Backend image rendering as plugin (#11966)

* rendering: headless chrome progress

* renderer: minor change

* grpc: version hell

* updated grpc libs

* wip: minor progess

* rendering: new image rendering plugin is starting to work

* feat: now phantomjs works as well and updated alerting to use new rendering service

* refactor: renamed renderer package and service to rendering to make renderer name less confusing (rendering is internal service that handles the renderer plugin now)

* rendering: now render key is passed and render auth is working in plugin mode

* removed unneeded lines from gitignore

* rendering: now plugin mode supports waiting for all panels to complete rendering

* fix: LastSeenAt fix for render calls, was not set which causes a lot of updates to Last Seen at during rendering, this should fix sqlite db locked issues in seen in previous releases

* change: changed render tz url parameter to use proper timezone name as chrome does not handle UTC offset TZ values

* fix: another update to tz param generation

* renderer: added http mode to renderer service, new ini setting [rendering] server_url

vendor/github.com/uber/jaeger-client-go/sampler.go

@@ -19,6 +19,7 @@ import (
 	"math"
 	"net/url"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/uber/jaeger-client-go/log"
@@ -373,13 +374,16 @@ func (s *adaptiveSampler) update(strategies *sampling.PerOperationSamplingStrate
 // for the appropriate sampling strategy, constructs a corresponding sampler and
 // delegates to it for sampling decisions.
 type RemotelyControlledSampler struct {
+	// These fields must be first in the struct because `sync/atomic` expects 64-bit alignment.
+	// Cf. https://github.com/uber/jaeger-client-go/issues/155, https://goo.gl/zW7dgq
+	closed int64 // 0 - not closed, 1 - closed
+
 	sync.RWMutex
 	samplerOptions
 
 	serviceName string
-	timer       *time.Ticker
 	manager     sampling.SamplingManager
-	pollStopped sync.WaitGroup
+	doneChan    chan *sync.WaitGroup
 }
 
 type httpSamplingManager struct {
@@ -406,10 +410,9 @@ func NewRemotelyControlledSampler(
 	sampler := &RemotelyControlledSampler{
 		samplerOptions: options,
 		serviceName:    serviceName,
-		timer:          time.NewTicker(options.samplingRefreshInterval),
 		manager:        &httpSamplingManager{serverURL: options.samplingServerURL},
+		doneChan:       make(chan *sync.WaitGroup),
 	}
-
 	go sampler.pollController()
 	return sampler
 }
@@ -449,11 +452,15 @@ func (s *RemotelyControlledSampler) IsSampled(id TraceID, operation string) (boo
 
 // Close implements Close() of Sampler.
 func (s *RemotelyControlledSampler) Close() {
-	s.RLock()
-	s.timer.Stop()
-	s.RUnlock()
+	if swapped := atomic.CompareAndSwapInt64(&s.closed, 0, 1); !swapped {
+		s.logger.Error("Repeated attempt to close the sampler is ignored")
+		return
+	}
 
-	s.pollStopped.Wait()
+	var wg sync.WaitGroup
+	wg.Add(1)
+	s.doneChan <- &wg
+	wg.Wait()
 }
 
 // Equal implements Equal() of Sampler.
@@ -471,15 +478,33 @@ func (s *RemotelyControlledSampler) Equal(other Sampler) bool {
 }
 
 func (s *RemotelyControlledSampler) pollController() {
-	// in unit tests we re-assign the timer Ticker, so need to lock to avoid data races
-	s.Lock()
-	timer := s.timer
-	s.Unlock()
+	ticker := time.NewTicker(s.samplingRefreshInterval)
+	defer ticker.Stop()
+	s.pollControllerWithTicker(ticker)
+}
 
-	for range timer.C {
-		s.updateSampler()
+func (s *RemotelyControlledSampler) pollControllerWithTicker(ticker *time.Ticker) {
+	for {
+		select {
+		case <-ticker.C:
+			s.updateSampler()
+		case wg := <-s.doneChan:
+			wg.Done()
+			return
+		}
 	}
-	s.pollStopped.Add(1)
+}
+
+func (s *RemotelyControlledSampler) getSampler() Sampler {
+	s.Lock()
+	defer s.Unlock()
+	return s.sampler
+}
+
+func (s *RemotelyControlledSampler) setSampler(sampler Sampler) {
+	s.Lock()
+	defer s.Unlock()
+	s.sampler = sampler
 }
 
 func (s *RemotelyControlledSampler) updateSampler() {