pymongo Invalid type in attribute sequence when using sessions

[sanzoghenzo]

#1555 introduced a bug when using pymongo sessions, the instrumentor now outputs the message

Invalid type dict in attribute value sequence. Expected one of ['bool', 'str', 'bytes', 'int', 'float'] or None

while exiting the session.
After some debugging, I realized that this id triggered by the "endSessions" command, that triggers the CommandStartedEvent with a SON command like this:

SON([('endSessions', [{'id': Binary(b'U\xf4\x19x\xdd\xd8FK\x80\x13\x97\xcc_U\xd5L', 4)}]), ('$db', 'admin')])

and the collection variable becomes a list of dictionaries instead of the expected string.

Describe your environment

• python 3.10
• windows 10, but also on linux/docker
• pymongo 4.4.1
• opentelemetry-instrumentation-pymongo 0.40b0
• opentelemetry 1.19.0

Steps to reproduce

from opentelemetry import trace
from opentelemetry.instrumentation.pymongo import PymongoInstrumentor
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.trace.export import BatchSpanProcessor, ConsoleSpanExporter
from pymongo import MongoClient

provider = TracerProvider()
processor = BatchSpanProcessor(ConsoleSpanExporter())
provider.add_span_processor(processor)
trace.set_tracer_provider(provider)

PymongoInstrumentor().instrument()
client = MongoClient()
session = client.start_session()
RECORD = {"test": "123"}
db = client["MongoDB_Database"]
collection = db["MongoDB_Collection"]
collection.find_one(RECORD)
session.end_session()
client.close()

What is the expected behavior?
span.set_attribute(SpanAttributes.DB_MONGODB_COLLECTION) should not be called if the collection variable is not a string

What is the actual behavior?
The set_attribute method is called and the message above is output in the console.

Additional context
Another solution would be to check for the pymongo command names that doesn't have/need a collection name

[WolfEYc]

+1

[UltimateLobster]

+1, this seems like an easy fix. I wonder why the PR was not merged even a year later.