#!/usr/bin/python
# -*- coding: utf-8 -*-

# (c) 2013, James Cammarata <jcammarata@ansibleworks.com>
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.

DOCUMENTATION = '''
---
module: accelerate
short_description: Enable accelerated mode on remote node
description:
     - This modules launches an ephemeral I(accelerate) daemon on the remote node which
       Ansible can use to communicate with nodes at high speed.
     - The daemon listens on a configurable port for a configurable amount of time.
     - Fireball mode is AES encrypted
version_added: "1.3"
options:
  port:
    description:
      - TCP port for the socket connection
    required: false
    default: 5099
    aliases: []
  minutes:
    description:
      - The I(accelerate) listener daemon is started on nodes and will stay around for
        this number of minutes before turning itself off.
    required: false
    default: 30
notes:
    - See the advanced playbooks chapter for more about using accelerated mode.
requirements: [ "python-keyczar" ]
author: James Cammarata
'''

EXAMPLES = '''
# To use accelerate mode, simply add "accelerate: true" to your play. The initial
# key exchange and starting up of the daemon will occur over SSH, but all commands and
# subsequent actions will be conducted over the raw socket connection using AES encryption

- hosts: devservers
  accelerate: true
  tasks:
      - command: /usr/bin/anything
'''

import os
import os.path
import tempfile
import sys
import shutil
import socket
import struct
import time
import base64
import getpass
import syslog
import signal
import time
import signal
import traceback

import SocketServer

syslog.openlog('ansible-%s' % os.path.basename(__file__))
PIDFILE = os.path.expanduser("~/.accelerate.pid")

# the chunk size to read and send, assuming mtu 1500 and 
# leaving room for base64 (+33%) encoding and header (100 bytes)
# 4 * (975/3) + 100 = 1400 
# which leaves room for the TCP/IP header
CHUNK_SIZE=10240

def log(msg):
    syslog.syslog(syslog.LOG_NOTICE|syslog.LOG_DAEMON, msg)

if os.path.exists(PIDFILE):
    try:
        data = int(open(PIDFILE).read())
        try:
            os.kill(data, signal.SIGKILL)
        except OSError:
            pass
    except ValueError:
        pass
    os.unlink(PIDFILE)

HAS_KEYCZAR = False
try:
    from keyczar.keys import AesKey
    HAS_KEYCZAR = True
except ImportError:
    pass

# NOTE: this shares a fair amount of code in common with async_wrapper, if async_wrapper were a new module we could move
# this into utils.module_common and probably should anyway

def daemonize_self(module, password, port, minutes):
    # daemonizing code: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/66012
    try:
        pid = os.fork()
        if pid > 0:
            log("exiting pid %s" % pid)
            # exit first parent
            module.exit_json(msg="daemonized accelerate on port %s for %s minutes" % (port, minutes))
    except OSError, e:
        log("fork #1 failed: %d (%s)" % (e.errno, e.strerror))
        sys.exit(1)

    # decouple from parent environment
    os.chdir("/")
    os.setsid()
    os.umask(022)

    # do second fork
    try:
        pid = os.fork()
        if pid > 0:
            log("daemon pid %s, writing %s" % (pid, PIDFILE))
            pid_file = open(PIDFILE, "w")
            pid_file.write("%s" % pid)
            pid_file.close()
            log("pidfile written")
            sys.exit(0)
    except OSError, e:
        log("fork #2 failed: %d (%s)" % (e.errno, e.strerror))
        sys.exit(1)

    dev_null = file('/dev/null','rw')
    os.dup2(dev_null.fileno(), sys.stdin.fileno())
    os.dup2(dev_null.fileno(), sys.stdout.fileno())
    os.dup2(dev_null.fileno(), sys.stderr.fileno())
    log("daemonizing successful")

class ThreadedTCPServer(SocketServer.ThreadingTCPServer):
    def __init__(self, server_address, RequestHandlerClass, module, password):
        self.module = module
        self.key = AesKey.Read(password)
        self.allow_reuse_address = True
        self.timeout = None
        SocketServer.ThreadingTCPServer.__init__(self, server_address, RequestHandlerClass)

class ThreadedTCPRequestHandler(SocketServer.BaseRequestHandler):
    def send_data(self, data):
        packed_len = struct.pack('Q', len(data))
        return self.request.sendall(packed_len + data)

    def recv_data(self):
        header_len = 8 # size of a packed unsigned long long
        data = b""
        while len(data) < header_len:
            d = self.request.recv(1024)
            if not d:
                return None
            data += d
        data_len = struct.unpack('Q',data[:header_len])[0]
        data = data[header_len:]
        while len(data) < data_len:
            d = self.request.recv(1024)
            if not d:
                return None
            data += d
        return data

    def handle(self):
        while True:
            #log("waiting for data")
            data = self.recv_data()
            if not data:
                break
            try:
                #log("got data, decrypting")
                data = self.server.key.Decrypt(data)
                #log("decryption done")
            except:
                log("bad decrypt, skipping...")
                data2 = json.dumps(dict(rc=1))
                data2 = self.server.key.Encrypt(data2)
                send_data(client, data2)
                return

            #log("loading json from the data")
            data = json.loads(data)

            mode = data['mode']
            response = {}
            if mode == 'command':
                response = self.command(data)
            elif mode == 'put':
                response = self.put(data)
            elif mode == 'fetch':
                response = self.fetch(data)

            data2 = json.dumps(response)
            data2 = self.server.key.Encrypt(data2)
            self.send_data(data2)

    def command(self, data):
        if 'cmd' not in data:
            return dict(failed=True, msg='internal error: cmd is required')
        if 'tmp_path' not in data:
            return dict(failed=True, msg='internal error: tmp_path is required')
        if 'executable' not in data:
            return dict(failed=True, msg='internal error: executable is required')

        #log("executing: %s" % data['cmd'])
        rc, stdout, stderr = self.server.module.run_command(data['cmd'], executable=data['executable'], close_fds=True)
        if stdout is None:
            stdout = ''
        if stderr is None:
            stderr = ''
        #log("got stdout: %s" % stdout)
        #log("got stderr: %s" % stderr)

        return dict(rc=rc, stdout=stdout, stderr=stderr)

    def fetch(self, data):
        if 'in_path' not in data:
            return dict(failed=True, msg='internal error: in_path is required')

        try:
            fd = file(data['in_path'], 'rb')
            fstat = os.stat(data['in_path'])
            log("FETCH file is %d bytes" % fstat.st_size)
            while fd.tell() < fstat.st_size:
                data = fd.read(CHUNK_SIZE)
                last = False
                if fd.tell() >= fstat.st_size:
                    last = True
                data = dict(data=base64.b64encode(data), last=last)
                data = json.dumps(data)
                data = self.server.key.Encrypt(data)

                if self.send_data(data):
                    return dict(failed=True, stderr="failed to send data")

                response = self.recv_data()
                if not response:
                    log("failed to get a response, aborting")
                    return dict(failed=True, stderr="Failed to get a response from %s" % self.host)
                response = self.server.key.Decrypt(response)
                response = json.loads(response)

                if response.get('failed',False):
                    log("got a failed response from the master")
                    return dict(failed=True, stderr="Master reported failure, aborting transfer")
        except Exception, e:
            tb = traceback.format_exc()
            log("failed to fetch the file: %s" % tb)
            return dict(failed=True, stderr="Could not fetch the file: %s" % str(e))
        finally:
            fd.close()

        return dict()

    def put(self, data):
        if 'data' not in data:
            return dict(failed=True, msg='internal error: data is required')
        if 'out_path' not in data:
            return dict(failed=True, msg='internal error: out_path is required')

        final_path = None
        final_user = None
        if 'user' in data and data.get('user') != getpass.getuser():
            log("the target user doesn't match this user, we'll move the file into place via sudo")
            (fd,out_path) = tempfile.mkstemp(prefix='ansible.', dir=os.path.expanduser('~/.ansible/tmp/'))
            out_fd = os.fdopen(fd, 'w', 0)
            final_path = data['out_path']
            final_user = data['user']
        else:
            out_path = data['out_path']
            out_fd = open(out_path, 'w')

        try:
            bytes=0
            while True:
                out = base64.b64decode(data['data'])
                bytes += len(out)
                out_fd.write(out)
                response = json.dumps(dict())
                response = self.server.key.Encrypt(response)
                self.send_data(response)
                if data['last']:
                    break
                data = self.recv_data()
                if not data:
                    raise ""
                data = self.server.key.Decrypt(data)
                data = json.loads(data)
        except:
            tb = traceback.format_exc()
            log("failed to put the file: %s" % tb)
            return dict(failed=True, stdout="Could not write the file")
        finally:
            #log("wrote %d bytes" % bytes)
            out_fd.close()

        if final_path:
            log("moving %s to %s" % (out_path, final_path))
            self.server.module.atomic_move(out_path, final_path)
        return dict()

def daemonize(module, password, port, minutes):
    try:
        daemonize_self(module, password, port, minutes)

        def catcher(signum, _):
            module.exit_json(msg='timer expired')

        signal.signal(signal.SIGALRM, catcher)
        signal.setitimer(signal.ITIMER_REAL, 60 * minutes)

        server = ThreadedTCPServer(("0.0.0.0", port), ThreadedTCPRequestHandler, module, password)
        server.allow_reuse_address = True
        
        log("serving!")
        server.serve_forever(poll_interval=1.0)
    except Exception, e:
        tb = traceback.format_exc()
        log("exception caught, exiting accelerated mode: %s\n%s" % (e, tb))
        sys.exit(0)

def main():
    module = AnsibleModule(
        argument_spec = dict(
            port=dict(required=False, default=5099),
            password=dict(required=True),
            minutes=dict(required=False, default=30),
        ),
        supports_check_mode=True
    )

    password  = base64.b64decode(module.params['password'])
    port      = int(module.params['port'])
    minutes   = int(module.params['minutes'])

    if not HAS_KEYCZAR:
        module.fail_json(msg="keyczar is not installed")

    daemonize(module, password, port, minutes)


# this is magic, see lib/ansible/module_common.py
#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
main()