BUGFIX: Use atomic reads/writes for heartbeats.

api/health/checks.go

@@ -53,7 +53,7 @@ func (c gosundheitCheck) Execute() (interface{}, error) { return c.checkFn() }
 
 // heartbeater provides a getter to the most recently observed heartbeat
 type heartbeater interface {
-	GetHeartbeat() time.Time
+	GetHeartbeat() int64
 }
 
 // HeartbeatCheckFn returns a CheckFn that checks the given heartbeater has
@@ -62,11 +62,11 @@ func HeartbeatCheckFn(hb heartbeater, max time.Duration) CheckFn {
 	return func() (data interface{}, err error) {
 		// Get the heartbeat and create a data set to return to the caller
 		hb := hb.GetHeartbeat()
-		data = map[string]int64{"heartbeat": hb.UTC().Unix()}
+		data = map[string]int64{"heartbeat": hb}
 
 		// If the current time is after the last known heartbeat + the limit then
 		// mark our check as failed
-		if hb.Add(max).Before(time.Now()) {
+		if time.Unix(hb, 0).Add(max).Before(time.Now()) {
 			err = ErrHeartbeatNotDetected
 		}
 		return data, err

networking/handshake_handlers.go

@@ -22,6 +22,7 @@ import (
 	"strconv"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"time"
 	"unsafe"
 
@@ -148,7 +149,7 @@ type Handshake struct {
 	awaitingLock sync.Mutex
 	awaiting     []*networking.AwaitingConnections
 
-	lastHeartbeat time.Time
+	lastHeartbeat int64
 }
 
 // Initialize to the c networking library. This should only be done once during
@@ -599,12 +600,12 @@ func (nm *Handshake) checkCompatibility(peerVersion string) bool {
 
 // heartbeat registers a new heartbeat to signal liveness
 func (nm *Handshake) heartbeat() {
-	nm.lastHeartbeat = nm.clock.Time()
+	atomic.StoreInt64(&nm.lastHeartbeat, nm.clock.Time().Unix())
 }
 
 // GetHeartbeat returns the most recent heartbeat time
-func (nm *Handshake) GetHeartbeat() time.Time {
-	return nm.lastHeartbeat
+func (nm *Handshake) GetHeartbeat() int64 {
+	return atomic.LoadInt64(&nm.lastHeartbeat)
 }
 
 // peerHandler notifies a change to the set of connected peers