Support self-hosted github installations

[tz-lom]

This PR enables support for self-hosted GitHub installations

I've tested it with the following setup

repo = Remotes.GitHub("XXX/YYY.git";host="AAA.com")

deploydocs(;
    deploy_config = Documenter.GitHubActions(
        "gh.asml.com",
        "https://pages.AAA.com/XXX/YYY"
    ),
    repo = repo,
    push_preview = true,

Both deployment and notification worked well

Was made during JuliaCon 2025 hackathon!

[mortenpi]

This looks fine to me! Could we also make sure that it's documented in the relevant docstrings please?

• Documenter.jl/src/deployconfig.jl

  Lines 295 to 316 in e972ea2

  	"""
  	GitHubActions <: DeployConfig
  	Implementation of `DeployConfig` for deploying from GitHub Actions.
  	The following environment variables influences the build
  	when using the `GitHubActions` configuration:
  	- `GITHUB_EVENT_NAME`: must be set to `push`, `workflow_dispatch`, or `schedule`.
  	This avoids deployment on pull request builds.
  	- `GITHUB_REPOSITORY`: must match the value of the `repo` keyword to [`deploydocs`](@ref).
  	- `GITHUB_REF`: must match the `devbranch` keyword to [`deploydocs`](@ref), alternatively
  	correspond to a git tag.
  	- `GITHUB_TOKEN` or `DOCUMENTER_KEY`: used for authentication with GitHub,
  	see the manual section for [GitHub Actions](@ref) for more information.
  	The `GITHUB_*` variables are set automatically on GitHub Actions, see the
  	[documentation](https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/store-information-in-variables#default-environment-variables).
  	"""

• Documenter.jl/src/utilities/Remotes.jl

  Lines 105 to 120 in e972ea2

  	"""
  	GitHub(user :: AbstractString, repo :: AbstractString)
  	GitHub(remote :: AbstractString)
  	Represents a remote Git repository hosted on GitHub. The repository is identified by the
  	names of the user (or organization) and the repository: `GitHub(user, repository)`. E.g.:
  	```julia
  	makedocs(
  	repo = GitHub("JuliaDocs", "Documenter.jl")
  	)
  	```
  	The single-argument constructor assumes that the user and repository parts are separated by
  	a slash (e.g. `JuliaDocs/Documenter.jl`).
  	"""

[tz-lom]

This looks fine to me! Could we also make sure that it's documented in the relevant docstrings please?

I've updated documentation and hopefully - coverage.
But I want to mention that documentation is miss leading at this moment:

makedocs(
    repo = GitHub("JuliaDocs", "Documenter.jl")
)

The one above will probably work, but the one bellow will not (not because of my changes)

deploydocs(
    repo = GitHub("JuliaDocs", "Documenter.jl")
)

Is it just me reading documentation in a wrong way?

[mortenpi]

Do we have somewhere where we advertise passing e.g. GitHub() to deploydocs's repo=? I think right now we just accept a string there. I agree that it's a bit unfortunate that you can't just pass the object form there (we should probably expand that), but I am not sure there's anything misleading anywhere?

[tz-lom]

Do we have somewhere where we advertise passing e.g. GitHub() to deploydocs's repo=? I think right now we just accept a string there. I agree that it's a bit unfortunate that you can't just pass the object form there (we should probably expand that), but I am not sure there's anything misleading anywhere?

No, I can't find anything in documentation, but in output of the build I see this:

and with repo parameter in deploydocs this is totally misleading.

Anyway, I've double checked that this PR works in self-hosted environment, do you need anything else or you can merge it?

[tz-lom]

@mortenpi , can you review this please?

[mortenpi]

Sorry for the delay. Unfortunately, I do have a couple of questions. I think my main concern is to make sure this doesn't affect existing setups.

[mortenpi]

I took the liberty of removing host for the single-argument method. I think it would be better if it stays single-argument. If we want to add support for overriding the host, then let's figure out some syntax for the string, like github.selfhosted:Org/Repo.jl, which we can regex.

[mortenpi]

If we hard-code github_host here, it feels like we should also hard-code the API URL? I also have a minor security concern here, where this could allow someone redirect the API calls somewhere (including the token) by somehow attacking the GITHUB_API_URL environment variable (for normal GitHub-hosted repos).

Suggested change

	github_api = get(ENV, "GITHUB_API_URL", "") # https://api.github.com
	# Compute GitHub Pages URL from repository
	parts = split(github_repository, "/")
	github_pages_url = if length(parts) == 2
	owner, repo = parts
	"https://$(owner).github.io/$(repo)/"
	else
	""
	end
	return GitHubActions(github_repository, github_event_name, github_ref, "github.com", github_api, github_pages_url)
	# Compute GitHub Pages URL from repository
	parts = split(github_repository, "/")
	github_pages_url = if length(parts) == 2
	owner, repo = parts
	"https://$(owner).github.io/$(repo)/"
	else
	""
	end
	return GitHubActions(github_repository, github_event_name, github_ref, "github.com", "https://api.github.com", github_pages_url)

[mortenpi]

Is GITHUB_API_URL something that is configurable for a self-hosted instance, or can we assume it's api.$(host)?

There's also GITHUB_SERVER_URL, which could potentially be used for determining host automatically? Or would that not be reliable and/or two automagical?

[mortenpi]

I feel like that for clarity, it would be better to capture the host and string-compare later, rather than dynamically constructing the regex.