Jenkins groovy routine to wait for apt lock before running commands.

aptCmd.groovy

/**
  * Wait for apt lock to be free, then run command.
  * @param aptArgs E.g. `install -y emacs xterm`
 */
void call(String aptArgs) {
    def timeout = 120  // wait for lock this long
    def fileno = 1000  // unused file descriptor number
    def lockfile = "/var/lib/dpkg/lock"
    sh """
        /usr/bin/sudo bash -c "(flock --timeout $timeout $fileno; apt $aptArgs) $fileno> $lockfile"
    """
}