Move docs over from infra repo

Author: oli-obk

src/SUMMARY.md

@@ -54,6 +54,7 @@
         - [Bors](./infra/docs/bors.md)
         - [Crater agents](./infra/docs/crater-agents.md)
         - [Custom GitHub Actions runners](./infra/docs/gha-self-hosted.md)
+        - [GitHub App for dev-desktops](./infra/docs/dev-desktop-github-app.md)
         - [Discord moderation bot](./infra/docs/discord-mods-bot.md)
         - [Domain names and DNS](./infra/docs/dns.md)
         - [docs.rs](./infra/docs/docs-rs.md)

src/infra/docs/dev-desktop-github-app.md

@@ -0,0 +1,56 @@
+# Github App for pushing to github from the dev-desktops
+
+These instructions are for server-side setup and debugging of the dev-desktop github app.
+The user only needs to be directed to the app installation URL
+and everything should just work for them.
+
+We're using the python github library for all github operations.
+You can find the docs at https://pygithub.readthedocs.io/en/latest/introduction.html
+
+## How to setup an App
+
+1. Go to https://github.com/settings/apps
+2. New Github App
+3. Fill out metadata (name and url)
+4. disable WebHook checkbox
+5. Set `Contents - Repository contents, commits, branches, downloads, releases, and merges.` to read/write
+6. Set `Workflows - Update GitHub Action workflow files.` to read/write
+7. Set to "enable on any account"
+8. Create App
+9. Go to https://github.com/settings/apps/{your_app_name_here} and copy the `App ID` into `app_id.txt` (same folder as `gen_temp_access_token.py`)
+
+### How to generate a .pem file for your App
+
+1. Go to https://github.com/settings/apps/{your_app_name_here}#private-key and generate a private key
+2. Download starts, save it to somewhere private.
+3. copy the .pem file into the same folder as the `gen_temp_access_token.py` and name it `dev-desktop.private-key.pem`
+
+### How to install the app for a user
+
+1. direct the user to https://github.com/settings/apps/{your_app_name_here}/installations
+2. let them install it on the org/user they want to and restrict to the repositories they want to use
+
+### How to generate a temporary access token for a specific user
+
+1. invoke `gen_temp_access_token.py <github_username> <github_repository_name>`
+
+## Integration into git command line
+
+We're using [credential-helpers](https://git-scm.com/docs/gitcredentials#Documentation/gitcredentials.txt).
+For debugging a credential helper, have it in userspace and invoke it with
+
+`git -c credential.helper -c credential.UseHttpPath=true /path/to/helper push origin branch`
+
+Note that this does not work for remotes that are registered with ssh urls. You must use https!
+
+The first command line argument is `get`, `store` or `remove`.
+In our case, we just abort (`exit(0)`) for everything but `get`, as we regenerate credentials on every invocation anyway.
+
+The actual arguments are passed via stdin and usually look like
+
+```
+protocol=https
+host=github.com
+path=your_repo.git
+```
+