Remove stale PR preview cleanup (#4721)

This reverts the stale PR preview cleanup. This feature removed previews
for open PRs that have been inactive for over two weeks.

We decided to remove it for the following reasons:

1. We originally introduced this to improve the reliability and speed of
preview deployments. However, we're not sure it makes a noticeable
difference; there are usually only one or two stale previews at any one
point in time (vs ~20-30 previews in total).

2. Even with the small number of stale previews, the expiration has
inconvenienced writers who needed to share previews with stakeholders.

3. The final straw is that the tests are broken in a really nasty way:
They fail on the GitHub actions MacOS runner but pass on our local MacOS
machines. When I deleted the failing test to debug things, the Windows
runner started showing even more crazy errors. I have no idea what's
causing it but it's related to the `datetime` library and I think it's
going to take a lot of time to fix. I also think there's a real risk the
code is actually broken and it's not just a test problem. With points 1
& 2, we decided to just remove the feature.

Author: frankharkins

scripts/pr-previews/cleanup.py

@@ -15,10 +15,7 @@
 import json
 import logging
 import shutil
-import time
 from pathlib import Path
-from datetime import datetime
-from typing import TypedDict
 
 logger = logging.getLogger(__name__)
 
@@ -32,9 +29,6 @@
 
 INITIAL_COMMIT = "499a5040585d02593cdd8237e19c9ee4a84ae126"
 
-SEVEN_DAYS_IN_SECONDS = 60 * 60 * 24 * 7
-PR_EXPIRATION_TIME_SECONDS = SEVEN_DAYS_IN_SECONDS
-
 
 def main() -> None:
     setup_git_account()
@@ -63,137 +57,22 @@ def main() -> None:
         logger.info("Cleaned up closed PR previews")
 
 
-class PrFolders(TypedDict):
-    all_open: set[str]
-    open_stale: set[str]
-
-
-def determine_stale(
-    api_response: str, current_time: int, expiration_period: int
-) -> PrFolders:
-    # We parse the JSON into `{ number: int, updatedAt: int }[]`
-    def parse_updated_at(data):
-        """Converts "updatedAt" fields from iso strings into unix timestamps"""
-        if "updatedAt" in data:
-            iso_format = data["updatedAt"]
-            timestamp = datetime.fromisoformat(iso_format).timestamp()
-            data["updatedAt"] = timestamp
-        return data
-
-    parsed = json.loads(api_response, object_hook=parse_updated_at)
-    all_pr_numbers = (pr["number"] for pr in parsed)
-
-    # ========================================================
-    # Extract stale PRs
-    # ========================================================
-
-    def is_stale(updated_at: int) -> bool:
-        return (current_time - updated_at) > expiration_period
-
-    stale_pr_numbers = (pr["number"] for pr in parsed if is_stale(pr["updatedAt"]))
-
-    # === Return folder names ===
-    def number_to_folder(num: int) -> str:
-        return f"pr-{num}"
-
-    return {
-        "all_open": set(map(number_to_folder, all_pr_numbers)),
-        "open_stale": set(map(number_to_folder, stale_pr_numbers)),
-    }
-
-
-def get_pr_folders() -> PrFolders:
-    api_response = run_subprocess(
-        [
-            "gh",
-            "pr",
-            "list",
-            "--state",
-            "open",
-            "--json",
-            "number,updatedAt",
-            "--limit",
-            "1000",
-        ]
+def get_active_pr_folders() -> 'set[str]':
+    raw = run_subprocess(
+        ["gh", "pr", "list", "--state", "open", "--json", "number", "--limit", "1000"]
     ).stdout
-    return determine_stale(api_response, int(time.time()), PR_EXPIRATION_TIME_SECONDS)
-
+    # `raw` is JSON string of form: { number: int }[]
+    return {f"pr-{obj['number']}" for obj in json.loads(raw)}
 
 def delete_closed_pr_folders() -> None:
-    pr_folders = get_pr_folders()
-
+    active_pr_folders = get_active_pr_folders()
     for folder in Path(".").glob("pr-*"):
-        is_closed = folder.name not in pr_folders["all_open"]
+        is_closed = folder.name not in active_pr_folders
         if is_closed:
             logger.info(f"Deleting {folder} as PR is closed")
             shutil.rmtree(folder)
-            continue
-
-        is_stale = folder.name in pr_folders["open_stale"]
-        if is_stale:
-            logger.info(f"Deleting {folder} as it is stale")
-            shutil.rmtree(folder)
-            continue
 
 
 if __name__ == "__main__":
     configure_logging()
     main()
-
-
-# =====
-# TESTS
-# =====
-
-
-def test_determine_stale_empty_list():
-    assert determine_stale("[]", 0, 1) == {"all_open": set(), "open_stale": set()}
-
-
-def test_determine_stale_active_pr():
-    api_response = """[{
-      "number": 1,
-      "updatedAt": "1970-01-01T01:00:00"
-    }]"""
-    assert determine_stale(api_response, current_time=0, expiration_period=1) == {
-        "all_open": {"pr-1"},
-        "open_stale": set(),
-    }
-
-
-def test_determine_stale_stale_pr():
-    # unix_epoch = "1970-01-01T01:00:00"
-    # (checked wih `datetime.fromtimestamp(0).isoformat()`)
-    api_response = """[{
-      "number": 1,
-      "updatedAt": "1970-01-01T01:00:00"
-    }]"""
-    assert determine_stale(api_response, current_time=100, expiration_period=10) == {
-        "all_open": {"pr-1"},
-        "open_stale": {"pr-1"},
-    }
-
-
-def test_determine_stale_many_results():
-    api_response = """[
-      {
-        "number": 1,
-        "updatedAt": "1970-01-01T01:00:00"
-      },
-      {
-        "number": 2,
-        "updatedAt": "1970-01-02T01:00:00"
-      },
-      {
-        "number": 3,
-        "updatedAt": "1970-01-03T01:00:00"
-      }
-    ]"""
-    current_time = int(datetime(1970, 1, 4, 1, 0).timestamp())  # 4th Jan, 1970
-    two_days_in_seconds = 60 * 60 * 24 * 2
-    assert determine_stale(
-        api_response, current_time, expiration_period=two_days_in_seconds
-    ) == {
-        "all_open": {"pr-1", "pr-2", "pr-3"},
-        "open_stale": {"pr-1"},
-    }

tox.ini

@@ -34,6 +34,4 @@ deps =
   -e scripts/image-tester
   -e scripts/notebook-normalizer
   pytest
-commands =
-  pytest
-  pytest scripts/pr-previews/cleanup.py
+commands = pytest