gather_metrics.py

#!/usr/bin/env python

"""
The main module file that will be invoked by the one line installer.

Usage: gather_metrics [optional log file]

If log file is provided, then errors will be logged to such file.
Otherwise, all errors will be flushed.

It first checks the dependency this module needs.
Detects application and calls the appropriate plugin installer.
Catches ctrl+c to prevent long error message and exit the system
with return code of 1.
"""

import socket
import sys
import getopt
from datetime import datetime
import subprocess

import conf_collectd_plugin as conf
import install_utils as utils
import config

# Python required base version
REQ_VERSION = (2, 7)


def check_version():
    cur_version = sys.version_info
    utils.print_step('  Checking python version')
    if cur_version < REQ_VERSION:
        sys.stderr.write(
            'Your Python interpreter is older '
            'than what we have tested, we suggest upgrading '
            'to a newer 2.7 version before continuing.\n')
        sys.exit()
    utils.print_success()


def port_scan(host, port):
    """
    Using ipv4, TCP connection to test whether a port is
    being used.
    """
    # AF_INET specifies ipv4, SOCK_STREAM for TCP
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

    try:
        sock.connect((host, port))
    except socket.error:
        return False
    except KeyboardInterrupt:
        print 'Scanning interrupted'
        sys.exit()
    except socket.gaierror:
        print 'Hostname could not be resolved'
        sys.exit()
    else:
        return port
    finally:
        sock.close()


def detect_used_ports():
    """
    Scan through localhost 0-1024 ports
    """
    MAX_PORT = 1025
    DEFAULT_HOST = '127.0.0.1'
    open_ports = []
    socket.setdefaulttimeout(1)
    for port in range(0, MAX_PORT):
        res = port_scan(DEFAULT_HOST, port)
        if res:
            open_ports.append(port)
        # debugging purpose to see if program is running
        if port % 5000 == 0 and port != 0:
            sys.stderr.write('.')
    return open_ports


def detect_applications():
    """
    Current collectd plugin support:
    apache.
    Want: nginx, sql, postgres, amcq
    This function uses unix command ps -A and check whether
    the supported application is listed.
    """

    try:
        res = subprocess.check_output(
            'ps -A', shell=True,
            stderr=subprocess.STDOUT,
            executable='/bin/bash')
    except:
        print 'Unexpected error.'
        sys.exit(1)

    if 'apache' in res or 'httpd' in res:
        conf.install_apache_plugin()
    if 'nginx' in res:
        print 'Has nginx'
    if 'sql' in res:
        print 'Has sql'
    if 'postgres' in res:
        print 'Has postgres'
    if 'AMCQ' in res:
        print 'Has AMCQ'


if __name__ == '__main__':
    check_version()
    conf.check_collectd_exists()
    conf.check_collectd_path()

    # the first argument will be the log file
    if len(sys.argv) > 1:
        config.INSTALL_LOG = sys.argv[1]
    else:
        config.INSTALL_LOG = '/dev/null'

    try:
        conf.print_log()
        detect_applications()
    except KeyboardInterrupt:
        sys.stderr.write('\nQuitting the installer via keyboard interrupt.')
        sys.exit(1)