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Viewing changes to grackle/service.py

  • Committer: William Grant
  • Date: 2012-01-22 06:41:06 UTC
  • Revision ID: william.grant@canonical.com-20120122064106-6at8ool919624m0z
Let the HTTP client decide count and order (to an extent).

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__metaclass__ = type
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import httplib
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import logging
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import os
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from signal import SIGKILL
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import simplejson
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import sys
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from wsgiref.simple_server import make_server
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from wsgiref.util import shift_path_info
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from grackle.store import (
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    MemoryStore,
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    )
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15
 
 
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class GrackleService:
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    """A request handler that forwards to server.store."""
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19
 
    def __init__(self, store):
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        self.store = store
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        self.logger = logging.getLogger('http')
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    def __call__(self, environ, start_response):
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        self.environ = environ
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        self.start_response = start_response
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        self.method = environ['REQUEST_METHOD']
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        self.host_port = shift_path_info(environ)
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        self.application = shift_path_info(environ)
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        self.path = environ['PATH_INFO'].split('/')[1:]
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        self.query_string = environ['QUERY_STRING']
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        return self.handle_request()
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    def handle_request(self):
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        if self.method == 'PUT':
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            return self.do_PUT()
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        if self.method == 'POST':
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            return self.do_POST()
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        if self.method == 'GET':
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            return self.do_GET()
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    def send_response(self, code, headers={}, reason=None):
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        if reason is None:
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            reason = httplib.responses[code]
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        response_code = '%s %s' % (code, reason)
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        response_headers = {'content-type': 'application/json'}
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        response_headers.update(headers.items())
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        self.start_response(response_code, response_headers.items())
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    def do_PUT(self):
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        """Create an archive or message on PUT."""
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        if len(self.path) == 1:
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            # This expected path is /archive/archive_id.
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            try:
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                self.store.put_archive(self.path[0])
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                self.send_response(httplib.CREATED)
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            except Exception, error:
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                self.send_response(
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                    httplib.BAD_REQUEST, reason=error.__doc__)
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        elif len(self.path) == 2:
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            # This expected path is /archive/archive_id/message_id.
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            try:
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                put_input = self.environ['wsgi.input']
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                message = put_input.read(int(self.environ['CONTENT_LENGTH']))
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                self.store.put_message(self.path[0], self.path[1], message)
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                self.send_response(httplib.CREATED)
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            except:
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                self.send_response(httplib.BAD_REQUEST)
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        return []
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    def do_POST(self):
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        """Change a message on POST."""
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        if len(self.path) == 2:
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            # This expected path is /archive/archive_id/message_id.
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            try:
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                # This expected path is /archive/archive_id/message_id.
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                response = self.store.hide_message(
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                    self.path[0], self.path[1], self.query_string)
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                self.send_response(httplib.OK)
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                return [simplejson.dumps(response)]
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            except:
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                self.send_response(httplib.BAD_REQUEST)
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                return []
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    def do_GET(self):
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        """Retrieve a list of messages on GET."""
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        try:
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            response = self.store.get_messages(
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                self.path[0], self.query_string)
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            self.send_response(httplib.OK)
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            return [simplejson.dumps(response)]
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        except Exception, error:
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            self.send_response(httplib.BAD_REQUEST, reason=error.__doc__)
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            return []
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    def log_message(self, format, *args):
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        """Override log_message to use standard Python logging."""
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        message = "%s - - [%s] %s\n" % (
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            self.address_string(), self.log_date_time_string(), format % args)
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        self.logger.info(message)
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class ForkedFakeService:
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    """A Grackle service fake, as a ContextManager."""
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    def __init__(self, port, message_archives=None, write_logs=False):
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        """Constructor.
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        :param port: The tcp port to use.
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        :param message_archives: A dict of lists of dicts representing
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            archives of messages. The outer dict represents the archive,
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            the list represents the list of messages for that archive.
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        :param write_logs: If true, log messages will be written to stdout.
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        """
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        self.pid = None
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        self.port = port
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        if message_archives is None:
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            self.message_archives = {}
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        else:
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            self.message_archives = message_archives
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        self.read_end, self.write_end = os.pipe()
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        self.write_logs = write_logs
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    @staticmethod
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    def from_client(client, message_archives=None):
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        """Instantiate a ForkedFakeService from the client.
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127
 
        :param port: The client to provide service for.
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        :param message_archives: A dict of lists of dicts representing
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            archives of messages. The outer dict represents the archive,
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            the list represents the list of messages for that archive.
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        """
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        return ForkedFakeService(client.port, message_archives)
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    def is_ready(self):
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        """Tell the parent process that the server is ready for writes."""
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        os.write(self.write_end, 'asdf')
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    def __enter__(self):
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        """Run the service.
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        Fork and start a server in the child.  Return when the server is ready
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        for use."""
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        pid = os.fork()
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        if pid == 0:
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            self.start_server()
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        self.pid = pid
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        os.read(self.read_end, 1)
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        return
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150
 
    def start_server(self):
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        """Start the HTTP server."""
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        app = GrackleService(MemoryStore(self.message_archives))
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        service = make_server('', self.port, app)
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        self.is_ready()
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        if self.write_logs:
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            logging.basicConfig(
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                stream=sys.stderr, level=logging.INFO)
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        service.serve_forever()
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160
 
    def __exit__(self, exc_type, exc_val, traceback):
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        os.kill(self.pid, SIGKILL)
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164
 
def application(environ, start_response):
165
 
    start_response('200 OK', [('Content-Type', 'text/plain')])
166
 
    return "Hello World"
167
 
 
168
 
 
169
 
if __name__ == '__main__':
170
 
    app = GrackleService(MemoryStore({}))
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    service = make_server('', 8787, app)
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    service.serve_forever()