Hosting Documentation

After going through the Package Guide and Doctests page you will need to host the generated documentation somewhere for potential users to read. This guide will describe how to set up automatic updates for your package docs using either the Travis CI build service or GitHub Actions together with GitHub Pages for hosting the generated HTML files. This is the same approach used by this package to host its own docs – the docs you're currently reading.

Overview

Once set up correctly, the following will happen each time you push new updates to your package repository:

• Buildbots will start up and run your package tests in a "Test" stage.
• After the Test stage completes, a single bot will run a new "Documentation" stage, which will build the documentation.
• If the documentation is built successfully, the bot will attempt to push the generated HTML pages back to GitHub.

Note that the hosted documentation does not update when you (or other contributors) make pull requests; you see updates only when you merge to the trunk branch (typically, master or main) or push new tags.

In the upcoming sections we describe how to configure the build service to run the documentation build stage. In general it is easiest to choose the same service as the one testing your package. If you don't explicitly select the service with the deploy_config keyword argument to deploydocs Documenter will try to automatically detect which system is running and use that.

Travis CI

To tell Travis that we want a new build stage, we can add the following to an existing .travis.yml file. Note that the snippet below will not work by itself and must be accompanied by a complete Travis file.

jobs:
  include:
    - stage: "Documentation"
      julia: 1
      os: linux
      script:
        - julia --project=docs/ -e 'using Pkg; Pkg.develop(PackageSpec(path=pwd()));
                                               Pkg.instantiate()'
        - julia --project=docs/ docs/make.jl
      after_success: skip

where the julia: and os: entries decide the worker from which the docs are built and deployed. In the example above we will thus build and deploy the documentation from a linux worker running Julia 1 (the latest stable version). For more information on how to setup a build stage, see the Travis manual for Build Stages.

The three lines in the script: section do the following:

1. Instantiate the doc-building environment (i.e. docs/Project.toml, see below).
2. Install your package in the doc-build environment.
3. Run the docs/make.jl script, which builds and deploys the documentation.

Authentication: SSH Deploy Keys

In order to push the generated documentation from Travis you need to add deploy keys. Deploy keys provide push access to a single repository, to allow secure deployment of generated documentation from the builder to GitHub. The SSH keys can be generated with DocumenterTools.genkeys from the DocumenterTools package.

Install and load DocumenterTools with

pkg> add DocumenterTools

julia> using DocumenterTools

Then call the DocumenterTools.genkeys function as follows:

julia> using DocumenterTools
julia> DocumenterTools.genkeys(user="MyUser", repo="MyPackage.jl")

where MyPackage is the name of the package you would like to create deploy keys for and MyUser is your GitHub username. Note that the keyword arguments are optional and can be omitted.

If the package is checked out in development mode with ] dev MyPackage, you can also use DocumenterTools.genkeys as follows:

julia> using MyPackage
julia> DocumenterTools.genkeys(MyPackage)

where MyPackage is the package you would like to create deploy keys for. The output will look similar to the text below:

[ Info: add the public key below to https://github.com/USER/REPO/settings/keys
      with read/write access:

[SSH PUBLIC KEY HERE]

[ Info: add a secure environment variable named 'DOCUMENTER_KEY' to
  https://travis-ci.com/USER/REPO/settings with value:

[LONG BASE64 ENCODED PRIVATE KEY]

Follow the instructions that are printed out, namely:

1. Add the public ssh key to your settings page for the GitHub repository that you are setting up by following the .../settings/keys link provided. Click on Add deploy key, enter the name documenter as the title, and copy the public key into the Key field. Check Allow write access to allow Documenter to commit the generated documentation to the repo.

2. Next add the long private key to the Travis settings page using the provided link. Again note that you should include no whitespace when copying the key. In the Environment Variables section add a key with the name DOCUMENTER_KEY and the value that was printed out. Do not set the variable to be displayed in the build log. Then click Add.

   Security warning

   To reiterate: make sure that this key is hidden. In particular, in the Travis CI settings the "Display value in build log" option should be OFF for the variable, so that it does not get printed when the tests run. This base64-encoded string contains the unencrypted private key that gives full write access to your repository, so it must be kept safe. Also, make sure that you never expose this variable in your tests, nor merge any code that does. You can read more about Travis environment variables in Travis User Documentation.

GitHub Actions

To run the documentation build from GitHub Actions, create a new workflow configuration file called .github/workflows/documentation.yml with the following contents:

name: Documentation

on:
  push:
    branches:
      - master # update to match your development branch (master, main, dev, trunk, ...)
    tags: '*'
  pull_request:

jobs:
  build:
    permissions:
      actions: write
      contents: write
      pull-requests: read
      statuses: write
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: julia-actions/setup-julia@v2
        with:
          version: '1'
      - uses: julia-actions/cache@v2
      - name: Install dependencies
        run: julia --project=docs/ -e 'using Pkg; Pkg.develop(PackageSpec(path=pwd())); Pkg.instantiate()'
      - name: Build and deploy
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # If authenticating with GitHub Actions token
          DOCUMENTER_KEY: ${{ secrets.DOCUMENTER_KEY }} # If authenticating with SSH deploy key
        run: julia --project=docs/ docs/make.jl

This will install Julia, checkout the correct commit of your repository, and run the build of the documentation. The julia-version:, julia-arch: and os: entries decide the environment from which the docs are built and deployed. The example above builds and deploys the documentation from an Ubuntu worker running Julia 1.

The commands in the lines in the run: section do the same as for Travis, see the previous section.

name: TagBot
on:
  issue_comment:
    types:
      - created
  workflow_dispatch:
jobs:
  TagBot:
    if: github.event_name == 'workflow_dispatch' || github.actor == 'JuliaTagBot'
    runs-on: ubuntu-latest
    steps:
      - uses: JuliaRegistries/TagBot@v1
        with:
          token: ${{ secrets.GITHUB_TOKEN }}
          ssh: ${{ secrets.DOCUMENTER_KEY }}

Authentication: GITHUB_TOKEN

When running from GitHub Actions it is possible to authenticate using the GitHub Actions authentication token (GITHUB_TOKEN). This is done by adding

GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

to the configuration file, as showed in the previous section.

Authentication: SSH Deploy Keys

It is also possible to authenticate using a SSH deploy key, just as described in the SSH Deploy Keys section for Travis CI. You can generate the key in the same way, and then set the encoded key as a secret environment variable in your repository settings. You also need to make the key available for the doc building workflow by adding

DOCUMENTER_KEY: ${{ secrets.DOCUMENTER_KEY }}

to the configuration file, as showed in the previous section. See GitHub's manual for Encrypted secrets for more information.

Permissions

The following GitHub Actions job or workflow permissions are required to successfully use deploydocs:

permissions:
  contents: write  # Required when authenticating with `GITHUB_TOKEN`, not needed when authenticating with SSH deploy keys
  pull-requests: read  # Required when using `push_preview=true`
  statuses: write  # Optional, used to report documentation build statuses

Add code coverage from documentation builds

If you want code run during the documentation deployment to be covered by Codecov, you can edit the end of the docs part of your workflow configuration file so that docs/make.jl is run with the --code-coverage=user flag and the coverage reports are uploaded to Codecov:

      - run: julia --project=docs/ --code-coverage=user docs/make.jl
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          DOCUMENTER_KEY: ${{ secrets.DOCUMENTER_KEY }}
      - uses: julia-actions/julia-processcoverage@v1
      - uses: codecov/codecov-action@v4

docs/Project.toml

The doc-build environment docs/Project.toml includes Documenter and other doc-build dependencies your package might have. If Documenter is the only dependency, then the Project.toml should include the following:

[deps]
Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"

[compat]
Documenter = "1.8"

Note that it is recommended that you have a [compat] section, like the one above, in your Project.toml file, which would restrict Documenter's version that gets installed when the build runs. This is to make sure that your builds do not start failing suddenly due to a new major release of Documenter, which may include breaking changes. However, it also means that you will not get updates to Documenter automatically, and hence need to upgrade Documenter's major version yourself.

The deploydocs Function

At the moment your docs/make.jl file probably only contains

using Documenter, PACKAGE_NAME

makedocs()

We'll need to add an additional function call to this file after makedocs which would perform the deployment of the docs to the gh-pages branch. Add the following at the end of the file:

deploydocs(
    repo = "github.com/USER_NAME/PACKAGE_NAME.jl.git",
)

where USER_NAME and PACKAGE_NAME must be set to the appropriate names. Note that repo should not specify any protocol, i.e. it should not begin with https:// or git@.

See the deploydocs function documentation for more details.

.gitignore

Add the following to your package's .gitignore file

docs/build/

These are needed to avoid committing generated content to your repository.

gh-pages Branch

By default, Documenter pushes documentation to the gh-pages branch. If the branch does not exist it will be created automatically by deploydocs. If it does exist then Documenter simply adds an additional commit with the built documentation. You should be aware that Documenter may overwrite existing content without warning.

If you wish to create the gh-pages branch manually, that can be done creating an "orphan" branch, with the git checkout --orphan option.

You also need to make sure that you have gh-pages branch and / (root) selected as the source of the GitHub Pages site in your GitHub repository settings, so that GitHub would actually serve the contents as a website.

Cleaning up gh-pages

The gh-pages branch can become very large, especially when push_preview is enabled to build documentation for each pull request. To clean up the branch and remove stale documentation previews, a GitHub Actions workflow like the following can be used.

name: Doc Preview Cleanup

on:
  pull_request:
    types: [closed]

# Ensure that only one "Doc Preview Cleanup" workflow is force pushing at a time
concurrency:
  group: doc-preview-cleanup
  cancel-in-progress: false

jobs:
  doc-preview-cleanup:
    runs-on: ubuntu-latest
    permissions:
      contents: write
    steps:
      - name: Checkout gh-pages branch
        uses: actions/checkout@v4
        with:
          ref: gh-pages
      - name: Delete preview and history + push changes
        run: |
          if [ -d "${preview_dir}" ]; then
              git config user.name "Documenter.jl"
              git config user.email "documenter@juliadocs.github.io"
              git rm -rf "${preview_dir}"
              git commit -m "delete preview"
              git branch gh-pages-new $(echo "delete history" | git commit-tree HEAD^{tree})
              git push --force origin gh-pages-new:gh-pages
          fi
        env:
          preview_dir: previews/PR${{ github.event.number }}

This workflow was based on CliMA/ClimaTimeSteppers.jl (Apache License 2.0).

The permissions: line above is described in the GitHub Docs; an alternative is to give GitHub workflows write permissions under the repo settings, e.g., https://github.com/<USER>/<REPO>.jl/settings/actions.

Woodpecker CI

To run a documentation build from Woodpecker CI, one should create an access token from their forge of choice: GitHub, GitLab, or Codeberg (or any Gitea instance). This access token should be added to Woodpecker CI as a secret named as project_access_token. The case does not matter since this will be passed as uppercase environment variables to your pipeline. Next, create a new pipeline configuration file called .woodpecker.yml with the following contents:

• Woodpecker 0.15.x and pre-1.0.0

  pipeline:
      docs:
      when:
          branch: main  # update to match your development branch
      image: julia
      commands:
          - julia --project=docs/ -e 'using Pkg; Pkg.develop(PackageSpec(path=pwd())); Pkg.instantiate()'
          - julia --project=docs/ docs/make.jl
      secrets: [ project_access_token ]  # access token is a secret
  

• Woodpecker 1.0.x and onwards

  steps:
      docs:
      when:
          branch: main  # update to match your development branch
      image: julia
      commands:
          - julia --project=docs/ -e 'using Pkg; Pkg.develop(PackageSpec(path=pwd())); Pkg.instantiate()'
          - julia --project=docs/ docs/make.jl
      secrets: [ project_access_token ]  # access token is a secret
  

This will pull an image of julia from docker and run the following commands from commands: which instantiates the project for development and then runs the make.jl file and builds and deploys the documentation to a branch which defaults to pages which you can modify to something else e.g. GitHub → gh-pages, Codeberg → pages.

Documentation Versions

By default the documentation is deployed as follows:

• Documentation built for a tag <tag_prefix>vX.Y.Z will be stored in a folder vX.Y.Z, determined by the tag_prefix keyword to deploydocs ("" by default).

• Documentation built from the devbranch branch (master by default) is stored in a folder determined by the devurl keyword to deploydocs (dev by default).

Which versions will show up in the version selector is determined by the versions argument to deploydocs. For examples of non-default tag_prefix usage, see Deploying from a monorepo.

Unless a custom domain is being used, the pages are found at:

https://USER_NAME.github.io/PACKAGE_NAME.jl/vX.Y.Z
https://USER_NAME.github.io/PACKAGE_NAME.jl/dev

By default Documenter will create a link called stable that points to the latest release

https://USER_NAME.github.io/PACKAGE_NAME.jl/stable

It is recommended to use this link, rather than the versioned links, since it will be updated with new releases.

Once your documentation has been pushed to the gh-pages branch you should add links to your README.md pointing to the stable (and perhaps dev) documentation URLs. It is common practice to make use of "badges" similar to those used for Travis and AppVeyor build statuses or code coverage. Adding the following to your package README.md should be all that is necessary:

[![](https://img.shields.io/badge/docs-stable-blue.svg)](https://USER_NAME.github.io/PACKAGE_NAME.jl/stable)
[![](https://img.shields.io/badge/docs-dev-blue.svg)](https://USER_NAME.github.io/PACKAGE_NAME.jl/dev)

PACKAGE_NAME and USER_NAME should be replaced with their appropriate values. The colour and text of the image can be changed by altering docs-stable-blue as described on shields.io, though it is recommended that package authors follow this standard to make it easier for potential users to find documentation links across multiple package README files.

Fixing broken release deployments

It can happen that, for one reason or another, the documentation for a tagged version of your package fails to deploy and a fix would require changes to the source code (e.g. a misconfigured make.jl). However, as registered tags should not be changed, you can not simply update the original tag (e.g. v1.2.3) with the fix.

In this situation, you can manually create and push a tag for the commit with the fix that has the same version number, but also some build metadata (e.g. v1.2.3+doc1). For Git, this is a completely different tag, so it won't interfere with anything. But when Documenter runs on this tag, it will ignore the build metadata and deploy the docs as if they were for version v1.2.3.

Note that, as with normal tag builds, you need to make sure that your CI that runs Documenter is configured to run on such tags (e.g. that the regex constraining the branches the CI runs on is broad enough etc).

Deploying without the versioning scheme

Documenter supports deployment directly to the website root ignoring any version subfolders as described in the previous section. This can be useful if you use Documenter for something that is not a versioned project, for example. To do this, pass versions = nothing to the deploydocs function. Now the pages should be found directly at

https://USER_NAME.github.io/PACKAGE_NAME.jl/

Preview builds are still deployed to the previews subfolder.

Out-of-repo deployment

Sometimes the gh-pages branch can become really large, either just due to a large number of commits over time, or due figures and other large artifacts. In those cases, it can be useful to deploy the docs in the gh-pages of a separate repository. The following steps can be used to deploy the documentation of a "source" repository on a "target" repo:

1. Run DocumenterTools.genkeys() to generate a pair of keys
2. Add the deploy key to the "target" repository
3. Add the DOCUMENTER_KEY secret to the "source" repository (that runs the documentation workflow)
4. Adapt docs/make.jl to deploy on "target" repository:

# url of target repo
repo = "github.com/TargetRepoOrg/TargetRepo.git"

# You have to override the corresponding environment variable that
# deplodocs uses to determine if it is deploying to the correct repository.
# For GitHub, it's the GITHUB_REPOSITORY variable:
withenv("GITHUB_REPOSITORY" => repo) do
  deploydocs(repo=repo)
end

Deploying from a monorepo

Documenter.jl supports building documentation for a package that lives in a monorepo, e.g., in a repository that contains multiple packages (including one potentially top level)

Here's one example of setting up documentation for a repository that has the following structure: one top level package and two subpackages PackageA.jl and PackageB.jl:

.
├── README.md
├── docs
|   ├── make.jl
│   └── Project.toml
├── src/...
├── PackageA.jl
│   ├── docs
|   │   ├── make.jl
|   │   └── Project.toml
│   └── src/...
└── PackageB.jl
    ├── docs
    │   ├── make.jl
    │   └── Project.toml
    └── src/...

The three respective make.jl scripts should contain deploydocs settings that look something like

# In ./docs/make.jl
deploydocs(; repo = "github.com/USER_NAME/PACKAGE_NAME.jl.git",
            # ...any additional kwargs
            )

# In ./PackageA.jl/docs/make.jl
deploydocs(; repo = "github.com/USER_NAME/PACKAGE_NAME.jl.git",
             dirname="PackageA",
             tag_prefix="PackageA-",
             # ...any additional kwargs
             )

# In ./PackageB.jl/docs/make.jl
deploydocs(; repo = "github.com/USER_NAME/PACKAGE_NAME.jl.git",
             dirname="PackageB",
             tag_prefix="PackageB-",
             # ...any additional kwargs
             )

To build separate docs for each package, create three separate buildbot configurations, one for each package. Depending on the service used, the section that calls each make.jl script will need to be configured appropriately, e.g.,

# In the configuration file that builds docs for the top level package
run: julia --project=docs/ docs/make.jl

# In the configuration file that builds docs for PackageA.jl
run: julia --project=PackageA.jl/docs/ PackageA.jl/docs/make.jl

# In the configuration file that builds docs for PackageB.jl
run: julia --project=PackageB.jl/docs/ PackageB.jl/docs/make.jl

Releases of each subpackage should be tagged with that same prefix, namely v0.3.2 (for the top-level package), PackageA-v0.1.2, and PackageB-v3.2+extra_build_tags. which will then trigger versioned documentation deployments. Similarly to Documentation Versions, unless a custom domain is used these three separate sets of pages will be found at:

https://USER_NAME.github.io/PACKAGE_NAME.jl/vX.Y.Z
https://USER_NAME.github.io/PACKAGE_NAME.jl/dev
https://USER_NAME.github.io/PACKAGE_NAME.jl/stable  # Links to most recent top level version

https://USER_NAME.github.io/PACKAGE_NAME.jl/PackageA/vX.Y.Z
https://USER_NAME.github.io/PACKAGE_NAME.jl/PackageA/dev
https://USER_NAME.github.io/PACKAGE_NAME.jl/PackageA/stable  # Links to most recent PackageA version

https://USER_NAME.github.io/PACKAGE_NAME.jl/PackageB/vX.Y.Z
https://USER_NAME.github.io/PACKAGE_NAME.jl/PackageB/dev
https://USER_NAME.github.io/PACKAGE_NAME.jl/PackageB/stable  # Links to most recent PackageB version

While they won't automatically reference one another, such referencing can be added manually (e.g. by linking to https://USER_NAME.github.io/PACKAGE_NAME.jl/PackageA/stable from the docs built for PackageB).

Deployment systems

It is possible to customize Documenter to use other systems then the ones described in the sections above. This is done by passing a configuration (a DeployConfig) to deploydocs by the deploy_config keyword argument. Documenter supports Travis, GitHubActions, GitLab, and Buildkite natively, but it is easy to define your own by following the simple interface described below.

DeployConfig

Documenter.deploy_folder(cfg::DeployConfig; repo, devbranch, push_preview, devurl,
                         tag_prefix, kwargs...)

DeployDecision(; kwargs...)

Documenter.authentication_method(::DeployConfig)

Documenter.authenticated_repo_url(cfg::DeployConfig)

Documenter.documenter_key(cfg::DeployConfig)

Documenter.documenter_key_previews(cfg::DeployConfig)

Travis <: DeployConfig

GitHubActions <: DeployConfig

GitLab <: DeployConfig

Buildkite <: DeployConfig

Woodpecker <: DeployConfig

labels:
  platform: linux/amd64

steps:
  docs:
    when:
      branch:
        - main
    image: opensuse/tumbleweed
    commands:
      - zypper --non-interactive install openssh juliaup git
      - /usr/bin/julia --project=docs/ --startup-file=no --history-file=no -e "import Pkg; Pkg.instantiate()"
      - /usr/bin/julia --project=docs/ --startup-file=no --history-file=no -e docs/make.jl
    secrets: [ documenter_key, project_access_token ]

platforms: linux/amd64

pipeline:
  docs:
    when:
      branch:
        - main
    image: opensuse/tumbleweed
    commands:
      - zypper --non-interactive install openssh juliaup git
      - /usr/bin/julia --project=docs/ --startup-file=no --history-file=no -e "import Pkg; Pkg.instantiate()"
      - /usr/bin/julia --project=docs/ --startup-file=no --history-file=no -e docs/make.jl
    secrets: [ documenter_key, project_access_token ]