Define busy error type in processor and return related error in gRPC handler (#2314)

Signed-off-by: Pavol Loffay <[email protected]>

Author: pavolloffay

Diff for: cmd/collector/app/handler/grpc_handler.go

@@ -18,6 +18,8 @@ import (
 	"context"
 
 	"go.uber.org/zap"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
 
 	"github.com/jaegertracing/jaeger/cmd/collector/app/processor"
 	"github.com/jaegertracing/jaeger/proto-gen/api_v2"
@@ -49,6 +51,9 @@ func (g *GRPCHandler) PostSpans(ctx context.Context, r *api_v2.PostSpansRequest)
 		SpanFormat:       processor.ProtoSpanFormat,
 	})
 	if err != nil {
+		if err == processor.ErrBusy {
+			return nil, status.Errorf(codes.ResourceExhausted, err.Error())
+		}
 		g.logger.Error("cannot process spans", zap.Error(err))
 		return nil, err
 	}

Diff for: cmd/collector/app/processor/interface.go

@@ -15,11 +15,15 @@
 package processor
 
 import (
+	"errors"
 	"io"
 
 	"github.com/jaegertracing/jaeger/model"
 )
 
+// ErrBusy signalizes that processor cannot process incoming data
+var ErrBusy = errors.New("server busy")
+
 // SpansOptions additional options passed to processor along with the spans.
 type SpansOptions struct {
 	SpanFormat       SpanFormat

Diff for: cmd/collector/app/span_processor.go

@@ -16,7 +16,6 @@
 package app
 
 import (
-	"fmt"
 	"sync"
 	"time"
 
@@ -164,7 +163,7 @@ func (sp *spanProcessor) ProcessSpans(mSpans []*model.Span, options processor.Sp
 	for i, mSpan := range mSpans {
 		ok := sp.enqueueSpan(mSpan, options.SpanFormat, options.InboundTransport)
 		if !ok && sp.reportBusy {
-			return nil, fmt.Errorf("server busy")
+			return nil, processor.ErrBusy
 		}
 		retMe[i] = ok
 	}