Lib for executing command-line on Docker images. Shares similar interface to "child_process".

docker_shell.js

const
    _ = require('lodash'),
    spawn = require('child_process').spawn,
    bacon = require('baconjs');

const bufferUp = function(stream){
    return bacon
        .fromEvent(stream, 'data')
        .takeUntil(bacon.fromEvent(stream, 'close').take(1))
        .fold([], '.concat')
        .map(Buffer.concat)
};

const DockerShell = class {

    constructor(settings = {
        tls_verify: 1,
        host: "tcp://localhost:2376",
        cert_path: "",
        machine_name: "localhost"
    }){
        this._env = {
            "DOCKER_TLS_VERIFY": settings["tls_verify"],
            "DOCKER_HOST": settings["host"],
            "DOCKER_CERT_PATH": settings["cert_path"],
            "DOCKER_MACHINE_NAME": settings["machine_name"]
        };
    }

    spawn(imageName, args, { env } = {}){
        return spawn('docker', ["run", "--rm -i", _.map( env || {}, (val, key)=>`-e "${key}"="${val}"`), imageName, args.join(' ')], {
            env: this._env,
            shell: true,
            cwd: __dirname,
            stdio: []
        });
    }

    exec(imageName, args, options){
        let dockerShell = this.spawn(imageName, args, options);

        const cnv = (function(encoding){ return encoding ? (buf)=>buf.toString(encoding) :  _.identity })(options.encoding);

        return bacon
            .combineTemplate({
                stdout: bufferUp(dockerShell.stdout).map(cnv),
                stderr: bufferUp(dockerShell.stderr).map(cnv),
                code: bacon.fromEvent(dockerShell, 'close').take(1)
            })
            .flatMap(({ stderr, stdout, code }) => bacon.once(code > 0 ? new bacon.Error(stderr) :  stdout))
            .take(1)
            .endOnError()
            .toPromise();
    }
};

module.exports = DockerShell;