refactor(instagram): enhance batch processing for access block handling

Updated the fan_out function to allow partial results when encountering blocked targets. Instead of aborting the entire batch on a hard login wall, the function now tracks blocked statuses and raises InstagramAccessBlockedError only if all targets are blocked. This change improves the scraper's resilience and efficiency in handling Instagram's access restrictions.

surfsense_backend/app/proprietary/platforms/instagram/scraper.py

@@ -124,23 +124,24 @@ async def fan_out(
 
     Each worker opens ONE proxy session and reuses it across the sequential jobs
     it pulls, so only the first job per worker pays the proxy handshake + the
-    cookie warm-up. A bad job yields nothing rather than aborting the batch;
-    workers are cancelled and their sessions closed if the consumer stops early.
+    cookie warm-up. Partial results (matches the reddit sibling): one blocked or
+    failed target yields nothing rather than aborting the batch — Instagram is
+    an aggregation, not an atomic transaction, so 4/5 good targets beat 0/5. But
+    if EVERY target was refused (zero items AND a hard block seen), the whole run
+    couldn't reach anonymous data, so we surface ``InstagramAccessBlockedError``
+    (-> 403) instead of a misleading empty success. Workers are cancelled and
+    their sessions closed if the consumer stops early.
     """
     if not jobs:
         return
     job_queue: asyncio.Queue[AsyncIterator[dict[str, Any]]] = asyncio.Queue()
     for job in jobs:
         job_queue.put_nowait(job)
-    # A batch of items on success, or a hard-block exception to re-raise on the
-    # consumer side. The consumer reads exactly one entry per job, so a worker
-    # MUST put something for every job it pulls — raising instead would strand
-    # the error on a dead task and deadlock the consumer on ``results.get()``.
-    results: asyncio.Queue[list[dict[str, Any]] | InstagramAccessBlockedError] = (
-        asyncio.Queue()
-    )
+    results: asyncio.Queue[list[dict[str, Any]]] = asyncio.Queue()
+    blocked = False  # set if any target hit a hard login/auth wall
 
     async def worker() -> None:
+        nonlocal blocked
         holder = None
         try:
             holder = await open_proxy_holder()
@@ -160,10 +161,10 @@ async def fan_out(
                     else:
                         items = [item async for item in job]
                 except InstagramAccessBlockedError as e:
-                    # A hard login wall aborts the batch. Hand it to the consumer
-                    # via the queue (not ``raise``) so it never deadlocks waiting.
-                    await results.put(e)
-                    return
+                    # Partial results: a blocked target must not kill the batch.
+                    # Record it so a fully-blocked run can still surface the 403.
+                    blocked = True
+                    logger.warning("[instagram] target blocked: %s", e)
                 except Exception as e:  # one bad target must not kill the run
                     logger.warning("[instagram] fan-out job failed: %s", e)
                 await results.put(items)
@@ -172,18 +173,24 @@ async def fan_out(
                 await holder.close()
 
     tasks = [asyncio.create_task(worker()) for _ in range(min(concurrency, len(jobs)))]
+    emitted = 0
     try:
         for _ in range(len(jobs)):
-            batch = await results.get()
-            if isinstance(batch, InstagramAccessBlockedError):
-                raise batch
-            for item in batch:
+            for item in await results.get():
+                emitted += 1
                 yield item
     finally:
         for task in tasks:
             if not task.done():
                 task.cancel()
         await asyncio.gather(*tasks, return_exceptions=True)
+    # Reached only on natural exhaustion (an early-stop close raises GeneratorExit
+    # inside the loop and skips this). Nothing came back AND a wall was hit ->
+    # the run was fully refused, so fail loud rather than return empty.
+    if emitted == 0 and blocked:
+        raise InstagramAccessBlockedError(
+            "Instagram refused anonymous access to every target"
+        )
 
 
 def _emit(partial: dict[str, Any], *, input_url: str | None) -> dict[str, Any]: