Command Monitoring

Overview

This guide shows you how to use the Rust driver to monitor the outcome of commands that the driver sends to your MongoDB deployment.

You can use information about command events in your application, or you can monitor commands to learn more about how the driver executes them.

This guide includes the following sections:

• Event Descriptions describes the command events that the driver can generate

• Event Subscription Example provides sample code that shows how to subscribe to a command event

• Example Event Documents provides samples of each command event

• Additional Information provides links to resources and API documentation for types and methods mentioned in this guide

Event Descriptions

You can subscribe to one or more of the following command monitoring events:

Event Subscription Example

You can access one or more command events by subscribing to them in your application. The following example connects to a MongoDB deployment and subscribes to the CommandStartedEvent event type:

struct CommandStartHandler;
impl CommandEventHandler for CommandStartHandler {
    fn handle_command_started_event(&self, event: CommandStartedEvent) {
        eprintln!("Command started: {:?}", event);
    }
}
let handler: Arc<dyn CommandEventHandler> = Arc::new(CommandStartHandler);
client_options.command_event_handler = Some(handler);
let client = Client::with_options(client_options)?;
// ... perform actions with the client to generate events

Example Event Documents

The following sections show sample output for each type of command monitoring event.

CommandStartedEvent {
  request_id: 12,
  db: "testdb",
  command_name: "find",
  connection: ...,
  command: ...,
  service_id: ...
}

CommandSucceededEvent {
    duration: ...,
    reply: ...,
    command_name: "find",
    request_id: 12,
    connection: ...,
    service_id: ...,
}

CommandFailedEvent {
    duration: ...,
    command_name: "find",
    failure: ...,
    request_id: 12,
    connection: ...,
    service_id: ...,
}

Additional Information

To learn more about monitoring a MongoDB deployment, see the How to Monitor MongoDB article.

To learn more about performing MongoDB operations, see the CRUD Operations guides.