func configureCircuitBreaker()

in codegen/template_bundle/template_files.go [1656:1710]
55 lines of code
17 McCabe index (conditional complexity)

func configureCircuitBreaker(deps *module.Dependencies, timeoutVal int, circuitBreakerName string, qpsLevel string) {
	// sleepWindowInMilliseconds sets the amount of time, after tripping the circuit,
	// to reject requests before allowing attempts again to determine if the circuit should again be closed
	sleepWindowInMilliseconds := 5000
	// maxConcurrentRequests sets how many requests can be run at the same time, beyond which requests are rejected
	maxConcurrentRequests := 20
	// errorPercentThreshold sets the error percentage at or above which the circuit should trip open
	errorPercentThreshold := 20
	// requestVolumeThreshold sets a minimum number of requests that will trip the circuit in a rolling window of 10s
	// For example, if the value is 20, then if only 19 requests are received in the rolling window of 10 seconds
	// the circuit will not trip open even if all 19 failed.
	requestVolumeThreshold := 20
	// parses circuit breaker configurations
	if deps.Default.Config.ContainsKey(CircuitBreakerConfigKey) {
		var config CircuitBreakerConfig
		deps.Default.Config.MustGetStruct(CircuitBreakerConfigKey, &config)
		parameters := config.Parameters
		// first checks if level exists in configurations then assigns parameters
		// if "default" qps level assigns default parameters from circuit breaker configurations
		if settings, ok := parameters[qpsLevel]; ok {
			if sleep, ok := settings["sleepWindowInMilliseconds"]; ok {
				sleepWindowInMilliseconds = sleep
			}
			if max, ok := settings["maxConcurrentRequests"]; ok {
				maxConcurrentRequests = max
			}
			if errorPercent, ok := settings["errorPercentThreshold"]; ok {
				errorPercentThreshold = errorPercent
			}
			if reqVolThreshold, ok := settings["requestVolumeThreshold"]; ok {
				requestVolumeThreshold = reqVolThreshold
			}
		}
	}
	// client settings override parameters
	if deps.Default.Config.ContainsKey("clients.{{$clientID}}.sleepWindowInMilliseconds") {
		sleepWindowInMilliseconds = int(deps.Default.Config.MustGetInt("clients.{{$clientID}}.sleepWindowInMilliseconds"))
	}
	if deps.Default.Config.ContainsKey("clients.{{$clientID}}.maxConcurrentRequests") {
		maxConcurrentRequests = int(deps.Default.Config.MustGetInt("clients.{{$clientID}}.maxConcurrentRequests"))
	}
	if deps.Default.Config.ContainsKey("clients.{{$clientID}}.errorPercentThreshold") {
		errorPercentThreshold = int(deps.Default.Config.MustGetInt("clients.{{$clientID}}.errorPercentThreshold"))
	}
	if deps.Default.Config.ContainsKey("clients.{{$clientID}}.requestVolumeThreshold") {
		requestVolumeThreshold = int(deps.Default.Config.MustGetInt("clients.{{$clientID}}.requestVolumeThreshold"))
	}
	hystrix.ConfigureCommand(circuitBreakerName, hystrix.CommandConfig{
			MaxConcurrentRequests:  maxConcurrentRequests,
			ErrorPercentThreshold:  errorPercentThreshold,
			SleepWindow:            sleepWindowInMilliseconds,
			RequestVolumeThreshold: requestVolumeThreshold,
			Timeout:                timeoutVal,
		})
}