98 lines
2.5 KiB
Go
98 lines
2.5 KiB
Go
|
// Copyright 2018, OpenCensus Authors
|
||
|
|
//
|
||
|
|
// 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 ocagent
|
||
|
|
|
||
|
|
import (
|
||
|
|
"math/rand"
|
||
|
|
"sync/atomic"
|
||
|
|
"time"
|
||
|
|
)
|
||
|
|
|
||
|
|
const (
|
||
|
|
sDisconnected int32 = 5 + iota
|
||
|
|
sConnected
|
||
|
|
)
|
||
|
|
|
||
|
|
func (ae *Exporter) setStateDisconnected() {
|
||
|
|
atomic.StoreInt32(&ae.connectionState, sDisconnected)
|
||
|
|
select {
|
||
|
|
case ae.disconnectedCh <- true:
|
||
|
|
default:
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (ae *Exporter) setStateConnected() {
|
||
|
|
atomic.StoreInt32(&ae.connectionState, sConnected)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (ae *Exporter) connected() bool {
|
||
|
|
return atomic.LoadInt32(&ae.connectionState) == sConnected
|
||
|
|
}
|
||
|
|
|
||
|
|
const defaultConnReattemptPeriod = 10 * time.Second
|
||
|
|
|
||
|
|
func (ae *Exporter) indefiniteBackgroundConnection() error {
|
||
|
|
defer func() {
|
||
|
|
ae.backgroundConnectionDoneCh <- true
|
||
|
|
}()
|
||
|
|
|
||
|
|
connReattemptPeriod := ae.reconnectionPeriod
|
||
|
|
if connReattemptPeriod <= 0 {
|
||
|
|
connReattemptPeriod = defaultConnReattemptPeriod
|
||
|
|
}
|
||
|
|
|
||
|
|
// No strong seeding required, nano time can
|
||
|
|
// already help with pseudo uniqueness.
|
||
|
|
rng := rand.New(rand.NewSource(time.Now().UnixNano() + rand.Int63n(1024)))
|
||
|
|
|
||
|
|
// maxJitter: 1 + (70% of the connectionReattemptPeriod)
|
||
|
|
maxJitter := int64(1 + 0.7*float64(connReattemptPeriod))
|
||
|
|
|
||
|
|
for {
|
||
|
|
// Otherwise these will be the normal scenarios to enable
|
||
|
|
// reconnections if we trip out.
|
||
|
|
// 1. If we've stopped, return entirely
|
||
|
|
// 2. Otherwise block until we are disconnected, and
|
||
|
|
// then retry connecting
|
||
|
|
select {
|
||
|
|
case <-ae.stopCh:
|
||
|
|
return errStopped
|
||
|
|
|
||
|
|
case <-ae.disconnectedCh:
|
||
|
|
// Normal scenario that we'll wait for
|
||
|
|
}
|
||
|
|
|
||
|
|
if err := ae.connect(); err == nil {
|
||
|
|
ae.setStateConnected()
|
||
|
|
} else {
|
||
|
|
ae.setStateDisconnected()
|
||
|
|
}
|
||
|
|
|
||
|
|
// Apply some jitter to avoid lockstep retrials of other
|
||
|
|
// agent-exporters. Lockstep retrials could result in an
|
||
|
|
// innocent DDOS, by clogging the machine's resources and network.
|
||
|
|
jitter := time.Duration(rng.Int63n(maxJitter))
|
||
|
|
<-time.After(connReattemptPeriod + jitter)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (ae *Exporter) connect() error {
|
||
|
|
cc, err := ae.dialToAgent()
|
||
|
|
if err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
return ae.enableConnectionStreams(cc)
|
||
|
|
}
|