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This commit is contained in:
Peter Bourgon 2015-10-07 15:39:45 +02:00
parent 9f0d0ba5a7
commit 9ae8b38549
5 changed files with 44 additions and 33 deletions

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@ -1,19 +1,27 @@
# runsvinit [![Circle CI](https://circleci.com/gh/peterbourgon/runsvinit.svg?style=svg)](https://circleci.com/gh/peterbourgon/runsvinit) # runsvinit [![Circle CI](https://circleci.com/gh/peterbourgon/runsvinit.svg?style=svg)](https://circleci.com/gh/peterbourgon/runsvinit)
If you have a Docker container that's a collection of runit-supervised daemons, If you have a Docker container that's a collection of runit-supervised daemons, this process is suitable for use as the ENTRYPOINT.
this process is suitable for use as the ENTRYPOINT.
See [the example](https://github.com/peterbourgon/runsvinit/tree/master/example). See [the example](https://github.com/peterbourgon/runsvinit/tree/master/example).
**Why not just exec runsvdir?** **Why not use runit(8) directly?**
`docker stop` issues SIGTERM (or, in a future version of Docker, perhaps another custom signal) [runit(8)](http://smarden.org/runit/runit.8.html) is designed to be used as process 1.
but if runsvdir receives a signal, And, if you provide an `/etc/service/ctrlaltdel` script, it will be executed when runit receives the INT signal.
it doesn't wait for its supervised processes to exit before returning. So, we could use that hook to gracefully terminate our services.
If you don't care about graceful shutdown of your daemons, no problem, you don't need this tool. But Docker only sends TERM on `docker stop`.
**Why not wrap runsvdir in a simple shell script?** Note that the container stop signal [will become configurable](https://github.com/docker/docker/pull/15307) in Docker 1.9.
Once Docker 1.9 ships, this utility will be obsolete.
This works great: **Why not just exec runsvdir(8) directly?**
If [runsvdir(8)](http://smarden.org/runit/runsvdir.8.html) receives a signal, it doesn't wait for its supervised processes to exit before returning.
**Why not wrap runsvdir(8) in a simple shell script?**
Process 1 has the additional responsibility of [reaping orphaned child processes](https://blog.phusion.nl/2015/01/20/docker-and-the-pid-1-zombie-reaping-problem/).
To the best of my knowledge, there is no sane way to do this with a shell script.
Otherwise, indeed, this would work great:
```sh ```sh
#!/bin/sh #!/bin/sh
@ -30,14 +38,10 @@ trap "sv_stop; exit" SIGTERM
wait wait
``` ```
...except it doesn't [reap orphaned child processes](https://blog.phusion.nl/2015/01/20/docker-and-the-pid-1-zombie-reaping-problem/)
and is therefore unsuitable for being PID 1.
**Why not use my_init from [phusion/baseimage-docker](https://github.com/phusion/baseimage-docker)?** **Why not use my_init from [phusion/baseimage-docker](https://github.com/phusion/baseimage-docker)?**
That works great — if you're willing to add python3 to your Docker images :) my_init depends on Python 3, which might be a big dependency for such a small responsibility.
**So this is just a stripped-down my_init in Go?** **So this is just a stripped-down my_init in Go?**
Basically, yes. Basically, yes.

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@ -2,9 +2,9 @@
docker: runsvinit docker: runsvinit
docker build -t runsvinit-example . docker build -t runsvinit-example .
runsvinit: runsvinit-linux-amd64.tgz runsvinit: $GOPATH/bin/runsvinit
tar zxf $< cp $< $@
runsvinit-linux-amd64.tgz: $GOPATH/bin/runsvinit:
wget --quiet https://github.com/peterbourgon/runsvinit/releases/download/v2.0.0/runsvinit-linux-amd64.tgz go get -u github.com/peterbourgon/runsvinit

14
main.go
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@ -8,6 +8,7 @@ import (
"os/signal" "os/signal"
"path/filepath" "path/filepath"
"strings" "strings"
"sync"
"syscall" "syscall"
) )
@ -121,7 +122,7 @@ func shutdown(sv string, s signaler) {
return return
} }
var stopped []string var wg sync.WaitGroup
for _, match := range matches { for _, match := range matches {
fi, err := os.Stat(match) fi, err := os.Stat(match)
if err != nil { if err != nil {
@ -134,14 +135,19 @@ func shutdown(sv string, s signaler) {
} }
service := filepath.Base(match) service := filepath.Base(match)
stop := cmd(sv, "stop", service) stop := cmd(sv, "stop", service)
debugf("stopping %s...", service)
wg.Add(1)
go func() {
defer wg.Done()
if err := stop.Run(); err != nil { if err := stop.Run(); err != nil {
infof("%s: %v", strings.Join(stop.Args, " "), err) infof("%s: %v", strings.Join(stop.Args, " "), err)
continue } else {
debugf("stopped %s", service)
} }
stopped = append(stopped, service) }()
} }
wg.Wait()
debugf("stopped %d: %s", len(stopped), strings.Join(stopped, ", "))
debugf("stopping supervisor with signal %s...", sig) debugf("stopping supervisor with signal %s...", sig)
if err := s.Signal(sig); err != nil { if err := s.Signal(sig); err != nil {
info(err) info(err)

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@ -1,6 +1,6 @@
GO?=go GO ?= go
SUDO?= SUDO ?=
RM?=--rm RMCONTAINER ?= --rm
.PHONY: test clean .PHONY: test clean
@ -15,7 +15,7 @@ runsvinit: ../*.go
env GOOS=linux GOARCH=amd64 $(GO) build -o $@ github.com/peterbourgon/runsvinit env GOOS=linux GOARCH=amd64 $(GO) build -o $@ github.com/peterbourgon/runsvinit
zombie: .build.uptodate zombie: .build.uptodate
$(SUDO) docker run $(RM) -v $(shell pwd):/mount zombietest-build cc -Wall -Werror -o /mount/zombie /zombie.c $(SUDO) docker run $(RMCONTAINER) -v $(shell pwd):/mount zombietest-build cc -Wall -Werror -o /mount/zombie /zombie.c
.build.uptodate: build/zombie.c build/Dockerfile .build.uptodate: build/zombie.c build/Dockerfile
$(SUDO) docker build -t zombietest-build build/ $(SUDO) docker build -t zombietest-build build/

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@ -11,14 +11,15 @@ function zombies() {
} }
function stop_rm() { function stop_rm() {
docker stop $1 docker stop $1 >/dev/null
docker rm $1 #docker logs $1
docker rm $1 >/dev/null
} }
SLEEP=1 SLEEP=1
RC=0 RC=0
C=$(docker run -d zombietest /runsvinit -reap=false) C=$(docker run -d zombietest /runsvinit -reap=false -debug)
sleep $SLEEP sleep $SLEEP
NOREAP=$(zombies) NOREAP=$(zombies)
echo -n without reaping, we have $NOREAP zombies... echo -n without reaping, we have $NOREAP zombies...
@ -31,7 +32,7 @@ else
fi fi
stop_rm $C stop_rm $C
C=$(docker run -d zombietest /runsvinit) C=$(docker run -d zombietest /runsvinit -debug)
sleep $SLEEP sleep $SLEEP
YESREAP=$(zombies) YESREAP=$(zombies)
echo -n with reaping, we have $YESREAP zombies... echo -n with reaping, we have $YESREAP zombies...