add pymongo support (#65)

* add pymongo support

* fix comment

* fix comment

* add all information from pymongo, rename subsegments

* add copyright information comment

Author: xplorld

aws_xray_sdk/core/patcher.py

@@ -11,6 +11,7 @@
     'sqlite3',
     'mysql',
     'httplib',
+    'pymongo',
 )
 
 _PATCHED_MODULES = set()

aws_xray_sdk/ext/pymongo/__init__.py

@@ -0,0 +1,4 @@
+# Copyright © 2018 Clarity Movement Co. All rights reserved.
+from .patch import patch
+
+__all__ = ['patch']

aws_xray_sdk/ext/pymongo/patch.py

@@ -0,0 +1,55 @@
+# Copyright © 2018 Clarity Movement Co. All rights reserved.
+from pymongo import monitoring
+from aws_xray_sdk.core import xray_recorder
+
+
+class XrayCommandListener(monitoring.CommandListener):
+    """
+    A listener that traces all pymongo db commands to AWS Xray.
+    Creates a subsegment for each mongo db conmmand.
+
+    name: 'mydb@127.0.0.1:27017'
+    records all available information provided by pymongo,
+    except for `command` and `reply`. They may contain business secrets.
+    If you insist to record them, specify `record_full_documents=True`.
+    """
+
+    def __init__(self, record_full_documents):
+        super(XrayCommandListener, self).__init__()
+        self.record_full_documents = record_full_documents
+
+    def started(self, event):
+        host, port = event.connection_id
+        host_and_port_str = f'{host}:{port}'
+
+        subsegment = xray_recorder.begin_subsegment(
+            f'{event.database_name}@{host_and_port_str}', 'remote')
+        subsegment.put_annotation('mongodb_command_name', event.command_name)
+        subsegment.put_annotation('mongodb_connection_id', host_and_port_str)
+        subsegment.put_annotation('mongodb_database_name', event.database_name)
+        subsegment.put_annotation('mongodb_operation_id', event.operation_id)
+        subsegment.put_annotation('mongodb_request_id', event.request_id)
+        if self.record_full_documents:
+            subsegment.put_metadata('mongodb_command', event.command)
+
+    def succeeded(self, event):
+        subsegment = xray_recorder.current_subsegment()
+        subsegment.put_annotation('mongodb_duration_micros', event.duration_micros)
+        if self.record_full_documents:
+            subsegment.put_metadata('mongodb_reply', event.reply)
+        xray_recorder.end_subsegment()
+
+    def failed(self, event):
+        subsegment = xray_recorder.current_subsegment()
+        subsegment.add_fault_flag()
+        subsegment.put_annotation('mongodb_duration_micros', event.duration_micros)
+        subsegment.put_metadata('failure', event.failure)
+        xray_recorder.end_subsegment()
+
+
+def patch(record_full_documents=False):
+    # ensure `patch()` is idempotent
+    if hasattr(monitoring, '_xray_enabled'):
+        return
+    setattr(monitoring, '_xray_enabled', True)
+    monitoring.register(XrayCommandListener(record_full_documents))