Nodetime reveals response time and other internals of HTTP requests and underlying HTTP/database calls in your Node.js application. Coupled with related process and OS state information it enables tracing performance problems down to the root cause. Nodetime supports multiple APIs including native HTTP client, file system, cluster and sockets, Socket.io, Redis, MongoDB, MySQL, PostgreSQL, Memcached and Cassandra. HTTP based data stores like CouchDB and Riak are supported via HTTP API.
The profiler running within the application securely sends profiling data to the Nodetime server, where it is stored and sent to the browser in real-time. Profiling data is kept on the server only for 10 minutes.
Nodetime is a high level profiler. By hooking up to various APIs it gives developers clear API level visibility of performance, i.e. time and CPU usage, averages, stack traces and much more.
Install Nodetime with npm
npm install nodetime
It should be the first require statement in your node application, e.g. at the first line of your main module
require('nodetime').profile()
After your start your application, a link of the form https://nodetime.com/[session_id] will be printed to the console, where the session will be your unique id for accessing the profiler server. Copy the link into your browser and you're done! No need to refresh the browser, new data will appear as it arrives from the profiler.
It is possible to get session id programmatically:
var nodetime = require('nodetime');
nodetime.on('session', function(id) {
// do something with session id here
});
nodetime.profile();
Nodetime automatically detects if an application is running under constant load, e.g. production, or it is being tested or debugged. Under load Nodetime will capture and send only the slowest requests and related information. In debug mode it will send all requests to the profiler server.
It is also possible to disable sending profiling data to the server and dump everything to the console by passing stdout or headless flag at initialization, e.g. require('nodetime').profile({stdout: true})
You can always get the samples by subscribing to sample event:
nodetime.on('sample', function(sample) {
// do something with the sample
});
require('nodetime') - returns a singleton instance of Nodetime object
profile(options) - starts the profiler. Options are:
headless- if true, no data is sent to the serverstdout- if true, dumps samples usingconsole.log(). Also setsheadlessto true. Explicitly setheadlessto false if you want both, the dump and sending to Nodetime serverdebug- used for debugging nodetime itself, so hopefully you won't need it
on('session', function(id) {}) - Emitted when a unique session id is received from the server. The event is not emitted if in headless mode.
on('sample', function(sample) {}) - Sample object represents a profiled request. If an application is under some load, only slowest samples are emitted every minute. Otherwise samples are emitted after each request. Important: the stucture of sample object will not be kept backwards compatible in future versions.
Nodetime is based on probes hooked into API calls and callbacks using wrappers. It measures time, adds variables and creates objects, which naturally causes overhead. Although, the probes are mostly attached around calls involving network communication and are triggered only during server requests, which makes the overhead insignificant. However, it is recommended to measure overhead for specific cases.
Copyright (c) 2012 Dmitri Melikyan
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