watch.rb in arborist-0.0.1.pre20160829140603

- old
+ new

@@ -8,45 +8,89 @@
 
 # Command to watch events in an Arborist manager.
 module Arborist::CLI::Watch
 	extend Arborist::CLI::Subcommand
 
+	HEARTBEAT_CHARACTERS = %w[💓 💗]
+
 	desc 'Watch events in an Arborist manager'
 
 	command :watch do |cmd|
 		cmd.action do |globals, options, args|
 			client = Arborist::Client.new
-			subid  = client.subscribe( identifier: '_' )
-
 			sock = client.event_api
-			sock.subscribe( subid )
+
+			subid = subscribe_to_node_events( client )
 			prompt.say "Subscription %p" % [ subid ]
 
+			# Watch for system events as well
+			prompt.say "Subscribing to manager heartbeat events."
+			sock.subscribe( 'sys.heartbeat' )
+
 			begin
+				last_runid = nil
 				prompt.say "Watching for events on manager at %s" % [ client.event_api_url ]
 				loop do
 					msgsubid = sock.recv
 					raise "Partial write?!" unless sock.rcvmore?
 					raw_event = sock.recv
-
 					event = MessagePack.unpack( raw_event )
-					prompt.say "[%s] %s\n" % [
-						hl(Time.now.strftime('%Y-%m-%d %H:%M:%S %Z')).color(:dark, :white),
-						hl(dump_event( event )).color( :dark, :white )
-					]
+
+					case msgsubid
+					when 'sys.heartbeat'
+						this_runid = event['run_id']
+
+						if last_runid && last_runid != this_runid
+							self.log.warn "Manager restart: re-subscribing."
+							sock.unsubscribe( subid )
+							subid = subscribe_to_node_events( client )
+							prompt.say "New subscription %p" % [ subid ]
+						else
+							self.log.debug "Manager is alive (runid: %s)" % [ this_runid ]
+						end
+
+						$stderr.print( heartbeat() )
+						last_runid = this_runid
+					when 'sys.node_added'
+						prompt.say "[%s] «Node added» %s\n" % [
+							hl(Time.now.strftime('%Y-%m-%d %H:%M:%S %Z')).color(:dark, :white),
+							hl(event['node']).color( :bold, :cyan )
+						]
+					when 'sys.node_removed'
+						prompt.say "[%s] »Node removed« %s\n" % [
+							hl(Time.now.strftime('%Y-%m-%d %H:%M:%S %Z')).color(:dark, :white),
+							hl(event['node']).color( :dark, :cyan )
+						]
+					else
+						prompt.say "[%s] %s\n" % [
+							hl(Time.now.strftime('%Y-%m-%d %H:%M:%S %Z')).color(:dark, :white),
+							hl(dump_event( event )).color( :dark, :white )
+						]
+					end
 				end
 			ensure
+				self.log.info "Unsubscribing from subscription %p" % [ subid ]
 				client.unsubscribe( subid )
 			end
 		end
 	end
 
 
 	###############
 	module_function
 	###############
 
+	### Establish a subscription to all node events via the specified +client+.
+	def subscribe_to_node_events( client )
+		subid = client.subscribe( identifier: '_' )
+		sock = client.event_api
+
+		sock.subscribe( subid )
+		return subid
+	end
+
+
 	### Return a String representation of the specified +event+.
 	def dump_event( event )
 		event_type = event['type']
 		id = event['identifier']
 
@@ -80,9 +124,16 @@
 					hl( val1 ).color( :yellow ),
 					hl( val2 ).color( :bold, :yellow )
 				]
 			end
 		end.join( hl(", ").color(:dark, :white) )
+	end
+
+
+	### Return a heartbeat string for the current time.
+	def heartbeat
+		idx = (Time.now.to_i % HEARTBEAT_CHARACTERS.length) - 1
+		return " " + HEARTBEAT_CHARACTERS[ idx ] + "\x08\x08"
 	end
 
 end # module Arborist::CLI::Watch
 