Please, Run!

Pleaserun is a tool to generate startup scripts for the wasteland of sorrow that is process launchers.

Ideally, you should be able to specify a configuration of how to run a given service command (like apache, syslog-ng, whatever), and this tool should be able to spit out a script or config file for your target platform.

What's going on here?

With pleaserun, you can generate the following launchers/scripts/whatever:

launchd
upstart
systemd
runit
sysv init

Want more? It's easy to add things. File an issue and ask away!

Installation

gem install pleaserun

Your First Process

First, we need a program to run!

Example: redis

For no particular reason, this example will choose redis to run. The idea is to simulate the same workflow you would normally go through in production: acquire software, deploy it, run it. Pleaserun helps you with the 'run it' part, but first let's get redis and build it.

wget http://download.redis.io/releases/redis-2.8.6.tar.gz
tar -zxf redis-2.8.6.tar.gz
cd redis-2.8.6
make -j4
make install PREFIX=/tmp/redis

Assuming the above succeeds (it did for me!), we now have redis installed to /tmp/redis:

% ls /tmp/redis/bin
redis-benchmark redis-check-aof redis-check-dump redis-cli redis-server

You might be thinking - why /tmp? This is just a demo! That's why! :)

Generate a runner

What platform are you on? Do you know the best way to run a server process? I can never remember.

Luckily, pleaserun remembers.

# Run as root so pleaserun has permissions to write to
# any files required to install this as a service!
% sudo pleaserun --install /tmp/redis/bin/redis-server
No platform selected. Autodetecting... {:platform=>"upstart", :version=>"1.5", :level=>:warn}
No name given, setting reasonable default {:name=>"redis-server", :level=>:warn}
Writing file {:destination=>"/etc/init/redis-server.conf"}
Writing file {:destination=>"/etc/init.d/redis-server"}

Note: The --install flag above tells pleaserun to install it on this current system. The default behavior without this flag is to install it in a temp directory so you can copy it elsewhere if desired.

Now what? You can see above it automatically detected that "Upstart 1.5" was the right process runner to target. Let's try using it!

% status redis-server
redis-server stop/waiting

% sudo start redis-server
redis-server start/running, process 395

% status redis-server
redis-server start/running, process 395

% ps -fwwp 395
UID        PID  PPID  C STIME TTY          TIME CMD
root       395     1  0 06:27 ?        00:00:00 /tmp/redis/bin/redis-server *:6379

# Is it running? Let's check with redis-cli
% redis-cli
127.0.0.1:6379> ping
PONG

% sudo stop redis-server
redis-server stop/waiting

Bam. Pretty easy, right? Let's recap!

Recap

You ran pleaserun --install /tmp/redis/bin/redis-server
Pleaserun detected the platform as Upstart 1.5
You didn't have to write an init script.
You didn't have to know how to write an Upstart config.

Overview

See pleaserun --help for a list of flags. Basics:

-p lets you set the platform to target. If not specified, this is automatically detected based on your current system/environment.
-v lets you set the version of the platform to target. Useful in cases where things like Upstart 0.6.5 differ wildly in configuration from Upstart 1.5
--name the name of the process. This shows up as /etc/init.d/the-name-you-give for sysv, or the name you use to reference the service with upstart, systemd, or launchd, etc!
--prestart lets you run a command before starting the main program. This can be used to do config or validation checks before you start a program. If the prestart exits nonzero, the start of the process will be aborted.

A silly example:

# Generate a LSB 3.1-compliant SYSV-style init script
% pleaserun --install -p sysv -v lsb-3.1 --name sleeper /bin/sleep 60
Writing file {:destination=>"/etc/init.d/sleeper"}
Writing file {:destination=>"/etc/default/sleeper"}

# Try it!
% /etc/init.d/sleeper status          
sleeper is not running

% sudo /etc/init.d/sleeper start
sleeper started.

% ps -fwp $(cat /var/run/sleeper.pid)
UID        PID  PPID  C STIME TTY          TIME CMD
root     50473     1  0 22:36 pts/7    00:00:00 /bin/sleep 60

One last thing!

Please enjoy running things! If you are not enjoying this program, then something is wrong, and we can fix it together :)

If you are having a bad time, it is a bug!

All contributions welcome (bug reports, feature requests, bug fixes, new features, etc!)

grtodd/pleaserun