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:

`javascript
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:

`javascript
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.

$3

---

#### 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.

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=thrift* - when transport is set to proto, the Tracer will use Proto over HTTP as a transport rather than Thrift.~~ ALWAYS THRIFT. GOOGLE PROTOBUFFERS USE eval() SO CANNOT RUN IN BROWSER EXTENSIONS: https://github.com/lightstep/lightstep-tracer-javascript/issues/141

$3

---

#### generateTraceURL()

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

`js
...
span.finish();

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

License

The MIT License.

Copyright (c) 2016, LightStep