86 lines
2.8 KiB
Go
86 lines
2.8 KiB
Go
// Copyright (c) 2017 Uber Technologies, Inc.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package metrics
|
|
|
|
import (
|
|
"fmt"
|
|
"reflect"
|
|
"strings"
|
|
)
|
|
|
|
// Init initializes the passed in metrics and initializes its fields using the passed in factory.
|
|
func Init(metrics interface{}, factory Factory, globalTags map[string]string) {
|
|
if err := initMetrics(metrics, factory, globalTags); err != nil {
|
|
panic(err.Error())
|
|
}
|
|
}
|
|
|
|
// initMetrics uses reflection to initialize a struct containing metrics fields
|
|
// by assigning new Counter/Gauge/Timer values with the metric name retrieved
|
|
// from the `metric` tag and stats tags retrieved from the `tags` tag.
|
|
//
|
|
// Note: all fields of the struct must be exported, have a `metric` tag, and be
|
|
// of type Counter or Gauge or Timer.
|
|
func initMetrics(m interface{}, factory Factory, globalTags map[string]string) error {
|
|
// Allow user to opt out of reporting metrics by passing in nil.
|
|
if factory == nil {
|
|
factory = NullFactory
|
|
}
|
|
|
|
counterPtrType := reflect.TypeOf((*Counter)(nil)).Elem()
|
|
gaugePtrType := reflect.TypeOf((*Gauge)(nil)).Elem()
|
|
timerPtrType := reflect.TypeOf((*Timer)(nil)).Elem()
|
|
|
|
v := reflect.ValueOf(m).Elem()
|
|
t := v.Type()
|
|
for i := 0; i < t.NumField(); i++ {
|
|
tags := make(map[string]string)
|
|
for k, v := range globalTags {
|
|
tags[k] = v
|
|
}
|
|
field := t.Field(i)
|
|
metric := field.Tag.Get("metric")
|
|
if metric == "" {
|
|
return fmt.Errorf("Field %s is missing a tag 'metric'", field.Name)
|
|
}
|
|
if tagString := field.Tag.Get("tags"); tagString != "" {
|
|
tagPairs := strings.Split(tagString, ",")
|
|
for _, tagPair := range tagPairs {
|
|
tag := strings.Split(tagPair, "=")
|
|
if len(tag) != 2 {
|
|
return fmt.Errorf(
|
|
"Field [%s]: Tag [%s] is not of the form key=value in 'tags' string [%s]",
|
|
field.Name, tagPair, tagString)
|
|
}
|
|
tags[tag[0]] = tag[1]
|
|
}
|
|
}
|
|
var obj interface{}
|
|
if field.Type.AssignableTo(counterPtrType) {
|
|
obj = factory.Counter(metric, tags)
|
|
} else if field.Type.AssignableTo(gaugePtrType) {
|
|
obj = factory.Gauge(metric, tags)
|
|
} else if field.Type.AssignableTo(timerPtrType) {
|
|
obj = factory.Timer(metric, tags)
|
|
} else {
|
|
return fmt.Errorf(
|
|
"Field %s is not a pointer to timer, gauge, or counter",
|
|
field.Name)
|
|
}
|
|
v.Field(i).Set(reflect.ValueOf(obj))
|
|
}
|
|
return nil
|
|
}
|