reword <commit> = use commit, but edit the commit message
+  # e, edit <commit> = use commit, but stop for amending
+  # s, squash <commit> = use commit, but meld into previous commit
+  # f, fixup <commit> = like "squash", but discard this commit's log message
+
+  ...
+
+  ```
+
+3. Use a command line text editor to change the word `pick` to `squash` for the commits you want to squash, then save your changes and continue the rebase:
+
+  ```
+  pick 2ebe926 Original commit
+  squash 31f33e9 Address feedback
+  pick b0315fe Second unit of work
+
+  ...
+
+  ```
+
+  Output (after saving changes) is similar to:
+
+  ```
+  [detached HEAD 61fdded] Second unit of work
+   Date: Thu Mar 5 19:01:32 2020 +0100
+   2 files changed, 15 insertions(+), 1 deletion(-)
+
+   ...
+
+  Successfully rebased and updated refs/heads/master.
+  ```
+4. Force push your changes to your remote branch:
+
+  ```
+  git push --force
+  ```
+
+For mass automated fixups (e.g. automated doc formatting), use one or more
+commits for the changes to tooling and a final commit to apply the fixup en
+masse. This makes reviews easier.
+
+### Merging a commit
+
+Once you've received review and approval, your commits are squashed, your PR is ready for merging.
+
+Merging happens automatically after both a  Reviewer and Approver have approved the PR. If you haven't squashed your commits, they may ask you to do so before approving a PR.
+
+### Reverting a commit
+
+In case you wish to revert a commit, use the following instructions.
+
+_If you have upstream write access_, please refrain from using the
+`Revert` button in the GitHub UI for creating the PR, because GitHub
+will create the PR branch inside the main repository rather than inside your fork.
+
+- Create a branch and sync it with upstream.
+
+  ```sh
+  # Depending on which repository you are working from,
+  # the default branch may be called 'main' instead of 'master'.
+
+  # create a branch
+  git checkout -b myrevert
+
+  # sync the branch with upstream
+  git fetch upstream
+  git rebase upstream/master
+  ```
+- If the commit you wish to revert is a:<br>
+  - **merge commit:**
+
+    ```sh
+    # SHA is the hash of the merge commit you wish to revert
+    git revert -m 1 SHA
+    ```
+
+  - **single commit:**
+
+    ```sh
+    # SHA is the hash of the single commit you wish to revert
+    git revert SHA
+    ```
+
+- This will create a new commit reverting the changes. Push this new commit to your remote.
+
+```sh
+git push ${your_remote_name} myrevert
+```
+
+- [Create a Pull Request](#7-create-a-pull-request) using this branch.