From c6fc27fdbbdcff19a61ea35f99d85377e39f6566 Mon Sep 17 00:00:00 2001 From: Garrett D'Amore Date: Sat, 6 Apr 2024 10:56:42 -0700 Subject: Proto pages done. --- docs/ref/proto/push.adoc | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 docs/ref/proto/push.adoc (limited to 'docs/ref/proto/push.adoc') diff --git a/docs/ref/proto/push.adoc b/docs/ref/proto/push.adoc new file mode 100644 index 00000000..4f228c77 --- /dev/null +++ b/docs/ref/proto/push.adoc @@ -0,0 +1,39 @@ +## Push Protocol (_PUSH_) + +The ((_PUSH_ protocol))(((protocol, _PUSH_))) is one half of a ((pipeline pattern)). +The other side is the xref:pull.adoc[_PULL_] protocol. + +In the pipeline pattern, pushers distribute messages to pullers. +Each message sent by a pusher will be sent to one of its ready peer pullers, chosen in a round-robin fashion. +This property makes this pattern useful in ((load-balancing)) scenarios. + +#### Socket Operations + +The xref:nng_push_open.adoc[`nng_push0_open`] call creates a pusher socket. +This socket may be used to send messages, but is unable to receive them. +Attempts to receive messages will result in `NNG_ENOTSUP`. + +Send operations will observe flow control (back-pressure), so that only peers capable of accepting a message will be considered. +If no peer is available to receive a message, then the send operation will wait until one is available, or the operation times out. + +NOTE: Although the pipeline protocol honors flow control, and attempts to avoid dropping messages, no guarantee of delivery is made. +Furthermore, as there is no capability for message acknowledgment, applications that need reliable delivery are encouraged to consider the xref:nng_req.adoc[_REQ_] protocol instead. + +#### Protocol Versions + +Only version 0 of this protocol is supported.footnote:[At the time of writing, no other versions of this protocol have been defined.] + +#### Protocol Options + +xref:nng_options.adoc#NNG_OPT_SENDBUF[`NNG_OPT_SENDBUF`]:: + + (`int`, 0 - 8192) + Normally this is set to zero, indicating that send operations are unbuffered. + In unbuffered operation, send operations will wait until a suitable peer is available to receive the message. + If this is set to a positive value (up to 8192), then an intermediate buffer is provided for the socket with the specified depth (in messages). + +NOTE: Transport layer buffering may occur in addition to any socket buffer determined by this option. + +#### Protocol Headers + +The _PUSH_ protocol has no protocol-specific headers. -- cgit v1.2.3-70-g09d2