commit 06298eec730aa2664bb61d4cce4ef56dfce91ee3
Author: Cecylia Bocovich <[email protected]>
Date: Mon Dec 2 13:22:05 2019 -0500
Added another lock to protect broker stats
Added another lock to the metrics struct to synchronize accesses to the
broker stats. There's a possible race condition if stats are updated at
the same time they are being logged.
---
broker/broker.go | 10 +++++++++-
broker/metrics.go | 5 +++++
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/broker/broker.go b/broker/broker.go
index a5b0edf..17c677e 100644
--- a/broker/broker.go
+++ b/broker/broker.go
@@ -38,7 +38,7 @@ type BrokerContext struct {
// Map keeping track of snowflakeIDs required to match SDP answers from
// the second http POST.
idToSnowflake map[string]*Snowflake
- // Synchronization for the
+ // Synchronization for the snowflake map and heap
snowflakeLock sync.Mutex
proxyPolls chan *ProxyPoll
metrics *Metrics
@@ -181,14 +181,18 @@ func proxyPolls(ctx *BrokerContext, w
http.ResponseWriter, r *http.Request) {
if err != nil {
log.Println("Error processing proxy IP: ", err.Error())
} else {
+ ctx.metrics.lock.Lock()
ctx.metrics.UpdateCountryStats(remoteIP, proxyType)
+ ctx.metrics.lock.Unlock()
}
// Wait for a client to avail an offer to the snowflake, or timeout if
nil.
offer := ctx.RequestOffer(sid, proxyType)
var b []byte
if nil == offer {
+ ctx.metrics.lock.Lock()
ctx.metrics.proxyIdleCount++
+ ctx.metrics.lock.Unlock()
b, err = messages.EncodePollResponse("", false)
if err != nil {
@@ -227,7 +231,9 @@ func clientOffers(ctx *BrokerContext, w
http.ResponseWriter, r *http.Request) {
numSnowflakes := ctx.snowflakes.Len()
ctx.snowflakeLock.Unlock()
if numSnowflakes <= 0 {
+ ctx.metrics.lock.Lock()
ctx.metrics.clientDeniedCount++
+ ctx.metrics.lock.Unlock()
w.WriteHeader(http.StatusServiceUnavailable)
return
}
@@ -241,7 +247,9 @@ func clientOffers(ctx *BrokerContext, w
http.ResponseWriter, r *http.Request) {
// Wait for the answer to be returned on the channel or timeout.
select {
case answer := <-snowflake.answerChannel:
+ ctx.metrics.lock.Lock()
ctx.metrics.clientProxyMatchCount++
+ ctx.metrics.lock.Unlock()
if _, err := w.Write(answer); err != nil {
log.Printf("unable to write answer with error: %v", err)
}
diff --git a/broker/metrics.go b/broker/metrics.go
index bf5ce29..ea4d220 100644
--- a/broker/metrics.go
+++ b/broker/metrics.go
@@ -39,6 +39,9 @@ type Metrics struct {
proxyIdleCount uint
clientDeniedCount uint
clientProxyMatchCount uint
+
+ //synchronization for access to snowflake metrics
+ lock sync.Mutex
}
func (s CountryStats) Display() string {
@@ -161,6 +164,7 @@ func (m *Metrics) logMetrics() {
}
func (m *Metrics) printMetrics() {
+ m.lock.Lock()
m.logger.Println("snowflake-stats-end",
time.Now().UTC().Format("2006-01-02 15:04:05"), fmt.Sprintf("(%d s)",
int(metricsResolution.Seconds())))
m.logger.Println("snowflake-ips", m.countryStats.Display())
m.logger.Println("snowflake-ips-total", len(m.countryStats.standalone)+
@@ -171,6 +175,7 @@ func (m *Metrics) printMetrics() {
m.logger.Println("snowflake-idle-count", binCount(m.proxyIdleCount))
m.logger.Println("client-denied-count", binCount(m.clientDeniedCount))
m.logger.Println("client-snowflake-match-count",
binCount(m.clientProxyMatchCount))
+ m.lock.Unlock()
}
// Restores all metrics to original values
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