monitoring – Tools for monitoring driver events.

Tools to monitor driver events.

New in version 3.1.

Use register() to register global listeners for specific events. Listeners must inherit from one of the abstract classes below and implement the correct functions for that class.

For example, a simple command logger might be implemented like this:

import logging

from pymongo import monitoring

class CommandLogger(monitoring.CommandListener):

    def started(self, event):
        logging.info("Command {0.command_name} with request id "
                     "{0.request_id} started on server "
                     "{0.connection_id}".format(event))

    def succeeded(self, event):
        logging.info("Command {0.command_name} with request id "
                     "{0.request_id} on server {0.connection_id} "
                     "succeeded in {0.duration_micros} "
                     "microseconds".format(event))

    def failed(self, event):
        logging.info("Command {0.command_name} with request id "
                     "{0.request_id} on server {0.connection_id} "
                     "failed in {0.duration_micros} "
                     "microseconds".format(event))

monitoring.register(CommandLogger())

Server discovery and monitoring events are also available. For example:

class ServerLogger(monitoring.ServerListener):

    def opened(self, event):
        logging.info("Server {0.server_address} added to topology "
                     "{0.topology_id}".format(event))

    def description_changed(self, event):
        previous_server_type = event.previous_description.server_type
        new_server_type = event.new_description.server_type
        if new_server_type != previous_server_type:
            # server_type_name was added in PyMongo 3.4
            logging.info(
                "Server {0.server_address} changed type from "
                "{0.previous_description.server_type_name} to "
                "{0.new_description.server_type_name}".format(event))

    def closed(self, event):
        logging.warning("Server {0.server_address} removed from topology "
                        "{0.topology_id}".format(event))


class HeartbeatLogger(monitoring.ServerHeartbeatListener):

    def started(self, event):
        logging.info("Heartbeat sent to server "
                     "{0.connection_id}".format(event))

    def succeeded(self, event):
        # The reply.document attribute was added in PyMongo 3.4.
        logging.info("Heartbeat to server {0.connection_id} "
                     "succeeded with reply "
                     "{0.reply.document}".format(event))

    def failed(self, event):
        logging.warning("Heartbeat to server {0.connection_id} "
                        "failed with error {0.reply}".format(event))

class TopologyLogger(monitoring.TopologyListener):

    def opened(self, event):
        logging.info("Topology with id {0.topology_id} "
                     "opened".format(event))

    def description_changed(self, event):
        logging.info("Topology description updated for "
                     "topology id {0.topology_id}".format(event))
        previous_topology_type = event.previous_description.topology_type
        new_topology_type = event.new_description.topology_type
        if new_topology_type != previous_topology_type:
            # topology_type_name was added in PyMongo 3.4
            logging.info(
                "Topology {0.topology_id} changed type from "
                "{0.previous_description.topology_type_name} to "
                "{0.new_description.topology_type_name}".format(event))
        # The has_writable_server and has_readable_server methods
        # were added in PyMongo 3.4.
        if not event.new_description.has_writable_server():
            logging.warning("No writable servers available.")
        if not event.new_description.has_readable_server():
            logging.warning("No readable servers available.")

    def closed(self, event):
        logging.info("Topology with id {0.topology_id} "
                     "closed".format(event))

Connection monitoring and pooling events are also available. For example:

class ConnectionPoolLogger(ConnectionPoolListener):

    def pool_created(self, event):
        logging.info("[pool {0.address}] pool created".format(event))

    def pool_cleared(self, event):
        logging.info("[pool {0.address}] pool cleared".format(event))

    def pool_closed(self, event):
        logging.info("[pool {0.address}] pool closed".format(event))

    def connection_created(self, event):
        logging.info("[pool {0.address}][conn #{0.connection_id}] "
                     "connection created".format(event))

    def connection_ready(self, event):
        logging.info("[pool {0.address}][conn #{0.connection_id}] "
                     "connection setup succeeded".format(event))

    def connection_closed(self, event):
        logging.info("[pool {0.address}][conn #{0.connection_id}] "
                     "connection closed, reason: "
                     "{0.reason}".format(event))

    def connection_check_out_started(self, event):
        logging.info("[pool {0.address}] connection check out "
                     "started".format(event))

    def connection_check_out_failed(self, event):
        logging.info("[pool {0.address}] connection check out "
                     "failed, reason: {0.reason}".format(event))

    def connection_checked_out(self, event):
        logging.info("[pool {0.address}][conn #{0.connection_id}] "
                     "connection checked out of pool".format(event))

    def connection_checked_in(self, event):
        logging.info("[pool {0.address}][conn #{0.connection_id}] "
                     "connection checked into pool".format(event))

Event listeners can also be registered per instance of MongoClient:

client = MongoClient(event_listeners=[CommandLogger()])

Note that previously registered global listeners are automatically included when configuring per client event listeners. Registering a new global listener will not add that listener to existing client instances.

Note

Events are delivered synchronously. Application threads block waiting for event handlers (e.g. started()) to return. Care must be taken to ensure that your event handlers are efficient enough to not adversely affect overall application performance.

Warning

The command documents published through this API are not copies. If you intend to modify them in any way you must copy them in your event handler first.

pymongo.monitoring.register(listener)

Register a global event listener.

Parameters:
class pymongo.monitoring.CommandListener

Abstract base class for command listeners.

Handles CommandStartedEvent, CommandSucceededEvent, and CommandFailedEvent.

failed(event)

Abstract method to handle a CommandFailedEvent.

Parameters:
started(event)

Abstract method to handle a CommandStartedEvent.

Parameters:
succeeded(event)

Abstract method to handle a CommandSucceededEvent.

Parameters:
class pymongo.monitoring.ServerListener

Abstract base class for server listeners. Handles ServerOpeningEvent, ServerDescriptionChangedEvent, and ServerClosedEvent.

New in version 3.3.

closed(event)

Abstract method to handle a ServerClosedEvent.

Parameters:
description_changed(event)

Abstract method to handle a ServerDescriptionChangedEvent.

Parameters:
opened(event)

Abstract method to handle a ServerOpeningEvent.

Parameters:
class pymongo.monitoring.ServerHeartbeatListener

Abstract base class for server heartbeat listeners.

Handles ServerHeartbeatStartedEvent, ServerHeartbeatSucceededEvent, and ServerHeartbeatFailedEvent.

New in version 3.3.

failed(event)

Abstract method to handle a ServerHeartbeatFailedEvent.

Parameters:
started(event)

Abstract method to handle a ServerHeartbeatStartedEvent.

Parameters:
succeeded(event)

Abstract method to handle a ServerHeartbeatSucceededEvent.

Parameters:
class pymongo.monitoring.TopologyListener

Abstract base class for topology monitoring listeners. Handles TopologyOpenedEvent, TopologyDescriptionChangedEvent, and TopologyClosedEvent.

New in version 3.3.

closed(event)

Abstract method to handle a TopologyClosedEvent.

Parameters:
description_changed(event)

Abstract method to handle a TopologyDescriptionChangedEvent.

Parameters:
opened(event)

Abstract method to handle a TopologyOpenedEvent.

Parameters:
class pymongo.monitoring.ConnectionPoolListener

Abstract base class for connection pool listeners.

Handles all of the connection pool events defined in the Connection Monitoring and Pooling Specification: PoolCreatedEvent, PoolClearedEvent, PoolClosedEvent, ConnectionCreatedEvent, ConnectionReadyEvent, ConnectionClosedEvent, ConnectionCheckOutStartedEvent, ConnectionCheckOutFailedEvent, ConnectionCheckedOutEvent, and ConnectionCheckedInEvent.

New in version 3.9.

connection_check_out_failed(event)

Abstract method to handle a ConnectionCheckOutFailedEvent.

Emitted when the driver’s attempt to check out a connection fails.

Parameters:
connection_check_out_started(event)

Abstract method to handle a ConnectionCheckOutStartedEvent.

Emitted when the driver starts attempting to check out a connection.

Parameters:
connection_checked_in(event)

Abstract method to handle a ConnectionCheckedInEvent.

Emitted when the driver checks in a Connection back to the Connection Pool.

Parameters:
connection_checked_out(event)

Abstract method to handle a ConnectionCheckedOutEvent.

Emitted when the driver successfully checks out a Connection.

Parameters:
connection_closed(event)

Abstract method to handle a ConnectionClosedEvent.

Emitted when a Connection Pool closes a Connection.

Parameters:
connection_created(event)

Abstract method to handle a ConnectionCreatedEvent.

Emitted when a Connection Pool creates a Connection object.

Parameters:
connection_ready(event)

Abstract method to handle a ConnectionReadyEvent.

Emitted when a Connection has finished its setup, and is now ready to use.

Parameters:
pool_cleared(event)

Abstract method to handle a PoolClearedEvent.

Emitted when a Connection Pool is cleared.

Parameters:
pool_closed(event)

Abstract method to handle a PoolClosedEvent.

Emitted when a Connection Pool is closed.

Parameters:
pool_created(event)

Abstract method to handle a PoolCreatedEvent.

Emitted when a Connection Pool is created.

Parameters:
class pymongo.monitoring.CommandStartedEvent(command, database_name, *args)

Event published when a command starts.

Parameters:
  • command: The command document.
  • database_name: The name of the database this command was run against.
  • request_id: The request id for this operation.
  • connection_id: The address (host, port) of the server this command was sent to.
  • operation_id: An optional identifier for a series of related events.
command

The command document.

command_name

The command name.

connection_id

The address (host, port) of the server this command was sent to.

database_name

The name of the database this command was run against.

operation_id

An id for this series of events or None.

request_id

The request id for this operation.

class pymongo.monitoring.CommandSucceededEvent(duration, reply, command_name, request_id, connection_id, operation_id)

Event published when a command succeeds.

Parameters:
  • duration: The command duration as a datetime.timedelta.
  • reply: The server reply document.
  • command_name: The command name.
  • request_id: The request id for this operation.
  • connection_id: The address (host, port) of the server this command was sent to.
  • operation_id: An optional identifier for a series of related events.
command_name

The command name.

connection_id

The address (host, port) of the server this command was sent to.

duration_micros

The duration of this operation in microseconds.

operation_id

An id for this series of events or None.

reply

The server failure document for this operation.

request_id

The request id for this operation.

class pymongo.monitoring.CommandFailedEvent(duration, failure, *args)

Event published when a command fails.

Parameters:
  • duration: The command duration as a datetime.timedelta.
  • failure: The server reply document.
  • command_name: The command name.
  • request_id: The request id for this operation.
  • connection_id: The address (host, port) of the server this command was sent to.
  • operation_id: An optional identifier for a series of related events.
command_name

The command name.

connection_id

The address (host, port) of the server this command was sent to.

duration_micros

The duration of this operation in microseconds.

failure

The server failure document for this operation.

operation_id

An id for this series of events or None.

request_id

The request id for this operation.

class pymongo.monitoring.ServerDescriptionChangedEvent(previous_description, new_description, *args)

Published when server description changes.

New in version 3.3.

new_description

The new ServerDescription.

previous_description

The previous ServerDescription.

server_address

The address (host, port) pair of the server

topology_id

A unique identifier for the topology this server is a part of.

class pymongo.monitoring.ServerOpeningEvent(server_address, topology_id)

Published when server is initialized.

New in version 3.3.

server_address

The address (host, port) pair of the server

topology_id

A unique identifier for the topology this server is a part of.

class pymongo.monitoring.ServerClosedEvent(server_address, topology_id)

Published when server is closed.

New in version 3.3.

server_address

The address (host, port) pair of the server

topology_id

A unique identifier for the topology this server is a part of.

class pymongo.monitoring.TopologyDescriptionChangedEvent(previous_description, new_description, *args)

Published when the topology description changes.

New in version 3.3.

new_description

The new TopologyDescription.

previous_description

The previous TopologyDescription.

topology_id

A unique identifier for the topology this server is a part of.

class pymongo.monitoring.TopologyOpenedEvent(topology_id)

Published when the topology is initialized.

New in version 3.3.

topology_id

A unique identifier for the topology this server is a part of.

class pymongo.monitoring.TopologyClosedEvent(topology_id)

Published when the topology is closed.

New in version 3.3.

topology_id

A unique identifier for the topology this server is a part of.

class pymongo.monitoring.ServerHeartbeatStartedEvent(connection_id)

Published when a heartbeat is started.

New in version 3.3.

connection_id

The address (host, port) of the server this heartbeat was sent to.

class pymongo.monitoring.ServerHeartbeatSucceededEvent(duration, reply, *args)

Fired when the server heartbeat succeeds.

New in version 3.3.

connection_id

The address (host, port) of the server this heartbeat was sent to.

duration

The duration of this heartbeat in microseconds.

reply

An instance of IsMaster.

class pymongo.monitoring.ServerHeartbeatFailedEvent(duration, reply, *args)

Fired when the server heartbeat fails, either with an “ok: 0” or a socket exception.

New in version 3.3.

connection_id

The address (host, port) of the server this heartbeat was sent to.

duration

The duration of this heartbeat in microseconds.

reply

A subclass of Exception.

class pymongo.monitoring.PoolCreatedEvent(address, options)

Published when a Connection Pool is created.

Parameters:
  • address: The address (host, port) pair of the server this Pool is attempting to connect to.

New in version 3.9.

address

The address (host, port) pair of the server the pool is attempting to connect to.

options

Any non-default pool options that were set on this Connection Pool.

class pymongo.monitoring.PoolClearedEvent(address)

Published when a Connection Pool is cleared.

Parameters:
  • address: The address (host, port) pair of the server this Pool is attempting to connect to.

New in version 3.9.

address

The address (host, port) pair of the server the pool is attempting to connect to.

class pymongo.monitoring.PoolClosedEvent(address)

Published when a Connection Pool is closed.

Parameters:
  • address: The address (host, port) pair of the server this Pool is attempting to connect to.

New in version 3.9.

address

The address (host, port) pair of the server the pool is attempting to connect to.

class pymongo.monitoring.ConnectionCreatedEvent(address, connection_id)

Published when a Connection Pool creates a Connection object.

NOTE: This connection is not ready for use until the ConnectionReadyEvent is published.

Parameters:
  • address: The address (host, port) pair of the server this Connection is attempting to connect to.
  • connection_id: The integer ID of the Connection in this Pool.

New in version 3.9.

address

The address (host, port) pair of the server this connection is attempting to connect to.

connection_id

The ID of the Connection.

class pymongo.monitoring.ConnectionReadyEvent(address, connection_id)

Published when a Connection has finished its setup, and is ready to use.

Parameters:
  • address: The address (host, port) pair of the server this Connection is attempting to connect to.
  • connection_id: The integer ID of the Connection in this Pool.

New in version 3.9.

address

The address (host, port) pair of the server this connection is attempting to connect to.

connection_id

The ID of the Connection.

class pymongo.monitoring.ConnectionClosedReason

An enum that defines values for reason on a ConnectionClosedEvent.

New in version 3.9.

ERROR = 'error'

The connection experienced an error, making it no longer valid.

IDLE = 'idle'

The connection became stale by being idle for too long (maxIdleTimeMS).

POOL_CLOSED = 'poolClosed'

The pool was closed, making the connection no longer valid.

STALE = 'stale'

The pool was cleared, making the connection no longer valid.

class pymongo.monitoring.ConnectionClosedEvent(address, connection_id, reason)

Published when a Connection is closed.

Parameters:
  • address: The address (host, port) pair of the server this Connection is attempting to connect to.
  • connection_id: The integer ID of the Connection in this Pool.
  • reason: A reason explaining why this connection was closed.

New in version 3.9.

address

The address (host, port) pair of the server this connection is attempting to connect to.

connection_id

The ID of the Connection.

reason

A reason explaining why this connection was closed.

The reason must be one of the strings from the ConnectionClosedReason enum.

class pymongo.monitoring.ConnectionCheckOutStartedEvent(address)

Published when the driver starts attempting to check out a connection.

Parameters:
  • address: The address (host, port) pair of the server this Connection is attempting to connect to.

New in version 3.9.

address

The address (host, port) pair of the server this connection is attempting to connect to.

class pymongo.monitoring.ConnectionCheckOutFailedReason

An enum that defines values for reason on a ConnectionCheckOutFailedEvent.

New in version 3.9.

CONN_ERROR = 'connectionError'

The connection check out attempt experienced an error while setting up a new connection.

POOL_CLOSED = 'poolClosed'

The pool was previously closed, and cannot provide new connections.

TIMEOUT = 'timeout'

The connection check out attempt exceeded the specified timeout.

class pymongo.monitoring.ConnectionCheckOutFailedEvent(address, reason)

Published when the driver’s attempt to check out a connection fails.

Parameters:
  • address: The address (host, port) pair of the server this Connection is attempting to connect to.
  • reason: A reason explaining why connection check out failed.

New in version 3.9.

address

The address (host, port) pair of the server this connection is attempting to connect to.

reason

A reason explaining why connection check out failed.

The reason must be one of the strings from the ConnectionCheckOutFailedReason enum.

class pymongo.monitoring.ConnectionCheckedOutEvent(address, connection_id)

Published when the driver successfully checks out a Connection.

Parameters:
  • address: The address (host, port) pair of the server this Connection is attempting to connect to.
  • connection_id: The integer ID of the Connection in this Pool.

New in version 3.9.

address

The address (host, port) pair of the server this connection is attempting to connect to.

connection_id

The ID of the Connection.

class pymongo.monitoring.ConnectionCheckedInEvent(address, connection_id)

Published when the driver checks in a Connection into the Pool.

Parameters:
  • address: The address (host, port) pair of the server this Connection is attempting to connect to.
  • connection_id: The integer ID of the Connection in this Pool.

New in version 3.9.

address

The address (host, port) pair of the server this connection is attempting to connect to.

connection_id

The ID of the Connection.