GitHub.jl

GitHub.jl provides a Julia interface to the GitHub API v3. Using GitHub.jl, you can do things like:

• query for basic repository, organization, and user information
• programmatically take user-level actions (e.g. starring a repository, commenting on an issue, etc.)
• set up listeners that can detect and respond to repository events
• create and retrieve commit statuses (i.e. report CI pending/failure/success statuses to GitHub)

Here's a table of contents for this rather lengthy README:

1. Response Types

2. REST Methods

3. Authentication

4. Pagination

5. Handling Webhook Events

6. GitHub Enterprise

GitHub's JSON responses are parsed and returned to the caller as types of the form G<:GitHub.GitHubType. Here's some useful information about these types:

• All fields are Union{Nothing, T}.

• Field names generally match the corresponding field in GitHub's JSON representation (the exception is "type", which has the corresponding field name typ to avoid the obvious language conflict).

• GitHubTypes can be passed as arguments to API methods in place of (and in combination with) regular identifying properties. For example, create_status(repo, commit) could be called as:

  • create_status(::GitHub.Repo, ::GitHub.Commit)
  • create_status(::GitHub.Repo, ::AbstractString) where the second argument is the SHA
  • create_status(::AbstractString, ::GitHub.Commit) where the first argument is the full qualified repo name
  • create_status(::AbstractString, ::AbstractString) where the first argument is the repo name, and the second is the SHA

Here's a table that matches up the provided GitHubTypes with their corresponding API documentation, as well as alternative identifying values:

You can inspect which fields are available for a type G<:GitHubType by calling fieldnames(G).

GitHub.jl implements a bunch of methods that make REST requests to GitHub's API. The below sections list these methods (note that a return type of Tuple{Vector{T}, Dict} means the result is paginated).

All REST methods accept the following keyword arguments:

To authenticate your requests to GitHub, you'll need to generate an appropriate access token. Then, you can do stuff like the following (this example assumes that you set an environmental variable GITHUB_AUTH containing the access token):

import GitHub
myauth = GitHub.authenticate(ENV["GITHUB_AUTH"]) # don't hardcode your access tokens!
GitHub.star("JuliaWeb/GitHub.jl"; auth = myauth)  # star the GitHub.jl repo as the user identified by myauth

As you can see, you can propagate the identity/permissions of the myauth token to GitHub.jl's methods by passing auth = myauth as a keyword argument.

Note that if authentication is not provided, they'll be subject to the restrictions GitHub imposes on unauthenticated requests (such as stricter rate limiting)

GitHub apps (formerly called integrations) have their own authentication format based on JSON Web Tokens. When creating a GitHub app, you will be prompted to download your app's private key. You can use this private key to authenticate as a Github App using the JWTAuth type:

appauth = JWTAuth(1234, "privkey.pem") # Replace with your app id/privkey file

The following shows a complete example that opens an issue on every repository on which your application gets installed:

listener = GitHub.EventListener() do event
    # On installation, open an issue on every repository we got installed in
    if event.kind == "installation"
        # Authenticate as the application
        appauth = GitHub.JWTAuth(1234, "privkey.pem")
        # Now, get permissions for this particular installation
        installation = Installation(event.payload["installation"])
        auth = create_access_token(installation, appauth)
        for repo in event.payload["repositories"]
            create_issue(GitHub.Repo(repo), auth=auth,
                params = Dict(
                    :title => "Hello World",
                    :body => "Thank you for installing me - I needed that"
            ))
        end
    end
    return HTTP.Response(200)
end
GitHub.run(listener, host=IPv4(0,0,0,0), port=8888)

GitHub will often paginate results for requests that return multiple items. On the GitHub.jl side of things, it's pretty easy to see which methods return paginated results by referring to the REST Methods documentation; if a method returns a Tuple{Vector{T}, Dict}, that means its results are paginated.

Paginated methods return both the response values, and some pagination metadata. You can use the per_page/page query parameters and the page_limit keyword argument to configure result pagination.

For example, let's request a couple pages of GitHub.jl's PRs, and configure our result pagination to see how it works:

# show all PRs (both open and closed), and give me 3 items per page starting at page 2
julia> myparams = Dict("state" => "all", "per_page" => 3, "page" => 2);

julia> prs, page_data = pull_requests("JuliaWeb/GitHub.jl"; params = myparams, page_limit = 2);

julia> prs # 3 items per page * 2 page limit == 6 items, as expected
6-element Array{GitHub.PullRequest,1}:
 GitHub.PullRequest(44)
 GitHub.PullRequest(43)
 GitHub.PullRequest(42)
 GitHub.PullRequest(41)
 GitHub.PullRequest(39)
 GitHub.PullRequest(38)

julia> page_data
Dict{String,String} with 4 entries:
  "prev"  => "https://api.github.com/repositories/16635105/pulls?page=2&per_page=3&state=all"
  "next"  => "https://api.github.com/repositories/16635105/pulls?page=4&per_page=3&state=all"
  "first" => "https://api.github.com/repositories/16635105/pulls?page=1&per_page=3&state=all"
  "last"  => "https://api.github.com/repositories/16635105/pulls?page=7&per_page=3&state=all"

In the above, prs contains the results from page 2 and 3. We know this because we specified page 2 as our starting page ("page" => 2), and limited the response to 2 pages max (page_limit = 2). In addition, we know that exactly 2 pages were actually retrieved, since there are 6 items and we said each page should only contain 3 items ("per_page" => 3).

The values provided by page_data are the same values that are included in the Link header of the last requested item. You can continue paginating by starting a new paginated request at one of these links using the start_page keyword argument:

# Continue paging, starting with `page_data["next"]`.
# Note that the `params` kwarg can't be used here because
# the link passed to `start_page` has its own parameters
julia> prs2, page_data2 = pull_requests("JuliaWeb/GitHub.jl"; page_limit = 2, start_page = page_data["next"]);

julia> prs2
6-element Array{GitHub.PullRequest,1}:
 GitHub.PullRequest(37)
 GitHub.PullRequest(34)
 GitHub.PullRequest(32)
 GitHub.PullRequest(30)
 GitHub.PullRequest(24)
 GitHub.PullRequest(22)

julia> page_data2
Dict{String,String} with 4 entries:
  "prev"  => "https://api.github.com/repositories/16635105/pulls?page=4&per_page=3&state=all"
  "next"  => "https://api.github.com/repositories/16635105/pulls?page=6&per_page=3&state=all"
  "first" => "https://api.github.com/repositories/16635105/pulls?page=1&per_page=3&state=all"
  "last"  => "https://api.github.com/repositories/16635105/pulls?page=7&per_page=3&state=all"

GitHub.jl comes with configurable EventListener and CommentListener types that can be used as basic servers for parsing and responding to events delivered by GitHub's repository Webhooks.

When an EventListener receives an event, it performs some basic validation and wraps the event payload (and some other data) in a WebhookEvent type. This WebhookEvent instance, along with the provided Authorization, is then fed to the server's handler function, which the user defines to determine the server's response behavior. The handler function is expected to return an HTTP.Response that is then sent back to GitHub.

The EventListener constructor takes the following keyword arguments:

• auth: GitHub authorization (usually with repo-level permissions).
• secret: A string used to verify the event source. If the event is from a GitHub Webhook, it's the Webhook's secret. If a secret is not provided, the server won't validate the secret signature of incoming requests.
• repos: A vector of Repos (or fully qualified repository names) listing all acceptable repositories. All repositories are whitelisted by default.
• events: A vector of event names listing all acceptable events (e.g. ["commit_comment", "pull_request"]). All events are whitelisted by default.
• forwards: A vector of URIs.URIs (or URI strings) to which any incoming requests should be forwarded (after being validated by the listener)

Here's an example that demonstrates how to construct and run an EventListener that does benchmarking on every commit and PR:

import GitHub
import URIs
# EventListener settings
myauth = GitHub.authenticate(ENV["GITHUB_AUTH"])
mysecret = ENV["MY_SECRET"]
myevents = ["pull_request", "push"]
myrepos = [GitHub.Repo("owner1/repo1"), "owner2/repo2"] # can be Repos or repo names
myforwards = [URIs.URI("http://myforward1.com"), "http://myforward2.com"] # can be URIs.URIs or URI strings

# Set up Status parameters
pending_params = Dict(
    "state" => "pending",
    "context" => "Benchmarker",
    "description" => "Running benchmarks..."
)

success_params = Dict(
    "state" => "success",
    "context" => "Benchmarker",
    "description" => "Benchmarks complete!"
)

error_params(err) = Dict(
    "state" => "error",
    "context" => "Benchmarker",
    "description" => "Error: $err"
)

# We can use Julia's `do` notation to set up the listener's handler function
listener = GitHub.EventListener(auth = myauth,
                                secret = mysecret,
                                repos = myrepos,
                                events = myevents,
                                forwards = myforwards) do event
    kind, payload, repo = event.kind, event.payload, event.repository

    if kind == "pull_request" && payload["action"] == "closed"
        return HTTP.Response(200)
    end

    if event.kind == "push"
        sha = event.payload["after"]
    elseif event.kind == "pull_request"
        sha = event.payload["pull_request"]["head"]["sha"]
    end

    GitHub.create_status(repo, sha; auth = myauth, params = pending_params)

    try
        # run_and_log_benchmarks isn't actually a defined function, but you get the point
        run_and_log_benchmarks(event, "\$(sha)-benchmarks.csv")
    catch err
        GitHub.create_status(repo, sha; auth = myauth, params = error_params(err))
        return HTTP.Response(500)
    end

    GitHub.create_status(repo, sha; auth = myauth, params = success_params)

    return HTTP.Response(200)
end

# Start the listener on localhost at port 8000
GitHub.run(listener, IPv4(127,0,0,1), 8000)

A CommentListener is a special kind of EventListener that allows users to pass data to the listener's handler function via commenting. This is useful for triggering events on repositories that require configuration settings.

A CommentListener automatically filters out all non-comment events, and then checks the body of each comment event against a trigger Regex supplied by the user. If a match is found in the comment, then the CommentListener calls its handler function, passing it the event and the corresponding RegexMatch.

The CommentListener constructor takes the following keyword arguments:

• auth: same as EventListener
• secret: same as EventListener
• repos: same as EventListener
• forwards: same as EventListener
• check_collab: If true, only acknowledge comments made by repository collaborators. Note that, if check_collab is true, auth must have the appropriate permissions to query the comment's repository for the collaborator status of the commenter. check_collab is true by default.
• use_access_token: If check_collab is set to true and auth is using JWT authentication for GitHub Apps, then set this to true.

For example, let's set up a silly CommentListener that responds to the commenter with a greeting. To give a demonstration of the desired behavior, if a collaborator makes a comment like:

Man, I really would like to be greeted today.

`sayhello("Bob", "outgoing")`

We want the CommentLister to reply:

Hello, Bob, you look very outgoing today!

Here's the code that will make this happen:

import GitHub

# CommentListener settings
trigger = r"`sayhello\(.*?\)`"
myauth = GitHub.authenticate(ENV["GITHUB_AUTH"])
mysecret = ENV["MY_SECRET"]

# We can use Julia's `do` notation to set up the listener's handler function.
# Note that, in our example case, `phrase` will be "`sayhello(\"Bob\", \"outgoing\")`"
listener = GitHub.CommentListener(trigger; auth = myauth, secret = mysecret) do event, phrase
    # In our example case, this code sets name to "Bob" and adjective to "outgoing"
    name, adjective = matchall(r"\".*?\"", phrase)
    comment_params = Dict("body" => "Hello, $name, you look very $adjective today!")

    # Parse the original comment event for all the necessary reply info
    comment = GitHub.Comment(event.payload["comment"])

    if event.kind == "issue_comment"
        comment_kind = :issue
        reply_to = event.payload["issue"]["number"]
    elseif event.kind == "commit_comment"
        comment_kind = :commit
        reply_to = comment.commit_id
    elseif event.kind == "pull_request_review_comment"
        comment_kind = :review
        reply_to = event.payload["pull_request"]["number"]
        # load required query params for review comment creation
        comment_params["commit_id"] = comment.commit_id
        comment_params["path"] = comment.path
        comment_params["position"] = comment.position
    end

    # send the comment creation request to GitHub
    GitHub.create_comment(event.repository, reply_to, comment_kind; auth = myauth, params = comment_params)

    return HTTP.Response(200)
end

# Start the listener on localhost at port 8000
GitHub.run(listener, IPv4(127,0,0,1), 8000)

This library work with github.com, and also with self-hosted github, a.k.a. GitHub Enterprise.

To use it with self-hosted github, you need to create GitHubWebAPI structure and pass it to functions when needed. Following example shows obtaining repository info private/Package.jl on github instance with API https://git.company.com/api/v3.

import GitHub
import URIs

api = GitHub.GitHubWebAPI(URIs.URI("https://git.company.com/api/v3"))
myauth = GitHub.authenticate(api, ENV["GITHUB_AUTH"])
myrepo = GitHub.repo(api, "private/Package.jl", auth=myauth)

You can generate public-private key pairs with GitHub.genkeys. Here's an example adding a deploy key and secret, in this case to deploy documentation via GitHub Actions:

pubkey, privkey = GitHub.genkeys()
create_deploykey(repo; auth, params=Dict("key"=>pubkey, "title"=>"Documenter", "read_only"=>false))
create_secret(repo, "DOCUMENTER_KEY"; auth, value=privkey)

privkey is sent in encrypted form to GitHub. Do not share privkey with others or post it publicly; doing so breaches the security of your repository. You can read more about the meaning of SSH keys and their security implications.