Fix comments and do a little modification

hystrix/hystrix.go

@@ -28,7 +28,7 @@ type command struct {
 	ticket       *struct{}
 	start        time.Time
 	errChan      chan error
-	finished     chan bool
+	finished     chan struct{}
 	fallbackOnce *sync.Once
 	circuit      *CircuitBreaker
 	run          runFunc
@@ -58,11 +58,11 @@ func Go(name string, run runFunc, fallback fallbackFunc) chan error {
 		fallback:     fallback,
 		start:        time.Now(),
 		errChan:      make(chan error, 1),
-		finished:     make(chan bool, 1),
+		finished:     make(chan struct{}, 1),
 		fallbackOnce: &sync.Once{},
 	}
 
-	// dont have methods with explicit params and returns
+	// don't have methods with explicit params and returns
 	// let data come in and out naturally, like with any closure
 	// explicit error return to give place for us to kill switch the operation (fallback)
 
@@ -74,11 +74,11 @@ func Go(name string, run runFunc, fallback fallbackFunc) chan error {
 	cmd.circuit = circuit
 
 	go func() {
-		defer func() { cmd.finished <- true }()
+		defer func() { cmd.finished <- struct{}{} }()
 
 		// Circuits get opened when recent executions have shown to have a high error rate.
 		// Rejecting new executions allows backends to recover, and the circuit will allow
-		// new traffic when it feels a healthly state has returned.
+		// new traffic when it feels a healthy state has returned.
 		if !cmd.circuit.AllowRequest() {
 			cmd.errorWithFallback(ErrCircuitOpen)
 			return

hystrix/metric_collector/metric_collector.go

@@ -40,7 +40,7 @@ func (m *metricCollectorRegistry) Register(initMetricCollector func(string) Metr
 }
 
 // MetricCollector represents the contract that all collectors must fulfill to gather circuit statistics.
-// Implementations of this interface do not have to maintain locking around thier data stores so long as
+// Implementations of this interface do not have to maintain locking around their data stores so long as
 // they are not modified outside of the hystrix context.
 type MetricCollector interface {
 	// IncrementAttempts increments the number of updates.

hystrix/settings.go

@@ -35,8 +35,10 @@ type CommandConfig struct {
 	ErrorPercentThreshold  int `json:"error_percent_threshold"`
 }
 
-var circuitSettings map[string]*Settings
-var settingsMutex *sync.RWMutex
+var (
+	circuitSettings map[string]*Settings
+	settingsMutex   *sync.RWMutex
+)
 
 func init() {
 	circuitSettings = make(map[string]*Settings)
@@ -52,9 +54,6 @@ func Configure(cmds map[string]CommandConfig) {
 
 // ConfigureCommand applies settings for a circuit
 func ConfigureCommand(name string, config CommandConfig) {
-	settingsMutex.Lock()
-	defer settingsMutex.Unlock()
-
 	timeout := DefaultTimeout
 	if config.Timeout != 0 {
 		timeout = config.Timeout
@@ -80,6 +79,9 @@ func ConfigureCommand(name string, config CommandConfig) {
 		errorPercent = config.ErrorPercentThreshold
 	}
 
+	settingsMutex.Lock()
+	defer settingsMutex.Unlock()
+
 	circuitSettings[name] = &Settings{
 		Timeout:                time.Duration(timeout) * time.Millisecond,
 		MaxConcurrentRequests:  max,