Using Git Gadget

Vincent Nijs

2019-10-09

Git Gadget

Build Status

gitgadget is an R-studio addin for version control and assignment management using git. The assignment management functions currently support the GitLab API. PRs for use with GitHub are welcome. For alternative that uses GitHub see https://github.com/rundel/ghclass although this does not (currently) have a shiny user interface.

gitgadget is not intended as a tool for all-things-git. For that you need something like sourcetree. gitgadget provides a few additional features not (yet) available in R-studio that can be useful to students and faculty using git for classes. For an excellent discussion of this level of functionality see happy git with R and talk about version control by Jenny Bryan and git for humans by Alice Bartlett.

gitgadget requires Rstudio version 1.2 or later. Please use the issue tracker on GitHub to suggest enhancements or report problems. To install the latest version of gitgadget use the command below:

install.packages("gitgadget", repos = "https://radiant-rstats.github.io/minicran/")

To start gitgadget click on the Addins menu in Rstudio and then on gitgadget.

On macOS, you will you will need to run the command below from a terminal to get access to git commands:

xcode-select --install;

On Windows you will need to install git bash from https://git-scm.com/download/win. Alternatively, you can use the following installer that we use with our students to ensure git is setup correctly for use with gitgadget:

https://rady.ucsd.edu/faculty/directory/vnijs/RSM-MSBA-Computing-Environment-Latest.exe

Note: Hover over any button in the gitgadget application for additional information about what clicking the button will accomplish

Introduce

To start using git and gitgadget first introduce yourself to git. Set a global user name and email for git (e.g., your GitLab user name and email). By default, gitgadget will try to turn on an appropriate credential helper for your operating system. See http://happygitwithr.com/credential-caching.html for additional information.

To create and fork repos and collect merge requests you will need to provide a GitLab personal access token. First create the token on GitLab and then copy-and-paste it in the Token input.

Unless you plan to use gitgadget to manage student assignments, select student as the User type. Finally, enter the main directory where you plan to clone code repos (e.g., “C:/Users/me/git”)

If you want to use an SSH key, make sure to click on the Introduce button, restart Rstudio, and then click on the SSH key button. Copy the key shown in GitGadget to the gitlab.com page that should have opened in your default browser. To securely connect to gitlab from your computer you will need to restart Rstudio and use git clone [email protected] from a terminal in Rstudio the first time you clone a repo. After that, cloning, creating, etc. from GitGadget should work smoothly. See the videos below for a demonstration.

Note: On Windows we recommend cloning and creating repos using HTTPS rather than SSH

Setup for git and gitlab

https://youtu.be/FQx_3EDQaXc

Individual assignment practice

https://youtu.be/CANV6-mfZ9I

Group assignment practice

https://youtu.be/uwqUHl3z37o

Note: In these videos we use a docker container (see https://github.com/radiant-rstats/docker/tree/master/install) but this is not required

Create (GitLab only)

Enter the path to a local directory to create a repo on GitLab. If the local directory does not yet exist it will be created. You can also click the Open button and navigate to an existing directory. If a Group name is provided it will be used to place the repo on GitLab. This is recommended if you are using gitgadget for assignment management. If left blank, the GitLab user name will be used as the group. A Prefix can be added and will default to the value of git.prefix in .Renviron (see Initial settings below). The prefix can be used to avoid conflicting assignment names across classes (e.g., multiple classes using “assignment1”).

If you selected faculty as the User type in the Introduce tab you will have the option to upload a CSV file with student tokens (see below). If a user file is provided, a radio button will be shown that can be used to indicate if the work should be completed individually or in teams. Furthermore, you can choose if you want to hide or show the master class repo to students. Hiding the master repo can avoid confusion where a student might accidentally clone the wrong repo (i.e., the class repo rather than their own fork) and not be able to push there changes back to gitlab. Showing the master repo, on the other hand, will make it possible to sync any changes to the class repo after it was forked for each student.

If a CSV file with TA information is specified they will be added as “Maintainer” to the class repo. The will also be added as “Maintainer” to all created student (or team) forks. TA information should include userid, token, and email.

Clone

Clone a repo from GitLab (or GitHub) (e.g., [email protected]:username/test-repo.git). The name for the directory placed inside Base directory to clone repo into will be taken from the repo name unless a Custom directory to clone repo into is provided. If there is no R-studio project file (.Rproj) in the remote repo, one will be created.

Note: To activate an HTTPS credential helper the first time you clone a repo from GitHub or GitLab you will be asked to provide your username and password in the Rstudio terminal

Note: To use an SSH key with GitGadget you should clone from a terminal the first time. See the video linked above (Setup for git and gitlab) for a demo. As mentioned above, for Windows users we recommend using HTTPS to clone and create repos.

Branch

Create a local branch from the active branch by providing a name for the new branch and clicking Create local. Link and push to the (GitLab) remote by clicking the Link remote button. If remote branches exist click the Check out button to work with a branch locally. If branches other than master exist you can Merge branches or delete them if they are no longer needed. To undo a merge-in-progress, e.g., with merge conflicts, click the Abort merge button. Unlink remote will not remove the local or the remote branch but only the link to the remote (i.e., the push/pull arrows in R-studio will gray-out).

Note: Changes to the list of available branches may only be visible in R-studio after clicking the refresh button in the Git tab.

Sync

To commit changes to the local copy of your repo provide a Commit message and then click the Commit button. If you committed changes you are not sure about, the Undo button will let you revert the latest commit (after confirmation).

If the remote repo contains changes you do not yet have locally press the Pull button. To add committed local changes to the remote repo, click the Push button. It you completely broke the local repo and want to start over with a clean copy of the remote repo, press the Reset button.

If the repo you are working on is a fork you probably want to make sure it is up to date and merge any changes into the version you are working on locally. The first step is to ensure that git knows about the upstream repo you forked from. Copy the SSH or HTTPS link to clone the original repo into the Sync repo with remote it was forked from input in the Sync tab and then press Sync. The repo you forked will now be added as a remote. Click Merge to update your local copy of the repo with any changes to the original remote repo. Fix merge conflicts, if any, and proceed to work on the local repo. To undo a merge with merge conflicts click the Abort merge button. Click the Unlink to remove the reference to the upstream repo you forked from.

Collect (GitLab only)

Collect assignments from students/teams using Merge Requests (MR) on GitLab. Inputs will only be shown if the user type in the Introduce tab is set to faculty.

If a CSV file with TA information is specified they removed from (Hide) or added to (Show) to all created student (or team) forks as a “Maintainer”. TA information should include userid, token, and email.

To collect and fetch assignments linked to class repo you must first open a clone of that repo in Rstudio and provide your Token. The Assignment name input should now show the assignment repo name on gitlab.com. Next, indicate of the assignment was individual or team and click the Collect button to generate Merge Requests for all students (or team leads). Once this step is completed you can review and comment on the MRs using the GitLab UI. Collecting assignments requires that MRs be generated, which in turn requires that the class repo be visible to students. The Hide button can be used to ensure students will not have access to the MRs. However, since this is likely to be after the assignment due data, visibility of the class repo and MRs may not be or much concern. The Show button will provide students access to the class repo and MRs.

To view, run, and edit the MRs locally, press the Fetch button. After fetching all MRs they are converted to branches using the student-id as the branch name and pushed back up to the server. Switch between branches to test code and provide comments and/or fixes. Use the Git tab in R-studio or the Sync tab in gitgadget to push local changes to the remote branch. Notify students of the comments/fixes by providing a link to the branch in the comments on the original MR.

If students update their assignment repo these changes will be visible in the MRs as long as the class repo is visible to students (click the Show button to ensure access). If you want to Fetch these updates for local review you should first delete the existing branches for one or more students. This can be done through the Branch tab by selecting all branches you want to delete and clicking the Delete local button. Then click the Fetch button in the Collect tab again to obtain the latest version.

Assignment management

Key functions in git.R that can be accessed through the gitgadget interface are:

create_group(...)

Used to create a group for a course. The Group name variable should be set to something like “school-courseid-year”. This creates the group and adds students as, for example, reporters with read-only access on GitLab. Make sure to specify a valid permission number.

create_repo(...)

To create an assignment repo set Local directory to the directory with the assignment files. A Prefix could be added to avoid conflicts across courses that might use the same assignment name (e.g., assignment1). Access this functionality through the Create tab in gitgadget.

assign_work(...)

Forks the assignment repo uploaded by a faculty member or TA for each student/team and creates the appropriate groups for team work. This requires a csv file with the structure shown below, including the students’ (GitLab) private token.

userid team email token
id1 team1 px…….
id2 team1 n9…….
id3 team2 VR…….

Note: Markdown for the table above was generated using tablegenerator.com

collect_work(...)

Generates Merge Requests for all students or teams. Requires a csv file with the structure shown above.

fetch_work(...)

Fetch Merge Requests for all students or teams from the GitLab server. After fetching all MRs they are converted to branches using the student-id as the branch name and pushed back up to the server. Switch between branches to test code and provide comments. Push to update the remote branch with the local changes.

Initial settings

GitGadget supports the following input from an .Renviron file (e.g., “C:/Users/me/.Renviron”). The easiest way to view .Renviron is to click on the Check button in the Introduce tab or use usethis::edit_r_environ().