goext/mongo/event/doc.go

57 lines
2.6 KiB
Go

// Copyright (C) MongoDB, Inc. 2017-present.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
// Package event is a library for monitoring events from the MongoDB Go
// driver. Monitors can be set for commands sent to the MongoDB cluster,
// connection pool changes, or changes on the MongoDB cluster.
//
// Monitoring commands requires specifying a CommandMonitor when constructing
// a mongo.Client. A CommandMonitor can be set to monitor started, succeeded,
// and/or failed events. A CommandStartedEvent can be correlated to its matching
// CommandSucceededEvent or CommandFailedEvent through the RequestID field. For
// example, the following code collects the names of started events:
//
// var commandStarted []string
// cmdMonitor := &event.CommandMonitor{
// Started: func(_ context.Context, evt *event.CommandStartedEvent) {
// commandStarted = append(commandStarted, evt.CommandName)
// },
// }
// clientOpts := options.Client().ApplyURI("mongodb://localhost:27017").SetMonitor(cmdMonitor)
// client, err := mongo.Connect(context.Background(), clientOpts)
//
// Monitoring the connection pool requires specifying a PoolMonitor when constructing
// a mongo.Client. The following code tracks the number of checked out connections:
//
// var int connsCheckedOut
// poolMonitor := &event.PoolMonitor{
// Event: func(evt *event.PoolEvent) {
// switch evt.Type {
// case event.GetSucceeded:
// connsCheckedOut++
// case event.ConnectionReturned:
// connsCheckedOut--
// }
// },
// }
// clientOpts := options.Client().ApplyURI("mongodb://localhost:27017").SetPoolMonitor(poolMonitor)
// client, err := mongo.Connect(context.Background(), clientOpts)
//
// Monitoring server changes specifying a ServerMonitor object when constructing
// a mongo.Client. Different functions can be set on the ServerMonitor to
// monitor different kinds of events. See ServerMonitor for more details.
// The following code appends ServerHeartbeatStartedEvents to a slice:
//
// var heartbeatStarted []*event.ServerHeartbeatStartedEvent
// svrMonitor := &event.ServerMonitor{
// ServerHeartbeatStarted: func(e *event.ServerHeartbeatStartedEvent) {
// heartbeatStarted = append(heartbeatStarted, e)
// }
// }
// clientOpts := options.Client().ApplyURI("mongodb://localhost:27017").SetServerMonitor(svrMonitor)
// client, err := mongo.Connect(context.Background(), clientOpts)
package event