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 8, 10 and 12 on AIX, Linux, macOS, SmartOS and
Windows. Node.js 12 and later contain similar functionality in the built-in
Diagnostic Report feature.
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('node-report');
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.
api.js- report triggered by JavaScript API call.exception.js- report triggered by unhandled exception.fatalerror.js- report triggered by fatal error on JavaScript heap out of memory.loop.js- looping application, report triggered using kill-USR2 <pid>.