monkey/chaos_monkey/transport/http.py

import urllib, BaseHTTPServer, threading, os.path
import monkeyfs
from logging import getLogger
from base import TransportProxyBase, update_last_serve_time
from urlparse import urlsplit
import select
import socket

__author__ = 'hoffer'

LOG = getLogger(__name__)


class FileServHTTPRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
    protocol_version = "HTTP/1.1"
    filename = ""

    def version_string(self):
        return "Microsoft-IIS/7.5."

    @staticmethod
    def report_download():
        pass

    def do_POST(self):
        self.send_error(501, "Unsupported method (POST)")
        return 

    def do_GET(self):
        """Serve a GET request."""
        f, start_range, end_range = self.send_head()
        if f:
            f.seek(start_range, 0)
            chunk = 0x1000
            total = 0
            while chunk > 0:
                if start_range + chunk > end_range:
                    chunk = end_range - start_range
                try:
                    self.wfile.write(f.read(chunk))
                except:
                    break
                total += chunk
                start_range += chunk

            if f.tell() == monkeyfs.getsize(self.filename):
                self.report_download()

            f.close()

    def do_HEAD(self):
        """Serve a HEAD request."""
        f, start_range, end_range = self.send_head()
        if f:
            f.close()

    def send_head(self):
        if self.path != '/'+urllib.quote(os.path.basename(self.filename)):
            self.send_error (500, "")
            return        
        f = None
        try:
            f = monkeyfs.open(self.filename, 'rb')
        except IOError:
            self.send_error(404, "File not found")
            return None, 0, 0
        size = monkeyfs.getsize(self.filename)
        start_range = 0
        end_range = size
        
        if "Range" in self.headers:
            s, e = self.headers['range'][6:].split('-', 1)
            sl = len(s)
            el = len(e)
            if sl > 0:
                start_range = int(s)
                if el > 0:
                    end_range = int(e) + 1
            elif el > 0:
                ei = int(e)
                if ei < size:
                    start_range = size - ei
            
            if start_range == 0 and end_range - start_range >= size:
                self.send_response(200)
            else:
                self.send_response(206)
        else:
            self.send_response(200)

        self.send_header("Content-type", "application/octet-stream")                    
        self.send_header("Content-Range", 'bytes ' + str(start_range) + '-' + str(end_range - 1) + '/' + str(size))
        self.send_header("Content-Length", min(end_range - start_range, size))
        self.end_headers()
        return f, start_range, end_range

    def log_message(self, format, *args):
        LOG.debug("FileServHTTPRequestHandler: %s - - [%s] %s" % (self.address_string(),
                                                                  self.log_date_time_string(),
                                                                  format % args))


class HTTPConnectProxyHandler(BaseHTTPServer.BaseHTTPRequestHandler):
    timeout = 30              # timeout with clients, set to None not to make persistent connection
    proxy_via = None          # pseudonym of the proxy in Via header, set to None not to modify original Via header
    protocol_version = "HTTP/1.1"    

    def version_string(self):
        return ""

    def do_CONNECT(self):
        # just provide a tunnel, transfer the data with no modification
        req = self
        reqbody = None
        req.path = "https://%s/" % req.path.replace(':443', '')

        u = urlsplit(req.path)
        address = (u.hostname, u.port or 443)
        try:
            conn = socket.create_connection(address)
        except socket.error, e:
            LOG.debug("HTTPConnectProxyHandler: Got exception while trying to connect to %s: %s" % (repr(address), e))
            self.send_error(504)    # 504 Gateway Timeout
            return
        self.send_response(200, 'Connection Established')
        self.send_header('Connection', 'close')
        self.end_headers()

        conns = [self.connection, conn]
        keep_connection = True
        while keep_connection:
            keep_connection = False
            rlist, wlist, xlist = select.select(conns, [], conns, self.timeout)
            if xlist:
                break
            for r in rlist:
                other = conns[1] if r is conns[0] else conns[0]
                data = r.recv(8192)
                if data:
                    other.sendall(data)
                    keep_connection = True
                    update_last_serve_time()
        conn.close()

    def log_message(self, format, *args):
        LOG.debug("HTTPConnectProxyHandler: %s - [%s] %s" %
                  (self.address_string(), self.log_date_time_string(), format % args))


class InternalHTTPServer(BaseHTTPServer.HTTPServer):
    def handle_error(self, request, client_address):
        #ToDo: debug log error
        # import sys
        # import traceback
        # print >>sys.stderr, '-'*40
        # print >>sys.stderr, 'Exception happened during processing of request from', client_address
        # traceback.print_exc()
        # print >>sys.stderr, '-'*40        
        pass


class HTTPServer(threading.Thread):
    def __init__(self, local_ip, local_port, filename, max_downloads=1):
        self._local_ip = local_ip
        self._local_port = local_port
        self._filename = filename
        self.max_downloads = max_downloads
        self.downloads = 0
        self._stopped = False
        threading.Thread.__init__(self)

    def run(self):
        class TempHandler(FileServHTTPRequestHandler):
            filename = self._filename

            @staticmethod
            def report_download():
                self.downloads += 1

        httpd = InternalHTTPServer((self._local_ip, self._local_port), TempHandler)
        httpd.timeout = 0.5
        
        while not self._stopped and self.downloads < self.max_downloads:
            httpd.handle_request()

        self._stopped = True

    def stop(self, timeout=60):
        self._stopped = True
        self.join(timeout)


class HTTPConnectProxy(TransportProxyBase):
    def run(self):
        httpd = InternalHTTPServer((self.local_host, self.local_port), HTTPConnectProxyHandler)
        httpd.timeout = 30
        while not self._stopped:
            httpd.handle_request()