lightstep-tracer

LightStep distributed tracing library for Node.js and the browser.

Installation

npm install --save lightstep-tracer opentracing

All modern browsers and Node versions >= 0.12 are supported.

Getting started

To use LightStep as the OpenTracing binding, initialize the global Tracer with the LightStep implementation:

var opentracing = require('opentracing');
var lightstep   = require('lightstep-tracer');

opentracing.initGlobalTracer(new lightstep.Tracer({
    access_token   : '{your_access_token}',
    component_name : '{your_service_or_app_name}',
}));

The LightStep JavaScript Tracing Cookbook is a good next stop for information on how to quickly instrument your system. If you want to try something out quickly in your browser code, see the browser quick start example.

• For more information about using the OpenTracing API, see http://opentracing.io/
• See examples/browser for a complete JavaScript browser example
• See examples/node for a complete Node.js server-side example

The browser version of the code can be explicitly included using the following, which can be helpful in some browserify (or similar) setups:

var lightstep = require('lightstep-tracer/browser');

LightStep-specific API

The OpenTracing standard JavaScript API is documented here. The following describes LightStep-specific options and methods.

LightStep

---

new Tracer(options)

Required options

• access_token string required - the project access token
• component_name string required - the string identifier for the application, service, or process

Standard options

• verbosity number optional, default=1 - controls the level of logging to the console
  • 0 - the client library will never log to the console
  • 1 - error reporting will be throttled to the first error per minute
  • 2 - all errors are logged to the console
  • 3 - all errors, warnings, and info statements are logged to the console
  • 4 - all log statements, including debugging details
• collector_host string optional - custom collector hostname
• collector_port number optional - custom collector port
• collector_path string optional - custom collector base path (if served behind a reverse proxy)
• collector_encryption string optional, default='tls'
  • tls - use HTTPS encrypted connections
  • none - use HTTP plain-text connections

Browser-specific initialization options

• instrument_page_load bool - creates a long-lived single span for the entire page view and is recommended for short-page visits in a multi-page website. For a single-page web app, this behavior may be undesirable. Defaults to false. This must be set at initialization, changes after initialization will have no effect.

• xhr_instrumentation bool - if false, disables automatic instrumentation of XMLHttpRequests (XHRs). This must be set at initialization; changes after initialization will have no effect. Defaults to false.

• xhr_url_inclusion_patterns RegExp[] - an array of regular expressions used to whitelist URLs for XMLHttpRequest auto-instrumentation. The default value is wildcard matching all strings. For a given URL to be instrumented, it must match at least one regular expression in xhr_url_inclusion_patterns and not match any regular expressions in xhr_url_exclusion_patterns.

• xhr_url_exclusion_patterns RegExp[] - an array of regular expressions used to exclude URLs from XMLHttpRequest auto-instrumentation. The default value is an empty array. For a given URL to be instrumented, it must match at least one regular expression in xhr_url_inclusion_patterns and not match any regular expressions in xhr_url_exclusion_patterns.

• fetch_instrumentation bool - if false, disables automatic instrumentation of window.fetch. This must be set at initialization; changes after initialization will have no effect. Defaults to false.

• fetch_url_inclusion_patterns RegExp[] - an array of regular expressions used to whitelist URLs for window.fetch auto-instrumentation. The default value is wildcard matching all strings. For a given URL to be instrumented, it must match at least one regular expression in fetch_url_inclusion_patterns and not match any regular expressions in fetch_url_exclusion_patterns.

• fetch_url_exclusion_patterns RegExp[] - an array of regular expressions used to exclude URLs from window.fetch auto-instrumentation. The default value is an empty array. For a given URL to be instrumented, it must match at least one regular expression in fetch_url_inclusion_patterns and not match any regular expressions in fetch_url_exclusion_patterns.

• include_cookies bool - if true, includes cookies in the span logs for both window.fetch and XMLHttpRequest. Defaults to true.

node-specific initialization options

• nodejs_instrumentation bool - if false, disables automatic instrumentation of node requests. This must be set at initialization; changes after initialization will have no effect. Defaults to false.

• nodejs_url_inclusion_patterns RegExp[] - an array of regular expressions used to whitelist URLs for XMLHttpRequest auto-instrumentation. The default value is wildcard matching all strings. For a given URL to be instrumented, it must match at least one regular expression in nodejs_url_inclusion_patterns and not match any regular expressions in nodejs_url_exclusion_patterns.

• nodejs_url_exclusion_patterns RegExp[] - an array of regular expressions used to exclude URLs from XMLHttpRequest auto-instrumentation. The default value is an empty array. For a given URL to be instrumented, it must match at least one regular expression in nodejs_url_inclusion_patterns and not match any regular expressions in nodejs_url_exclusion_patterns.

Non-standard options

NOTE: Future API compatibility on non-standard options is not guaranteed.

• disable_reporting_loop bool optional, default=false - if true, the timer that automatically sends reports to the collector will be disabled. This option is independent of disable_report_on_exit.
• disable_report_on_exit bool optional, default=false - if true, the final report that is automatically sent at process exit in Node or page unload in the browser will not be sent.
• report_timeout_millis number optional, default=30000 - the default timeout value, in milliseconds, for reports to the LightStep collector
• gzip_json_requests bool optional, default=true - if true, the reports will be gzipped before sent to the collector.
• default_span_tags string optional - an associative array of tags to add to every span started by the tracer (e.g., the active user id in a browser client)
• delay_initial_report_millis int optional, default=1000 - maximum additional delay of the initial report in addition to the normal reporting interval. A value between zero and this maximum will be selected as the actual delay. This can be useful when concurrently launching a large number of new processes and there is a desire to distribute the initial reports over a window of time.
• error_throttle_millis int optional, default=60000 - when verbosity is set to 1, this the minimum time between logged errors.
• transport string optional, default=proto - when transport is set to thrift, the Tracer will use Thrift as its transport instead of Proto over HTTP.
• logger function(level: string, message: string, payload: any): void optional - specify a custom logger function. Possible level values are debug, info, warn and error. By default messages will be logged to the console.
• disable_meta_event_reporting bool optional, default=false - when disable_meta_event_reporting is set to true, the tracer will disable meta event reporting even if requested by the Satellite.
• propagators dictionary optional, defaults={ [opentracing.FORMAT_HTTP_HEADERS]: new lightstep.LightStepPropagator(), [opentracing.FORMAT_TEXT_MAP]: new lightstep.LightStepPropagator(), [opentracing.FORMAT_BINARY]: new lightstep.UnsupportedPropagator() }: Allows inject/extract to use custom propagators for different formats. This package includes B3Propagator that supports B3 headers on text maps and http headers. DDPropagator supports DataDog trace headers.

An example configuration using custom propagators might look like:

const tracer = new lightstep.Tracer({
  propagators: {
    [opentracing.FORMAT_HTTP_HEADERS]: new lightstep.DDPropagator(),
    [opentracing.FORMAT_TEXT_MAP]: new lightstep.B3Propagator()
  }
})

SpanImp

---

generateTraceURL()

Returns an absolute URL to the LightStep application for the trace containing this span. It is safe to call this method after finish().

...
span.finish();

var url = span.generateTraceURL())
console.log('View the trace for this span at:', url);

License

The MIT License.

Copyright (c) 2016, LightStep