The question was asked how Drone clones a repository. I wanted to document this in Discourse so that others could benefit from the answer (and ask follow-up questions). A common misconception is that the agent clones the repository, or that the repository is cloned inside the agent container, which is not the case.
Drone adds a default clone step to every Pipeline. The clone steps executes the clone plugin, which is pretty much just a vanilla Drone plugin that handles cloning the repository. You can find the plugin here.
Let’s say we have the following configuration file:
kind: pipeline name: default steps: - name: build image: golang commands: - go build - go test
Conceptually speaking, Drone automatically prepends the clone step to your Pipeline (demonstrated below). The plugin then clones your repository to the shared workspace volume.
kind: pipeline name: default steps: + - name: clone + image: drone/git - name: build image: golang commands: - go build - go test
Since the clone plugin is just a Docker container, it can be easily run locally:
docker run \ -e DRONE_COMMIT_SHA=15e3f9b7e16332eee3bbdff9ef31f95d23c5da2c \ -e DRONE_COMMIT_BRANCH=master \ -e DRONE_REMOTE_URL=https://github.com/drone/envsubst drone/git \ drone/git
The clone credentials are passed via the below environment variables (private repositories only)
DRONE_NETRC_MACHINE=github.com DRONE_NETRC_USERNAME= DRONE_NETRC_PASSWORD=
The username and password vary based on your source code management system. If your source code management system is github, for example, the password is x-oauth-basic and the username is the oauth token.
There are two caveats to this behavior:
- the credentials are only passed to the plugin if the repository is private or DRONE_GIT_ALWAYS_AUTH=true
- if you set DRONE_GIT_USERNAME and DRONE_GIT_PASSWORD, these values are used as the username and password