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Contents
module DaemonKit
# Simple pidfile handling for daemon processes
class PidFile
def initialize( path )
@path = path.to_absolute_path
end
def exists?
File.exists?( @path )
end
# Returns true if the process is running
def running?
return false unless self.exists?
# Check if process is in existence
# The simplest way to do this is to send signal '0'
# (which is a single system call) that doesn't actually
# send a signal
begin
Process.kill(0, self.pid)
return true
rescue Errno::ESRCH
return false
rescue ::Exception # for example on EPERM (process exists but does not belong to us)
return true
#rescue Errno::EPERM
# return false
end
end
# Return the pid contained in the pidfile, or nil
def pid
return nil unless self.exists?
File.open( @path ) { |f|
return f.gets.to_i
}
end
def ensure_stopped!
if self.running?
puts "Process already running with id #{self.pid}"
exit 1
end
end
def cleanup
File.delete( @path ) rescue Errno::ENOENT
end
alias zap cleanup
def write!
File.open( @path, 'w' ) { |f|
f.puts Process.pid
}
end
end
end
Version data entries
49 entries across 49 versions & 7 rubygems