Executing a remote SSH command in background

Whenever you execute a SSH command on a remote host it will wait until that process ends. Even with Unix targets if you add a "&" on the end of the command and/or add "nohup" on the beginning you will still wait. Same obviously applies in OpenAF:

var aTarget = { 
    host : "some.host",
    port : 22,
    login: "me",
    pass : "change"
    //id: "~/.ssh/mykey_rsa"
}

var res = $ssh(aTarget)
.sh("nohup wget https://download.dokuwiki.org/src/dokuwiki/dokuwiki-stable.tgz &")
.get();

// res will have all the output from wget as if '&' was never there in the first place

The reason is related to how SSH works. While any of the stdout, stderr or stdin are "open" the execution command won't end. So a simple way to solve it is to change the execution command to:

var res = $ssh(aTarget)
.sh("nohup wget https://download.dokuwiki.org/src/dokuwiki/dokuwiki-stable.tgz 2> wget.out > /dev/null < /dev/null &")
.get();

// res.stdout and res.stderr now don't shown anything since the process was
// left running on the server

Later you can check the execution command output:

var res = $ssh(aTarget).sh("cat wget.out").get(0).stdout;

What about promises?

Yes, you could code something like:

var res;
var promise = $do(() => {
    res = $ssh(aTarget)
          .sh("wget https://download.dokuwiki.org/src/dokuwiki/dokuwiki-stable.tgz")
          .get();
});

But if you are running on a cloud function (e.g. AWS Lambda) payed by execution time you don't want to wait for the promise to be fullfilled (specially if the download will or might take some time).