如何在停止服务的地方检查服务状态

Question

I noted very weird behavior when I want to run service apache2 status on my node. This is code:

 app.post('/getStatus', jsonParser, function(req,res){

   exec("service apache2 status", function(err, stdout){
    if(err) throw err;
    var statuspmtatmp = /Active: [a-z]* [\(][a-z]*[\)]/g.exec(stdout.toString())[0];

    res.json(statuspmtatmp);
   });

}); 

When I run this command when apache is running everything is ok, but when I stop apache and they I try to check status I get error:

Error: Command failed: /bin/sh -c service apache2 status
at ChildProcess.exithandler (child_process.js:213:12)
at emitTwo (events.js:87:13)
at ChildProcess.emit (events.js:172:7)
at maybeClose (internal/child_process.js:821:16)
at Socket.<anonymous> (internal/child_process.js:319:11)
at emitOne (events.js:77:13)
at Socket.emit (events.js:169:7)
at Pipe._onclose (net.js:469:12)

What is wrong? Why when apache is running everything is ok?

Answer 1

You are checking for errors and throwing the error on this line:

if(err) throw err;

So the execution stop and throw an error

Do

if(err){
   //code to handle the error
}

As you can read in node docs :

If a callback function is provided, it is called with the arguments (error, stdout, stderr). On success, error will be null. On error, error will be an instance of Error. The error.code property will be the exit code of the child process while error.signal will be set to the signal that terminated the process. Any exit code other than 0 is considered to be an error.