Use reserved concurrency to limit report handling concurrency

This is a much nicer fix for the race condition issue.

Author: christopher-dG

serverless.yml

@@ -31,6 +31,7 @@ functions:
       - http: ANY /{any+}
   reports:
     handler: tagbot.web.reports.handler
+    reservedConcurrency: 1
     events:
       - sqs:
           arn: !GetAtt reports.Arn

stubs/boto3.pyi

@@ -1,7 +1,7 @@
 from typing import Literal
 
 class QueueType:
-    def send_message(self, *, MessageBody: str, DelaySeconds: int) -> object: ...
+    def send_message(self, *, MessageBody: str) -> object: ...
 
 class SQS:
     @staticmethod

tagbot/web/__init__.py

@@ -2,7 +2,6 @@
 import logging
 import os
 
-from random import randrange
 from typing import Dict, Optional, Tuple, TypeVar, Union, cast
 
 import boto3
@@ -15,7 +14,6 @@
 HTML = StatusOptional[str]
 JSON = StatusOptional[Dict[str, object]]
 
-MAX_DELAY = 900
 SQS = boto3.resource("sqs", region_name=os.getenv("AWS_REGION", "us-east-1"))
 REPORTS_QUEUE = SQS.Queue(os.getenv("REPORTS_QUEUE", ""))
 TAGBOT_REPO_NAME = os.getenv("TAGBOT_REPO", "")
@@ -80,9 +78,5 @@ def report() -> JSON:
         "run": request.json["run"],
         "stacktrace": request.json["stacktrace"],
     }
-    # Because the GitHub Action usually runs on the hour, we tend to get a lot of
-    # requests at once, which botches the duplicate report detection.
-    # To deal with that, wait a random period before the message becomes available.
-    delay = randrange(MAX_DELAY)
-    REPORTS_QUEUE.send_message(MessageBody=json.dumps(payload), DelaySeconds=delay)
-    return {"status": "Submitted error report", "delay": delay}, 200
+    REPORTS_QUEUE.send_message(MessageBody=json.dumps(payload))
+    return {"status": "Submitted error report"}, 200

test/web/test_web.py

@@ -61,14 +61,11 @@ def test_index(client):
     assert b"Home" in resp.data
 
 
-@patch("tagbot.web.randrange", return_value=10)
 @patch("tagbot.web.REPORTS_QUEUE")
-def test_report(REPORTS_QUEUE, randrange, client):
+def test_report(REPORTS_QUEUE, client):
     payload = {"image": "img", "repo": "repo", "run": "123", "stacktrace": "ow"}
     resp = client.post("/report", json=payload)
     assert resp.status_code == 200
     assert resp.is_json
-    assert resp.json == {"status": "Submitted error report", "delay": 10}
-    REPORTS_QUEUE.send_message.assert_called_with(
-        MessageBody=json.dumps(payload), DelaySeconds=10
-    )
+    assert resp.json == {"status": "Submitted error report"}
+    REPORTS_QUEUE.send_message.assert_called_with(MessageBody=json.dumps(payload))