Make cycle show classify progress and prevent overlapping runs

- cycle now prints per-article classify progress (flushed) so the long step is
  clearly alive rather than appearing hung.
- An exclusive flock guards the cycle so a manual run and the systemd timer (or
  two timer ticks) cannot overlap and contend on the database and model.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

goodnews/cli.py

@@ -255,26 +255,56 @@ def check_feeds(conn: sqlite3.Connection, include_inactive: bool = False) -> Non
 
 def run_cycle(conn: sqlite3.Connection, args: argparse.Namespace) -> None:
     """One end-to-end pass for a scheduler: poll due sources, classify the new
-    arrivals, rebuild today's brief. Each step is independent and non-fatal so a
-    down model endpoint or empty day never aborts the whole cycle.
+    arrivals, dedup, rebuild today's brief. Each step is independent and
+    non-fatal so a down model endpoint or empty day never aborts the cycle.
+
+    Holds an exclusive lock so a manual run and the systemd timer (or two timer
+    ticks) can never overlap and contend on the database and model.
     """
+    import fcntl
+
+    lock_path = Path(args.db).parent / ".goodnews-cycle.lock"
+    lock_file = open(lock_path, "w")
+    try:
+        fcntl.flock(lock_file, fcntl.LOCK_EX | fcntl.LOCK_NB)
+    except OSError:
+        print("cycle: another cycle is already running; skipping")
+        lock_file.close()
+        return
+    try:
+        _run_cycle_locked(conn, args)
+    finally:
+        fcntl.flock(lock_file, fcntl.LOCK_UN)
+        lock_file.close()
+
+
+def _run_cycle_locked(conn: sqlite3.Connection, args: argparse.Namespace) -> None:
     init_db(conn)
 
     if args.force:
         poll_result = poll_all_sources(conn)
     else:
         poll_result = poll_due_sources(conn)
-    print(f"poll: {_format_result(poll_result)}")
+    print(f"poll: {_format_result(poll_result)}", flush=True)
 
     if not args.no_classify:
         client = llm_client_from_args(args)
+
+        def _progress(done: int, total: int, article_id: int) -> None:
+            print(f"  classify {done}/{total} (article {article_id})", flush=True)
+
         try:
             results = classify_articles(
-                conn, client, limit=args.classify_limit, include_rejected=True, only_unclassified=True
+                conn,
+                client,
+                limit=args.classify_limit,
+                include_rejected=True,
+                only_unclassified=True,
+                progress=_progress,
             )
-            print(f"classify: {len(results)} new article(s) scored by {client.model}")
+            print(f"classify: {len(results)} new article(s) scored by {client.model}", flush=True)
         except Exception as exc:  # endpoint down, timeout, etc. — keep going
-            print(f"classify: skipped ({exc})")
+            print(f"classify: skipped ({exc})", flush=True)
 
     if not args.no_dedup:
         try:

goodnews/llm.py

@@ -5,6 +5,7 @@ import os
 import sqlite3
 import urllib.error
 import urllib.request
+from collections.abc import Callable
 from dataclasses import dataclass
 
 from .taxonomy import (
@@ -226,12 +227,13 @@ def classify_articles(
     include_rejected: bool = False,
     dry_run: bool = False,
     only_unclassified: bool = False,
+    progress: "Callable[[int, int, int], None] | None" = None,
 ) -> list[tuple[int, dict]]:
     rows = _classification_candidates(
         conn, limit=limit, include_rejected=include_rejected, only_unclassified=only_unclassified
     )
     results = []
-    for row in rows:
+    for index, row in enumerate(rows, start=1):
         try:
             scores = client.classify(row)
         except RuntimeError as exc:
@@ -244,6 +246,8 @@ def classify_articles(
         if not dry_run:
             upsert_article_score(conn, row["id"], scores)
             conn.commit()
+        if progress is not None:
+            progress(index, len(rows), row["id"])
     return results