support runtime.ServeMux opts for grpc-gateway

pkg/weather/recorder/recorders/memory/memory.go

@@ -25,6 +25,11 @@ type MemoryRecorder struct {
 	*sync.RWMutex
 }
 
+// No meaningful health check to do here
+func (r *MemoryRecorder) Ping(ctx context.Context) error {
+	return nil
+}
+
 func (r *MemoryRecorder) Init(ctx context.Context, opts *recorders.RecorderOpts) {
 	if opts.RetainLast < 1 {
 		opts.RetainLast = DEF_RETAIN_LAST

pkg/weather/recorder/recorders/noop/noop.go

@@ -20,4 +20,6 @@ func (n *NoopRecorder) Get(context.Context, *pb.GetWeatherRequest) ([]*weather.W
 
 func (n *NoopRecorder) Count(context.Context) int { return 0 }
 
+func (n *NoopRecorder) Ping(context.Context) error { return nil }
+
 func (r *NoopRecorder) Name() string { return "no-op recorder" }

pkg/weather/recorder/recorders/recorders.go

@@ -19,5 +19,6 @@ type Recorder interface {
 	Set(context.Context, *weather.WeatherUpdate) error
 	Get(context.Context, *pb.GetWeatherRequest) ([]*weather.WeatherUpdate, error)
 	Count(context.Context) int // Best Effort
+	Ping(context.Context) error
 	Name() string
 }

pkg/weather/recorder/recorders/redis/redis.go

@@ -36,6 +36,11 @@ type RedisRecorder struct {
 	*sync.RWMutex
 }
 
+func (r *RedisRecorder) Ping(ctx context.Context) error {
+	_, err := r.redis.Ping(ctx).Result()
+	return err
+}
+
 func (r *RedisRecorder) Init(ctx context.Context, opts *recorders.RecorderOpts) {
 	if opts.AppConfig.RecorderConfig.RedisConfig == nil {
 		panic("refusing to init redis recorder with no redisConfig")