html_url,issue_url,id,node_id,user,user_label,created_at,updated_at,author_association,body,reactions,issue,issue_label,performed_via_github_app https://github.com/simonw/datasette/issues/1231#issuecomment-781560865,https://api.github.com/repos/simonw/datasette/issues/1231,781560865,MDEyOklzc3VlQ29tbWVudDc4MTU2MDg2NQ==,9599,simonw,2021-02-18T18:50:38Z,2021-02-18T18:50:38Z,OWNER,"I started trying to use locks to resolve this but I've not figured out the right way to do that yet - here's my first experiment: ```diff diff --git a/datasette/app.py b/datasette/app.py index 9e15a16..1681c9d 100644 --- a/datasette/app.py +++ b/datasette/app.py @@ -217,6 +217,7 @@ class Datasette: self.inspect_data = inspect_data self.immutables = set(immutables or []) self.databases = collections.OrderedDict() + self._refresh_schemas_lock = threading.Lock() if memory or not self.files: self.add_database(Database(self, is_memory=True), name=""_memory"") # memory_name is a random string so that each Datasette instance gets its own @@ -324,6 +325,13 @@ class Datasette: self.client = DatasetteClient(self) async def refresh_schemas(self): + return + if self._refresh_schemas_lock.locked(): + return + with self._refresh_schemas_lock: + await self._refresh_schemas() + + async def _refresh_schemas(self): internal_db = self.databases[""_internal""] if not self.internal_db_created: await init_internal_db(internal_db) ```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",811367257,Race condition errors in new refresh_schemas() mechanism, https://github.com/simonw/datasette/issues/1231#issuecomment-781560989,https://api.github.com/repos/simonw/datasette/issues/1231,781560989,MDEyOklzc3VlQ29tbWVudDc4MTU2MDk4OQ==,9599,simonw,2021-02-18T18:50:53Z,2021-02-18T18:50:53Z,OWNER,Ideally I'd figure out a way to replicate this error in a concurrent unit test.,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",811367257,Race condition errors in new refresh_schemas() mechanism, https://github.com/simonw/datasette/issues/1231#issuecomment-881204343,https://api.github.com/repos/simonw/datasette/issues/1231,881204343,IC_kwDOBm6k_c40hhx3,9599,simonw,2021-07-16T06:13:11Z,2021-07-16T06:13:11Z,OWNER,This just broke the `datasette-graphql` test suite: https://github.com/simonw/datasette-graphql/issues/77 - I need to figure out a solution here.,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",811367257,Race condition errors in new refresh_schemas() mechanism, https://github.com/simonw/datasette/issues/1231#issuecomment-881204782,https://api.github.com/repos/simonw/datasette/issues/1231,881204782,IC_kwDOBm6k_c40hh4u,9599,simonw,2021-07-16T06:14:12Z,2021-07-16T06:14:12Z,OWNER,"Here's the traceback I got from `datasette-graphql` (annoyingly only running the tests in GitHub Actions CI - I've not been able to replicate on my laptop yet): ``` tests/test_utils.py . [100%] =================================== FAILURES =================================== _________________________ test_graphql_examples[path0] _________________________ ds = path = PosixPath('/home/runner/work/datasette-graphql/datasette-graphql/examples/filters.md') @pytest.mark.asyncio @pytest.mark.parametrize( ""path"", (pathlib.Path(__file__).parent.parent / ""examples"").glob(""*.md"") ) async def test_graphql_examples(ds, path): content = path.read_text() query = graphql_re.search(content)[1] try: variables = variables_re.search(content)[1] except TypeError: variables = ""{}"" expected = json.loads(json_re.search(content)[1]) response = await ds.client.post( ""/graphql"", json={ ""query"": query, ""variables"": json.loads(variables), }, ) > assert response.status_code == 200, response.json() E AssertionError: {'data': {'repos_arraycontains': None, 'users_contains': None, 'users_date': None, 'users_endswith': None, ...}, 'erro..."", 'path': ['users_gt']}, {'locations': [{'column': 5, 'line': 34}], 'message': ""'rows'"", 'path': ['users_gte']}, ...]} E assert 500 == 200 E + where 500 = .status_code tests/test_graphql.py:142: AssertionError ----------------------------- Captured stderr call ----------------------------- table databases already exists table databases already exists table databases already exists table databases already exists table databases already exists table databases already exists table databases already exists table databases already exists table databases already exists table databases already exists table databases already exists table databases already exists table databases already exists table databases already exists table databases already exists table databases already exists table databases already exists table databases already exists table databases already exists table databases already exists table databases already exists Traceback (most recent call last): File ""/opt/hostedtoolcache/Python/3.7.11/x64/lib/python3.7/site-packages/datasette/app.py"", line 1171, in route_path response = await view(request, send) File ""/opt/hostedtoolcache/Python/3.7.11/x64/lib/python3.7/site-packages/datasette/views/base.py"", line 151, in view request, **request.scope[""url_route""][""kwargs""] File ""/opt/hostedtoolcache/Python/3.7.11/x64/lib/python3.7/site-packages/datasette/views/base.py"", line 123, in dispatch_request await self.ds.refresh_schemas() File ""/opt/hostedtoolcache/Python/3.7.11/x64/lib/python3.7/site-packages/datasette/app.py"", line 338, in refresh_schemas await init_internal_db(internal_db) File ""/opt/hostedtoolcache/Python/3.7.11/x64/lib/python3.7/site-packages/datasette/utils/internal_db.py"", line 16, in init_internal_db block=True, File ""/opt/hostedtoolcache/Python/3.7.11/x64/lib/python3.7/site-packages/datasette/database.py"", line 102, in execute_write return await self.execute_write_fn(_inner, block=block) File ""/opt/hostedtoolcache/Python/3.7.11/x64/lib/python3.7/site-packages/datasette/database.py"", line 118, in execute_write_fn raise result File ""/opt/hostedtoolcache/Python/3.7.11/x64/lib/python3.7/site-packages/datasette/database.py"", line 139, in _execute_writes result = task.fn(conn) File ""/opt/hostedtoolcache/Python/3.7.11/x64/lib/python3.7/site-packages/datasette/database.py"", line 100, in _inner return conn.execute(sql, params or []) sqlite3.OperationalError: table databases already exists ```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",811367257,Race condition errors in new refresh_schemas() mechanism, https://github.com/simonw/datasette/issues/1231#issuecomment-881663968,https://api.github.com/repos/simonw/datasette/issues/1231,881663968,IC_kwDOBm6k_c40jR_g,9599,simonw,2021-07-16T19:18:42Z,2021-07-16T19:18:42Z,OWNER,The race condition happens inside this method - initially with the call to `await init_internal_db()`: https://github.com/simonw/datasette/blob/dd5ee8e66882c94343cd3f71920878c6cfd0da41/datasette/app.py#L334-L359,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",811367257,Race condition errors in new refresh_schemas() mechanism, https://github.com/simonw/datasette/issues/1231#issuecomment-881664408,https://api.github.com/repos/simonw/datasette/issues/1231,881664408,IC_kwDOBm6k_c40jSGY,9599,simonw,2021-07-16T19:19:35Z,2021-07-16T19:19:35Z,OWNER,"The only place that calls `refresh_schemas()` is here: https://github.com/simonw/datasette/blob/dd5ee8e66882c94343cd3f71920878c6cfd0da41/datasette/views/base.py#L120-L124 Ideally only one call to `refresh_schemas()` would be running at any one time.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",811367257,Race condition errors in new refresh_schemas() mechanism, https://github.com/simonw/datasette/issues/1231#issuecomment-881665383,https://api.github.com/repos/simonw/datasette/issues/1231,881665383,IC_kwDOBm6k_c40jSVn,9599,simonw,2021-07-16T19:21:35Z,2021-07-16T19:21:35Z,OWNER,"https://stackoverflow.com/a/25799871/6083 has a good example of using `asyncio.Lock()`: ```python stuff_lock = asyncio.Lock() async def get_stuff(url): async with stuff_lock: if url in cache: return cache[url] stuff = await aiohttp.request('GET', url) cache[url] = stuff return stuff ```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",811367257,Race condition errors in new refresh_schemas() mechanism, https://github.com/simonw/datasette/issues/1231#issuecomment-881668759,https://api.github.com/repos/simonw/datasette/issues/1231,881668759,IC_kwDOBm6k_c40jTKX,9599,simonw,2021-07-16T19:27:46Z,2021-07-16T19:27:46Z,OWNER,"Second attempt at this: ```diff diff --git a/datasette/app.py b/datasette/app.py index 5976d8b..5f348cb 100644 --- a/datasette/app.py +++ b/datasette/app.py @@ -224,6 +224,7 @@ class Datasette: self.inspect_data = inspect_data self.immutables = set(immutables or []) self.databases = collections.OrderedDict() + self._refresh_schemas_lock = asyncio.Lock() self.crossdb = crossdb if memory or crossdb or not self.files: self.add_database(Database(self, is_memory=True), name=""_memory"") @@ -332,6 +333,12 @@ class Datasette: self.client = DatasetteClient(self) async def refresh_schemas(self): + if self._refresh_schemas_lock.locked(): + return + async with self._refresh_schemas_lock: + await self._refresh_schemas() + + async def _refresh_schemas(self): internal_db = self.databases[""_internal""] if not self.internal_db_created: await init_internal_db(internal_db) ```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",811367257,Race condition errors in new refresh_schemas() mechanism, https://github.com/simonw/datasette/issues/1231#issuecomment-881671706,https://api.github.com/repos/simonw/datasette/issues/1231,881671706,IC_kwDOBm6k_c40jT4a,9599,simonw,2021-07-16T19:32:05Z,2021-07-16T19:32:05Z,OWNER,The test suite passes with that change.,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",811367257,Race condition errors in new refresh_schemas() mechanism, https://github.com/simonw/datasette/issues/1231#issuecomment-881674857,https://api.github.com/repos/simonw/datasette/issues/1231,881674857,IC_kwDOBm6k_c40jUpp,9599,simonw,2021-07-16T19:38:39Z,2021-07-16T19:38:39Z,OWNER,I can't replicate the race condition locally with or without this patch. I'm going to push the commit and then test the CI run from `datasette-graphql` that was failing against it.,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",811367257,Race condition errors in new refresh_schemas() mechanism, https://github.com/simonw/datasette/issues/1231#issuecomment-881677620,https://api.github.com/repos/simonw/datasette/issues/1231,881677620,IC_kwDOBm6k_c40jVU0,9599,simonw,2021-07-16T19:44:12Z,2021-07-16T19:44:12Z,OWNER,"That fixed the race condition in the `datasette-graphql` tests, which is the only place that I've been able to successfully replicate this. I'm going to land this change.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",811367257,Race condition errors in new refresh_schemas() mechanism,