protocol.rst

Protocol v1

pseud uses to transport its messages ØMQ with ROUTER sockets. the structure of every frames follow this specification.

ENVELOPE + PSEUD MESSAGE

ENVELOPE

The envelope belongs to ømq typology to route messages to right recipient. the are separated from pseud message with empty delimiter ''. Basically the envelope will be :

['peer_identity', '']

PSEUD MESSAGE

FRAME 0: VERSION of current protocol :

utf-8 string 'v1'

FRAME 1: message uuid :

bytes uuid4 or empty string for hearbeat messages

FRAME 2: message type :

byte

FRAME 3: body :

WORK, OK, ERROR and HELLO expect msgpack.
AUTHENTICATED, UNAUTHORIZED and HEARTBEAT expect utf-8 strings.

MESSAGE TYPES

WORK

'\x03'

the body content is a tuple of 3 items

1. dotted name of the rpc-callable
2. tuple of positional arguments
3. dict of keyword arguments

OK

'\x01'

ERROR

'\x10'

the body content is a tuple of 3 items

1. string of Exception class name e.g. 'AttributeError'
2. message of the exception
3. Remote traceback

UNAUTHORIZED

'\x11'

HELLO

'\x02'

the body content is a tuple of 2 items

1. login
2. password

AUTHENTICATED

'\x04'

HEARTBEAT

'\x06'

COMMUNICATION

1. client sends work to server and receive successful answer.

   client	->	<-	server
   	WORK
   		OK

2. client sends work to server and receive an error.

   client	->	<-	server
   	WORK
   		ERROR

3. server sends work to client and receive successful answer.

   client	->	<-	server
   		WORK
   	OK

4. client sends an heartbeat

   client	->	<-	server
   	HEARTBEAT

5. server sends an heartbeat

   client	->	<-	server
   		HEARTBEAT

6. client send a job and server requires authentication

   client	->	<-	server
   	WORK
   		UNAUTHORIZED
   	HELLO
   		AUTHENTICATED
   	WORK
   		OK

7. client send a job and server requires authentication but fails

   client	->	<-	server
   	WORK
   		UNAUTHORIZED
   	HELLO
   		UNAUTHORIZED