[extension/encoding/googlecloudlogentryencoding] accept short ALPN protocol tokens (h2, h3)

.chloggen/gclog-encoding-h2-protocol.yaml

@@ -0,0 +1,5 @@
+change_type: bug_fix
+component: extension/google_cloud_logentry_encoding
+note: "Accept short ALPN protocol tokens (e.g. `h2`, `h3`) in `httpRequest.protocol` that do not contain a `/`; previously any protocol string without a slash was rejected with an error, causing log entries from Google Cloud Load Balancers that switched to reporting `h2` for HTTP/2 to be silently dropped."
+issues: [45214]
+change_logs: [user]

extension/encoding/googlecloudlogentryencodingextension/log_entry.go

@@ -232,21 +232,32 @@ func handleHTTPRequestField(attributes pcommon.Map, req *httpRequest) error {
 	}
 
 	if req.Protocol != "" {
-		if strings.Count(req.Protocol, "/") != 1 {
-			return fmt.Errorf(
-				`invalid protocol %q: expected exactly one "/" (format "<name>/<version>", e.g. "HTTP/1.1")`,
-				req.Protocol,
-			)
-		}
-		name, version, found := strings.Cut(req.Protocol, "/")
-		if !found || name == "" || version == "" {
-			return fmt.Errorf(
-				`invalid protocol %q: name or version is missing (expected format "<name>/<version>", e.g. "HTTP/1.1")`,
-				req.Protocol,
-			)
+		name, version, hasSlash := strings.Cut(req.Protocol, "/")
+		if !hasSlash {
+			// Short ALPN token (RFC 7301). Map the well-known HTTP variants to
+			// "http" + numeric version so telemetry stays consistent with the
+			// "HTTP/1.1" form; unknown tokens fall back to the raw value as the
+			// protocol name with no version.
+			switch strings.ToLower(req.Protocol) {
+			case "h2", "h2c":
+				attributes.PutStr(string(conventions.NetworkProtocolNameKey), "http")
+				attributes.PutStr(string(conventions.NetworkProtocolVersionKey), "2")
+			case "h3":
+				attributes.PutStr(string(conventions.NetworkProtocolNameKey), "http")
+				attributes.PutStr(string(conventions.NetworkProtocolVersionKey), "3")
+			default:
+				attributes.PutStr(string(conventions.NetworkProtocolNameKey), strings.ToLower(req.Protocol))
+			}
+		} else {
+			if name == "" || version == "" {
+				return fmt.Errorf("invalid protocol %q: name or version is missing", req.Protocol)
+			}
+			if strings.Contains(version, "/") {
+				return fmt.Errorf("invalid protocol %q: expected at most one \"/\"", req.Protocol)
+			}
+			attributes.PutStr(string(conventions.NetworkProtocolNameKey), strings.ToLower(name))
+			attributes.PutStr(string(conventions.NetworkProtocolVersionKey), version)
 		}
-		attributes.PutStr(string(conventions.NetworkProtocolNameKey), strings.ToLower(name))
-		attributes.PutStr(string(conventions.NetworkProtocolVersionKey), version)
 	}
 
 	shared.PutInt(string(conventions.HTTPResponseStatusCodeKey), req.Status, attributes)

extension/encoding/googlecloudlogentryencodingextension/log_entry_test.go

@@ -112,11 +112,54 @@ func TestHandleHTTPRequestField(t *testing.T) {
 			expectsErr: "failed to parse request url",
 		},
 		{
-			name: "invalid protocol",
+			// Short ALPN token — well-known HTTP variants are normalised to
+			// name="http" + numeric version so telemetry stays consistent with
+			// the HTTP/1.1 form (regression test for #45214).
+			name: "h2 protocol normalised to http/2",
 			request: &httpRequest{
-				Protocol: "invalid",
+				Protocol: "h2",
 			},
-			expectsErr: `expected exactly one "/"`,
+			expectsAttributes: map[string]any{
+				"network.protocol.name":    "http",
+				"network.protocol.version": "2",
+			},
+		},
+		{
+			name: "h2c protocol normalised to http/2",
+			request: &httpRequest{
+				Protocol: "h2c",
+			},
+			expectsAttributes: map[string]any{
+				"network.protocol.name":    "http",
+				"network.protocol.version": "2",
+			},
+		},
+		{
+			name: "h3 protocol normalised to http/3",
+			request: &httpRequest{
+				Protocol: "h3",
+			},
+			expectsAttributes: map[string]any{
+				"network.protocol.name":    "http",
+				"network.protocol.version": "3",
+			},
+		},
+		{
+			// Non-HTTP short ALPN token falls through to the raw-name path.
+			name: "unknown short ALPN token preserved as name",
+			request: &httpRequest{
+				Protocol: "mqtt",
+			},
+			expectsAttributes: map[string]any{
+				"network.protocol.name": "mqtt",
+			},
+		},
+		{
+			name: "invalid protocol — too many slashes",
+			request: &httpRequest{
+				Protocol: "a/b/c",
+			},
+			expectsErr: `at most one "/"`,
 		},
 		{
 			name: "invalid protocol 2",