monkey/chaos_monkey/transport/http.py

import urllib, BaseHTTPServer, threading, os.path
import shutil
import struct
import monkeyfs
from logging import getLogger

__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)
        fs = os.fstat(f.fileno())
        size = int(fs[6])
        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 InternalHTTPServer(BaseHTTPServer.HTTPServer):
    def handle_error(self, request, client_address):
        #ToDo: find a better error message.
        #LOG.debug("HTTPServer error from %s:%s" % client_address)
        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)