service: initial version

mitogen/service.py

@@ -0,0 +1,83 @@
+# Copyright 2017, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice, this
+# list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+import logging
+
+import mitogen.core
+import mitogen.master
+from mitogen.core import LOG
+
+
+class Service(object):
+    well_known_id = None
+    max_message_size = 0
+
+    def __init__(self, router):
+        self.router = router
+        self.recv = mitogen.core.Receiver(router, self.well_known_id)
+        self.running = True
+
+    def validate_args(self, args):
+        return True
+
+    def run_once(self):
+        msg = self.recv.get()
+        if len(msg.data) > self.max_message_size:
+            LOG.error('%r: larger than permitted size: %r', self, msg)
+            msg.reply(mitogen.core.CallError('Message size exceeded'))
+            return
+
+        args = msg.unpickle(throw=False)
+        if ( args == mitogen.core._DEAD or
+             isinstance(args, mitogen.core.CallError) or
+             not self.validate_args(args)):
+            LOG.warning('Received junk message: %r', args)
+            return
+
+        try:
+            msg.reply(self.dispatch(args, msg))
+        except Exception, e:
+            LOG.exception('While invoking %r.dispatch()', self)
+            msg.reply(mitogen.core.CallError(e))
+
+    def run(self):
+        while self.running:
+            self.run_once()
+
+
+class Pool(object):
+    def __init__(self, router, services, size=1):
+        self.services = list(services)
+        self.select = mitogen.master.Select()
+
+
+
+def call(context, handle, obj):
+    msg = mitogen.core.Message.pickled(obj, handle=handle)
+    recv = context.send_async(msg)
+    return recv.get().unpickle()