monitoring/visitor_expvar.go (61 lines of code) (raw):
// Licensed to Elasticsearch B.V. under one or more contributor
// license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright
// ownership. Elasticsearch B.V. licenses this file to you 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 monitoring
import (
"encoding/json"
"expvar"
"strconv"
)
// VisitExpvars iterates all expvar metrics using the Visitor interface.
// The top-level metrics "memstats" and "cmdline", plus all monitoring.X metric types
// are ignored.
func VisitExpvars(vs Visitor) {
vs.OnRegistryStart()
expvar.Do(makeExparVisitor(0, vs))
vs.OnRegistryFinished()
}
func DoExpvars(f func(string, interface{})) {
VisitExpvars(NewKeyValueVisitor(f))
}
func makeExparVisitor(level int, vs Visitor) func(expvar.KeyValue) {
return func(kv expvar.KeyValue) {
if ignoreExpvar(level, kv) {
return
}
name := kv.Key
variable := kv.Value
switch v := variable.(type) {
case *expvar.Int:
i, _ := strconv.ParseInt(v.String(), 10, 64)
vs.OnKey(name)
vs.OnInt(i)
case *expvar.Float:
f, _ := strconv.ParseFloat(v.String(), 64)
vs.OnKey(name)
vs.OnFloat(f)
case *expvar.Map:
vs.OnKey(name)
vs.OnRegistryStart()
v.Do(makeExparVisitor(level+1, vs))
vs.OnRegistryFinished()
default:
vs.OnKey(name)
s := v.String()
if len(s) >= 2 && s[0] == '"' && s[len(s)-1] == '"' {
var tmp string
if err := json.Unmarshal([]byte(s), &tmp); err == nil {
s = tmp
}
}
vs.OnString(s)
}
}
}
// ignore if `monitoring` variable or some other internals
// automatically registered by expvar against our wishes
func ignoreExpvar(level int, kv expvar.KeyValue) bool {
switch kv.Value.(type) {
case makeExpvar, Var:
return true
}
if level == 0 {
switch kv.Key {
case "memstats", "cmdline":
return true
}
}
return false
}