improve performance for attributes http/dup

CHANGELOG.md

@@ -30,6 +30,13 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
   - `go.opentelemetry.io/contrib/instrumentation/github.com/labstack/echo/otelecho`
   - `go.opentelemetry.io/contrib/instrumentation/net/http/httptrace/otelhttptrace`
   - `go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp`
+- Improve performance by reducing allocations for http request when using `OTEL_SEMCONV_STABILITY_OPT_IN=http/dup` in the modules below. (#7180)
+  - `go.opentelemetry.io/contrib/instrumentation/github.com/emicklei/go-restful/otelrestful`
+  - `go.opentelemetry.io/contrib/instrumentation/github.com/gin-gonic/gin/otelgin`
+  - `go.opentelemetry.io/contrib/instrumentation/github.com/gorilla/mux/otelmux`
+  - `go.opentelemetry.io/contrib/instrumentation/github.com/labstack/echo/otelecho`
+  - `go.opentelemetry.io/contrib/instrumentation/net/http/httptrace/otelhttptrace`
+  - `go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp`
 
   The `OTEL_SEMCONV_STABILITY_OPT_IN=http/dup` environment variable can be still used to emit both the v1.20.0 and v1.26.0 semantic conventions.
   It is however impossible to emit only the 1.20.0 semantic conventions, as the next release will drop support for that environment variable. (#6899)

instrumentation/github.com/emicklei/go-restful/otelrestful/internal/semconv/env.go

@@ -62,15 +62,19 @@
 // If the primary server name is not known, server should be an empty string.
 // The req Host will be used to determine the server instead.
 func (s HTTPServer) RequestTraceAttrs(server string, req *http.Request, opts RequestTraceAttrsOpts) []attribute.KeyValue {
+	attrs := CurrentHTTPServer{}.RequestTraceAttrs(server, req, opts)
 	if s.duplicate {
-		return append(OldHTTPServer{}.RequestTraceAttrs(server, req), CurrentHTTPServer{}.RequestTraceAttrs(server, req, opts)...)
+		return OldHTTPServer{}.RequestTraceAttrs(server, req, attrs)
 	}
-	return CurrentHTTPServer{}.RequestTraceAttrs(server, req, opts)
+	return attrs
 }
 
 func (s HTTPServer) NetworkTransportAttr(network string) []attribute.KeyValue {
 	if s.duplicate {
-		return append([]attribute.KeyValue{OldHTTPServer{}.NetworkTransportAttr(network)}, CurrentHTTPServer{}.NetworkTransportAttr(network))
+		return []attribute.KeyValue{
+			OldHTTPServer{}.NetworkTransportAttr(network),
+			CurrentHTTPServer{}.NetworkTransportAttr(network),
+		}
 	}
 	return []attribute.KeyValue{
 		CurrentHTTPServer{}.NetworkTransportAttr(network),
@@ -81,10 +85,11 @@
 //
 // If any of the fields in the ResponseTelemetry are not set the attribute will be omitted.
 func (s HTTPServer) ResponseTraceAttrs(resp ResponseTelemetry) []attribute.KeyValue {
+	attrs := CurrentHTTPServer{}.ResponseTraceAttrs(resp)
 	if s.duplicate {
-		return append(OldHTTPServer{}.ResponseTraceAttrs(resp), CurrentHTTPServer{}.ResponseTraceAttrs(resp)...)
+		return OldHTTPServer{}.ResponseTraceAttrs(resp, attrs)
 	}
-	return CurrentHTTPServer{}.ResponseTraceAttrs(resp)
+	return attrs
 }
 
 // Route returns the attribute for the route.
@@ -208,19 +213,20 @@
 
 // RequestTraceAttrs returns attributes for an HTTP request made by a client.
 func (c HTTPClient) RequestTraceAttrs(req *http.Request) []attribute.KeyValue {
+	attrs := CurrentHTTPClient{}.RequestTraceAttrs(req)
 	if c.duplicate {
-		return append(OldHTTPClient{}.RequestTraceAttrs(req), CurrentHTTPClient{}.RequestTraceAttrs(req)...)
+		return OldHTTPClient{}.RequestTraceAttrs(req, attrs)
 	}
-	return CurrentHTTPClient{}.RequestTraceAttrs(req)
+	return attrs
 }
 
 // ResponseTraceAttrs returns metric attributes for an HTTP request made by a client.
 func (c HTTPClient) ResponseTraceAttrs(resp *http.Response) []attribute.KeyValue {
+	attrs := CurrentHTTPClient{}.ResponseTraceAttrs(resp)
 	if c.duplicate {
-		return append(OldHTTPClient{}.ResponseTraceAttrs(resp), CurrentHTTPClient{}.ResponseTraceAttrs(resp)...)
+		return OldHTTPClient{}.ResponseTraceAttrs(resp, attrs)
 	}
-
-	return CurrentHTTPClient{}.ResponseTraceAttrs(resp)
+	return attrs
 }
 
 func (c HTTPClient) Status(code int) (codes.Code, string) {
@@ -297,9 +303,10 @@
 }
 
 func (s HTTPClient) TraceAttributes(host string) []attribute.KeyValue {
+	attrs := CurrentHTTPClient{}.TraceAttributes(host)
 	if s.duplicate {
-		return append(OldHTTPClient{}.TraceAttributes(host), CurrentHTTPClient{}.TraceAttributes(host)...)
+		return OldHTTPClient{}.TraceAttributes(host, attrs)
 	}
 
-	return CurrentHTTPClient{}.TraceAttributes(host)
+	return attrs
 }

instrumentation/github.com/emicklei/go-restful/otelrestful/internal/semconv/env_test.go

@@ -151,8 +151,8 @@ func TestHTTPClientTraceAttributes(t *testing.T) {
 			optinVal: "http/dup",
 
 			wantAttributes: []attribute.KeyValue{
-				attribute.String("net.host.name", "example.com"),
 				attribute.String("server.address", "example.com"),
+				attribute.String("net.host.name", "example.com"),
 			},
 		},
 	} {
@@ -188,8 +188,8 @@ func TestClientTraceAttributes(t *testing.T) {
 			host:     "example.com",
 
 			wantAttributes: []attribute.KeyValue{
-				attribute.String("net.host.name", "example.com"),
 				attribute.String("server.address", "example.com"),
+				attribute.String("net.host.name", "example.com"),
 			},
 		},
 	} {

instrumentation/github.com/emicklei/go-restful/otelrestful/internal/semconv/v1.20.0.go

@@ -37,8 +37,8 @@
 //
 // If the primary server name is not known, server should be an empty string.
 // The req Host will be used to determine the server instead.
-func (o OldHTTPServer) RequestTraceAttrs(server string, req *http.Request) []attribute.KeyValue {
-	return semconvutil.HTTPServerRequest(server, req, semconvutil.HTTPServerRequestOptions{})
+func (o OldHTTPServer) RequestTraceAttrs(server string, req *http.Request, attrs []attribute.KeyValue) []attribute.KeyValue {
+	return semconvutil.HTTPServerRequest(server, req, semconvutil.HTTPServerRequestOptions{}, attrs)
 }
 
 func (o OldHTTPServer) NetworkTransportAttr(network string) attribute.KeyValue {
@@ -48,9 +48,7 @@
 // ResponseTraceAttrs returns trace attributes for telemetry from an HTTP response.
 //
 // If any of the fields in the ResponseTelemetry are not set the attribute will be omitted.
-func (o OldHTTPServer) ResponseTraceAttrs(resp ResponseTelemetry) []attribute.KeyValue {
-	attributes := []attribute.KeyValue{}
-
+func (o OldHTTPServer) ResponseTraceAttrs(resp ResponseTelemetry, attributes []attribute.KeyValue) []attribute.KeyValue {
 	if resp.ReadBytes > 0 {
 		attributes = append(attributes, semconv.HTTPRequestContentLength(int(resp.ReadBytes)))
 	}
@@ -179,12 +177,12 @@
 
 type OldHTTPClient struct{}
 
-func (o OldHTTPClient) RequestTraceAttrs(req *http.Request) []attribute.KeyValue {
-	return semconvutil.HTTPClientRequest(req)
+func (o OldHTTPClient) RequestTraceAttrs(req *http.Request, attrs []attribute.KeyValue) []attribute.KeyValue {
+	return semconvutil.HTTPClientRequest(req, attrs)
 }
 
-func (o OldHTTPClient) ResponseTraceAttrs(resp *http.Response) []attribute.KeyValue {
-	return semconvutil.HTTPClientResponse(resp)
+func (o OldHTTPClient) ResponseTraceAttrs(resp *http.Response, attrs []attribute.KeyValue) []attribute.KeyValue {
+	return semconvutil.HTTPClientResponse(resp, attrs)
 }
 
 func (o OldHTTPClient) MetricAttributes(req *http.Request, statusCode int, additionalAttributes []attribute.KeyValue) []attribute.KeyValue {
@@ -270,8 +268,6 @@
 }
 
 // TraceAttributes returns attributes for httptrace.
-func (c OldHTTPClient) TraceAttributes(host string) []attribute.KeyValue {
-	return []attribute.KeyValue{
-		semconv.NetHostName(host),
-	}
+func (c OldHTTPClient) TraceAttributes(host string, attrs []attribute.KeyValue) []attribute.KeyValue {
+	return append(attrs, semconv.NetHostName(host))
 }

instrumentation/github.com/emicklei/go-restful/otelrestful/internal/semconvutil/httpconv.go

@@ -10,6 +10,7 @@
 import (
 	"fmt"
 	"net/http"
+	"slices"
 	"strings"
 
 	"go.opentelemetry.io/otel/attribute"
@@ -32,18 +33,18 @@
 // attributes. If a complete set of attributes can be generated using the
 // request contained in resp. For example:
 //
-//	append(HTTPClientResponse(resp), ClientRequest(resp.Request)...)
-func HTTPClientResponse(resp *http.Response) []attribute.KeyValue {
-	return hc.ClientResponse(resp)
+//	HTTPClientResponse(resp, ClientRequest(resp.Request)))
+func HTTPClientResponse(resp *http.Response, attrs []attribute.KeyValue) []attribute.KeyValue {
+	return hc.ClientResponse(resp, attrs)
 }
 
 // HTTPClientRequest returns trace attributes for an HTTP request made by a client.
 // The following attributes are always returned: "http.url", "http.method",
 // "net.peer.name". The following attributes are returned if the related values
 // are defined in req: "net.peer.port", "user_agent.original",
 // "http.request_content_length".
-func HTTPClientRequest(req *http.Request) []attribute.KeyValue {
-	return hc.ClientRequest(req)
+func HTTPClientRequest(req *http.Request, attrs []attribute.KeyValue) []attribute.KeyValue {
+	return hc.ClientRequest(req, attrs)
 }
 
 // HTTPClientRequestMetrics returns metric attributes for an HTTP request made by a client.
@@ -81,8 +82,8 @@
 // "http.target", "net.host.name". The following attributes are returned if
 // they related values are defined in req: "net.host.port", "net.sock.peer.addr",
 // "net.sock.peer.port", "user_agent.original", "http.client_ip".
-func HTTPServerRequest(server string, req *http.Request, opts HTTPServerRequestOptions) []attribute.KeyValue {
-	return hc.ServerRequest(server, req, opts)
+func HTTPServerRequest(server string, req *http.Request, opts HTTPServerRequestOptions, attrs []attribute.KeyValue) []attribute.KeyValue {
+	return hc.ServerRequest(server, req, opts, attrs)
 }
 
 // HTTPServerRequestMetrics returns metric attributes for an HTTP request received by a
@@ -159,8 +160,8 @@
 // attributes. If a complete set of attributes can be generated using the
 // request contained in resp. For example:
 //
-//	append(ClientResponse(resp), ClientRequest(resp.Request)...)
-func (c *httpConv) ClientResponse(resp *http.Response) []attribute.KeyValue {
+//	ClientResponse(resp, ClientRequest(resp.Request))
+func (c *httpConv) ClientResponse(resp *http.Response, attrs []attribute.KeyValue) []attribute.KeyValue {
 	/* The following semantic conventions are returned if present:
 	http.status_code                int
 	http.response_content_length    int
@@ -172,8 +173,11 @@
 	if resp.ContentLength > 0 {
 		n++
 	}
+	if n == 0 {
+		return attrs
+	}
 
-	attrs := make([]attribute.KeyValue, 0, n)
+	attrs = slices.Grow(attrs, n)
 	if resp.StatusCode > 0 {
 		attrs = append(attrs, c.HTTPStatusCodeKey.Int(resp.StatusCode))
 	}
@@ -188,7 +192,7 @@
 // "net.peer.name". The following attributes are returned if the related values
 // are defined in req: "net.peer.port", "user_agent.original",
 // "http.request_content_length", "user_agent.original".
-func (c *httpConv) ClientRequest(req *http.Request) []attribute.KeyValue {
+func (c *httpConv) ClientRequest(req *http.Request, attrs []attribute.KeyValue) []attribute.KeyValue {
 	/* The following semantic conventions are returned if present:
 	http.method                     string
 	user_agent.original             string
@@ -227,8 +231,7 @@
 		n++
 	}
 
-	attrs := make([]attribute.KeyValue, 0, n)
-
+	attrs = slices.Grow(attrs, n)
 	attrs = append(attrs, c.method(req.Method))
 
 	var u string
@@ -311,7 +314,7 @@
 // related values are defined in req: "net.host.port", "net.sock.peer.addr",
 // "net.sock.peer.port", "user_agent.original", "http.client_ip",
 // "net.protocol.name", "net.protocol.version".
-func (c *httpConv) ServerRequest(server string, req *http.Request, opts HTTPServerRequestOptions) []attribute.KeyValue {
+func (c *httpConv) ServerRequest(server string, req *http.Request, opts HTTPServerRequestOptions, attrs []attribute.KeyValue) []attribute.KeyValue {
 	/* The following semantic conventions are returned if present:
 	http.method             string
 	http.scheme             string
@@ -394,7 +397,7 @@
 		n++
 	}
 
-	attrs := make([]attribute.KeyValue, 0, n)
+	attrs = slices.Grow(attrs, n)
 
 	attrs = append(attrs, c.method(req.Method))
 	attrs = append(attrs, c.scheme(req.TLS != nil))

instrumentation/github.com/emicklei/go-restful/otelrestful/internal/semconvutil/httpconv_test.go

@@ -27,7 +27,7 @@ func TestHTTPClientResponse(t *testing.T) {
 		StatusCode:    stat,
 		ContentLength: n,
 	}
-	got := HTTPClientResponse(resp)
+	got := HTTPClientResponse(resp, nil)
 	assert.Equal(t, 2, cap(got), "slice capacity")
 	assert.ElementsMatch(t, []attribute.KeyValue{
 		attribute.Key("http.status_code").Int(stat),
@@ -55,7 +55,7 @@ func TestHTTPSClientRequest(t *testing.T) {
 			attribute.String("http.url", "https://127.0.0.1:443/resource"),
 			attribute.String("net.peer.name", "127.0.0.1"),
 		},
-		HTTPClientRequest(req),
+		HTTPClientRequest(req, nil),
 	)
 }
 
@@ -115,7 +115,7 @@ func TestHTTPClientRequest(t *testing.T) {
 			attribute.String("user_agent.original", agent),
 			attribute.Int("http.request_content_length", n),
 		},
-		HTTPClientRequest(req),
+		HTTPClientRequest(req, nil),
 	)
 }
 
@@ -156,7 +156,7 @@ func TestHTTPClientRequestMetrics(t *testing.T) {
 func TestHTTPClientRequestRequired(t *testing.T) {
 	req := new(http.Request)
 	var got []attribute.KeyValue
-	assert.NotPanics(t, func() { got = HTTPClientRequest(req) })
+	assert.NotPanics(t, func() { got = HTTPClientRequest(req, nil) })
 	want := []attribute.KeyValue{
 		attribute.String("http.method", "GET"),
 		attribute.String("http.url", ""),
@@ -248,7 +248,7 @@ func TestHTTPServerRequest(t *testing.T) {
 					attribute.String("net.protocol.version", "1.1"),
 					attribute.String("http.target", "/"),
 				},
-				HTTPServerRequest("", got, tt.httpServerRequestOpts))
+				HTTPServerRequest("", got, tt.httpServerRequestOpts, nil))
 		})
 	}
 }
@@ -301,22 +301,22 @@ func TestHTTPServerName(t *testing.T) {
 	)
 	portStr := strconv.Itoa(port)
 	server := host + ":" + portStr
-	assert.NotPanics(t, func() { got = HTTPServerRequest(server, req, HTTPServerRequestOptions{}) })
+	assert.NotPanics(t, func() { got = HTTPServerRequest(server, req, HTTPServerRequestOptions{}, nil) })
 	assert.Contains(t, got, attribute.String("net.host.name", host))
 	assert.Contains(t, got, attribute.Int("net.host.port", port))
 
 	req = &http.Request{Host: "alt.host.name:" + portStr}
 	// The server parameter does not include a port, ServerRequest should use
 	// the port in the request Host field.
-	assert.NotPanics(t, func() { got = HTTPServerRequest(host, req, HTTPServerRequestOptions{}) })
+	assert.NotPanics(t, func() { got = HTTPServerRequest(host, req, HTTPServerRequestOptions{}, nil) })
 	assert.Contains(t, got, attribute.String("net.host.name", host))
 	assert.Contains(t, got, attribute.Int("net.host.port", port))
 }
 
 func TestHTTPServerRequestFailsGracefully(t *testing.T) {
 	req := new(http.Request)
 	var got []attribute.KeyValue
-	assert.NotPanics(t, func() { got = HTTPServerRequest("", req, HTTPServerRequestOptions{}) })
+	assert.NotPanics(t, func() { got = HTTPServerRequest("", req, HTTPServerRequestOptions{}, nil) })
 	want := []attribute.KeyValue{
 		attribute.String("http.method", "GET"),
 		attribute.String("http.scheme", "http"),

instrumentation/github.com/emicklei/go-restful/otelrestful/restful.go

@@ -6,11 +6,12 @@ package otelrestful // import "go.opentelemetry.io/contrib/instrumentation/githu
 import (
 	"github.com/emicklei/go-restful/v3"
 
-	"go.opentelemetry.io/contrib/instrumentation/github.com/emicklei/go-restful/otelrestful/internal/semconv"
-	"go.opentelemetry.io/contrib/instrumentation/github.com/emicklei/go-restful/otelrestful/internal/semconvutil"
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/propagation"
 	oteltrace "go.opentelemetry.io/otel/trace"
+
+	"go.opentelemetry.io/contrib/instrumentation/github.com/emicklei/go-restful/otelrestful/internal/semconv"
+	"go.opentelemetry.io/contrib/instrumentation/github.com/emicklei/go-restful/otelrestful/internal/semconvutil"
 )
 
 // ScopeName is the instrumentation scope name.
@@ -45,7 +46,7 @@ func OTelFilter(service string, opts ...Option) restful.FilterFunction {
 		spanName := route
 
 		opts := []oteltrace.SpanStartOption{
-			oteltrace.WithAttributes(semconvutil.HTTPServerRequest(service, r, semconvutil.HTTPServerRequestOptions{})...),
+			oteltrace.WithAttributes(semconvutil.HTTPServerRequest(service, r, semconvutil.HTTPServerRequestOptions{}, nil)...),
 			oteltrace.WithSpanKind(oteltrace.SpanKindServer),
 		}
 		if route != "" {