tracker~RequestLogger(options)

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

new RequestLogger(options)

Creates a new instance of RequestLogger.

Parameters:

Name Type Description

options

Object

Properties

Name	Type	Attributes	Description
`slowThreshold`	Number	<optional>	The threshold in milliseconds beyond which queries are considered 'slow' and logged as such by the driver.
`requestSizeThreshold`	Number	<optional>	The threshold in bytes beyond which requests are considered 'large' and logged as such by the driver.
`logNormalRequests`	Boolean	<optional>	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.
`logErroredRequests`	Boolean	<optional>	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.
`messageMaxQueryLength`	Number	<optional>	The maximum amount of characters that are logged from the query portion of the message. Defaults to 500.
`messageMaxParameterValueLength`	Number	<optional>	The maximum amount of characters of each query parameter value that will be included in the message. Defaults to 50.
`messageMaxErrorStackTraceLength`	Number	<optional>	The maximum amount of characters of the stack trace that will be included in the message. Defaults to 200.

Implements:

module:tracker~RequestTracker

Source

tracker/request-logger.js, line 25

Example

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 });

emitter :EventEmitter

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

Type:

EventEmitter

Source

tracker/request-logger.js, line 77

logErroredRequests :Boolean

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

Type:

Boolean

Source

tracker/request-logger.js, line 70

logNormalRequests :Boolean

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

Type:

Boolean

Source

tracker/request-logger.js, line 63

onError(host, query, parameters, executionOptions, requestLength, err, 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 \| Array<any>	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<any> \| Object \| 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()`).

Implements:

module:tracker~RequestTracker#onError

Source

tracker/request-logger.js, line 136

onSuccess(host, query, parameters, executionOptions, requestLength, responseLength, 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 \| Array<any>	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<any> \| Object \| 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()`).

Implements:

module:tracker~RequestTracker#onSuccess

Source

tracker/request-logger.js, line 84