diff options
Diffstat (limited to 'Godeps/_workspace/src/github.com/rcrowley/go-metrics/registry.go')
-rw-r--r-- | Godeps/_workspace/src/github.com/rcrowley/go-metrics/registry.go | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/Godeps/_workspace/src/github.com/rcrowley/go-metrics/registry.go b/Godeps/_workspace/src/github.com/rcrowley/go-metrics/registry.go new file mode 100644 index 000000000..1f9d82c2a --- /dev/null +++ b/Godeps/_workspace/src/github.com/rcrowley/go-metrics/registry.go @@ -0,0 +1,180 @@ +package metrics + +import ( + "fmt" + "reflect" + "sync" +) + +// DuplicateMetric is the error returned by Registry.Register when a metric +// already exists. If you mean to Register that metric you must first +// Unregister the existing metric. +type DuplicateMetric string + +func (err DuplicateMetric) Error() string { + return fmt.Sprintf("duplicate metric: %s", string(err)) +} + +// A Registry holds references to a set of metrics by name and can iterate +// over them, calling callback functions provided by the user. +// +// This is an interface so as to encourage other structs to implement +// the Registry API as appropriate. +type Registry interface { + + // Call the given function for each registered metric. + Each(func(string, interface{})) + + // Get the metric by the given name or nil if none is registered. + Get(string) interface{} + + // Gets an existing metric or registers the given one. + // The interface can be the metric to register if not found in registry, + // or a function returning the metric for lazy instantiation. + GetOrRegister(string, interface{}) interface{} + + // Register the given metric under the given name. + Register(string, interface{}) error + + // Run all registered healthchecks. + RunHealthchecks() + + // Unregister the metric with the given name. + Unregister(string) + + // Unregister all metrics. (Mostly for testing.) + UnregisterAll() +} + +// The standard implementation of a Registry is a mutex-protected map +// of names to metrics. +type StandardRegistry struct { + metrics map[string]interface{} + mutex sync.Mutex +} + +// Create a new registry. +func NewRegistry() Registry { + return &StandardRegistry{metrics: make(map[string]interface{})} +} + +// Call the given function for each registered metric. +func (r *StandardRegistry) Each(f func(string, interface{})) { + for name, i := range r.registered() { + f(name, i) + } +} + +// Get the metric by the given name or nil if none is registered. +func (r *StandardRegistry) Get(name string) interface{} { + r.mutex.Lock() + defer r.mutex.Unlock() + return r.metrics[name] +} + +// Gets an existing metric or creates and registers a new one. Threadsafe +// alternative to calling Get and Register on failure. +// The interface can be the metric to register if not found in registry, +// or a function returning the metric for lazy instantiation. +func (r *StandardRegistry) GetOrRegister(name string, i interface{}) interface{} { + r.mutex.Lock() + defer r.mutex.Unlock() + if metric, ok := r.metrics[name]; ok { + return metric + } + if v := reflect.ValueOf(i); v.Kind() == reflect.Func { + i = v.Call(nil)[0].Interface() + } + r.register(name, i) + return i +} + +// Register the given metric under the given name. Returns a DuplicateMetric +// if a metric by the given name is already registered. +func (r *StandardRegistry) Register(name string, i interface{}) error { + r.mutex.Lock() + defer r.mutex.Unlock() + return r.register(name, i) +} + +// Run all registered healthchecks. +func (r *StandardRegistry) RunHealthchecks() { + r.mutex.Lock() + defer r.mutex.Unlock() + for _, i := range r.metrics { + if h, ok := i.(Healthcheck); ok { + h.Check() + } + } +} + +// Unregister the metric with the given name. +func (r *StandardRegistry) Unregister(name string) { + r.mutex.Lock() + defer r.mutex.Unlock() + delete(r.metrics, name) +} + +// Unregister all metrics. (Mostly for testing.) +func (r *StandardRegistry) UnregisterAll() { + r.mutex.Lock() + defer r.mutex.Unlock() + for name, _ := range r.metrics { + delete(r.metrics, name) + } +} + +func (r *StandardRegistry) register(name string, i interface{}) error { + if _, ok := r.metrics[name]; ok { + return DuplicateMetric(name) + } + switch i.(type) { + case Counter, Gauge, GaugeFloat64, Healthcheck, Histogram, Meter, Timer: + r.metrics[name] = i + } + return nil +} + +func (r *StandardRegistry) registered() map[string]interface{} { + r.mutex.Lock() + defer r.mutex.Unlock() + metrics := make(map[string]interface{}, len(r.metrics)) + for name, i := range r.metrics { + metrics[name] = i + } + return metrics +} + +var DefaultRegistry Registry = NewRegistry() + +// Call the given function for each registered metric. +func Each(f func(string, interface{})) { + DefaultRegistry.Each(f) +} + +// Get the metric by the given name or nil if none is registered. +func Get(name string) interface{} { + return DefaultRegistry.Get(name) +} + +// Gets an existing metric or creates and registers a new one. Threadsafe +// alternative to calling Get and Register on failure. +func GetOrRegister(name string, i interface{}) interface{} { + return DefaultRegistry.GetOrRegister(name, i) +} + +// Register the given metric under the given name. Returns a DuplicateMetric +// if a metric by the given name is already registered. +func Register(name string, i interface{}) error { + return DefaultRegistry.Register(name, i) +} + +// Run all registered healthchecks. +func RunHealthchecks() { + DefaultRegistry.RunHealthchecks() +} + +// Unregister the metric with the given name. +func Unregister(name string) { + DefaultRegistry.Unregister(name) +} |