add http.request.synthetic attribute to server spans and metrics

.chloggen/add-synthetic-source.yaml

@@ -0,0 +1,22 @@
+# Use this changelog template to create an entry for release notes.
+#
+# If your change doesn't affect end users you should instead start
+# your pull request title with [chore] or use the "Skip Changelog" label.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the area of concern in the attributes-registry, (e.g. http, cloud, db)
+component: http
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add the http.request.synthetic attribute to track if spans and metrics are the result of real users, synthetic testing, or bots.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+# The values here must be integers.
+issues: [1127]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

docs/attributes-registry/http.md

@@ -22,11 +22,12 @@ This document defines semantic convention attributes in the HTTP namespace.
 | <a id="http-request-method-original" href="#http-request-method-original">`http.request.method_original`</a> | string | Original HTTP method sent by the client in the request line. | `GeT`; `ACL`; `foo` | ![Stable](https://img.shields.io/badge/-stable-lightgreen) |
 | <a id="http-request-resend-count" href="#http-request-resend-count">`http.request.resend_count`</a> | int | The ordinal number of request resending attempt (for any reason, including redirects). [3] | `3` | ![Stable](https://img.shields.io/badge/-stable-lightgreen) |
 | <a id="http-request-size" href="#http-request-size">`http.request.size`</a> | int | The total size of the request in bytes. This should be the total number of bytes sent over the wire, including the request line (HTTP/1.1), framing (HTTP/2 and HTTP/3), headers, and request body if any. | `1437` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| <a id="http-request-synthetic" href="#http-request-synthetic">`http.request.synthetic`</a> | string | A flag indicating that the request was synthetically created and did not originate from genuine client traffic. [4] | `bot`; `synthetic test` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
 | <a id="http-response-body-size" href="#http-response-body-size">`http.response.body.size`</a> | int | The size of the response payload body in bytes. This is the number of bytes transferred excluding headers and is often, but not always, present as the [Content-Length](https://www.rfc-editor.org/rfc/rfc9110.html#field.content-length) header. For requests using transport encoding, this should be the compressed size. | `3495` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
-| <a id="http-response-header" href="#http-response-header">`http.response.header.<key>`</a> | string[] | HTTP response headers, `<key>` being the normalized HTTP Header name (lowercase), the value being the header values. [4] | `http.response.header.content-type=["application/json"]`; `http.response.header.my-custom-header=["abc", "def"]` | ![Stable](https://img.shields.io/badge/-stable-lightgreen) |
+| <a id="http-response-header" href="#http-response-header">`http.response.header.<key>`</a> | string[] | HTTP response headers, `<key>` being the normalized HTTP Header name (lowercase), the value being the header values. [5] | `http.response.header.content-type=["application/json"]`; `http.response.header.my-custom-header=["abc", "def"]` | ![Stable](https://img.shields.io/badge/-stable-lightgreen) |
 | <a id="http-response-size" href="#http-response-size">`http.response.size`</a> | int | The total size of the response in bytes. This should be the total number of bytes sent over the wire, including the status line (HTTP/1.1), framing (HTTP/2 and HTTP/3), headers, and response body and trailers if any. | `1437` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
 | <a id="http-response-status-code" href="#http-response-status-code">`http.response.status_code`</a> | int | [HTTP response status code](https://tools.ietf.org/html/rfc7231#section-6). | `200` | ![Stable](https://img.shields.io/badge/-stable-lightgreen) |
-| <a id="http-route" href="#http-route">`http.route`</a> | string | The matched route, that is, the path template in the format used by the respective server framework. [5] | `/users/:userID?`; `{controller}/{action}/{id?}` | ![Stable](https://img.shields.io/badge/-stable-lightgreen) |
+| <a id="http-route" href="#http-route">`http.route`</a> | string | The matched route, that is, the path template in the format used by the respective server framework. [6] | `/users/:userID?`; `{controller}/{action}/{id?}` | ![Stable](https://img.shields.io/badge/-stable-lightgreen) |
 
 **[1]:** Instrumentations SHOULD require an explicit configuration of which headers are to be captured. Including all request headers can be a security risk - explicit configuration helps avoid leaking sensitive information.
 The `User-Agent` header is already captured in the `user_agent.original` attribute. Users MAY explicitly configure instrumentations to capture them even though it is not recommended.
@@ -49,11 +50,13 @@ Tracing instrumentations that do so, MUST also set `http.request.method_original
 
 **[3]:** The resend count SHOULD be updated each time an HTTP request gets resent by the client, regardless of what was the cause of the resending (e.g. redirection, authorization failure, 503 Server Unavailable, network issues, or any other).
 
-**[4]:** Instrumentations SHOULD require an explicit configuration of which headers are to be captured. Including all response headers can be a security risk - explicit configuration helps avoid leaking sensitive information.
+**[4]:** This flag can primarily be determined by the contents of the `user_agent.original` attribute. Instrumentations should determine what they consider synthetic or bot traffic, and set this attribute accordingly. This attribute is useful for distinguishing between genuine client traffic and synthetic traffic generated by bots or tests.
+
+**[5]:** Instrumentations SHOULD require an explicit configuration of which headers are to be captured. Including all response headers can be a security risk - explicit configuration helps avoid leaking sensitive information.
 Users MAY explicitly configure instrumentations to capture them even though it is not recommended.
 The attribute value MUST consist of either multiple header values as an array of strings or a single-item array containing a possibly comma-concatenated string, depending on the way the HTTP library provides access to headers.
 
-**[5]:** MUST NOT be populated when this is not supported by the HTTP server framework as the route attribute should have low-cardinality and the URI path can NOT substitute it.
+**[6]:** MUST NOT be populated when this is not supported by the HTTP server framework as the route attribute should have low-cardinality and the URI path can NOT substitute it.
 SHOULD include the [application root](/docs/http/http-spans.md#http-server-definitions) if there is one.
 
 `http.connection.state` has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.
@@ -78,6 +81,13 @@ SHOULD include the [application root](/docs/http/http-spans.md#http-server-defin
 | `PUT` | PUT method. | ![Stable](https://img.shields.io/badge/-stable-lightgreen) |
 | `TRACE` | TRACE method. | ![Stable](https://img.shields.io/badge/-stable-lightgreen) |
 
+`http.request.synthetic` has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.
+
+| Value  | Description | Stability |
+|---|---|---|
+| `bot` | bot source. | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| `synthetic test` | synthetic test source. | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+
 ## Deprecated HTTP Attributes
 
 Describes deprecated HTTP attributes.