143d9f71cc
ocagent allows users to send traces out of VK to a "standard" external forwarder (standard as in this is a format/protocol defined in the opencensus project). This allows uers to implement metrics for whatever backend they want without having to add it into VK directly.
95 lines
2.5 KiB
Go
95 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)
|
|
ae.disconnectedCh <- true
|
|
}
|
|
|
|
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)
|
|
}
|