Support for motor (async pymongo)

[jeff-goddard]

Is your feature request related to a problem? Please describe.
The Python Elastic APM agent does not automatically instrument async calls to mongodb using motor

Describe the solution you'd like
Support for automatic instrumentation of motor similar to the way pymongo is instrumented

Describe alternatives you've considered
For now we have lived without instrumentation, although it looks like it should be possible to adapt the pymongo wrappers

Additional context
This is the motor project: https://github.com/mongodb/motor
It should be similar to pymongo

[basepi]

Thanks for the request!

[glexey]

I found out that adopting opentelemetry's approach to tracing mongo driver events works well with motor. Here's a simple instrumenter based on this approach:

from elasticapm.traces import execution_context
from pymongo import monitoring

def instrument_app():
    mongo_tracer = MongoCommandTracer()
    monitoring.register(mongo_tracer)

class MongoCommandTracer(monitoring.CommandListener):

    def started(self, event: monitoring.CommandStartedEvent):
        command = event.command.get(event.command_name, "")
        name = event.command_name
        if command:
            name += f".{command}"

        transaction = execution_context.get_transaction()
        if transaction and transaction.is_sampled:
            transaction.begin_span(name=name, span_type="db", leaf=True, span_subtype="mongodb", span_action="query")

    def succeeded(self, event: monitoring.CommandSucceededEvent):
        transaction = execution_context.get_transaction()
        if transaction and transaction.is_sampled:
            transaction.end_span(skip_frames=0, duration=None, outcome="success")

    def failed(self, event: monitoring.CommandFailedEvent):
        transaction = execution_context.get_transaction()
        if transaction and transaction.is_sampled:
            transaction.end_span(skip_frames=0, duration=None, outcome="failure")

Original code adds extra metadata such as server host:port, which wasn't needed in my case.

[jeff-goddard]

Thanks @glexey

I added a few more parameters for my own use case, and this works well.

Not sure if something like this should replace the official instrumentation?