README.md 9.97 KB
Newer Older
Chris Bills's avatar
Chris Bills committed
1
#### **NOTE** - Replace xgitlab.cels.anl.gov with gitlab.cels.anl.gov in the examples if you are working with gitlab.cels.anl.gov.
Chris Bills's avatar
Chris Bills committed
2

Chris Bills's avatar
Chris Bills committed
3
## Contents of this Repository
Chris Bills's avatar
Chris Bills committed
4

Chris Bills's avatar
Chris Bills committed
5 6 7 8
* README.md       - This README / Quick Start Guide
* bash-functions  - File that contains some example functions
* bash-git_prompt - An example colorful prompt for bash to show git status
* git-aliases     - Some example aliases for `~/.gitconfig`
9

Chris Bills's avatar
Chris Bills committed
10
Examples and more information about bash-functions, bash-git_prompt and git-aliases below the Getting Started guide.
11

12
More information about branching, forking, rebasing, merging and all that good stuff can be found in this excellent (and free!) online book: https://git-scm.com/book/en/v2
13

14 15 16
### Getting Started with GitLab

1. Generate an SSH keypair for GitLab (optional)
Chris Bills's avatar
Chris Bills committed
17
  * `ssh-keygen -t rsa -b 2048 -f ~/.ssh/xgitlab.cels.anl.gov`
18 19

1. Add your SSH public key to your account on GitLab:
Chris Bills's avatar
Chris Bills committed
20
  1. Browse to: https://xgitlab.cels.anl.gov/profile/keys
21 22 23 24 25 26
  1. Click Add SSH Key (top-right)
  1. Set the title to something meaningful
  1. Copy your public key and paste it into the Key field
  1. Click Add Key

1. Add an entry for GitLab in your ~/.ssh/config file (Optional but very convenient)
Chris Bills's avatar
Chris Bills committed
27
  * This will allow you to type something like `git clone xgitlab:namespace/project.git` without needing to pass a username, fqdn, or ssh identity to git
28 29

```
Chris Bills's avatar
Chris Bills committed
30
Host  xgitlab
31
  User              git
Chris Bills's avatar
Chris Bills committed
32 33
  Hostname          xgitlab.cels.anl.gov
  IdentityFile      ~/.ssh/xgitlab.cels.anl.gov
34 35
```

36 37
### Cloning a Repository

Chris Bills's avatar
Chris Bills committed
38
Once you've set up SSH, cloning a repository hosted on GitLab is pretty simple and straightforward. The structure of a repository's URI is: <host>:<namespace>/<project>.git (example: xgitlab:systems/git-tips.git). Determine where you want to clone the repository; a directory like ~/projects/ works pretty well, but it really doesn't matter; wherever you are most comfortable working.
39 40

  * Change to your projects directory (e.g. `cd ~/projects`)
Chris Bills's avatar
Chris Bills committed
41
  * `git clone -o systems xgitlab:systems/git-tips.git`
42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78

That's it.

You should now have a copy of the Git Tips repository in ~/projects/git-tips (or wherever, you non-conformist, you...) It is cloned and the only remote repository (simply 'remote' for short) it knows about is named 'systems' (-o <name> gives the remote a name, the default is origin).

### Branch Workflow

In a branch-style workflow, contributors either maintain long-lived personal branches of a project, or create (and destroy) shorter lived branches for bringing in new features or fixing bugs.

Creating a new branch:

```
cd ~/projects/git-tips
git checkout -b foo     # create and checkout the branch 'foo'
```

You can change between branches by typing `git checkout <name_of_branch>`.

```
git checkout foo          # Change to local branch 'foo'
git merge --no-ff master  # Merge changes from 'master into the currently checked out branch; Creates a merge commit
git rebase master         # Rebase current branch on the commit master points to;
                          # e.g. Apply commits from master, then apply current branch commits
```

### Fork Workflow

The fork-style workflow is more complicated than the branch-style workflow because it necessitates working with multiple remotes, but is easier for individual contributors to work with, since you have a long-lived development environment set up.

Forking creates a clone of a particular project in your own personal name-space. This allows you to do your development work out of the way of anyone else, and work on features and bug fixes until they are ready to be shared with others.

The fork-style workflow is useful when there are numerous contributors managing long-lived branches on the main repository.

"Rewriting history" using tools like `git rebase` is a much smaller issue when working with a personal fork.

Forking a repository on GitLab:

Chris Bills's avatar
Chris Bills committed
79
* Browse to https://xgitlab.cels.anl.gov/systems/git-tips.git
80 81 82 83 84 85
* Click the button in the top right that says 'Fork'
* Select the namespace you want to create the fork in

Getting set up with your fork and multiple remotes:

```
Chris Bills's avatar
Chris Bills committed
86 87
git clone -o foo xgitlab:foo/git-tips.git           # Clone your fork
git remote add systems xgitlab:systems/git-tips.git # Add the 'systems' remote
88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104
```

You now have two remotes; 'foo' and 'systems'. You can push or pull code using either of them:

```
git push foo master             # Push local branch 'master' to remote 'foo'
git push systems master         # Push local branch 'master' to remote 'systems'
git push systems master:foo     # Push local branch 'master' to remote 'systems', branch 'foo'
git pull systems foo            # Pull changes from remote 'systems', branch 'foo'
git rebase bar systems/master   # Rebase your local branch 'bar' on top of the branch 'master' on systems; changes made to your local branch only
```

Ignore the 'rebase' example above if you're unfamiliar with rebase; it's only there for an example of how you can work with remotes. For more information about git, please read through [Pro Git](https://git-scm.com/book/en/v2).


### Contributing Changes

105
Whether you're using the fork or branch workflow, contributing your changes is pretty much the same process (at least when using GitLab).
106

107
Once you have made changes that you would like to contribute to a project, you will need to notify the maintainers (or "owners") of the project by making a Merge Request, within GitLab's Web UI.
108

109
Making a Merge Request will send an email to the person you assign it to, and will show a diff of your branch versus the branch you are asking to merge your changes into. Follow the steps below to make a Merge Request in GitLab:
110

111 112 113 114 115 116 117 118 119 120 121
1. Browse to the project's page on GitLab (e.g. https://xgitlab.cels.anl.gov/systems/git-tips.git) OR your forked repository's page
1. Locate and click '+ New Merge Request' near the top right of the page (Subject to change as GitLab evolves)
1. Select your source project and branch (e.g. systems/git-tips and 'foo', or username/git-tips and 'foo')
1. Select your target project and branch (e.g. systems/project and 'prod')
1. Click 'Compare Branches'
1. Describe what your branch does and what testing you've done: don't rely on commit messages.
1. Click 'Submit new merge request'

Now your changes are ready to be reviewed. The project maintainers may have followup questions for you or ask you to make changes.

Make any changes, as needed, and comment on the Merge Request when you are ready for another review. As long as you push your changes to the same branch of your initial Merge Request, you should not need to create another one.
122 123 124

### Bringing in Changes

125 126 127 128 129
If you are the maintainer of a project, you may need to respond to Merge Requests and occasionally bring changes in to the 'production' branch from contributor's forks or branches.

How you bring those changes in depends on your preferences; some people prefer merging and merge commits, where others prefer a cleaner / more linear history and using 'rebase'.

If you are responsible for maintaining a project, do yourself a favor and read about the various methods people use for bringing in changes.
130

131
Merging is easy, especially within GitLab, because it can essentially all be done through the web interface using Merge Requests. Rebase (in my opinion) provides a clearer linear history of the project, but requires more understanding of git than this simple guide strives to impart.
132

133
[Information on rebasing](http://git-scm.com/book/en/v2/Git-Branching-Rebasing)
Chris Bills's avatar
Chris Bills committed
134

135
[Rebase vs. Merge](http://git-scm.com/book/en/v2/Git-Branching-Rebasing#Rebase-vs.-Merge)
Chris Bills's avatar
Chris Bills committed
136

137
[Information on merging](http://git-scm.com/book/en/v2/Git-Branching-Basic-Branching-and-Merging)
138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157

### Migrating a Repository from Other Services

The process is fairly straightforward:

* Create a new project on GitLab; either a user or group project
* Clone the project from the original service (if it has not already been cloned somewhere you can work with it)
* Add a remote for the new GitLab project you created
* Push the repository to your new GitLab remote

```
git clone -o source <source_URI> migrate    # (optional) Clone the repository from the other service into the directory 'migrate'

# Checkout all remote branches locally (optional)
for branch in $(git branch -r | grep source | grep -v HEAD); do
  branch="${branch##*/}"
  git branch --track "$branch" source/"$branch"
done

# Where 'namespace' is the user/group, and 'project' is the name of the project on GitLab:
Chris Bills's avatar
Chris Bills committed
158 159 160
git remote add xgitlab xgitlab:<namespace>/<project>.git
git push xgitlab --all     # Push all local branches to the new remote
git push xgitlab --tags    # Push any local tags to GitLab (optional)
161
```
Chris Bills's avatar
Chris Bills committed
162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197

### bash-functions

A file that contains some example functions that can be helpful when working with git.

1. `gits [#]` - a function that displays a brief summary of changes and the previous 5 log messages and hash commits. If an optional number is provided, it will display that many log messages.

### bash-git_prompt

An example addition to the bash prompt that will show you which branch you currently have checked out, and what its status is.

#### Symbol meanings:
* `>` - Local branch is ahead of the branch it is tracking
* `<` - Local branch is behind the branch it is tracking
* `!` - Local and remote branches have diverged
* `+` - There is at least 1 local `stash`
* `?` - There are files in the git working directory that are untracked

Example:

![example prompt and gits output](media/example.png)

### git-aliases

A collection of useful git aliases. These can be placed in `~/.gitconfig` (recommended) or within a project's git config (not recommended).

* `co` - Alias for `checkout`, easier and quicker to type
* `last` - Display information about the most recent commit
* `unstage` - Reverse a `git add <file>` with `git unstage <file>`
* `ls` - list all the files currently tracked by git
* `vis` - display a pretty listing of log messages with a graph of the branching
* `today` - (Requires git v1.8+) displays log of commits since yesterday; e.g. today's commits
* `squash` - Does an interactive rebase of the previous # commits; useful for squashing commits
* `stashed` - Display information about stashes