docker怎么获取hostname？

# 从process中取出环境变量对象

let env = process.env;

console.log(JSON.stringify(env));

# env['HOST_Q']就是最终要获取的主机名

# output

[2019-04-17T06:54:12.951Z] [e1e7115e0a33] [info]: {"NODE_VERSION":"8.9.4","HOSTNAME":"e1e7115e0a33","YARN_VERSION":"1.3.2","HOME":"/root","HOST_Q":"emg-ubuntu-pub02","PATH":"/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin","PWD":"/"}

public class Test {

    public static void main(String[] args) {

        Map<String, String> map = System.getenv();

        String hostName = map.get("HOST_Q");

        System.out.println(hostName);  

    }

}