import subprocess, re, os, socket, resource, pwd, crypt, logging, sys, platform

def demote(user_uid, user_gid):

    def result():

        os.setgid(user_gid)

        os.setuid(user_uid)

    return result

class setuputil:

    @staticmethod

    def run_command(args, username=None, usercwd=None):

        try:

            if username:

                pw_record = pwd.getpwnam(username)

                env = os.environ.copy()

                env['HOME']  = pw_record.pw_dir

                env['LOGNAME']  = username

                env['USER']  = username

                if usercwd:

                    env['PWD']  = usercwd

                p = subprocess.Popen(args, preexec_fn=demote(pw_record.pw_uid, pw_record.pw_gid),

                                     cwd=usercwd, env=env, close_fds=True)

            else:

                p = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE, close_fds = True)

            outputs = p.communicate()

            for out in outputs:

                if out:

                    return (p.returncode, out)

        except OSError as os_e:

            return (os_e.errno, os_e.strerror)

        except ValueError as val_e:

            return (val_e.errno, val_e.strerror)

        else:

            return (p.returncode, outputs)

    @staticmethod

    def java_version():

        java_ver_pattern = '\"(\d+\.\d+).*\"'

        java_cmd = "java"

        if 'JAVA_HOME' in os.environ:

            java_cmd = os.environ['JAVA_HOME'] + "/bin/java"

        version = subprocess.check_output([java_cmd, '-version'], stderr=subprocess.STDOUT)

        if version:

            return re.search(java_ver_pattern, version).groups()[0]

        else:

            return None

    @staticmethod

    def start_app(es_exec, pid_file, es_user):

        rtcode, msg = setuputil.run_command([es_exec, '-d', '-p', pid_file], es_user)

        if rtcode:

            return (rtcode, msg)

        else:

            return (0, "OK")

MIN_JAVA_VERSION = 1.8



ELASTIC_USER = 'elastic'

ELASTIC_PASSWORD = 'elastic'

ELASTIC_PID = '/tmp/elasticpid'

def main():

    # set up java home

    os.environ['JAVA_HOME'] = '/shared/java8'

    j_ver = setuputil.java_version()

    if not j_ver or float(j_ver) < MIN_JAVA_VERSION:

        logging.error("Java isn't installed or java version is not up to date: %s", j_ver if j_ver else "None")

        return (1, "Java isn't installed or java version is not up to date: %s"%(j_ver if j_ver else "None"))

    rtcode, msg = setuputil.start_app('/opt/elasticsearch6.2.3/bin/elasticsearch', ELASTIC_PID, ELASTIC_USER)

    if rtcode:

        logging.error("Failed to start elasticsearch: %d, %s", rtcode, msg)

        return (rtcode, msg)

    else:

        logging.debug("Start elasticsearch: %s", msg)

        return (0, None)

if __name__ == '__main__':

    main()