Sending http request on node process exit

Question

I have written sample node application to handle error data such as database connection error, port conflict error, process uncaught exception. When error occurrs an http request is made to process the error. In such case when node process exist abnormally, I am able to handle exist in process.on('exit') function but I am not able to send http request, the process is exiting quickly.

Can any one suggest how to send http request and get the response on Node.js before process exit. Below is the sample code for sending http request on process exists

var http = require('http');
var errorData=null;
var sendErrorReport = function(data,callback){
    var options = {
        host : connection.host,
        path : "/api/errorReport",
        port : connection.port,
        method : 'POST',
        timeout: connection.timeInterval,
        headers:{
            'Content-Type':'application/json',
            'Content-Length': Buffer.byteLength(data)}
    }
    var request =  http.request(options,function(response){
        callback(response);
    });
    request.on('error',function(err){
        console.log("On Error");
        callback(err);
    });
    request.on('timeout', function(err){console.log("On Timeout");
        callback(err);});
    request.write(data);
    request.end();
}
process.on('uncaughtException', function ( err ) {
    errorData = err;
});
process.on('exit',function(code){
    sendErrorReport(errorData,function(err,res){
        console.log(res);
    });

})

If you handle `SIGINT` or `uncaughtException` events, you can call `process.exit` in the callback of the request. It should hang until you call that `.exit()` function. — Joshua, Aug 04 '17 at 13:21
Possible duplicate of [doing a cleanup action just before node.js exits](https://stackoverflow.com/questions/14031763/doing-a-cleanup-action-just-before-node-js-exits) — James, Aug 04 '17 at 13:21
In some cases I need to handle the process exit when uncaught exception is not thrown. — NandhiniTK, Aug 04 '17 at 13:30

score 1 · Answer 1 · answered Mar 19 '20 at 03:18

Hit on same problem, according to the doc https://nodejs.org/api/process.html#process_event_exit

"Event: 'exit' Listener functions must only perform synchronous operations." make it hard to send request to other system.

A possible workaround method is to to execute another script/cmd, eg.

import exec from 'child_process'

mocha.run(failures => {
  process.on('exit', () => {
    exec.execSync(some cmd, function (error, stderr) {
      if (error) {
        throw (error);
      }
 }
}

score 0 · Answer 2 · answered Mar 20 '18 at 14:50

0

In process.on('exit', [fn]) you cannot do any asynchronous action as stated in the docs. However, this is an anti-pattern also discovered in many libraries.

You need to rely on process.on('uncaughtException', [fn]) or any signal handlers like SIGTERM.

answered Mar 20 '18 at 14:50

eljefedelrodeodeljefe

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Sending http request on node process exit

2 Answers2