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Process monitoring tool. Inspired from Bluepill and God. Requires Ruby(MRI) >= 1.9.3-p194. Uses Celluloid and Celluloid::IO.

Little demo, shows general commands and how chain works:


Recommended installation on the server (system wide):

$ sudo /usr/local/ruby/1.9.3/bin/gem install eye
$ sudo ln -sf /usr/local/ruby/1.9.3/bin/eye /usr/local/bin/eye


We have used god and bluepill in production and always ran into bugs (segfaults, crashes, lost processes, kill not-related processes, load problems, deploy problems, …)

We wanted something more robust and production stable.

We wanted the features of bluepill and god, with a few extras like chains, nested configuring, mask matching, easy debug configs

I hope we’ve succeeded, we’re using eye in production and are quite happy.

Config example

examples/test.eye (more examples)


load submodules, here just for example


Eye self-configuration section

Eye.config do logger ‘/tmp/eye.log’ end

Adding application

Eye.application ‘test’ do # All options inherits down to the config leafs. # except env, which merging down

working_dir File.expand_path(File.join(File.dirname(__FILE__), %w[processes])) stdall ‘trash.log’ # stdout,err logs for processes by default env ‘APP_ENV’ => ‘production’ # global env for each processes trigger :flapping, times: 10, within: 1.minute, retry_in: 10.minutes check :cpu, every: 10.seconds, below: 100, times: 3 # global check for all processes

group ‘samples’ do chain grace: 5.seconds # chained start-restart with 5s interval, one by one.

# eye daemonized process
process :sample1 do
  pid_file '1.pid' # pid_path will be expanded with the working_dir
  start_command 'ruby ./sample.rb'

  # when no stop_command or stop_signals, default stop is [:TERM, 0.5, :KILL]
  # default `restart` command is `stop; start`

  daemonize true
  stdall 'sample1.log'

  # ensure the CPU is below 30% at least 3 out of the last 5 times checked
  check :cpu, below: 30, times: [3, 5]

# self daemonized process
process :sample2 do
  pid_file '2.pid'
  start_command 'ruby ./sample.rb -d --pid 2.pid --log sample2.log'
  stop_command 'kill -9 {PID}'

  # ensure the memory is below 300Mb the last 3 times checked
  check :memory, every: 20.seconds, below: 300.megabytes, times: 3


# daemon with 3 children process :forking do pid_file ‘forking.pid’ start_command ‘ruby ./forking.rb start’ stop_command ‘ruby forking.rb stop’ stdall ‘forking.log’

start_timeout 10.seconds
stop_timeout 5.seconds

monitor_children do
  restart_command 'kill -2 {PID}' # for this child process
  check :memory, below: 300.megabytes, times: 3


# eventmachine process, daemonized with eye process :event_machine do |p| pid_file ‘em.pid’ start_command ‘ruby em.rb’ stdout ‘em.log’ daemonize true stop_signals [:QUIT, 2.seconds, :KILL]

check :socket, addr: 'tcp://', every: 10.seconds, times: 2,
               timeout: 1.second, send_data: 'ping', expect_data: /pong/


# thin process, self daemonized process :thin do pid_file ‘thin.pid’ start_command ‘bundle exec thin start -R thin.ru -p 33233 -d -l thin.log -P thin.pid’ stop_signals [:QUIT, 2.seconds, :TERM, 1.seconds, :KILL]

check :http, url: '', pattern: /World/,
             every: 5.seconds, times: [2, 3], timeout: 1.second



Start eye daemon and/or load config:

$ eye l(oad) examples/test.eye

load folder with configs:

$ eye l examples/
$ eye l examples/*.rb

foreground load:

$ eye l CONF -f

If the eye daemon has already started and you call the load command, the config will be updated (into eye daemon). New objects(applications, groups, processes) will be added and monitored. Processes removed from the config will be removed (and stopped if the process has stop_on_delete true). Other objects will update their configs.

Process statuses:

$ eye i(nfo)

“est samples sample1 ………………….. up (21:52, 0%, 13Mb,

Maruku could not parse this XML/HTML: 
    sample2 ....................... up  (21:52, 0%, 12Mb, <4142>)
  event_machine ................... up  (21:52, 3%, 26Mb, <4112>)
  forking ......................... up  (21:52, 0%, 41Mb, <4203>)
    child-4206 .................... up  (21:52, 0%, 41Mb, <4206>)
    child-4211 .................... up  (21:52, 0%, 41Mb, <4211>)
    child-4214 .................... up  (21:52, 0%, 41Mb, <4214>)
  thin ............................ up  (21:53, 2%, 54Mb, <4228>)

$ eye i -j # show info in JSON format


start, stop, restart, delete, monitor, unmonitor

Command params (with restart for example):

$ eye r(estart) all
$ eye r test
$ eye r samples
$ eye r sample1
$ eye r sample*
$ eye r test:samples
$ eye r test:samples:sample1
$ eye r test:samples:sample*
$ eye r test:*sample*

Check config syntax:

$ eye c(heck) examples/test.eye

Config explain (for debug):

$ eye e(xplain) examples/test.eye

Log tracing (tail and grep):

$ eye t(race)
$ eye t test
$ eye t sample

Quit monitoring:

$ eye q(uit)
$ eye q -s # stop all processes and quit

Interactive info:

$ eye w(atch)

Process statuses history:

$ eye hi(story)

Eye daemon info:

$ eye x(info)
$ eye x -c # for show current config

Local Eye version LEye (like foreman):


Process states and events:


How to write Eye extensions, plugins, gems:

Eye-http Eye-rotate Eye-hipchat Plugin example

Eye related projects



Thanks Bluepill for the nice config ideas.