Execute Linux commands using ssh2-promise in NodeJS on remote server

Question

I am trying to execute command yum install <package_name> on a remote linux server using ssh2-promise package, But I could not get the command response back for further processing and validation.

I have tried the following,

// Node:33528) UnhandledPromiseRejectionWarning: Unhandled promise rejection.
(async function(){
        try {
            const data = await this.ssh.exec("yum  repolist all");
            console.log("resp: ", data); 
            } catch(e) {
                console.log(e)
            }
        })();  // This fails 

        const socket = await this.ssh.spawn("yum repolist all");
        socket.on('data', function(data) {
              console.log("resp: " , data); // I get binary data not the human readable output
        });


        // Node:33528) UnhandledPromiseRejectionWarning: Unhandled promise rejection.
        this.ssh.exec("yum install <name>").then((data) => {
            console.log("resp: yum repolist all output: ", data); // This also fails and throws exception

        });

        // Throws again (Node:33528) UnhandledPromiseRejectionWarning: Unhandled promise rejection.
        const output = await this.ssh.exec("yum upgrade <name>");
        console.log("resp: ", output)

I tried with proper try catch block as well, still throws unhandledPromise Exception. Can someone help me figure this out?

score 2 · Answer 1 · answered Jun 04 '20 at 10:38

2

i guess you get something like following in the output:

<Buffer 5b 73 75 64 6f 5d 20 70 61 73 73 77 6f 72 64 20 66 6f 72 20 64 61 72 74 68 63 75 63 75 6d 62 65 72 3a 20>

all you have to do is convert it to string using toString() function of JS.

answered Jun 04 '20 at 10:38

DarthCucumber

101
1
8

Yes, I will try and get back – cslrnr Jun 05 '20 at 09:19
it worked, i will go with the exec function instead of this and i made a mistake of calling async fn inside an async function – cslrnr Jun 06 '20 at 21:01

score 0 · Accepted Answer · answered Jun 06 '20 at 20:59

I made a mistake of calling an async function inside another async function , something like below,

public async runCommand() {
     (async function () {
    try {
        const data = await ssh.exec("yum repolist all");
        console.log("resp: ", data);
    } catch (e) {
        console.log("Error - " + e);
    }
    })(); 
}

Changed the function like below and it worked .

public async runCommand() { 
    try {
        const data = await ssh.exec("yum repolist all");
        console.log("resp: ", data);
    } catch (e) {
        console.log("Error - " + e);
    }
}

Execute Linux commands using ssh2-promise in NodeJS on remote server

2 Answers2