Jaeger exporter intermittent "data does not fit within one UDP packet"

[Baliedge]

Description

As a followup from #2663, I found there is a buffer overrun issue in the Jaeger exporter causing intermittent drops of trace batches. Traces appear randomly in Jaeger as incomplete or missing.

I apply the workaround in #2663 that configures MaxPacketSize in the Jaeger exporter to 1472 so to remain compatible with network interfaces with likely default 1500 MTU. While my application runs, errors randomly appear like:

2022/03/08 16:39:15 data does not fit within one UDP packet; size 1482, max 1472, spans 6

I've been able to "fix" with the following workaround patch:

diff --git a/exporters/jaeger/agent.go b/exporters/jaeger/agent.go
index d18d891a..b64522e5 100644
--- a/exporters/jaeger/agent.go
+++ b/exporters/jaeger/agent.go
@@ -242,7 +242,7 @@ func (a *agentClientUDP) flush(ctx context.Context, batch *gen.Batch) error {
 func (a *agentClientUDP) calcSizeOfSerializedThrift(ctx context.Context, thriftStruct thrift.TStruct) (int, error) {
        a.thriftBuffer.Reset()
        err := thriftStruct.Write(ctx, a.thriftProtocol)
-       return a.thriftBuffer.Len(), err
+       return a.thriftBuffer.Len() + 19, err
 }

 // Close implements Close() of io.Closer and closes the underlying UDP connection.

This is because I found that the actual packet size was always 19 bytes larger than the value returned by calcSizeOfSerializedThrift().

Environment

• OS: Occurs on Linux and Mac OS
• Architecture: amd64
• Go Version: 1.17
• opentelemetry-go version: v1.4.1

Steps To Reproduce

1. See Jaeger exporter sending oversized UDP thrift packets #2663 for tracer setup code example.
2. Build a trace with many spans with sufficient complexity that the spans must be sent in multiple batches. This increases the probability that the packet will be oversized. Consider this unit test:

func TestSequentialSpans(t *testing.T) {
	const nestLevels = 15

	for nesting := 0; nesting < nestLevels; nesting++ {
		t.Run(fmt.Sprintf("Nest %d levels", nesting), func(t *testing.T) {
			ctx, span = tracer.Start(context.Background(), t.Name())
			defer span.End()
			time.Sleep(10 * time.Millisecond)

			for i := 0; i < nesting; i++ {
				ctx, span2 = tracer.Start(ctx, fmt.Sprintf("Nest level %d", i + 1))
				time.Sleep(5 * time.Millisecond)
				span2.End()
			}
		})
	}
}

Expected behavior

• No errors should be printed by the Jaeger client.
• Trace is viewable from Jaeger UI in full detail.

[Baliedge]

Please disregard, I was not actually running latest versions of all the otel packages like I thought and so I did not have the recent fix from #2489. This resolved my issue.