themis-checker-server

A Ruby gem to create service checker for Themis Finals attack-defence CTF checking system.

Installation

gem install themis-checker-server

or just add gem 'themis-checker-server' to your Gemfile and run bundle.

Example

A service checker should subclass Themis::Checker::Server and override two methods.

Here's an example:

require 'themis/checker/server'
require 'themis/checker/result'

class SampleChecker < Themis::Checker::Server
    def push(endpoint, flag, adjunct, metadata)
        # business logic...
        return Themis::Checker::Result::UP, adjunct
    end

    def pull(endpoint, flag, adjunct, metadata)
        # business logic...
        Themis::Checker::Result::UP
    end
end

checker = SampleChecker.new
checker.run

Operation status

See themis-checker-result.

Configuration

Several environment variables should be specified to run service checker process:

BEANSTALKD_URI

A connection string for Beanstalk server.

TUBE_LISTEN

A Beanstalk tube to listen to commands from Themis Finals server.

TUBE_REPORT

A Beanstalk tube to report operation results to Themis Finals server.

LOG_LEVEL

An optional service checker log level. One of DEBUG, INFO, WARN, ERROR, FATAL or UNKNOWN. Default is INFO.

STDOUT_SYNC

An optional parameter controlling $stdout.sync.

Tips

Logging

There is a class member logger. You can use it in overriden push and pull methods as @logger.

Stopping service checker

Service checker process stops on INT signal.

Configuration for God process manager

(0...2).to_a.each do |num|
    God.watch do |w|
        w.group = 'SERVICE_ALIAS'
        w.name = "SERVICE_ALIAS-#{num}"
        w.dir = '/path/to/checker'
        w.uid = 'nobody'
        w.gid = 'nogroup'
        w.log = "/path/to/checker/logs/checker-#{num}.log"
        w.start = 'bundle exec ruby checker.rb'
        w.env = {
            'BEANSTALKD_URI' => '127.0.0.1:11300',
            'LOG_LEVEL' => 'INFO',
            'STDOUT_SYNC' => 'true',
            'TUBE_LISTEN' => 'themis.finals.service.SERVICE_ALIAS.listen',
            'TUBE_REPORT' => 'themis.finals.service.SERVICE_ALIAS.report'
        }
        w.stop_signal = 'INT'
        w.keepalive
    end
end

Configuration for Supervisor process manager

[program:themis.finals.service.SERVICE_ALIAS.checker]
command=/opt/rbenv/shims/bundle exec ruby checker.rb
process_name=checker-%(process_num)s
numprocs=2
numprocs_start=0
priority=300
autostart=false
autorestart=true
startsecs=1
startretries=3
exitcodes=0,2
stopsignal=INT
stopwaitsecs=10
stopasgroup=false
killasgroup=false
user=nobody
redirect_stderr=false
stdout_logfile=/path/to/checker/logs/checker-%(process_num)s-stdout.log
stdout_logfile_maxbytes=10MB
stdout_logfile_backups=10
stdout_capture_maxbytes=0
stdout_events_enabled=false
stderr_logfile=/path/to/checker/logs/checker-%(process_num)s-stderr.log
stderr_logfile_maxbytes=10MB
stderr_logfile_backups=10
stderr_capture_maxbytes=0
stderr_events_enabled=false
environment=APP_INSTANCE="%(process_num)s",BEANSTALKD_URI="127.0.0.1:11300",LOG_LEVEL="DEBUG",STDOUT_SYNC="true",TUBE_LISTEN="themis.finals.service.SERVICE_ALIAS.listen",TUBE_REPORT="themis.finals.service.SERVICE_ALIAS.report"
directory=/path/to/checker
serverurl=AUTO

[group:themis.finals.service.SERVICE_ALIAS]
programs=themis.finals.service.SERVICE_ALIAS.checker

License

MIT @ Alexander Pyatkin