Node.Js - exit out of exec after continuous commands

Question

I'm executing a few git commands in sequence, in particular, I'm following a git flow model,

e.g. when finishing a feature, I run,

git pull
git push -u origin branchname
git pull origin develop
git checkout develop
git merge branchname
git push

I run these commands using the exec module in node.js and I chain them one after another, like:

exec(command1,
     (err, stdout, stderr) => {
            if(err != null) {
                  //display an error message
                  return
            } else {
                  exec(command2, (err, stdout, stderr) =>{ ... }
            }

      }
)

And so on. The outputs are working correctly and the order is working. However, if one of those commands fail, I am breaking out of the chain.

I know that there is an async library that I could use with the same effect, per here. However, is this the best possible way to do that without resorting to a third-party library? How have other people done it?

I think what you are actually looking for is a shell script, not a node module. — Bergi, Mar 03 '17 at 00:12
@Bergi I'm using `if(!err)` and also I'm developing on Electron. — akcorp2003, Mar 03 '17 at 00:22
You haven't shown that in the code you posted. Please [edit] your question and provide your actual code. — Bergi, Mar 03 '17 at 02:40
Just updated it! I updated the wording of my question as well. — akcorp2003, Mar 03 '17 at 15:30

score 1 · Answer 1 · answered Mar 03 '17 at 00:06

Using async you can do this with eachSeries:

var commands = [
  'git pull',
  'git checkout',
  '...'
];

eachSeries(commands, (command, cb) => {
  exec(command, (err, stdout, stderr) => {
    cb(err);
  });
});

It's generally better to find a library that does this than to have to wrangle your own solution by hand.

score 1 · Accepted Answer · answered Mar 03 '17 at 15:44

However, is this the best possible way to do that without resorting to a third-party library?

No.

How have other people done it?

There are three kinds of other solutions:

just use that library. Being used is its entire purpose.
reinvent that library. Because then it's not third-party any more, whatever benefits that may have.

use promises! (And partial application)

function makeExec(command) {
    return function(/* ignore results */) {
        return new Promise(function(resolve, reject) {
            child_process.exec(command, function(err, stdout, stderr) {
                if (err != null) reject(Object.assign(err, {stderr}));
                else resolve(stdout);
            });
        });
    });
}
Promise.resolve()
.then(makeExec("git pull"))
.then(makeExec("git push -u origin branchname"))
.then(makeExec("git pull origin develop"))
.then(makeExec("git checkout develop"))
.then(makeExec("git merge branchname"))
.then(makeExec("git push"))
.catch(function(err) {
    //display an error message
})

I'm going to try going the route of the stackoverflow answer I linked in my question. Thanks for the feedback! — akcorp2003, Mar 03 '17 at 19:58

Node.Js - exit out of exec after continuous commands

2 Answers2