class RequestLogger

A request tracker that logs the requests executed through the session, according to a set of configurable options.

Members

EventEmitter

emitter

The object instance that emits 'slow', 'large', 'normal' and 'failure' events.

Boolean

logErroredRequests

Determines whether it should emit ‘failure’ events for every EXECUTE, QUERY and BATCH request execution that resulted in an error

Boolean

logNormalRequests

Determines whether it should emit ‘normal’ events for every EXECUTE, QUERY and BATCH request executed successfully, useful only for debugging

Constructor

new

RequestLogger

(Object options)

Creates a new instance of RequestLogger.

Examples:
Logging slow queries
const requestLogger = new RequestLogger({ slowThreshold: 1000 });
requestLogger.emitter.on('show', message => console.log(message));
// Add the requestLogger to the client options
const client = new Client({ contactPoints, requestTracker: requestLogger });
Parameters:
Name Type Description
options Object
options.slowThreshold optional Number

The threshold in milliseconds beyond which queries are considered ‘slow’ and logged as such by the driver.
options.requestSizeThreshold optional Number

The threshold in bytes beyond which requests are considered ‘large’ and logged as such by the driver.
options.logNormalRequests optional Boolean

Determines whether it should emit ‘normal’ events for every EXECUTE, QUERY and BATCH request executed successfully, useful only for debugging. This option can be modified after the client is connected using the property RequestLogger#logNormalRequests.
options.logErroredRequests optional Boolean

Determines whether it should emit ‘failure’ events for every EXECUTE, QUERY and BATCH request execution that resulted in an error. This option can be modified after the client is connected using the property RequestLogger#logErroredRequests.
options.messageMaxQueryLength optional Number

The maximum amount of characters that are logged from the query portion of the message. Defaults to 500.
options.messageMaxParameterValueLength optional Number

The maximum amount of characters of each query parameter value that will be included in the message. Defaults to 50.
options.messageMaxErrorStackTraceLength optional Number

The maximum amount of characters of the stack trace that will be included in the message. Defaults to 200.

Methods

onError

(Host host, String or Array query, Array, Object or null parameters, ExecutionOptions executionOptions, Number requestLength, Error err, Array<Number> latency)

Logs message if request execution was too large and/or encountered an error.

Parameters:
Name Type Description
host Host

The node that acted as coordinator of the request.
query String or Array

In the case of prepared or unprepared query executions, the provided query string. For batch requests, an Array containing the queries and parameters provided.
parameters Array, Object or null

In the case of prepared or unprepared query executions, the provided parameters.
executionOptions ExecutionOptions

The information related to the execution of the request.
requestLength Number

Length of the body of the request. When the failure occurred before the request was written to the wire, the length will be 0.
err Error

The error that caused that caused the request to fail.
latency Array<Number>

An array containing [seconds, nanoseconds] tuple, where nanoseconds is the remaining part of the real time that can’t be represented in second precision (see process.hrtime()).

onSuccess

(Host host, String or Array query, Array, Object or null parameters, ExecutionOptions executionOptions, Number requestLength, Number responseLength, Array<Number> latency)

Logs message if request execution was deemed too slow, large or if normal requests are logged.

Parameters:
Name Type Description
host Host

The node that acted as coordinator of the request.
query String or Array

In the case of prepared or unprepared query executions, the provided query string. For batch requests, an Array containing the queries and parameters provided.
parameters Array, Object or null

In the case of prepared or unprepared query executions, the provided parameters.
executionOptions ExecutionOptions

The information related to the execution of the request.
requestLength Number

Length of the body of the request.
responseLength Number

Length of the body of the response.
latency Array<Number>

An array containing [seconds, nanoseconds] tuple, where nanoseconds is the remaining part of the real time that can’t be represented in second precision (see process.hrtime()).