Scott Baker | 2d89798 | 2019-09-24 11:50:08 -0700 | [diff] [blame^] | 1 | package metrics |
| 2 | |
| 3 | import ( |
| 4 | "fmt" |
| 5 | "reflect" |
| 6 | "strings" |
| 7 | "sync" |
| 8 | ) |
| 9 | |
| 10 | // DuplicateMetric is the error returned by Registry.Register when a metric |
| 11 | // already exists. If you mean to Register that metric you must first |
| 12 | // Unregister the existing metric. |
| 13 | type DuplicateMetric string |
| 14 | |
| 15 | func (err DuplicateMetric) Error() string { |
| 16 | return fmt.Sprintf("duplicate metric: %s", string(err)) |
| 17 | } |
| 18 | |
| 19 | // A Registry holds references to a set of metrics by name and can iterate |
| 20 | // over them, calling callback functions provided by the user. |
| 21 | // |
| 22 | // This is an interface so as to encourage other structs to implement |
| 23 | // the Registry API as appropriate. |
| 24 | type Registry interface { |
| 25 | |
| 26 | // Call the given function for each registered metric. |
| 27 | Each(func(string, interface{})) |
| 28 | |
| 29 | // Get the metric by the given name or nil if none is registered. |
| 30 | Get(string) interface{} |
| 31 | |
| 32 | // GetAll metrics in the Registry. |
| 33 | GetAll() map[string]map[string]interface{} |
| 34 | |
| 35 | // Gets an existing metric or registers the given one. |
| 36 | // The interface can be the metric to register if not found in registry, |
| 37 | // or a function returning the metric for lazy instantiation. |
| 38 | GetOrRegister(string, interface{}) interface{} |
| 39 | |
| 40 | // Register the given metric under the given name. |
| 41 | Register(string, interface{}) error |
| 42 | |
| 43 | // Run all registered healthchecks. |
| 44 | RunHealthchecks() |
| 45 | |
| 46 | // Unregister the metric with the given name. |
| 47 | Unregister(string) |
| 48 | |
| 49 | // Unregister all metrics. (Mostly for testing.) |
| 50 | UnregisterAll() |
| 51 | } |
| 52 | |
| 53 | // The standard implementation of a Registry is a mutex-protected map |
| 54 | // of names to metrics. |
| 55 | type StandardRegistry struct { |
| 56 | metrics map[string]interface{} |
| 57 | mutex sync.RWMutex |
| 58 | } |
| 59 | |
| 60 | // Create a new registry. |
| 61 | func NewRegistry() Registry { |
| 62 | return &StandardRegistry{metrics: make(map[string]interface{})} |
| 63 | } |
| 64 | |
| 65 | // Call the given function for each registered metric. |
| 66 | func (r *StandardRegistry) Each(f func(string, interface{})) { |
| 67 | for name, i := range r.registered() { |
| 68 | f(name, i) |
| 69 | } |
| 70 | } |
| 71 | |
| 72 | // Get the metric by the given name or nil if none is registered. |
| 73 | func (r *StandardRegistry) Get(name string) interface{} { |
| 74 | r.mutex.RLock() |
| 75 | defer r.mutex.RUnlock() |
| 76 | return r.metrics[name] |
| 77 | } |
| 78 | |
| 79 | // Gets an existing metric or creates and registers a new one. Threadsafe |
| 80 | // alternative to calling Get and Register on failure. |
| 81 | // The interface can be the metric to register if not found in registry, |
| 82 | // or a function returning the metric for lazy instantiation. |
| 83 | func (r *StandardRegistry) GetOrRegister(name string, i interface{}) interface{} { |
| 84 | // access the read lock first which should be re-entrant |
| 85 | r.mutex.RLock() |
| 86 | metric, ok := r.metrics[name] |
| 87 | r.mutex.RUnlock() |
| 88 | if ok { |
| 89 | return metric |
| 90 | } |
| 91 | |
| 92 | // only take the write lock if we'll be modifying the metrics map |
| 93 | r.mutex.Lock() |
| 94 | defer r.mutex.Unlock() |
| 95 | if metric, ok := r.metrics[name]; ok { |
| 96 | return metric |
| 97 | } |
| 98 | if v := reflect.ValueOf(i); v.Kind() == reflect.Func { |
| 99 | i = v.Call(nil)[0].Interface() |
| 100 | } |
| 101 | r.register(name, i) |
| 102 | return i |
| 103 | } |
| 104 | |
| 105 | // Register the given metric under the given name. Returns a DuplicateMetric |
| 106 | // if a metric by the given name is already registered. |
| 107 | func (r *StandardRegistry) Register(name string, i interface{}) error { |
| 108 | r.mutex.Lock() |
| 109 | defer r.mutex.Unlock() |
| 110 | return r.register(name, i) |
| 111 | } |
| 112 | |
| 113 | // Run all registered healthchecks. |
| 114 | func (r *StandardRegistry) RunHealthchecks() { |
| 115 | r.mutex.RLock() |
| 116 | defer r.mutex.RUnlock() |
| 117 | for _, i := range r.metrics { |
| 118 | if h, ok := i.(Healthcheck); ok { |
| 119 | h.Check() |
| 120 | } |
| 121 | } |
| 122 | } |
| 123 | |
| 124 | // GetAll metrics in the Registry |
| 125 | func (r *StandardRegistry) GetAll() map[string]map[string]interface{} { |
| 126 | data := make(map[string]map[string]interface{}) |
| 127 | r.Each(func(name string, i interface{}) { |
| 128 | values := make(map[string]interface{}) |
| 129 | switch metric := i.(type) { |
| 130 | case Counter: |
| 131 | values["count"] = metric.Count() |
| 132 | case Gauge: |
| 133 | values["value"] = metric.Value() |
| 134 | case GaugeFloat64: |
| 135 | values["value"] = metric.Value() |
| 136 | case Healthcheck: |
| 137 | values["error"] = nil |
| 138 | metric.Check() |
| 139 | if err := metric.Error(); nil != err { |
| 140 | values["error"] = metric.Error().Error() |
| 141 | } |
| 142 | case Histogram: |
| 143 | h := metric.Snapshot() |
| 144 | ps := h.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999}) |
| 145 | values["count"] = h.Count() |
| 146 | values["min"] = h.Min() |
| 147 | values["max"] = h.Max() |
| 148 | values["mean"] = h.Mean() |
| 149 | values["stddev"] = h.StdDev() |
| 150 | values["median"] = ps[0] |
| 151 | values["75%"] = ps[1] |
| 152 | values["95%"] = ps[2] |
| 153 | values["99%"] = ps[3] |
| 154 | values["99.9%"] = ps[4] |
| 155 | case Meter: |
| 156 | m := metric.Snapshot() |
| 157 | values["count"] = m.Count() |
| 158 | values["1m.rate"] = m.Rate1() |
| 159 | values["5m.rate"] = m.Rate5() |
| 160 | values["15m.rate"] = m.Rate15() |
| 161 | values["mean.rate"] = m.RateMean() |
| 162 | case Timer: |
| 163 | t := metric.Snapshot() |
| 164 | ps := t.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999}) |
| 165 | values["count"] = t.Count() |
| 166 | values["min"] = t.Min() |
| 167 | values["max"] = t.Max() |
| 168 | values["mean"] = t.Mean() |
| 169 | values["stddev"] = t.StdDev() |
| 170 | values["median"] = ps[0] |
| 171 | values["75%"] = ps[1] |
| 172 | values["95%"] = ps[2] |
| 173 | values["99%"] = ps[3] |
| 174 | values["99.9%"] = ps[4] |
| 175 | values["1m.rate"] = t.Rate1() |
| 176 | values["5m.rate"] = t.Rate5() |
| 177 | values["15m.rate"] = t.Rate15() |
| 178 | values["mean.rate"] = t.RateMean() |
| 179 | } |
| 180 | data[name] = values |
| 181 | }) |
| 182 | return data |
| 183 | } |
| 184 | |
| 185 | // Unregister the metric with the given name. |
| 186 | func (r *StandardRegistry) Unregister(name string) { |
| 187 | r.mutex.Lock() |
| 188 | defer r.mutex.Unlock() |
| 189 | r.stop(name) |
| 190 | delete(r.metrics, name) |
| 191 | } |
| 192 | |
| 193 | // Unregister all metrics. (Mostly for testing.) |
| 194 | func (r *StandardRegistry) UnregisterAll() { |
| 195 | r.mutex.Lock() |
| 196 | defer r.mutex.Unlock() |
| 197 | for name, _ := range r.metrics { |
| 198 | r.stop(name) |
| 199 | delete(r.metrics, name) |
| 200 | } |
| 201 | } |
| 202 | |
| 203 | func (r *StandardRegistry) register(name string, i interface{}) error { |
| 204 | if _, ok := r.metrics[name]; ok { |
| 205 | return DuplicateMetric(name) |
| 206 | } |
| 207 | switch i.(type) { |
| 208 | case Counter, Gauge, GaugeFloat64, Healthcheck, Histogram, Meter, Timer: |
| 209 | r.metrics[name] = i |
| 210 | } |
| 211 | return nil |
| 212 | } |
| 213 | |
| 214 | func (r *StandardRegistry) registered() map[string]interface{} { |
| 215 | r.mutex.Lock() |
| 216 | defer r.mutex.Unlock() |
| 217 | metrics := make(map[string]interface{}, len(r.metrics)) |
| 218 | for name, i := range r.metrics { |
| 219 | metrics[name] = i |
| 220 | } |
| 221 | return metrics |
| 222 | } |
| 223 | |
| 224 | func (r *StandardRegistry) stop(name string) { |
| 225 | if i, ok := r.metrics[name]; ok { |
| 226 | if s, ok := i.(Stoppable); ok { |
| 227 | s.Stop() |
| 228 | } |
| 229 | } |
| 230 | } |
| 231 | |
| 232 | // Stoppable defines the metrics which has to be stopped. |
| 233 | type Stoppable interface { |
| 234 | Stop() |
| 235 | } |
| 236 | |
| 237 | type PrefixedRegistry struct { |
| 238 | underlying Registry |
| 239 | prefix string |
| 240 | } |
| 241 | |
| 242 | func NewPrefixedRegistry(prefix string) Registry { |
| 243 | return &PrefixedRegistry{ |
| 244 | underlying: NewRegistry(), |
| 245 | prefix: prefix, |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | func NewPrefixedChildRegistry(parent Registry, prefix string) Registry { |
| 250 | return &PrefixedRegistry{ |
| 251 | underlying: parent, |
| 252 | prefix: prefix, |
| 253 | } |
| 254 | } |
| 255 | |
| 256 | // Call the given function for each registered metric. |
| 257 | func (r *PrefixedRegistry) Each(fn func(string, interface{})) { |
| 258 | wrappedFn := func(prefix string) func(string, interface{}) { |
| 259 | return func(name string, iface interface{}) { |
| 260 | if strings.HasPrefix(name, prefix) { |
| 261 | fn(name, iface) |
| 262 | } else { |
| 263 | return |
| 264 | } |
| 265 | } |
| 266 | } |
| 267 | |
| 268 | baseRegistry, prefix := findPrefix(r, "") |
| 269 | baseRegistry.Each(wrappedFn(prefix)) |
| 270 | } |
| 271 | |
| 272 | func findPrefix(registry Registry, prefix string) (Registry, string) { |
| 273 | switch r := registry.(type) { |
| 274 | case *PrefixedRegistry: |
| 275 | return findPrefix(r.underlying, r.prefix+prefix) |
| 276 | case *StandardRegistry: |
| 277 | return r, prefix |
| 278 | } |
| 279 | return nil, "" |
| 280 | } |
| 281 | |
| 282 | // Get the metric by the given name or nil if none is registered. |
| 283 | func (r *PrefixedRegistry) Get(name string) interface{} { |
| 284 | realName := r.prefix + name |
| 285 | return r.underlying.Get(realName) |
| 286 | } |
| 287 | |
| 288 | // Gets an existing metric or registers the given one. |
| 289 | // The interface can be the metric to register if not found in registry, |
| 290 | // or a function returning the metric for lazy instantiation. |
| 291 | func (r *PrefixedRegistry) GetOrRegister(name string, metric interface{}) interface{} { |
| 292 | realName := r.prefix + name |
| 293 | return r.underlying.GetOrRegister(realName, metric) |
| 294 | } |
| 295 | |
| 296 | // Register the given metric under the given name. The name will be prefixed. |
| 297 | func (r *PrefixedRegistry) Register(name string, metric interface{}) error { |
| 298 | realName := r.prefix + name |
| 299 | return r.underlying.Register(realName, metric) |
| 300 | } |
| 301 | |
| 302 | // Run all registered healthchecks. |
| 303 | func (r *PrefixedRegistry) RunHealthchecks() { |
| 304 | r.underlying.RunHealthchecks() |
| 305 | } |
| 306 | |
| 307 | // GetAll metrics in the Registry |
| 308 | func (r *PrefixedRegistry) GetAll() map[string]map[string]interface{} { |
| 309 | return r.underlying.GetAll() |
| 310 | } |
| 311 | |
| 312 | // Unregister the metric with the given name. The name will be prefixed. |
| 313 | func (r *PrefixedRegistry) Unregister(name string) { |
| 314 | realName := r.prefix + name |
| 315 | r.underlying.Unregister(realName) |
| 316 | } |
| 317 | |
| 318 | // Unregister all metrics. (Mostly for testing.) |
| 319 | func (r *PrefixedRegistry) UnregisterAll() { |
| 320 | r.underlying.UnregisterAll() |
| 321 | } |
| 322 | |
| 323 | var DefaultRegistry Registry = NewRegistry() |
| 324 | |
| 325 | // Call the given function for each registered metric. |
| 326 | func Each(f func(string, interface{})) { |
| 327 | DefaultRegistry.Each(f) |
| 328 | } |
| 329 | |
| 330 | // Get the metric by the given name or nil if none is registered. |
| 331 | func Get(name string) interface{} { |
| 332 | return DefaultRegistry.Get(name) |
| 333 | } |
| 334 | |
| 335 | // Gets an existing metric or creates and registers a new one. Threadsafe |
| 336 | // alternative to calling Get and Register on failure. |
| 337 | func GetOrRegister(name string, i interface{}) interface{} { |
| 338 | return DefaultRegistry.GetOrRegister(name, i) |
| 339 | } |
| 340 | |
| 341 | // Register the given metric under the given name. Returns a DuplicateMetric |
| 342 | // if a metric by the given name is already registered. |
| 343 | func Register(name string, i interface{}) error { |
| 344 | return DefaultRegistry.Register(name, i) |
| 345 | } |
| 346 | |
| 347 | // Register the given metric under the given name. Panics if a metric by the |
| 348 | // given name is already registered. |
| 349 | func MustRegister(name string, i interface{}) { |
| 350 | if err := Register(name, i); err != nil { |
| 351 | panic(err) |
| 352 | } |
| 353 | } |
| 354 | |
| 355 | // Run all registered healthchecks. |
| 356 | func RunHealthchecks() { |
| 357 | DefaultRegistry.RunHealthchecks() |
| 358 | } |
| 359 | |
| 360 | // Unregister the metric with the given name. |
| 361 | func Unregister(name string) { |
| 362 | DefaultRegistry.Unregister(name) |
| 363 | } |