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Diffstat (limited to 'pydis_site/apps/api/github_utils.py')
| -rw-r--r-- | pydis_site/apps/api/github_utils.py | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/pydis_site/apps/api/github_utils.py b/pydis_site/apps/api/github_utils.py new file mode 100644 index 00000000..44c571c3 --- /dev/null +++ b/pydis_site/apps/api/github_utils.py @@ -0,0 +1,207 @@ +"""Utilities for working with the GitHub API.""" +import dataclasses +import datetime +import math +import typing + +import httpx +import jwt + +from pydis_site import settings + +MAX_RUN_TIME = datetime.timedelta(minutes=10) +"""The maximum time allowed before an action is declared timed out.""" + + +class ArtifactProcessingError(Exception): + """Base exception for other errors related to processing a GitHub artifact.""" + + status: int + + +class UnauthorizedError(ArtifactProcessingError): + """The application does not have permission to access the requested repo.""" + + status = 401 + + +class NotFoundError(ArtifactProcessingError): + """The requested resource could not be found.""" + + status = 404 + + +class ActionFailedError(ArtifactProcessingError): + """The requested workflow did not conclude successfully.""" + + status = 400 + + +class RunTimeoutError(ArtifactProcessingError): + """The requested workflow run was not ready in time.""" + + status = 408 + + +class RunPendingError(ArtifactProcessingError): + """The requested workflow run is still pending, try again later.""" + + status = 202 + + [email protected](frozen=True) +class WorkflowRun: + """ + A workflow run from the GitHub API. + + https://docs.github.com/en/rest/actions/workflow-runs#get-a-workflow-run + """ + + name: str + head_sha: str + created_at: str + status: str + conclusion: str + artifacts_url: str + + @classmethod + def from_raw(cls, data: dict[str, typing.Any]): + """Create an instance using the raw data from the API, discarding unused fields.""" + return cls(**{ + key.name: data[key.name] for key in dataclasses.fields(cls) + }) + + +def generate_token() -> str: + """ + Generate a JWT token to access the GitHub API. + + The token is valid for roughly 10 minutes after generation, before the API starts + returning 401s. + + Refer to: + https://docs.github.com/en/developers/apps/building-github-apps/authenticating-with-github-apps#authenticating-as-a-github-app + """ + now = datetime.datetime.now() + return jwt.encode( + { + "iat": math.floor((now - datetime.timedelta(seconds=60)).timestamp()), # Issued at + "exp": math.floor((now + datetime.timedelta(minutes=9)).timestamp()), # Expires at + "iss": settings.GITHUB_APP_ID, + }, + settings.GITHUB_APP_KEY, + algorithm="RS256" + ) + + +def authorize(owner: str, repo: str) -> httpx.Client: + """ + Get an access token for the requested repository. + + The process is roughly: + - GET app/installations to get a list of all app installations + - POST <app_access_token> to get a token to access the given app + - GET installation/repositories and check if the requested one is part of those + """ + client = httpx.Client( + base_url=settings.GITHUB_API, + headers={"Authorization": f"bearer {generate_token()}"}, + timeout=10, + ) + + try: + # Get a list of app installations we have access to + apps = client.get("app/installations") + apps.raise_for_status() + + for app in apps.json(): + # Look for an installation with the right owner + if app["account"]["login"] != owner: + continue + + # Get the repositories of the specified owner + app_token = client.post(app["access_tokens_url"]) + app_token.raise_for_status() + client.headers["Authorization"] = f"bearer {app_token.json()['token']}" + + repos = client.get("installation/repositories") + repos.raise_for_status() + + # Search for the request repository + for accessible_repo in repos.json()["repositories"]: + if accessible_repo["name"] == repo: + # We've found the correct repository, and it's accessible with the current auth + return client + + raise NotFoundError( + "Could not find the requested repository. Make sure the application can access it." + ) + + except BaseException as e: + # Close the client if we encountered an unexpected exception + client.close() + raise e + + +def check_run_status(run: WorkflowRun) -> str: + """Check if the provided run has been completed, otherwise raise an exception.""" + created_at = datetime.datetime.strptime(run.created_at, settings.GITHUB_TIMESTAMP_FORMAT) + run_time = datetime.datetime.utcnow() - created_at + + if run.status != "completed": + if run_time <= MAX_RUN_TIME: + raise RunPendingError( + f"The requested run is still pending. It was created " + f"{run_time.seconds // 60}:{run_time.seconds % 60 :>02} minutes ago." + ) + else: + raise RunTimeoutError("The requested workflow was not ready in time.") + + if run.conclusion != "success": + # The action failed, or did not run + raise ActionFailedError(f"The requested workflow ended with: {run.conclusion}") + + # The requested action is ready + return run.artifacts_url + + +def get_artifact(owner: str, repo: str, sha: str, action_name: str, artifact_name: str) -> str: + """Get a download URL for a build artifact.""" + client = authorize(owner, repo) + + try: + # Get the workflow runs for this repository + runs = client.get(f"/repos/{owner}/{repo}/actions/runs", params={"per_page": 100}) + runs.raise_for_status() + runs = runs.json() + + # Filter the runs for the one associated with the given SHA + for run in runs["workflow_runs"]: + run = WorkflowRun.from_raw(run) + if run.name == action_name and sha == run.head_sha: + break + else: + raise NotFoundError( + "Could not find a run matching the provided settings in the previous hundred runs." + ) + + # Check the workflow status + url = check_run_status(run) + + # Filter the artifacts, and return the download URL + artifacts = client.get(url) + artifacts.raise_for_status() + + for artifact in artifacts.json()["artifacts"]: + if artifact["name"] == artifact_name: + data = client.get(artifact["archive_download_url"]) + if data.status_code == 302: + return str(data.next_request.url) + + # The following line is left untested since it should in theory be impossible + data.raise_for_status() # pragma: no cover + + raise NotFoundError("Could not find an artifact matching the provided name.") + + finally: + client.close() |