Hi Laurent,
Please I apologize for the spam. I’m trying to do what you’ve explained in the last part of your answer. That related to fdholder. >From http://skarnet.org/software/s6/socket-activation.html: 1.- "Make sure you have an early supervision infrastructure running. Ideally, you would make s6-svscan your process 1." Ok. #> ps x | grep s6-svscan PID TTY STAT TIME COMMAND 1 ? Ss+ 0:00 s6-svscan -t0 /etc/s6 2.- "Start an early fd-holding service. Let's say the fd-holding daemon is listening on socket /service/fdholder/s." Ok. #> cat /etc/s6/fdholder/run #!/bin/bash exec s6-fdholder-daemon -i /etc/s6/fdholder/rules /etc/s6/fdholder/socket #> ls-recursive /etc/s6/fdholder /etc/s6/fdholder/rules/gid /etc/s6/fdholder/rules/uid /etc/s6/fdholder/rules/uid/default /etc/s6/fdholder/rules/uid/default/allow /etc/s6/fdholder/rules/uid/default/env/S6_FDHOLDER_LIST /etc/s6/fdholder/rules/uid/default/env/S6_FDHOLDER_STORE_REGEX = ^.*$ #> ps x | grep fdholder PID TTY STAT TIME COMMAND 53 ? S+ 0:00 s6-supervise fdholder 762 ? Ss 0:00 s6-fdholderd -i /etc/s6/fdholder/rules 3.- "For every Unix domain socket /my/socket you need to open, run s6-ipcserver-socketbinder /my/socket s6-fdholder-store /service/fdholder/s unix:/my/socket. You can do the same with INET domain sockets." /* #> s6-ipcserver-socketbinder /tmp/mysocket s6-fdholder-store /etc/s6/fdholder/socket MYSOCKET s6-fdholder-storec: fatal: unable to store fd: Broken pipe s6-fdholderd[20489]: segfault at 104fb ip 000000000040cd03 sp 00007fff8ffca460 error 4 in s6-fdholderd[400000+17000] */ #> s6-fdholder-list /etc/s6/fdholder/socket #> echo $? 0 #> s6-ipcserver-socketbinder /tmp/mysocket s6-fdholder-store /etc/s6/fdholder/socket MYSOCKET s6-fdholder-storec: fatal: unable to store fd: Operation not permitted #> echo $? 1 #> rm /etc/s6/fdholder/rules/uid/default/env/S6_FDHOLDER_LIST #> s6-fdholder-list /etc/s6/fdholder/socket #> echo $? 0 #> rm /etc/s6/fdholder/rules/uid/default/env/S6_FDHOLDER_STORE_REGEX #> s6-ipcserver-socketbinder /tmp/mysocket s6-fdholder-store /etc/s6/fdholder/socket MYSOCKET s6-fdholder-storec: fatal: unable to store fd: Broken pipe #> dmesg | tail -1 s6-fdholderd[23255]: segfault at f009 ip 000000000040cd03 sp 00007fff854aaa90 error 4 in s6-fdholderd[400000+17000] Questions: - I'm missing something? Segfault seems that something is going really wrong in here. - How would be the steps to create&use a pipe and forward log messages to it? 1.- s6-mkfifodir or mkpipe? 2.- How to register into the fdholder store? obviusly this won't work: s6-ipcserver-socketbinder /my/pipe s6-fdholder-store /etc/s6/fdholder/socket MYPIPE? 3.- How to pipe from holder to s6-log? s6-fdholder-retrieve /etc/s6/fdholder/socket MYPIPE s6-log ... ? Thanks in advance. On Wed, Feb 18, 2015 at 11:44 AM, Gorka Lertxundi <glertxu...@gmail.com> wrote: > Hi Laurent, > The second option is exactly what I was looking for. A supervised s6-log > process perfectly fits in my use case. > Log reliability via fdholder-daemon is new for me so I need to read more > about it. A lot of useful utilities in skarnet* which have gone unnoticed for > me! > Thanks again, > On Wed, Feb 18, 2015 at 11:16 AM, Laurent Bercot > <ska-supervis...@skarnet.org> wrote: >> On 18/02/2015 09:12, Gorka Lertxundi wrote: >>> Imagine I have a single process which generates multiple kind of logs, for >>> example, nginx, or even better mysql, which could generate three types of >>> logs: general, error and slow-query. Piping all of them to the same >>> destination in order to be eatable by s6-log, will converge typologies into >>> one log processing chain. >> Hi Gorka, >> I'm not sure what your objective is: >> 1. Being able to pipe several log sources into the same pipe to a >> unique s6-log process, which would then select lines on a token given >> in the input, and log into a separate logdir for each original source; >> or >> 2. Being able to have several supervised s6-log processes all reading >> from the same service, one per log flux. >> I don't recommend going after 1. Generally, if you have several log >> sources, you don't want to merge them into a single destination - that's >> the syslogd design and is inefficient. The sources are different for a >> reason, and it's always easier to concatenate several sets of logs for >> analysis than it is to parse information in a single set to retrieve the >> origin of a log line. But from this diagram: >>> general -> /dev/mypipe1 (prepend “g:”) --\ /-- if g >>> s6-log /generalpath >>> error -> /dev/mypipe2 (prepend “e:”) ---|— /dev/stdout -|--- if e >>> s6-log /errorpath >>> slow-quey -> /dev/mypipe3 (prepend “sq:”) --/ \-- if sq >>> s6-log /slow-query >> it looks like you're going after 2, and feel constrained by the need to >> pipe all the logs into the service's stdout for them to be picked up >> by a logger. >> So my answer to 2 is: don't feel constrained. The "one logger per >> service" model isn't an absolute one, it's just a special treatment >> of the common case by s6-svscan to make it easier; you can have as >> many log fluxes as you need, there just won't be any specific help >> from s6-svscan. >> - Create a supervised service (without its own logger!) that runs a >> s6-log process reading from a fifo for every flux you have: i.e. >> a "mysqld general-path log" service, a "mysqld error-path log" service, >> and a "mysqld slow-query log" service. >> - In your mysqld's run script, redirect the outputs of your daemon >> to the appropriate fifo. >> - There, you're done. But if you want the same guarantees of not >> losing any logs when you restart a s6-log process as s6-svscan gives >> you with a service's "native" logger, you should perform two more >> steps: >> * Make sure you have a s6-fdholder-daemon service running. >> * At some point in your initialization scripts, open each of your >> fifos for reading and store the descriptor into the fd-holding daemon. >> Now your fifos will never close - unless you kill the fdholder without >> transferring its contents first, so don't do that before shutdown time. >> Honestly, now that s6 can perform fd-holding, the specific logger >> handling performed by s6-svscan becomes largely irrelevant. I may even >> deprecate it in a very distant future. (Very distant! Please don't >> freak out.) >> HTH, >> -- >> Laurent
