module OpsScript

This module provides some basic features common to many operational unix scripts

Log file
PID file used to insure only one instance is running, handy if running from cron multiple times
Options processing with basic options for overriding default log attributes and logfile and pidfile location

Example¶ ↑

require 'ops_script'
include OpsScript
# Add your own custom options
option_parser.on "--bar", "The bar option" do
  options[:bar] = true
end
# Run your code
OpsScript.run do 
  puts "BAR" if options[:bar]
  log.info "My informational message"
  log.debug "This is a debug message"
  # do some stuff
end

The module provides these options

foo.rb -h
Usage: foo.rb [options]
        --debug                      enable debug output
        --logfile log_file           specify a different log file
                                     default is ../log/foo.log
        --log-retention retention    Number of old log files to keep,
                                     or frequency of rotation (daily, weekly or monthly). Defaults to monthly.
        --log-size size              Max size in bytes for logfile before rotating.
                                     Specify number of files to keep with log-retention option.
        --pidfile pid_file           specify a different pid file
                                     default is ../tmp/foo.pid
    -h, -?, --help                   Display this help

Constants

VERSION

Public Class Methods

log() click to toggle source

# File lib/ops_script.rb, line 135
def self.log
  @log ||= Logger.new(options[:log_file], options[:log_retention] || 'monthly', options[:log_size])
end

option_parser() click to toggle source

# File lib/ops_script.rb, line 65
def self.option_parser
  @option_parser ||= OptionParser.new
end

options() click to toggle source

# File lib/ops_script.rb, line 57
def self.options
  @options ||= {}
end

run() { || ... } click to toggle source

# File lib/ops_script.rb, line 144
def self.run
  process_options
  if already_running?
    puts "Found #{options[:pid_file]} file. Must be running already. Exiting."
    exit
  else
    create_directories
    create_pid
    log.level = Logger::INFO unless options[:debug]
    log.info "--"
    log.info "#{script} starting"
  end
  begin
    if block_given?
      yield
    else
      raise "No block given. Nothing to run."
    end
  rescue => e
    log.error e.message
    log.debug e.backtrace.join('\n')
    raise
  ensure
    log.info "#{script} exiting"
    log.close
    remove_pid
  end
end

script_basename() click to toggle source

# File lib/ops_script.rb, line 48
def script_basename
  File.basename $0, '.*'
end

Public Instance Methods

log() click to toggle source

Use log in your script to log messages

# File lib/ops_script.rb, line 131
def log
  OpsScript.log
end

option_parser() click to toggle source

# File lib/ops_script.rb, line 61
def option_parser
  OpsScript.option_parser
end

options() click to toggle source

# File lib/ops_script.rb, line 53
def options
  OpsScript.options
end

Private Instance Methods

already_running?() click to toggle source

# File lib/ops_script.rb, line 115
def already_running?
  File.exists?(options[:pid_file])
end

create_directories() click to toggle source

# File lib/ops_script.rb, line 109
def create_directories
  FileUtils.mkdir_p File.dirname(File.expand_path(options[:log_file]))
  FileUtils.mkdir_p File.dirname(File.expand_path(options[:pid_file]))
end

create_pid() click to toggle source

# File lib/ops_script.rb, line 120
def create_pid
  ::File.open(options[:pid_file], 'w' ){ |f| f.write("#{Process.pid}")}
end

process_options() click to toggle source

# File lib/ops_script.rb, line 69
def process_options
  options[:log_file] = File.expand_path("../../log/#{script_basename}.log", $0)
  options[:pid_file] = File.expand_path("../../tmp/#{script_basename}.pid", $0)
  
  option_parser.on_tail("-h","-?","--help", "Display this help") do
    puts option_parser
    exit
  end
  
  option_parser.on("--debug", "enable debug output") do
    options[:debug] = true
  end
  
  option_parser.on("--logfile log_file", "specify a different log file", "default is #{options[:log_file]}") do |p|
    options[:log_file] = p
  end
  
  option_parser.on("--log-retention retention", "Number of old log files to keep,",
  "or frequency of rotation (daily, weekly or monthly). Defaults to monthly.") do |r|
    options[:log_retention] = r
  end
  
  option_parser.on("--log-size size", "Max size in bytes for logfile before rotating.", 
  "Specify number of files to keep with log-retention option.") do |s|
    options[:log_size] = s
  end
  
  option_parser.on_tail("-h","-?","--help", "Display this help") do
    puts option_parser
    exit
  end
      
  option_parser.on("--pidfile pid_file", "specify a different pid file", "default is #{options[:pid_file]}") do |p|
    options[:pid_file] = p
  end
  
  option_parser.parse!
end

remove_pid() click to toggle source

# File lib/ops_script.rb, line 125
def remove_pid
  File.unlink(options[:pid_file])
end

script() click to toggle source

# File lib/ops_script.rb, line 139
def script
  File.basename $0
end

script_basename() click to toggle source

# File lib/ops_script.rb, line 48
def script_basename
  File.basename $0, '.*'
end