Adds Netlify Builds

Adds an action which builds and uploads the static site as an artifact,
and a fetch script to be run on the netlify builders.

2 files changed, 170 insertions, 0 deletions

diff --git a/static-builds/README.md b/static-builds/README.md
new file mode 100644
index 00000000..ee2c0910
--- /dev/null
+++ b/static-builds/README.md
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+# Static Builds
+This directory includes all the needed information to build and deploy static previews of the site.
+
+Static deployments use [django-distill](https://github.com/meeb/django-distill) to build the static content.
+The content is built in GitHub Actions, and is fetched and deployed by Netlify.
+
+
+## Instructions
+These are the configuration instructions to get started with static deployments.
+They are split into two parts:
+
+- [Building The Site](#building-the-site)
+- [Deploying To Netlify](#deploying-to-netlify)
+
+
+### Building The Site
+To get started with building, you can use the following command:
+
+```shell
+python -m pip install httpx==0.19.0
+python manage.py distill-local build --traceback --force --collectstatic
+```
+
+Alternatively, you can use the [Dockerfile](./Dockerfile) in this folder.
+
+Both output their builds to a `build/` directory.
+
+> Warning: If you are modifying the [build script](./netlify_build.py), make sure it is compatible with Python 3.8.
+
+
+### Deploying To Netlify
+To deploy to netlify, link your site GitHub repository to a netlify site, and use the following settings:
+
+Build Command:
+`python -m pip install httpx==0.19.0 && python static-builds/netlify_build.py`
+
+Publish Directory:
+`build`
+
+Environment Variables:
+- PYTHON_VERSION: 3.8
+- TOKEN: A GitHub token with access to download build artifacts.
+
+
+Note that at this time, if you are deploying to netlify yourself, you won't have access to the
+fa-icons pack we are using, which will lead to many missing icons on your preview.
+You can either update the pack to one which will work on your domain, or you'll have to live with the missing icons.
diff --git a/static-builds/netlify_build.py b/static-builds/netlify_build.py
new file mode 100644
index 00000000..6686e2ab
--- /dev/null
+++ b/static-builds/netlify_build.py
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+"""Build script to deploy project on netlify."""
+
+# WARNING: This file must remain compatible with python 3.8
+
+# This script performs all the actions required to build and deploy our project on netlify
+# It requires the following environment variable:
+
+# TOKEN: A GitHub access token that can download the artifact.
+#        For PAT, the only scope needed is `public_repos`
+
+# It depends on the following packages, which are set in the netlify UI:
+# httpx == 0.19.0
+
+import os
+import time
+import zipfile
+from pathlib import Path
+from urllib import parse
+
+import httpx
+
+API_URL = "https://api.github.com"
+OWNER, REPO = parse.urlparse(os.getenv("REPOSITORY_URL")).path.lstrip("/").split("/")[0:2]
+
+
+def get_build_artifact() -> str:
+    """Search for a build artifact, and return the download URL."""
+    print("Fetching build URL.")
+
+    if os.getenv("PULL_REQUEST").lower() == "true":
+        print(f"Fetching data for PR #{os.getenv('REVIEW_ID')}")
+
+        pull_url = f"{API_URL}/repos/{OWNER}/{REPO}/pulls/{os.getenv('REVIEW_ID')}"
+        pull_request = httpx.get(pull_url)
+        pull_request.raise_for_status()
+
+        commit_sha = pull_request.json()["head"]["sha"]
+
+        workflows_params = parse.urlencode({
+            "event": "pull_request",
+            "per_page": 100
+        })
+
+    else:
+        commit_sha = os.getenv("COMMIT_REF")
+
+        workflows_params = parse.urlencode({
+            "event": "push",
+            "per_page": 100
+        })
+
+    print(f"Fetching action data for commit {commit_sha}")
+
+    workflows = httpx.get(f"{API_URL}/repos/{OWNER}/{REPO}/actions/runs?{workflows_params}")
+    workflows.raise_for_status()
+
+    for run in workflows.json()["workflow_runs"]:
+        if run["name"] == "Build & Publish Static Preview" and commit_sha == run["head_sha"]:
+            print(f"Found action for this commit: {run['id']}\n{run['html_url']}")
+            break
+    else:
+        raise Exception("Could not find the workflow run for this event.")
+
+    polls = 0
+    while polls <= 20:
+        if run["status"] != "completed":
+            print("Action isn't completed, sleeping for 30 seconds.")
+            polls += 1
+            time.sleep(30)
+
+        elif run["conclusion"] != "success":
+            print("Aborting build due to a failure in a previous CI step.")
+            exit(0)
+
+        else:
+            print(f"Found artifact URL:\n{run['artifacts_url']}")
+            return run["artifacts_url"]
+
+        _run = httpx.get(run["url"])
+        _run.raise_for_status()
+        run = _run.json()
+
+    raise Exception("Polled for the artifact workflow, but it was not ready in time.")
+
+
+def download_artifact(url: str) -> None:
+    """Download a build artifact from `url`, and unzip the content."""
+    print("Fetching artifact data.")
+
+    artifacts = httpx.get(url)
+    artifacts.raise_for_status()
+    artifacts = artifacts.json()
+
+    if artifacts["total_count"] == "0":
+        raise Exception(f"No artifacts were found for this build, aborting.\n{url}")
+
+    for artifact in artifacts["artifacts"]:
+        if artifact["name"] == "static-build":
+            print("Found artifact with build.")
+            break
+    else:
+        raise Exception("Could not find an artifact with the expected name.")
+
+    zipped_content = httpx.get(artifact["archive_download_url"], headers={
+        "Authorization": f"token {os.getenv('TOKEN')}"
+    })
+    zipped_content.raise_for_status()
+
+    zip_file = Path("temp.zip")
+    zip_file.write_bytes(zipped_content.read())
+
+    with zipfile.ZipFile(zip_file, "r") as zip_ref:
+        zip_ref.extractall("build")
+
+    zip_file.unlink(missing_ok=True)
+
+    print("Wrote artifact content to target directory.")
+
+
+if __name__ == "__main__":
+    print("Build started")
+    artifact_url = get_build_artifact()
+    download_artifact(artifact_url)