`class Yowl`

Yowl causes random exceptions in victim processes.

Like a cat yowling in the night, this chaos operation randomly raises errors to test error handling and recovery.

Definitions

`def initialize(interval: 45, probability: 0.15, messages: nil)`

Create a new yowl chaos operation.

Signature

parameter　interval　Integer: How often to check for chaos opportunities.
parameter　probability　Float: Probability (0.0 to 1.0) of causing chaos on each check.
parameter　messages　Array<String>: Possible error messages to use.

Implementation

def initialize(interval: 45, probability: 0.15, messages: nil)
	@interval = interval
	@probability = probability
	@messages = messages || [
		"Yowl! Chaos kitty is not pleased!",
		"MEOWWWW! Something went wrong!",
		"Hiss! An unexpected error occurred!",
		"*Angry cat noises*",
		"The chaos kitty demands tribute!"
	]
	@victims = Set.new.compare_by_identity
end

`attr_reader :victims`

Signature

attribute　Set: The set of registered victims.

`def register(chaos_controller)`

Signature

parameter　chaos_controller　ChaosController: The chaos controller for the victim.

Implementation

def register(chaos_controller)
	Console.debug(self, "😺 Registering victim for yowl chaos.", id: chaos_controller.id)
	@victims.add(chaos_controller)
end

`def remove(chaos_controller)`

Remove a victim from the yowl chaos.

Signature

parameter　chaos_controller　ChaosController: The chaos controller for the victim.

Implementation

def remove(chaos_controller)
	@victims.delete(chaos_controller)
end

`def status`

Get status for the yowl chaos.

Signature

returns　Hash: Status including victim count and configuration.

Implementation

def status
	{
		yowl: {
			victims: @victims.size,
			probability: @probability,
			message_variants: @messages.size
		}
	}
end

`def unleash_yowl`

Unleash a yowl on a random victim.

Implementation

def unleash_yowl
	return if @victims.empty?
	
	# Pick a random victim
	victim = @victims.to_a.sample
	return unless victim
	
	# Check probability
	return unless rand < @probability
	
	# Pick a random message
	message = @messages.sample
	
	Console.info(self, "😾 *YOWWWWL* Error incoming!", id: victim.id, message: message)
	
	begin
		victim_proxy = victim.connection[:victim]
		if victim_proxy
			victim_proxy.raise_error(message: message)
		end
	rescue => error
		# This is expected - we're causing an error!
		Console.debug(self, "Yowl successful (error was raised)!", id: victim.id)
	end
end

`def run`

Run the yowl chaos operation.

Signature

returns　Async::Task: The task that is running the yowl chaos.

Implementation

def run
	Async do
		Loop.run(interval: @interval) do
			unleash_yowl
		end
	end
end