Starting a node.js script through PHP disables logs, permission issue apparrently

Question

I'm having a problem with my script. Currently, a PHP script turns on a node script and outputs the process ID like this:

<?php exec("/home/node /home/app/server.js 1>/dev/null & echo $!",$pid); if($pid) echo $pid; ?>

The script launches but it does not log anything.

Node.js script:

const winston = require('winston');
const {combine,timestamp,printf,colorize} = winston.format;

function getLogger(name,filename)
{
    let self = this;
    let o = {
        transports:[
            new winston.transports.Console({
                levels: winston.config.syslog.levels,
                colorize: true,
                label: name,
                format:winston.format.combine(
                    colorize(),
                    timestamp({
                        format: "YYYY-MM-DD HH:mm:ss"
                    }),
                    printf(info => {
                      return `${info.timestamp} [${info.level}] : ${info.message}`;
                    })
                )
            })
        ]
    };
    filename = filename || "";
    if(filename) o.transports.push(new winston.transports.File({
        filename:"./logs/"+filename,
        format:winston.format.combine(
            timestamp({
                format: "YYYY-MM-DD HH:mm:ss"
            }),
            printf(info => {
              return JSON.stringify({timestamp:info.timestamp,level: info.level,msg:info.message});
            })
        )
    }));
    winston.loggers.add(name, o);
    return winston.loggers.get(name);
}

var log = getLogger("SERVER","server.log");
log.info("Hello world");

At first I thought that output transporting to /dev/null is the problem, however, launching the exact same script through shell it works and logs fine. However, launched from PHP it does not.

What could be the cause of this?

EDIT:

This is how I call the PHP script:

$.ajax({
    url:'startnode.php',
    method:"POST",
    success:function(data){
        console.log(data);
    }
})

EDIT 2:

Could this be because of www-data user permissions? When I launch the node.js script from php, ps aux command says the node.js script is running from www-data user.

EDIT 3:

I changed to www-data user and tried running the script from the shell:

www-data@vps1130207:~$ /home/node /home/app/server.js
2018-11-13 19:43:05 [info] : Hello world
events.js:167
      throw er; // Unhandled 'error' event
      ^

Error: EACCES: permission denied, stat 'logs/server.log'
Emitted 'error' event at:
    at DerivedLogger.transportError (/home/app/node_modules/winston/lib/winston/logger.js:529:12)
    at File.emit (events.js:187:15)
    at stat (/home/app/node_modules/winston/lib/winston/transports/file.js:342:21)
    at fs.stat (/home/app/node_modules/winston/lib/winston/transports/file.js:371:16)
    at FSReqWrap.oncomplete (fs.js:152:21)

I've updated the question (unless you asked about the php script iself which is at the top.) — Ned, Nov 13 '18 at 16:11
Can you try removing the `method:"POST"` line from your `$.ajax(...` statement? — David R, Nov 13 '18 at 16:15
here is the same problem https://stackoverflow.com/questions/16740802/how-to-make-a-system-call-remotely/22953339#22953339 you need to give permission for the php user to allow it to run shell cmd. — Fermin Perdomo, Nov 13 '18 at 18:37
I already have www-data user added to `sudoers` file. The node.js file starts, but apparently it throws a permission error (see EDIT 3) — Ned, Nov 13 '18 at 19:27

score 0 · Answer 1 · answered Nov 15 '18 at 15:07

Issue has been fixed.

Apparently I was giving a wrong filename for winston, since the home folder for www-data user was /var/www, it was using that folder to make the logs instead of /home/app.

This fixed my issue:

if(filename) 
o.transports.push(new winston.transports.File({
    filename:__dirname+"/../logs/"+filename, //added __dirname here
    format:winston.format.combine(
        timestamp({
            format: "YYYY-MM-DD HH:mm:ss"
        }),
        printf(info => {
          return JSON.stringify({timestamp:info.timestamp,level: info.level,msg:info.message});
        })
    )
}));

Starting a node.js script through PHP disables logs, permission issue apparrently

1 Answers1