From 90b12bd71bb9fc79a4640b9112c13ef529d0196a Mon Sep 17 00:00:00 2001 From: Laurent Bercot Date: Fri, 5 Dec 2014 22:26:11 +0000 Subject: Initial commit --- doc/s6-ftrigrd.html | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) create mode 100644 doc/s6-ftrigrd.html (limited to 'doc/s6-ftrigrd.html') diff --git a/doc/s6-ftrigrd.html b/doc/s6-ftrigrd.html new file mode 100644 index 0000000..dbd611e --- /dev/null +++ b/doc/s6-ftrigrd.html @@ -0,0 +1,73 @@ + + + + + s6: the s6-ftrigrd program + + + + + + +

+s6
+Software
+skarnet.org +

+ +

The s6-ftrigrd program

+ +

+s6-ftrigrd is a helper program that manages a set of subscriptions to fifodirs as well +as regular expressions on events. It takes orders from its client program that controls +it via the ftrigr library, and notifies it when desired +events happen. +

+ +

Interface

+ +

+ s6-ftrigrd is not meant to be called directly. +

+ +

If the client program uses ftrigr_startf(), it spawns an instance of +s6-ftrigrd as a child. s6-ftrigrd's stdin is a pipe reading from the client; its +stdout is a pipe writing to the client; its stderr is the same as the client's; and +there's an additional pipe from s6-ftrigrd to the client, used for asynchronous +notifications.
If the client program uses ftrigr_start(), then it tries to connect +to a Unix domain socket. A ftrigrd service should be listening to that +socket, i.e. a Unix domain superserver such as +s6-ipcserver +spawning a s6-ftrigrd program on every connection. Then a s6-ftrigrd instance is created +for the client.
When the client uses ftrigr_end(), or closes s6-ftrigrd's stdin in +any way, s6-ftrigrd exits 0.

+ +

+ s6-ftrigrd handles the grunt work of creating fifos in a +fifodir for a subscriber. It also wakes up on every +event, and compares the chain of events it received on a given fifodir with the +client-provided regexp. If the chain of events matches the regexp, it notifies +the client. +

+ +

Notes

+ +

+ The connection management between the client and s6-ftrigrd is entirely done +by the skaclient +library. +

+ +

+ s6-ftrigrd is entirely asynchronous. It stores unread notifications into heap +memory; it can grow in size if there are a lot of events and the client fails +to read them. To avoid uncontrolled growth, make sure your client calls +ftrigr_update() as soon as ftrigr_fd() becomes readable. +

+ + + -- cgit v1.2.3