exit function not being called when setinterval is running

Question

I'm trying to write code that will return whether the server is already running or not. However, my tests are not working.

I want on process.exit to write a file that says the server is no longer running, and for when the server starts up, it to write that the server is running:

const { readdir, writeFile, writeFileSync, readFileSync } = require('fs')                                                                     
const IS_RUNNING_LOCATION = `${__dirname}/running.txt`                                                                                        
if (readFileSync(IS_RUNNING_LOCATION).toString() ===  'true')                                                                                 
  return                                                                                                                                      
process.on('exit', () => {                                                                                                                    
  writeFileSync(IS_RUNNING_LOCATION, 'false', {}, (err) => {                                                                                  
    if (!err) return console.log('written')                                                                                                                    
    console.log(err)                                                                                                                          
  })                                                                                                                                          
})                                                                                                                                            
writeFileSync(IS_RUNNING_LOCATION, 'true')             

setInterval(()=> console.log('running'), 1000)

However, with this code, when I exit with ^C, the on exit code is not run.

Can anyone tell me why this is the case or how I can fix it?

Duplicate of: https://stackoverflow.com/a/20165643/3042383 – lancew Aug 24 '17 at 15:59 — lancew, Aug 24 '17 at 15:59

score 0 · Answer 1 · answered Aug 24 '17 at 15:57

Found the answer here: doing a cleanup action just before node.js exits

This is the code I ended up using:

const { writeFileSync, readFileSync } = require('fs')                                                                     
const IS_RUNNING_LOCATION = `${__dirname}/.running`                                                                                           
if (readFileSync(IS_RUNNING_LOCATION).toString() ===  'true')                                                                                 
  process.exit(0)                                                                                                                             

writeFileSync(IS_RUNNING_LOCATION, 'true')                                                                                                    
function exitHandler(options, err) {                                                                                                          
  writefilesync(is_running_location, 'false', {}, (err) => {                                                                                  
    if (!err) return if (!err) return console.log('written')                                                                                  
    console.log(err)                                                                                                                          
  })                                                                                                                                          
  if (options.exit) process.exit();                                                                                                           
}                                                                                                                                             

process.on('exit', exitHandler.bind(null,{cleanup:true}))                                                                                     
process.on('SIGINT', exitHandler.bind(null, {exit:true}))                                                                                     
process.on('uncaughtException', exitHandler.bind(null, {exit:true}))

exit function not being called when setinterval is running

1 Answers1