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node-report

node-report

Delivers a human-readable diagnostic summary, written to file.

The report is intended for development, test and production use, to capture and preserve information for problem determination. It includes JavaScript and native stack traces, heap statistics, platform information and resource usage etc. With the report enabled, reports can be triggered on unhandled exceptions, fatal errors, signals and calls to a JavaScript API.

Supports Node.js versions 4, 6 and 8 on AIX, Linux, MacOS, SmartOS and Windows.

Usage

npm install node-report
node -r node-report app.js

A report will be triggered automatically on unhandled exceptions and fatal error events (for example out of memory errors), and can also be triggered by sending a USR2 signal to a Node.js process (not supported on Windows).

A report can also be triggered via an API call from a JavaScript application.

var nodereport = require('node-report');
nodereport.triggerReport();

The content of a report can also be returned as a JavaScript string via an API call from a JavaScript application.

var nodereport = require('nodereport');
var report_str = nodereport.getReport();
console.log(report_str);

The API can be used without adding the automatic exception and fatal error hooks and the signal handler, as follows:

var nodereport = require('node-report/api');
nodereport.triggerReport();

Content of the report consists of a header section containing the event type, date, time, PID and Node version, sections containing JavaScript and native stack traces, a section containing V8 heap information, a section containing libuv handle information and an OS platform information section showing CPU and memory usage and system limits. An example report can be triggered using the Node.js REPL:

$ node
> nodereport = require('node-report')
> nodereport.triggerReport()
Writing Node.js report to file: node-report.20161020.091102.8480.001.txt
Node.js report completed
>

When a report is triggered, start and end messages are issued to stderr and the filename of the report is returned to the caller. The default filename includes the date, time, PID and a sequence number. Alternatively, a filename can be specified as a parameter on the triggerReport() call.

nodereport.triggerReport("myReportName");

Both triggerReport() and getReport() can take an optional Error object as a parameter. If an Error object is provided, the message and stack trace from the object will be included in the report in the JavaScript Exception Details section. When using node-report to handle errors in a callback or an exception handler this allows the report to include the location of the original error as well as where it was handled. If both a filename and Error object are passed to triggerReport() the Error object should be the second parameter.

try {
  process.chdir('/foo/foo');
} catch (err) {
  nodereport.triggerReport(err);
}
  ...
});

Configuration

Additional configuration is available using the following APIs:

var nodereport = require('node-report/api');
nodereport.setEvents("exception+fatalerror+signal+apicall");
nodereport.setSignal("SIGUSR2|SIGQUIT");
nodereport.setFileName("stdout|stderr|<filename>");
nodereport.setDirectory("<full path>");
nodereport.setVerbose("yes|no");

Configuration on module initialization is also available via environment variables:

export NODEREPORT_EVENTS=exception+fatalerror+signal+apicall
export NODEREPORT_SIGNAL=SIGUSR2|SIGQUIT
export NODEREPORT_FILENAME=stdout|stderr|<filename>
export NODEREPORT_DIRECTORY=<full path>
export NODEREPORT_VERBOSE=yes|no

Examples

To see examples of reports generated from these events you can run the demonstration applications provided in the node-report github repository. These are Node.js applications which will prompt you to trigger the required event.

  1. api.js - report triggered by JavaScript API call.
  2. exception.js - report triggered by unhandled exception.
  3. fatalerror.js - report triggered by fatal error on JavaScript heap out of memory.
  4. loop.js - looping application, report triggered using kill -USR2 <pid>.

License

Licensed under the MIT License.