SSH与nodejs

Question

Attempting to create files and such on new vps that was created using api. This function does not run the second ssh command for some reason. Before this function is run there's another that is also run that sends a few commands to install packages before it installs the files. I have the function running after a timer has run out so that it can use some of the packages to run the commands like screen. It runs the first ssh but not the second one and i have tried with a timer up to 180 seconds.

function CreateServer( SIP, GUSER, SPORT ) {
var CDir = "";
var RPassword = generator.generate({
    length: 10,
    numbers: true
});
var ssh = new SSH({
    host: SIP,
    user: 'root',
    key: fs.readFileSync('serverkey.ppk')
    //pass: 'password'
});

ssh.exec('if test -d /home/' + GUSER + '; then echo "exist"; fi', {
    out: function(stdout) {
        CDir = stdout;
        //console.log(stdout);
    }
}).start();
setTimeout(function(){
    if(CDir == DMkdir) {
        console.log("User on machine not adding......");
        ssh.exec('chown -R ' + GUSER + ':' + GUSER + ' /home/' + GUSER + '; su - ' + GUSER + ' -c "cd /home/' + GUSER + '/steamcmd ; screen -mdSL ' + SIP + ':' + SPORT + ' ./steamcmd.sh +login anonymous +force_install_dir /home/' + GUSER + '/' + SIP + '.' + SPORT + ' +app_update 4020 validate +quit"', {
            out: function(stdout) {
                //console.log(stdout);
            }
        }).start();             
    } else {
        console.log("User not on machine adding......");
        ssh.exec('cd /home/; sudo adduser ' + GUSER + ' --gecos "First Last,RoomNumber,WorkPhone,HomePhone" --disabled-password; echo "' + GUSER + ':' + RPassword + '" | sudo chpasswd; cd /home/' + GUSER + '/; mkdir steamcmd; cd /home/' + GUSER + '/steamcmd; wget https://steamcdn-a.akamaihd.net/client/installer/steamcmd_linux.tar.gz; tar -xvzf steamcmd_linux.tar.gz; chown -R ' + GUSER + ':' + GUSER + ' /home/' + GUSER + '; su - ' + GUSER + ' -c "cd /home/' + GUSER + '/steamcmd ; screen -mdSL ' + SIP + ':' + SPORT + ' ./steamcmd.sh +login anonymous +force_install_dir /home/' + GUSER + '/' + SIP + '.' + SPORT + ' +app_update 4020 validate +quit"', {
            out: function(stdout) {
                console.log(stdout);
            }
        }).start();
    }
}, 5 * 1000);
return true;

}

Answer 1

I'm assuming everything is correct besides your problem with handling two asynchronous events. Given that I can't see where DMkdir is coming from and just of context of your other code I am assuming that just like CDir its value is being set asynchronously.

Assuming your using a recent version of node that uses native promises like Node version 6 and up then the following code will work for you. If your not using a more recent version of node you can use a promise library like bluebird or Q which will involve different syntax but it will be solved a similar way.

function sshPromise (string) {
    new Promise((resolve, reject) => {
      ssh.exec(string, {
          // on correct output the promise needs to be 
          // resolved by calling the resolve function with the data
          out: resolve
          // not sure what the error property is but it needs 
          // to reject the promise with the error data
          onError: reject
      }).start();
    });
}

var CDirPromise = sshPromise('if test -d /home/' + GUSER + '; then echo "exist"; fi');

var DMkdirPromise = sshPromise('whatever command you did for this one obviously not this string');

Promise.all([CDirPromise, DMkdirPromise]).then(function ([CDir, DMKdir]) {
    // this then method will fire when all the promises resolve.
    if(CDir == DMkdir) {
        console.log("User on machine not adding......");
        ssh.exec('chown -R ' + GUSER + ':' + GUSER + ' /home/' + GUSER + '; su - ' + GUSER + ' -c "cd /home/' + GUSER + '/steamcmd ; screen -mdSL ' + SIP + ':' + SPORT + ' ./steamcmd.sh +login anonymous +force_install_dir /home/' + GUSER + '/' + SIP + '.' + SPORT + ' +app_update 4020 validate +quit"', {
            out: function(stdout) {
                //console.log(stdout);
            }
        }).start();             
    } else {
        console.log("User not on machine adding......");
        ssh.exec('cd /home/; sudo adduser ' + GUSER + ' --gecos "First Last,RoomNumber,WorkPhone,HomePhone" --disabled-password; echo "' + GUSER + ':' + RPassword + '" | sudo chpasswd; cd /home/' + GUSER + '/; mkdir steamcmd; cd /home/' + GUSER + '/steamcmd; wget https://steamcdn-a.akamaihd.net/client/installer/steamcmd_linux.tar.gz; tar -xvzf steamcmd_linux.tar.gz; chown -R ' + GUSER + ':' + GUSER + ' /home/' + GUSER + '; su - ' + GUSER + ' -c "cd /home/' + GUSER + '/steamcmd ; screen -mdSL ' + SIP + ':' + SPORT + ' ./steamcmd.sh +login anonymous +force_install_dir /home/' + GUSER + '/' + SIP + '.' + SPORT + ' +app_update 4020 validate +quit"', {
            out: function(stdout) {
                console.log(stdout);
            }
        }).start();
    }
}).catch(function (err) {
    // handle the error one of the promises rejected.
});

You should do handling of errors as well (when saying ssh.exec there should be a way to handle the error output I just guessed it was onError but you should change it to what it actually is. I don't know what ssh library you are using so I just guessed it was onError .) as it seems currently that your code is not checking for errors being thrown.

I'll write just a bit about promises. They are very good for asynchronous events that happen once. They are also good at handling errors with these asynchronous events. A promise has three states: 'pending' which is an unfinished state, 'resolved' which is a successful finished state, or rejected which is an unsuccessful finished state likely caused by an error. You can handle resolved values in a promise with a .then method and handle rejected values with the .catch method.

I suggest reading the below links about Promises to truly get a grasp on them.

• MDN: "Using promises"
• MDN: "Promise.all"
• Google Developers: "JavaScript Promises: an Introduction"

Good luck. :)

EDIT:

Well according to the comments the problem is quite a bit simpler. All you really need to do is the following which is to just put your function to run after CDir is available on the out property of ssh.exec.

ssh.exec('if test -d /home/' + GUSER + '; then echo "exist"; fi', {
    out: function (CDir) {
        if(CDir == DMkdir) {
            console.log("User on machine not adding......");
            ssh.exec('chown -R ' + GUSER + ':' + GUSER + ' /home/' + GUSER + '; su - ' + GUSER + ' -c "cd /home/' + GUSER + '/steamcmd ; screen -mdSL ' + SIP + ':' + SPORT + ' ./steamcmd.sh +login anonymous +force_install_dir /home/' + GUSER + '/' + SIP + '.' + SPORT + ' +app_update 4020 validate +quit"', {
                out: function(stdout) {
                    //console.log(stdout);
                }
            }).start();             
        } else {
            console.log("User not on machine adding......");
            ssh.exec('cd /home/; sudo adduser ' + GUSER + ' --gecos "First Last,RoomNumber,WorkPhone,HomePhone" --disabled-password; echo "' + GUSER + ':' + RPassword + '" | sudo chpasswd; cd /home/' + GUSER + '/; mkdir steamcmd; cd /home/' + GUSER + '/steamcmd; wget https://steamcdn-a.akamaihd.net/client/installer/steamcmd_linux.tar.gz; tar -xvzf steamcmd_linux.tar.gz; chown -R ' + GUSER + ':' + GUSER + ' /home/' + GUSER + '; su - ' + GUSER + ' -c "cd /home/' + GUSER + '/steamcmd ; screen -mdSL ' + SIP + ':' + SPORT + ' ./steamcmd.sh +login anonymous +force_install_dir /home/' + GUSER + '/' + SIP + '.' + SPORT + ' +app_update 4020 validate +quit"', {
                out: function(stdout) {
                    console.log(stdout);
                }
            }).start();
        }
    }
}).start();