Fix panic on mercury server error (#13231)

* Fix panic on mercury server error

* Fix changelog wording

.changeset/eighty-hotels-sit.md

@@ -0,0 +1,5 @@
+---
+"chainlink": patch
+---
+
+Fix panic if mercury server returns error #bugfix

CHANGELOG.md

@@ -49,7 +49,7 @@
   You may disable if this results in excessive log volume. Disable like so:
 
   ```
-  [Pipeline]
+  [JobPipeline]
   VerboseLogging = false
   ```
 
@@ -79,7 +79,7 @@
 
 - [#12404](https://github.com/smartcontractkit/chainlink/pull/12404) [`b74079b672`](https://github.com/smartcontractkit/chainlink/commit/b74079b672f36fb0c241f90ea1e875ea3a9524da) Thanks [@HenryNguyen5](https://github.com/HenryNguyen5)! - Add OCR3 capability contract wrapper
 
-- [#12498](https://github.com/smartcontractkit/chainlink/pull/12498) [`1c576d0e34`](https://github.com/smartcontractkit/chainlink/commit/1c576d0e34d93a6298ddcb662ee89fd04eeda53e) Thanks [@samsondav](https://github.com/samsondav)! - Add new config option Pipeline.VerboseLogging
+- [#12498](https://github.com/smartcontractkit/chainlink/pull/12498) [`1c576d0e34`](https://github.com/smartcontractkit/chainlink/commit/1c576d0e34d93a6298ddcb662ee89fd04eeda53e) Thanks [@samsondav](https://github.com/samsondav)! - Add new config option JobPipeline.VerboseLogging
 
   VerboseLogging enables detailed logging of pipeline execution steps. This is
   disabled by default because it increases log volume for pipeline runs, but can
@@ -90,7 +90,7 @@
   Set it like the following example:
 
   ```
-  [Pipeline]
+  [JobPipeline]
   VerboseLogging = true
   ```
 

core/services/relay/evm/mercury/queue.go

@@ -25,7 +25,7 @@ type asyncDeleter interface {
 	AsyncDelete(req *pb.TransmitRequest)
 }
 
-var _ services.Service = (*TransmitQueue)(nil)
+var _ services.Service = (*transmitQueue)(nil)
 
 var transmitQueueLoad = promauto.NewGaugeVec(prometheus.GaugeOpts{
 	Name: "mercury_transmit_queue_load",
@@ -40,7 +40,7 @@ const promInterval = 6500 * time.Millisecond
 
 // TransmitQueue is the high-level package that everything outside of this file should be using
 // It stores pending transmissions, yielding the latest (highest priority) first to the caller
-type TransmitQueue struct {
+type transmitQueue struct {
 	services.StateMachine
 
 	cond         sync.Cond
@@ -62,11 +62,20 @@ type Transmission struct {
 	ReportCtx ocrtypes.ReportContext // contains priority information (latest epoch/round wins)
 }
 
+type TransmitQueue interface {
+	services.Service
+
+	BlockingPop() (t *Transmission)
+	Push(req *pb.TransmitRequest, reportCtx ocrtypes.ReportContext) (ok bool)
+	Init(transmissions []*Transmission)
+	IsEmpty() bool
+}
+
 // maxlen controls how many items will be stored in the queue
 // 0 means unlimited - be careful, this can cause memory leaks
-func NewTransmitQueue(lggr logger.Logger, serverURL, feedID string, maxlen int, asyncDeleter asyncDeleter) *TransmitQueue {
+func NewTransmitQueue(lggr logger.Logger, serverURL, feedID string, maxlen int, asyncDeleter asyncDeleter) TransmitQueue {
 	mu := new(sync.RWMutex)
-	return &TransmitQueue{
+	return &transmitQueue{
 		services.StateMachine{},
 		sync.Cond{L: mu},
 		lggr.Named("TransmitQueue"),
@@ -80,13 +89,13 @@ func NewTransmitQueue(lggr logger.Logger, serverURL, feedID string, maxlen int,
 	}
 }
 
-func (tq *TransmitQueue) Init(transmissions []*Transmission) {
+func (tq *transmitQueue) Init(transmissions []*Transmission) {
 	pq := priorityQueue(transmissions)
 	heap.Init(&pq) // ensure the heap is ordered
 	tq.pq = &pq
 }
 
-func (tq *TransmitQueue) Push(req *pb.TransmitRequest, reportCtx ocrtypes.ReportContext) (ok bool) {
+func (tq *transmitQueue) Push(req *pb.TransmitRequest, reportCtx ocrtypes.ReportContext) (ok bool) {
 	tq.cond.L.Lock()
 	defer tq.cond.L.Unlock()
 
@@ -111,7 +120,7 @@ func (tq *TransmitQueue) Push(req *pb.TransmitRequest, reportCtx ocrtypes.Report
 
 // BlockingPop will block until at least one item is in the heap, and then return it
 // If the queue is closed, it will immediately return nil
-func (tq *TransmitQueue) BlockingPop() (t *Transmission) {
+func (tq *transmitQueue) BlockingPop() (t *Transmission) {
 	tq.cond.L.Lock()
 	defer tq.cond.L.Unlock()
 	if tq.closed {
@@ -126,13 +135,13 @@ func (tq *TransmitQueue) BlockingPop() (t *Transmission) {
 	return t
 }
 
-func (tq *TransmitQueue) IsEmpty() bool {
+func (tq *transmitQueue) IsEmpty() bool {
 	tq.mu.RLock()
 	defer tq.mu.RUnlock()
 	return tq.pq.Len() == 0
 }
 
-func (tq *TransmitQueue) Start(context.Context) error {
+func (tq *transmitQueue) Start(context.Context) error {
 	return tq.StartOnce("TransmitQueue", func() error {
 		t := time.NewTicker(utils.WithJitter(promInterval))
 		wg := new(sync.WaitGroup)
@@ -148,7 +157,7 @@ func (tq *TransmitQueue) Start(context.Context) error {
 	})
 }
 
-func (tq *TransmitQueue) Close() error {
+func (tq *transmitQueue) Close() error {
 	return tq.StopOnce("TransmitQueue", func() error {
 		tq.cond.L.Lock()
 		tq.closed = true
@@ -159,7 +168,7 @@ func (tq *TransmitQueue) Close() error {
 	})
 }
 
-func (tq *TransmitQueue) monitorLoop(c <-chan time.Time, chStop <-chan struct{}, wg *sync.WaitGroup) {
+func (tq *transmitQueue) monitorLoop(c <-chan time.Time, chStop <-chan struct{}, wg *sync.WaitGroup) {
 	defer wg.Done()
 
 	for {
@@ -172,25 +181,25 @@ func (tq *TransmitQueue) monitorLoop(c <-chan time.Time, chStop <-chan struct{},
 	}
 }
 
-func (tq *TransmitQueue) report() {
+func (tq *transmitQueue) report() {
 	tq.mu.RLock()
 	length := tq.pq.Len()
 	tq.mu.RUnlock()
 	tq.transmitQueueLoad.Set(float64(length))
 }
 
-func (tq *TransmitQueue) Ready() error {
+func (tq *transmitQueue) Ready() error {
 	return nil
 }
-func (tq *TransmitQueue) Name() string { return tq.lggr.Name() }
-func (tq *TransmitQueue) HealthReport() map[string]error {
+func (tq *transmitQueue) Name() string { return tq.lggr.Name() }
+func (tq *transmitQueue) HealthReport() map[string]error {
 	report := map[string]error{tq.Name(): errors.Join(
 		tq.status(),
 	)}
 	return report
 }
 
-func (tq *TransmitQueue) status() (merr error) {
+func (tq *transmitQueue) status() (merr error) {
 	tq.mu.RLock()
 	length := tq.pq.Len()
 	closed := tq.closed
@@ -206,7 +215,7 @@ func (tq *TransmitQueue) status() (merr error) {
 
 // pop latest Transmission from the heap
 // Not thread-safe
-func (tq *TransmitQueue) pop() *Transmission {
+func (tq *transmitQueue) pop() *Transmission {
 	if tq.pq.Len() == 0 {
 		return nil
 	}

core/services/relay/evm/mercury/transmitter.go

@@ -144,10 +144,12 @@ type server struct {
 
 	c  wsrpc.Client
 	pm *PersistenceManager
-	q  *TransmitQueue
+	q  TransmitQueue
 
 	deleteQueue chan *pb.TransmitRequest
 
+	url string
+
 	transmitSuccessCount          prometheus.Counter
 	transmitDuplicateCount        prometheus.Counter
 	transmitConnectionErrorCount  prometheus.Counter
@@ -259,7 +261,7 @@ func (s *server) runQueueLoop(stopCh services.StopChan, wg *sync.WaitGroup, feed
 				s.transmitDuplicateCount.Inc()
 				s.lggr.Debugw("Transmit report success; duplicate report", "payload", hexutil.Encode(t.Req.Payload), "response", res, "reportCtx", t.ReportCtx)
 			default:
-				transmitServerErrorCount.WithLabelValues(feedIDHex, fmt.Sprintf("%d", res.Code)).Inc()
+				transmitServerErrorCount.WithLabelValues(feedIDHex, s.url, fmt.Sprintf("%d", res.Code)).Inc()
 				s.lggr.Errorw("Transmit report failed; mercury server returned error", "response", res, "reportCtx", t.ReportCtx, "err", res.Error, "code", res.Code)
 			}
 		}
@@ -284,6 +286,7 @@ func NewTransmitter(lggr logger.Logger, clients map[string]wsrpc.Client, fromAcc
 			pm,
 			NewTransmitQueue(cLggr, serverURL, feedIDHex, maxTransmitQueueSize, pm),
 			make(chan *pb.TransmitRequest, maxDeleteQueueSize),
+			serverURL,
 			transmitSuccessCount.WithLabelValues(feedIDHex, serverURL),
 			transmitDuplicateCount.WithLabelValues(feedIDHex, serverURL),
 			transmitConnectionErrorCount.WithLabelValues(feedIDHex, serverURL),