traces

Distributed tracing library inspired by zipkin.

Graphing

This modules includes no graphing functionality, however the image on this page was generated with traces-graph. By using traces.get(cycle) you can generate your own reports.

About

Traces works by collecting "cycles", which consist of one or more trace calls enabling you to report on the durations of any given subset of a cycle. For example an image upload "cycle" may look something like the following, where each aspect of this request/response cycled may be "traced" for inspection. Because of this association each Cycle must have its own "id", which may be unique identifier, allowing traces cross-process.

var cycle = require('traces');
var http = require('http');
 
var id = 0;
http.createServer(function(){
  var trace = cycle('upload', id++);
 
  // request comes in, start streaming data
  trace.start('request');
  trace.start('upload');
 
  // upload complete
  trace.end('upload');
 
  // resize
  trace.start('resize');
 
  // resize complete
  trace.end('resize');
 
  // respond
  trace.end('request');
})

trace(1)

The trace(1) executable is provided with this module, and serves as the in-memory "database" from which your nodes converse via axon. In the future persistence via pluggable stores may be supported.

Enabling probes

To enable a cycle you may use the TRACE environment variable. For example to enable all probes simply use TRACE="*", to enable only chat related cycles use TRACE=chat, for several use spaces or commas TRACE="chat request", TRACE=chat,request. You may also use wildcards such as TRACE=chat:*, and negation via TRACE="* -chat" to say "everything except chat".

API

exports#clearAll([fn]:Function)

Clear all results collected.

exports#clear(cycle:String, [fn]:Function)

Clear results collected for cycle.

exports#get(cycle:String, fn:Function)

Fetch all traces for cycle and invoke fn(err, traces).

The json returned is formatted as follows, keyed by the cycle id.

{
  "0": {
    "probes": {
      "request": {
        "start": 1351270875180,
        "end": 1351270875396
      },
      "resize": {
        "start": 1351270875257,
        "end": 1351270875346
      },
      "save": {
        "start": 1351270875257,
        "end": 1351270875307
      },
      "s3": {
        "start": 1351270875257,
        "end": 1351270875312
      }
    }
  },
  "1": {
    "probes": {
  ...

Cycle(id, name)

Initialize a new Tracer with the given id and name.

Cycle#start(type:String, [date]:Number|Date)

Trace start of type with optional date.

Cycle#end(type:String, [date]:Number|Date)

Trace end of type with optional date.

License

(The MIT License)

Copyright (c) 2012 TJ Holowaychuk <[e-mail]>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.