👷 Add custom GitHub actions to preview docs

.github/actions/comment-docs-preview-in-pr/Dockerfile

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+FROM python:3.7
+
+RUN pip install httpx "pydantic==1.5.1" pygithub
+
+COPY ./app /app
+
+CMD ["python", "/app/main.py"]

.github/actions/comment-docs-preview-in-pr/action.yml

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+name: Comment Docs Preview in PR
+description: Comment with the docs URL preview in the PR
+author: Sebastián Ramírez <tiangolo@gmail.com>
+inputs:
+  token:
+    description: Token for the repo. Can be passed in using {{ secrets.GITHUB_TOKEN }}
+    required: true
+  deploy_url:
+    description: The deployment URL to comment in the PR
+    required: true
+runs:
+  using: docker
+  image: Dockerfile

.github/actions/comment-docs-preview-in-pr/app/main.py

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+import logging
+import sys
+from pathlib import Path
+from typing import Optional
+
+import httpx
+from github import Github
+from github.PullRequest import PullRequest
+from pydantic import BaseModel, BaseSettings, SecretStr, ValidationError
+
+github_api = "https://api.github.com"
+
+
+class Settings(BaseSettings):
+    github_repository: str
+    github_event_path: Path
+    github_event_name: Optional[str] = None
+    input_token: SecretStr
+    input_deploy_url: str
+
+
+class PartialGithubEventHeadCommit(BaseModel):
+    id: str
+
+
+class PartialGithubEventWorkflowRun(BaseModel):
+    head_commit: PartialGithubEventHeadCommit
+
+
+class PartialGithubEvent(BaseModel):
+    workflow_run: PartialGithubEventWorkflowRun
+
+
+if __name__ == "__main__":
+    logging.basicConfig(level=logging.INFO)
+    settings = Settings()
+    logging.info(f"Using config: {settings.json()}")
+    g = Github(settings.input_token.get_secret_value())
+    repo = g.get_repo(settings.github_repository)
+    try:
+        event = PartialGithubEvent.parse_file(settings.github_event_path)
+    except ValidationError as e:
+        logging.error(f"Error parsing event file: {e.errors()}")
+        sys.exit(0)
+    use_pr: Optional[PullRequest] = None
+    for pr in repo.get_pulls():
+        if pr.head.sha == event.workflow_run.head_commit.id:
+            use_pr = pr
+            break
+    if not use_pr:
+        logging.error(
+            f"No PR found for hash: {event.workflow_run.head_commit.id}"
+        )
+        sys.exit(0)
+    github_headers = {
+        "Authorization": f"token {settings.input_token.get_secret_value()}"
+    }
+    url = f"{github_api}/repos/{settings.github_repository}/issues/{use_pr.number}/comments"
+    logging.info(f"Using comments URL: {url}")
+    response = httpx.post(
+        url,
+        headers=github_headers,
+        json={
+            "body": f"📝 Docs preview for commit {use_pr.head.sha} at: {settings.input_deploy_url}"
+        },
+    )
+    if not (200 <= response.status_code <= 300):
+        logging.error(f"Error posting comment: {response.text}")
+        sys.exit(1)
+    logging.info("Finished")