Fixup: Add once logging

httpbp/client_middlewares.go

@@ -262,6 +262,8 @@ func MaxConcurrency(maxConcurrency int64) ClientMiddleware {
 	}
 }
 
+var monitorClientLoggingOnce sync.Once
+
 // MonitorClient is an HTTP client middleware that wraps HTTP requests in a
 // client span.
 //
@@ -272,7 +274,10 @@ func MonitorClient(slug string) ClientMiddleware {
 		return mw
 	}
 	return func(next http.RoundTripper) http.RoundTripper {
-		// no-op
+		// no-op but log for once
+		monitorClientLoggingOnce.Do(func() {
+			slog.Warn("httpbp.MonitorClient: internalv2compat.V2TracingHTTPClientMiddleware() returned nil")
+		})
 		return next
 	}
 }

thriftbp/client_middlewares.go

@@ -3,7 +3,9 @@ package thriftbp
 import (
 	"context"
 	"errors"
+	"log/slog"
 	"strconv"
+	"sync"
 	"time"
 
 	"github.com/apache/thrift/lib/go/thrift"
@@ -186,6 +188,8 @@ type MonitorClientArgs struct {
 	ErrorSpanSuppressor errorsbp.Suppressor
 }
 
+var monitorClientLoggingOnce sync.Once
+
 // MonitorClient is a ClientMiddleware that wraps the inner thrift.TClient.Call
 // in a thrift client span.
 //
@@ -196,7 +200,10 @@ func MonitorClient(args MonitorClientArgs) thrift.ClientMiddleware {
 		return mw
 	}
 	return func(next thrift.TClient) thrift.TClient {
-		// no-op
+		// no-op but log for once
+		monitorClientLoggingOnce.Do(func() {
+			slog.Warn("thriftbp.MonitorClient: internalv2compat.V2TracingThriftClientMiddleware() returned nil")
+		})
 		return next
 	}
 }

thriftbp/server_middlewares.go

@@ -4,7 +4,9 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"log/slog"
 	"strconv"
+	"sync"
 	"time"
 
 	"github.com/apache/thrift/lib/go/thrift"
@@ -126,6 +128,8 @@ func wrapErrorForServerSpan(err error, suppressor errorsbp.Suppressor) error {
 	return thriftint.WrapBaseplateError(suppressor.Wrap(err))
 }
 
+var injectServerSpanLoggingOnce sync.Once
+
 // InjectServerSpan implements thrift.ProcessorMiddleware and injects a server
 // span into the `next` context.
 //
@@ -136,7 +140,10 @@ func InjectServerSpan(_ errorsbp.Suppressor) thrift.ProcessorMiddleware {
 		return mw
 	}
 	return func(name string, next thrift.TProcessorFunction) thrift.TProcessorFunction {
-		// no-op
+		// no-op but log for once
+		injectServerSpanLoggingOnce.Do(func() {
+			slog.Warn("thriftbp.InjectServerSpan: internalv2compat.V2TracingThriftServerMiddleware() returned nil")
+		})
 		return next
 	}
 }