Class: ProcessWanker::Service

Inherits:
Object
  • Object
show all
Includes:
Log
Defined in:
lib/service.rb

Direct Known Subclasses

DummyService, ProcessService, UpstartService

Constant Summary

Constants included from Log

Log::DEBUG, Log::ERROR, Log::INFO, Log::WARN

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Log

debug, error, info, log, set_level, warn

Constructor Details

#initialize(iparams) ⇒ Service 



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# File 'lib/service.rb', line 63

def initialize(iparams)

# extract params
extract_params(
  iparams,
  [
    :name,
    :tags,
    :group_name,
    :min_action_delay_secs,
    :start_grace_secs,
    :stop_grace_secs,
    :stable_secs,
    :fail_trigger_count,
    :fail_suppress_secs,
    :initial_state,
    :dependencies,
    :log_file,
    :watchdog_file,
    :watchdog_timeout_secs
  ])

  # warn about extra params
iparams.keys.each do |k|
  warn "warning: ignoring unrecognized parameter: #{k.to_s}"
end

  # apply defaults
  @params={
    :min_action_delay_secs      =>    1,
    :stable_secs                =>    20,
    :fail_trigger_count         =>    5,
    :fail_suppress_secs         =>    300,
    :group_name                 =>    "default",
    :start_grace_secs           =>   5,
    :stop_grace_secs            =>    5,
    :dependencies               =>   [],
  }.merge(@params)

@params[:tags] ||= []

# convert necessary things to symbols
@params[:initial_state] = @params[:initial_state].to_sym if(@params[:initial_state])

  # set state values
  @last_action_time=Time.at(0)
  @last_action=nil
  @current_state=safe_do_ping()
  @want_state=@params[:initial_state] || @current_state
  @prev_state=safe_do_ping()
  @last_transition_time=Time.at(0)
  @attempt_count=0
  @last_fail_time=Time.at(0)
  @show_state=""
  @suppress=false
@want_state_mode=:boot
@stable=false

  # register with the manager
  ServiceMgr::register_service(self)
end

Instance Attribute Details

#attempt_count ⇒ Object

Returns the value of attribute attempt_count.



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# File 'lib/service.rb', line 31

def attempt_count
  @attempt_count
end

#config_node ⇒ Object

Returns the value of attribute config_node.



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# File 'lib/service.rb', line 37

def config_node
  @config_node
end

#current_state ⇒ Object

Returns the value of attribute current_state.



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# File 'lib/service.rb', line 28

def current_state
  @current_state
end

#dependencies ⇒ Object

Returns the value of attribute dependencies.



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# File 'lib/service.rb', line 34

def dependencies
  @dependencies
end

#ignore ⇒ Object

Returns the value of attribute ignore.



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# File 'lib/service.rb', line 36

def ignore
  @ignore
end

#last_action_time ⇒ Object

Returns the value of attribute last_action_time.



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# File 'lib/service.rb', line 27

def last_action_time
  @last_action_time
end

#last_fail_time ⇒ Object

Returns the value of attribute last_fail_time.



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# File 'lib/service.rb', line 32

def last_fail_time
  @last_fail_time
end

#last_transition_time ⇒ Object

Returns the value of attribute last_transition_time.



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# File 'lib/service.rb', line 30

def last_transition_time
  @last_transition_time
end

#params ⇒ Object

current state



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# File 'lib/service.rb', line 25

def params
  @params
end

#prev_state ⇒ Object

Returns the value of attribute prev_state.



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# File 'lib/service.rb', line 29

def prev_state
  @prev_state
end

#show_state ⇒ Object

Returns the value of attribute show_state.



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# File 'lib/service.rb', line 33

def show_state
  @show_state
end

#stable ⇒ Object

Returns the value of attribute stable.



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# File 'lib/service.rb', line 39

def stable
  @stable
end

#suppress ⇒ Object

Returns the value of attribute suppress.



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# File 'lib/service.rb', line 35

def suppress
  @suppress
end

#want_state ⇒ Object

Returns the value of attribute want_state.



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# File 'lib/service.rb', line 26

def want_state
  @want_state
end

#want_state_mode ⇒ Object

Returns the value of attribute want_state_mode.



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# File 'lib/service.rb', line 38

def want_state_mode
  @want_state_mode
end

Instance Method Details

#check_action_delay(now, proposed_action) ⇒ Object

check the various timers, and see if we’re allowed to take action on a specific service at this point…



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# File 'lib/service.rb', line 437

def check_action_delay(now,proposed_action)

  elapsed=now - @last_action_time

  # check general-purpose between-action-delay
  return(false) if(elapsed < @params[:min_action_delay_secs])

  if(proposed_action == @last_action)

    # check grace periods
    return(false) if(@last_action == :start && elapsed < @params[:start_grace_secs])
    return(false) if(@last_action == :stop && elapsed < @params[:stop_grace_secs])

    # check failing suppression
    since_fail=now - @last_fail_time
    return(false) if(since_fail < @params[:fail_suppress_secs])
  end

  true
end

#do_ping ⇒ Object

return state (:up, :down)



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# File 'lib/service.rb', line 200

def do_ping
  raise "method not defined in base class"
end

#do_start(attempt_ct) ⇒ Object

start the service. should not block for a considerable amount of time



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# File 'lib/service.rb', line 180

def do_start(attempt_ct)
  raise "method not defined in base class"
end

#do_stop(attempt_ct) ⇒ Object

stop the service - should not block for a considerable amount of time



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# File 'lib/service.rb', line 190

def do_stop(attempt_ct)
  raise "method not defined in base class"
end

#extract_params(params, keys) ⇒ Object 



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# File 'lib/service.rb', line 146

def extract_params(params,keys)
  @params ||= {}
  keys.each do |k|
    @params[k]=params[k] if(params.has_key?(k))
    params.delete(k)
  end
end

#group_name ⇒ Object

return the name of the group this process belongs to



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# File 'lib/service.rb', line 170

def group_name
  @params[:group_name]
end

#matches_single(p, prev) ⇒ Object 



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# File 'lib/service.rb', line 507

def matches_single(p,prev)

  if(p == "all")
    return(true)
  elsif(p[0..0] == "/")
    r=Regexp.new(p.split("/")[1])
    return(true) if(group_name =~ r)
    return(true) if(name =~ r)
  elsif(p[0..0] == "~")
    return(prev && !matches_single(p[1..-1],false))
  elsif(p[0..3] == "tag:")
    tag=p[4..-1]
      return(true) if(params[:tags] && params[:tags].include?(tag))
  elsif(p == name)
    return(true)
  elsif(p == group_name)
    return(true)
  end

  prev
end

#matches_spec(spec) ⇒ Object 



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# File 'lib/service.rb', line 482

def matches_spec(spec)

  # ensure it's in array form
  spec=spec.split(",")

  # check for inversion on first item
  if(spec.first[0..0]=="~")
    # insert implicit "all" at front
    spec=["all"] + spec
  end

  matches=false
  spec.each do |p|
    matches = matches_single(p,matches)
  end
  matches

end

#name ⇒ Object

return the host-wide unique name of the service



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# File 'lib/service.rb', line 160

def name
  @params[:name]
end

#resolve_dependencies ⇒ Object

resolve dependencies through name lookup



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# File 'lib/service.rb', line 210

def resolve_dependencies

  @dependencies=[]
  params[:dependencies].each do |dep|
  ServiceMgr::instance.match_services(dep.service).each do |k,v|
    @dependencies << { :service => v, :dep => dep }
  end
  end
end

#safe_do(name) ⇒ Object

safe, exception-catching methods



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# File 'lib/service.rb', line 226

def safe_do(name)
  ProcessWanker::with_logged_rescue("#{name} - safe_do") do
    yield
  end
end

#safe_do_ping ⇒ Object 



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# File 'lib/service.rb', line 240

def safe_do_ping()
  p=:down
  safe_do("#{name}:do_start") { p=do_ping }
  p
end

#safe_do_start(attempt_ct) ⇒ Object 



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# File 'lib/service.rb', line 232

def safe_do_start(attempt_ct)
  safe_do("#{name}:do_start") { do_start(attempt_ct) }
end

#safe_do_stop(attempt_ct) ⇒ Object 



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# File 'lib/service.rb', line 236

def safe_do_stop(attempt_ct)
  safe_do("#{name}:do_start") { do_stop(attempt_ct) }
end

#set_want_state(state) ⇒ Object

set want state in response to a user request - clear all delay state, start with a clean slate.



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# File 'lib/service.rb', line 465

def set_want_state(state)
  @want_state = state
@want_state_mode = :user
  @attempt_count = 0
  @last_action_time = Time.at(0)
  @last_fail_time = Time.at(0)
  if(@want_state != @current_state)
    @show_state = "received #{state.inspect}"
  end
end

#tick ⇒ Object

main logic



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# File 'lib/service.rb', line 252

def tick

  #
  # get current time
  #

  now=Time.now

  #
  # get current state, check for change, record transition time
  #

  state = safe_do_ping()
  if(@current_state != state)
    @prev_state = @current_state
    @last_transition_time = now
    @current_state = state
  @stable = false
     @show_state = state.to_s
  end

  #
  # handle special :restart case
  #

  want=@want_state
  if(want == :restart)
    if(@current_state == :down)
      want = :up
      @want_state = :up
      @last_action_time = Time.now
    else
      want = :down
    end
  end

#
# check dependencies
#

deps_ok=true
@dependencies.each do |d|
  s=d[:service]
  if(s.current_state != :up)
    deps_ok=false
    next
  end
  tt=now - s.last_transition_time
  if(tt < d[:dep].up_for)
    deps_ok=false
  end
end
@suppress=(!deps_ok) && (@want_state != :down)
if(@suppress)
  want = :down
end

#
# have we been in the same state for a while?
#

stabilized=false
elapsed = now - @last_transition_time
   if(!@stable && elapsed >= @params[:stable_secs])
  stabilized=true
  @stable=true
end

#
# if we're up and stable, check watchdog timer
#

if(@stable && @current_state == :up && want == :up)
  if(@params[:watchdog_file] && @params[:watchdog_timeout_secs])
    timeout=true
    begin
      st = File.stat(@params[:watchdog_file])
      if((now - st.mtime) < @params[:watchdog_timeout_secs])
        timeout=false
      end
    rescue Exception => e
    end
    if(timeout)
      info("#{self.name}: watchdog file: #{@params[:watchdog_file]} has timed out")
      Event.dispatch("watchdog_timeout",self)
      @want_state = :restart
      want = :down
    end
  end
end

  #
  # are we in the desired state?
  #

  if(@current_state == want)

  # did we just stabilize?
  if(stabilized)

      @attempt_count = 0
      @show_state = @current_state.to_s + " [stable]"

    # was this request part of a user request? if not, notify
    if(@want_state_mode == :none && want == :up)
      Event::dispatch("restarted",self)
    end

    # clear request mode
    @want_state_mode=:none
    end

  # nothing more to do
    return
  end

#
# are we ignoring the process?
#

if(want == :ignore)
  @show_state = "#{@current_state.to_s} (ignored)"
  return
end

  #
  # is it too soon to do anything?
  #

proposed_action = { :up => :start , :down => :stop }[want]
return if(!check_action_delay(now,proposed_action))

  #
  # actually attempt to cause a change
  #

# update state
@attempt_count=0 if(proposed_action != @last_action)
@last_action=proposed_action
@last_action_time=now

# check for failing
   if(@attempt_count >= @params[:fail_trigger_count])
  info("#{self.name} has now had #{@attempt_count} attempts. considering it failed.")

     @show_state = "failing(#{proposed_action})"
     @last_fail_time = now
     @attempt_count = 0   # reset for next time

  Event::dispatch("fail-#{proposed_action.to_s}",self)

     return
   end

# was this request part of a user request? if not, notify
if(@want_state_mode == :none && proposed_action == :start && @attempt_count==0)
  Event::dispatch("restarting",self)
end

   # do it
@show_state = "#{proposed_action} [#{@attempt_count}]"
if(proposed_action == :start)

  Event::dispatch("pre-launch",self)

  info("calling do_start for #{self.name}")
  safe_do_start(@attempt_count)

else

  info("calling do_stop for #{self.name}")
  safe_do_stop(@attempt_count)

end
   @attempt_count += 1

end

#validate_params ⇒ Object 



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# File 'lib/service.rb', line 131

def validate_params()
  raise "no name provided" if(!params[:name])
  @params.keys.each do |k|
    if(!keys.include?(k))
      warn "warning: unrecognized parameter #{k.to_s} ignored"
    end
  end
end