feat(http): Add http.request.time_to_first_byte attribute (#131)

Co-authored-by: Lorenzo Cian <lorenzo.cian@sentry.io>

Author: Lms24

generated/attributes/http.md

@@ -20,6 +20,7 @@
   - [http.request.response_end](#httprequestresponse_end)
   - [http.request.response_start](#httprequestresponse_start)
   - [http.request.secure_connection_start](#httprequestsecure_connection_start)
+  - [http.request.time_to_first_byte](#httprequesttime_to_first_byte)
   - [http.request.worker_start](#httprequestworker_start)
   - [http.response.body.size](#httpresponsebodysize)
   - [http.response.header.\<key\>](#httpresponseheaderkey)
@@ -232,6 +233,17 @@ The UNIX timestamp representing the time immediately before the browser starts t
 | Exists in OpenTelemetry | No |
 | Example | `1732829555.73` |
 
+### http.request.time_to_first_byte
+
+The time in seconds from the browser's timeorigin to when the first byte of the request's response was received. See https://web.dev/articles/ttfb#measure-resource-requests
+
+| Property | Value |
+| --- | --- |
+| Type | `double` |
+| Has PII | false |
+| Exists in OpenTelemetry | No |
+| Example | `1.032` |
+
 ### http.request.worker_start
 
 The UNIX timestamp representing the timestamp immediately before dispatching the FetchEvent if a Service Worker thread is already running, or immediately before starting the Service Worker thread if it is not already running.

javascript/sentry-conventions/src/attributes.ts

@@ -3403,6 +3403,26 @@ export const HTTP_REQUEST_SECURE_CONNECTION_START = 'http.request.secure_connect
  */
 export type HTTP_REQUEST_SECURE_CONNECTION_START_TYPE = number;
 
+// Path: model/attributes/http/http__request__time_to_first_byte.json
+
+/**
+ * The time in seconds from the browser's timeorigin to when the first byte of the request's response was received. See https://web.dev/articles/ttfb#measure-resource-requests `http.request.time_to_first_byte`
+ *
+ * Attribute Value Type: `number` {@link HTTP_REQUEST_TIME_TO_FIRST_BYTE_TYPE}
+ *
+ * Contains PII: false
+ *
+ * Attribute defined in OTEL: No
+ *
+ * @example 1.032
+ */
+export const HTTP_REQUEST_TIME_TO_FIRST_BYTE = 'http.request.time_to_first_byte';
+
+/**
+ * Type for {@link HTTP_REQUEST_TIME_TO_FIRST_BYTE} http.request.time_to_first_byte
+ */
+export type HTTP_REQUEST_TIME_TO_FIRST_BYTE_TYPE = number;
+
 // Path: model/attributes/http/http__request__worker_start.json
 
 /**
@@ -6781,6 +6801,7 @@ export type Attributes = {
   [HTTP_REQUEST_RESPONSE_END]?: HTTP_REQUEST_RESPONSE_END_TYPE;
   [HTTP_REQUEST_RESPONSE_START]?: HTTP_REQUEST_RESPONSE_START_TYPE;
   [HTTP_REQUEST_SECURE_CONNECTION_START]?: HTTP_REQUEST_SECURE_CONNECTION_START_TYPE;
+  [HTTP_REQUEST_TIME_TO_FIRST_BYTE]?: HTTP_REQUEST_TIME_TO_FIRST_BYTE_TYPE;
   [HTTP_REQUEST_WORKER_START]?: HTTP_REQUEST_WORKER_START_TYPE;
   [HTTP_RESPONSE_BODY_SIZE]?: HTTP_RESPONSE_BODY_SIZE_TYPE;
   [HTTP_RESPONSE_HEADER_KEY]?: HTTP_RESPONSE_HEADER_KEY_TYPE;
@@ -7067,6 +7088,7 @@ export type FullAttributes = {
   [HTTP_REQUEST_RESPONSE_END]?: HTTP_REQUEST_RESPONSE_END_TYPE;
   [HTTP_REQUEST_RESPONSE_START]?: HTTP_REQUEST_RESPONSE_START_TYPE;
   [HTTP_REQUEST_SECURE_CONNECTION_START]?: HTTP_REQUEST_SECURE_CONNECTION_START_TYPE;
+  [HTTP_REQUEST_TIME_TO_FIRST_BYTE]?: HTTP_REQUEST_TIME_TO_FIRST_BYTE_TYPE;
   [HTTP_REQUEST_WORKER_START]?: HTTP_REQUEST_WORKER_START_TYPE;
   [HTTP_RESPONSE_BODY_SIZE]?: HTTP_RESPONSE_BODY_SIZE_TYPE;
   [HTTP_RESPONSE_HEADER_KEY]?: HTTP_RESPONSE_HEADER_KEY_TYPE;

model/attributes/http/http__request__time_to_first_byte.json

@@ -0,0 +1,11 @@
+{
+  "key": "http.request.time_to_first_byte",
+  "brief": "The time in seconds from the browser's timeorigin to when the first byte of the request's response was received. See https://web.dev/articles/ttfb#measure-resource-requests",
+  "type": "double",
+  "pii": {
+    "key": "false"
+  },
+  "is_in_otel": false,
+  "example": 1.032,
+  "sdks": ["javascript-browser"]
+}