From a3cdeecf0033919e3b5a79c17c19b5ac98719256 Mon Sep 17 00:00:00 2001 From: Laurent Bercot Date: Mon, 20 Jul 2015 20:20:54 +0000 Subject: - Add timeout-finish support and "down-readiness" - LOTS of refactoring to make this work - Remove s6-notifywhenup - s6-supervise now rocks the casbah - rc for 2.2.0.0 --- doc/s6-notifywhenup.html | 111 ----------------------------------------------- 1 file changed, 111 deletions(-) delete mode 100644 doc/s6-notifywhenup.html (limited to 'doc/s6-notifywhenup.html') diff --git a/doc/s6-notifywhenup.html b/doc/s6-notifywhenup.html deleted file mode 100644 index cdfa693..0000000 --- a/doc/s6-notifywhenup.html +++ /dev/null @@ -1,111 +0,0 @@ - - - - - - s6: the s6-notifywhenup program - - - - - - -

-s6
-Software
-skarnet.org -

- -

The s6-notifywhenup program

- - -
-Starting with s6-2.1.4.0, the s6-notifywhenup program has been deprecated, -because there was still a case (albeit extremely rare) where a race -condition would occur and readiness would be improperly advertised. -Readiness notification for a service can now be achieved via a -notification-fd file in the -service directory, containing the -number of the descriptor the service will write its readiness -notification newline to. The notification will directly be picked by -s6-supervise.
-
- -
- Quick upgrade recipe: for every service using s6-notifywhenup, -replace the s6-notifywhenup invocation in your run script with -fdmove 1 3, then perform echo 3 > notification-fd. -Done! -
- - -

-s6-notifywhenup launches a daemon while listening to a file descriptor, -and sends a 'U' event to a fifodir when it -receives something on that file descriptor. -

- -

-This page explains why this program is -needed. -

- -

Interface

- -

-     s6-notifywhenup [ -d fd ] [ -e fifodir ] [ -f ] [ -X ] [ -t timeout ] prog...
-

- -

s6-notifywhenup forks and executes prog... as the -parent, with a pipe from prog...'s stdout to the child.
The child waits for a newline (\n) to be written -on the pipe. When it gets it, it creates a -./supervise/ready file then sends a 'U' event to the -./event fifodir.
The child exits 0.

- -

Options

- -

-d fd : listen to -prog's output on descriptor fd. The default is 1.
-e fifodir : send a 'U' event to fifodir -fifodir. Default is ./event.
-f : simple fork. Normally, s6-notifywhenup doubleforks, -in order to accommodate for a -prog that does not expect to have a child and avoid a -pending zombie. This option avoids the doublefork, but it should only be -set if prog reaps even children it doesn't know it has.
-t timeout : if no EOF has been received -after timeout milliseconds, exit without sending the event. -Default is 0, meaning infinite.
-X : fake readiness. s6-notifywhenup will actually send -the newline itself before executing prog. This option should in -principle never be used.

- -

Notes

- -

s6-notifywhenup executes prog... as the parent in order -for prog to keep the same pid, which is vital for supervised -processes.
s6-notifywhenup can be used, for instance, with -s6-ipcserver -and its -1 option, so that reliable startup notification is -achieved. s6-notifywhenup -f s6-ipcserver -1 args will -send a 'U' event to ./event when s6-ipcserver is actually -listening to its socket.
The s6-svwait program can be used -to wait for 'U' events, as well as the -s6-svlisten1 and -s6-svlisten programs.
The supervise/ready file, when created, contains at least -the absolute time when s6-notifywhenup detected service readiness. The -format and contents of this file are subject to change.

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