pymongo instrumentation issue with ddtrace 2.14.x: AttributeError: 'NoneType' object has no attribute 'onto'

[pg-synth]

Hello,

We recently tried to bump our ddtrace lib from 2.9.x to 2.14 and encountered the following issue with pymongo (no other change were made beside the lib bump.

AttributeError: 'NoneType' object has no attribute 'onto'

We have the feeling it's a regression that appeared with the latest version.

Error details

Stack trace:

[....]
File "/home/lambda/pymongo/cursor.py", line 1243, in next
    if len(self.__data) or self._refresh():
  File "/home/lambda/pymongo/cursor.py", line 1160, in _refresh
    self.__send_message(q)
  File "/home/lambda/pymongo/cursor.py", line 1039, in __send_message
    response = client._run_operation(
  File "/home/lambda/pymongo/_csot.py", line 108, in csot_wrapper
    return func(self, *args, **kwargs)
  File "/home/lambda/pymongo/mongo_client.py", line 1431, in _run_operation
    return self._retryable_read(
  File "/home/lambda/pymongo/mongo_client.py", line 1540, in _retryable_read
    return self._retry_internal(
  File "/home/lambda/pymongo/_csot.py", line 108, in csot_wrapper
    return func(self, *args, **kwargs)
  File "/home/lambda/pymongo/mongo_client.py", line 1507, in _retry_internal
    ).run()
  File "/home/lambda/pymongo/mongo_client.py", line 2353, in run
    return self._read() if self._is_read else self._write()
  File "/home/lambda/pymongo/mongo_client.py", line 2483, in _read
    self._server = self._get_server()
  File "/home/lambda/pymongo/mongo_client.py", line 2439, in _get_server
    return self._client._select_server(
  File "/home/lambda/pymongo/mongo_client.py", line 1322, in _select_server
    server = topology.select_server(
  File "/home/lambda/pymongo/topology.py", line 358, in select_server
    def select_server(
  File "/home/lambda/ddtrace/contrib/internal/pymongo/client.py", line 104, in _trace_topology_select_server
    ddtrace.Pin.get_from(topology_instance).onto(server)
AttributeError: 'NoneType' object has no attribute 'onto'

Original lib code line in question

def _trace_topology_select_server(func, args, kwargs):
    server = func(*args, **kwargs)
    # Ensure the pin used on the traced mongo client is passed down to the topology instance
    # This allows us to pass the same pin in traced server objects.
    topology_instance = get_argument_value(args, kwargs, 0, "self")
    ddtrace.Pin.get_from(topology_instance).onto(server)
    return server

Instrumentation

Our bits of code patching pymongo and setting an override for the service name is very vanilla and follows the documentation recommendations:

import pymongo
from ddtrace import Pin, patch

from XXXX.mongodb.config import config

patch(pymongo=True)

client = pymongo.MongoClient(
    *config["client_args"],
    **config["client_kwargs"],
    uuidrepresentation="standard",
)

pin = Pin.override(client, service="XXX-CUSTOM")

db = client[config["database"]]
return_document = pymongo.ReturnDocument

def get_database():
    return client[config["database"]]

Other informations

Which version of dd-trace-py are you using?

2.14.2

Which libraries and their versions are you using?

pymongo: 4.8.0 datadog-lambda: 6.99.0

How can we reproduce your problem?

patch and pin with pymongo 4.8

[quinna-h]

Hello, thank you for submitting this issue!

Could you please provide a full reproduction? I wasn't able to reproduce the error with the provided snippet.

[DSNortsev]

Hello, we have the same issue after upgrading to ddtrace==2.14.4 and pymongo==4.10.1. I am not sure if I would be able to provide the exact steps to reproduce this issue.

[quinna-h]

Hi @DSNortsev @pg-synth ,

We recently merged a fix into ddtrace 2.15 and 2.14. Please feel free to re-open this issue or open a new issue if you are still facing issues!

[iherasymenko]

@quinna-h the issue is still reproducible with ddtrace 2.15.1. The producer can be found in the description of https://github.com/DataDog/dd-trace-py/issues/11287.

[quinna-h]

@iherasymenko Responded on linked issue, this change has not been yet been released but will be released in the next patch releases.