From 5219e4ce8f9aa082c5f91e248a9f66639c69727d Mon Sep 17 00:00:00 2001 From: Martin Lucina Date: Fri, 28 May 2010 00:49:13 +0200 Subject: Clarify socket types in documentation, reinstate ZMQ_PAIR --- doc/zmq.txt | 4 +-- doc/zmq_setsockopt.txt | 14 ++++---- doc/zmq_socket.txt | 91 +++++++++++++++++++++++++++++++------------------- 3 files changed, 65 insertions(+), 44 deletions(-) (limited to 'doc') diff --git a/doc/zmq.txt b/doc/zmq.txt index 003570a..fa15e43 100644 --- a/doc/zmq.txt +++ b/doc/zmq.txt @@ -90,8 +90,8 @@ Standard sockets present a _synchronous_ interface to either connection-mode reliable byte streams (SOCK_STREAM), or connection-less unreliable datagrams (SOCK_DGRAM). In comparison, 0MQ sockets present an abstraction of a asynchronous _message queue_, with the exact queueing semantics depending on -the socket type (_messaging pattern_) in use. See linkzmq:zmq_socket[3] for the -_messaging patterns_ provided. +the socket type in use. See linkzmq:zmq_socket[3] for the socket types +provided. 0MQ sockets being _asynchronous_ means that the timings of the physical connection setup and teardown, reconnect and effective delivery are organized diff --git a/doc/zmq_setsockopt.txt b/doc/zmq_setsockopt.txt index 8845a10..3bc1081 100644 --- a/doc/zmq_setsockopt.txt +++ b/doc/zmq_setsockopt.txt @@ -61,13 +61,13 @@ The 'ZMQ_AFFINITY' option shall set the I/O thread affinity for connections created by subsequent _zmq_connect()_ or _zmq_bind()_ calls on the specified 'socket'. -sockets. Affinity determines which threads from the 0MQ I/O thread pool -associated with the socket's _context_ shall handle newly created connections. -A value of zero specifies no affinity, meaning that work shall be distributed -fairly among all 0MQ I/O threads in the thread pool. For non-zero values, the -lowest bit corresponds to thread 1, second lowest bit to thread 2 and so on. -For example, a value of 3 specifies that subsequent connections on 'socket' -shall be handled exclusively by I/O threads 1 and 2. +Affinity determines which threads from the 0MQ I/O thread pool associated with +the socket's _context_ shall handle newly created connections. A value of zero +specifies no affinity, meaning that work shall be distributed fairly among all +0MQ I/O threads in the thread pool. For non-zero values, the lowest bit +corresponds to thread 1, second lowest bit to thread 2 and so on. For example, +a value of 3 specifies that subsequent connections on 'socket' shall be handled +exclusively by I/O threads 1 and 2. See also linkzmq:zmq_init[3] for details on allocating the number of I/O threads for a specific _context_. diff --git a/doc/zmq_socket.txt b/doc/zmq_socket.txt index e01921c..ebae5e1 100644 --- a/doc/zmq_socket.txt +++ b/doc/zmq_socket.txt @@ -19,7 +19,31 @@ The 'zmq_socket()' function shall create a 0MQ socket within the specified argument specifies the socket type, which determines the semantics of communication over the socket. -The following _messaging patterns_ are defined: +The following sections present the socket types defined by 0MQ, grouped by the +general _messaging pattern_ built from related socket types. + + +Request-reply pattern +~~~~~~~~~~~~~~~~~~~~~ +The request-reply pattern is used for sending requests from a _client_ to a +_service_, and receiving subsequent replies to each request sent. + +Socket type:: 'ZMQ_REQ' +Compatible peer sockets:: 'ZMQ_REP' + +A socket of type 'ZMQ_REQ' is used by a _client_ to send requests to and +receive replies from a _service_. This socket type allows only an alternating +sequence of _zmq_send(request)_ and subsequent _zmq_recv(reply)_ calls. Each +request sent is load-balanced among all connected _services_. + +Socket type:: 'ZMQ_REP' +Compatible peer sockets:: 'ZMQ_REQ' + +A socket of type 'ZMQ_REP' is used by a _service_ to receive requests from and +send replies to a _client_. This socket type allows only an alternating +sequence of _zmq_recv(request)_ and subsequent _zmq_send(reply)_ calls. Each +reply is routed to the _client_ that issued the last received request. + Publish-subscribe pattern ~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -43,49 +67,46 @@ which messages to subscribe to. The _zmq_send()_ function is not implemented for this socket type. -Request-reply pattern -~~~~~~~~~~~~~~~~~~~~~ -The request-reply pattern is used for sending requests from a _client_ to a -_service_, and receiving subsequent replies to each request sent. - -Socket type:: 'ZMQ_REQ' -Compatible peer sockets:: 'ZMQ_REP' +Pipeline pattern +~~~~~~~~~~~~~~~~ +The pipeline pattern is used for distributing data to _nodes_ arranged in +a pipeline. Data always flows *down* the pipeline, and each stage of the +pipeline is connected to at least one _node_. When a pipeline stage is +connected to multiple _nodes_ data is processed by all connected _nodes_ in +parallel. -A socket of type 'ZMQ_REQ' is used by a _client_ to send requests to and -receive replies from a _service_. This socket type allows only an alternating -sequence of _zmq_send(request)_ and subsequent _zmq_recv(reply)_ calls. Each -request sent is load-balanced among all connected _services_. +Socket type:: 'ZMQ_DOWNSTREAM' +Compatible peer sockets:: 'ZMQ_UPSTREAM' -Socket type:: 'ZMQ_REP' -Compatible peer sockets:: 'ZMQ_REQ' +A socket of type 'ZMQ_DOWNSTREAM' is used by a pipeline _node_ to send messages +to downstream pipeline _nodes_. Messages are load-balanced to all connected +downstream _nodes_. The _zmq_recv()_ function is not implemented for this +socket type. -A socket of type 'ZMQ_REP' is used by a _service_ to receive requests from and -send replies to a _client_. This socket type allows only an alternating -sequence of _zmq_recv(request)_ and subsequent _zmq_send(reply)_ calls. Each -reply is routed to the _client_ that issued the last received request. +Socket type:: 'ZMQ_UPSTREAM' +Compatible peer sockets:: 'ZMQ_DOWNSTREAM' +A socket of type 'ZMQ_UPSTREAM' is used by a pipeline _node_ to receive +messages from upstream pipeline _nodes_. Messages are fair-queued from among +all connected upstream _nodes_. The _zmq_send()_ function is not implemented +for this socket type. -Parallelized pipeline pattern -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -The parallelized pipeline pattern is used for distributing work between -_components_ of a pipeline. Work travels down the pipeline and at each stage -can be processed by any number of _components_ in parallel. -Socket type:: 'ZMQ_UPSTREAM' -Compatible peer sockets:: 'ZMQ_DOWNSTREAM' +Exclusive pair pattern +~~~~~~~~~~~~~~~~~~~~~~ +The exclusive pair pattern is used for communicating exclusively between two +peers. -A socket of type 'ZMQ_UPSTREAM' is used by a _component_ of a pipeline to -receive messages from upstream stages of the pipeline. Messages are fair-queued -from among all connected upstream _components_. The _zmq_send()_ function is -not implemented for this socket type. +Socket type:: 'ZMQ_PAIR' +Compatible peer sockets:: 'ZMQ_PAIR' -Socket type:: 'ZMQ_DOWNSTREAM' -Compatible peer sockets:: 'ZMQ_UPSTREAM' +A socket of type 'ZMQ_PAIR' can only be connected to a single peer at any one +time. No message routing or filtering is performed on messages sent over a +'ZMQ_PAIR' socket. -A socket of type 'ZMQ_DOWNSTREAM' is used by a _component_ of a pipeline to -send messages to downstream stages of the pipeline. Messages are load-balanced -to all connected downstream _components_. The _zmq_recv()_ function is not -implemented for this socket type. +NOTE: 'ZMQ_PAIR' sockets are experimental, and are currently missing several +features such as auto-reconnection. Developers should consider other patterns +in preference to the exclusive pair pattern. RETURN VALUE -- cgit v1.2.3 From da37c45b0c7200eea96118952e671972b71df4ce Mon Sep 17 00:00:00 2001 From: Martin Lucina Date: Fri, 28 May 2010 01:38:43 +0200 Subject: Clarify zmq_bind/zmq_connect Use the term 'endpoint' correctly, and drop the nonsense about local/remote addresses which doesn't clearly explain what is going on --- doc/zmq_bind.txt | 28 +++++++++++++++------------- doc/zmq_connect.txt | 26 ++++++++++++++------------ 2 files changed, 29 insertions(+), 25 deletions(-) (limited to 'doc') diff --git a/doc/zmq_bind.txt b/doc/zmq_bind.txt index 983ce93..c76d05a 100644 --- a/doc/zmq_bind.txt +++ b/doc/zmq_bind.txt @@ -4,34 +4,36 @@ zmq_bind(3) NAME ---- -zmq_bind - assign a local address to a socket +zmq_bind - accept connections on a socket SYNOPSIS -------- -*int zmq_bind (void '*socket', const char '*address');* +*int zmq_bind (void '*socket', const char '*endpoint');* DESCRIPTION ----------- -The _zmq_bind()_ function shall assign a local address specified by the -'address' argument to the socket referenced by the 'socket' argument. +The _zmq_bind()_ function shall create an endpoint for accepting connections +and bind it to the socket referenced by the 'socket' argument. -The 'address' argument is a string consisting of two parts as follows: -'transport'://'endpoint'. The 'transport' part specifies the underlying -transport protocol to use. The meaning of the 'endpoint' part is specific to +The 'endpoint' argument is a string consisting of two parts as follows: +'transport'`://`'address'. The 'transport' part specifies the underlying +transport protocol to use. The meaning of the 'address' part is specific to the underlying transport protocol selected. The following transports are defined: +'inproc':: local in-process (inter-thread) communication transport, see linkzmq:zmq_inproc[7] +'ipc':: local inter-process communication transport, see linkzmq:zmq_ipc[7] 'tcp':: unicast transport using TCP, see linkzmq:zmq_tcp[7] 'pgm', 'epgm':: reliable multicast transport using PGM, see linkzmq:zmq_pgm[7] -'ipc':: local inter-process communication transport, see linkzmq:zmq_ipc[7] -'inproc':: local in-process (inter-thread) communication transport, see linkzmq:zmq_inproc[7] -A single socket may have an arbitrary number of local addresses assigned to it -using _zmq_bind()_, while also being connected to an arbitrary number of peer -addresses using _zmq_connect()_. +With the exception of 'ZMQ_PAIR' sockets, a single socket may be connected to +multiple endpoints using _zmq_connect()_, while simultaneously accepting +incoming connections from multiple endpoints bound to the socket using +_zmq_bind()_. Refer to linkzmq:zmq_socket[3] for a description of the exact +semantics involved when connecting or binding a socket to multiple endpoints. RETURN VALUE @@ -63,7 +65,7 @@ EXAMPLE /* Create a ZMQ_PUB socket */ void *socket = zmq_socket (context, ZMQ_PUB); assert (socket); -/* Bind it to a in-process transport with the endpoint 'my_publisher' */ +/* Bind it to a in-process transport with the address 'my_publisher' */ int rc = zmq_bind (socket, "inproc://my_publisher"); assert (rc == 0); /* Bind it to a TCP transport on port 5555 of the 'eth0' interface */ diff --git a/doc/zmq_connect.txt b/doc/zmq_connect.txt index d31b87b..2bc8e4f 100644 --- a/doc/zmq_connect.txt +++ b/doc/zmq_connect.txt @@ -4,34 +4,36 @@ zmq_connect(3) NAME ---- -zmq_connect - connect a socket to a peer address +zmq_connect - connect a socket SYNOPSIS -------- -*int zmq_connect (void '*socket', const char '*address');* +*int zmq_connect (void '*socket', const char '*endpoint');* DESCRIPTION ----------- The _zmq_connect()_ function shall connect the socket referenced by the -'socket' argument to a peer address specified by the 'address' argument. +'socket' argument to the endpoint specified by the 'endpoint' argument. -The 'address' argument is a string consisting of two parts as follows: -'transport'`://`'endpoint'. The 'transport' part specifies the underlying -transport protocol to use. The meaning of the 'endpoint' part is specific to +The 'endpoint' argument is a string consisting of two parts as follows: +'transport'`://`'address'. The 'transport' part specifies the underlying +transport protocol to use. The meaning of the 'address' part is specific to the underlying transport protocol selected. The following transports are defined: +'inproc':: local in-process (inter-thread) communication transport, see linkzmq:zmq_inproc[7] +'ipc':: local inter-process communication transport, see linkzmq:zmq_ipc[7] 'tcp':: unicast transport using TCP, see linkzmq:zmq_tcp[7] 'pgm', 'epgm':: reliable multicast transport using PGM, see linkzmq:zmq_pgm[7] -'ipc':: local inter-process communication transport, see linkzmq:zmq_ipc[7] -'inproc':: local in-process (inter-thread) communication transport, see linkzmq:zmq_inproc[7] -A single socket may be connected to an arbitrary number of peer addresses using -_zmq_connect()_, while also having an arbitrary number of local addresses -assigned to it using _zmq_bind()_. +With the exception of 'ZMQ_PAIR' sockets, a single socket may be connected to +multiple endpoints using _zmq_connect()_, while simultaneously accepting +incoming connections from multiple endpoints bound to the socket using +_zmq_bind()_. Refer to linkzmq:zmq_socket[3] for a description of the exact +semantics involved when connecting or binding a socket to multiple endpoints. NOTE: The connection will not be performed immediately but as needed by 0MQ. Thus a successful invocation of _zmq_connect()_ does not indicate that a @@ -61,7 +63,7 @@ EXAMPLE /* Create a ZMQ_SUB socket */ void *socket = zmq_socket (context, ZMQ_SUB); assert (socket); -/* Connect it to an in-process transport with the endpoint 'my_publisher' */ +/* Connect it to an in-process transport with the address 'my_publisher' */ int rc = zmq_connect (socket, "inproc://my_publisher"); assert (rc == 0); /* Connect it to the host server001, port 5555 using a TCP transport */ -- cgit v1.2.3