better handling of failed redis connection + exec time updates (#1520)

This PR addresses a possible failure when Redis pod was inaccessible
from Crawler pod.
- Ensure crawl is set to 'waiting_for_capacity' if either no crawler
pods are available or no redis pod. previously, missing/inaccessible
redis would not result in 'waiting_for_capacity' if crawler pods are
available
- Rework logic: if no crawler and redis after >60 seconds, shutdown
redis. if crawler and no redis, init (or reinit) redis
- track 'lastUpdatedTime' in db when incrementing exec time to avoid
double counting if lastUpdatedTime has not changed, eg. if operator sync
fails.
- add redis timeout of 20 seconds to avoid timing out operator responses
if redis conn takes too long, assume unavailable

backend/btrixcloud/crawls.py

@@ -451,11 +451,14 @@ class CrawlOps(BaseCrawlOps):
         query = {"_id": crawl_id, "type": "crawl", "state": "running"}
         return await self.crawls.find_one_and_update(query, {"$set": {"stats": stats}})
 
-    async def inc_crawl_exec_time(self, crawl_id, exec_time):
+    async def inc_crawl_exec_time(self, crawl_id, exec_time, last_updated_time):
         """increment exec time"""
         return await self.crawls.find_one_and_update(
-            {"_id": crawl_id, "type": "crawl"},
-            {"$inc": {"crawlExecSeconds": exec_time}},
+            {"_id": crawl_id, "type": "crawl", "_lut": {"$ne": last_updated_time}},
+            {
+                "$inc": {"crawlExecSeconds": exec_time},
+                "$set": {"_lut": last_updated_time},
+            },
         )
 
     async def get_crawl_state(self, crawl_id):

backend/btrixcloud/k8sapi.py

@@ -67,7 +67,10 @@ class K8sAPI:
     async def get_redis_client(self, redis_url):
         """return redis client with correct params for one-time use"""
         return aioredis.from_url(
-            redis_url, decode_responses=True, auto_close_connection_pool=True
+            redis_url,
+            decode_responses=True,
+            auto_close_connection_pool=True,
+            socket_timeout=20,
         )
 
     # pylint: disable=too-many-arguments, too-many-locals

backend/btrixcloud/operator.py

@@ -942,8 +942,10 @@ class BtrixOperator(K8sAPI):
             if status.anyCrawlPodNewExit:
                 await self.log_crashes(crawl.id, status.podStatus, redis)
 
-            if not crawler_running:
+            if not crawler_running or not redis:
+                # if either crawler is not running or redis is inaccessible
                 if self.should_mark_waiting(status.state, crawl.started):
+                    # mark as waiting (if already running)
                     await self.set_state(
                         "waiting_capacity",
                         status,
@@ -951,25 +953,25 @@ class BtrixOperator(K8sAPI):
                         allowed_from=RUNNING_AND_STARTING_ONLY,
                     )
 
-                # for now, don't reset redis once inited
-                if status.lastActiveTime and (
-                    (dt_now() - from_k8s_date(status.lastActiveTime)).total_seconds()
-                    > REDIS_TTL
-                ):
-                    print(
-                        f"Pausing redis, no running crawler pods for >{REDIS_TTL} secs"
-                    )
-                    status.initRedis = False
+                if not crawler_running and redis:
+                    # if crawler running, but no redis, stop redis instance until crawler
+                    # is running
+                    if status.lastActiveTime and (
+                        (
+                            dt_now() - from_k8s_date(status.lastActiveTime)
+                        ).total_seconds()
+                        > REDIS_TTL
+                    ):
+                        print(
+                            f"Pausing redis, no running crawler pods for >{REDIS_TTL} secs"
+                        )
+                        status.initRedis = False
+                elif crawler_running and not redis:
+                    # if crawler is running, but no redis, init redis
+                    status.initRedis = True
+                    status.lastActiveTime = to_k8s_date(dt_now())
 
-                # if still running, resync after N seconds
-                status.resync_after = self.fast_retry_secs
-                return status
-
-            status.initRedis = True
-            status.lastActiveTime = to_k8s_date(dt_now())
-
-            if not redis:
-                # if still running, resync after N seconds
+                # if no crawler / no redis, resync after N seconds
                 status.resync_after = self.fast_retry_secs
                 return status
 
@@ -1182,7 +1184,16 @@ class BtrixOperator(K8sAPI):
                 max_duration = max(duration, max_duration)
 
         if exec_time:
-            await self.crawl_ops.inc_crawl_exec_time(crawl_id, exec_time)
+            if not await self.crawl_ops.inc_crawl_exec_time(
+                crawl_id, exec_time, status.lastUpdatedTime
+            ):
+                # if lastUpdatedTime is same as previous, something is wrong, don't update!
+                print(
+                    "Already updated for lastUpdatedTime, skipping execTime update!",
+                    flush=True,
+                )
+                return
+
             await self.org_ops.inc_org_time_stats(oid, exec_time, True)
             status.crawlExecTime += exec_time
             status.elapsedCrawlTime += max_duration