Define span structure for HTTP retries and redirects

CHANGELOG.md

@@ -102,6 +102,8 @@ release.
   ([#1916](https://github.com/open-telemetry/opentelemetry-specification/pull/1916))
 - Change meaning and discourage use of `faas.trigger` for FaaS clients (outgoing).
   ([#1921](https://github.com/open-telemetry/opentelemetry-specification/pull/1921))
+- Define span structure for HTTP retries and redirects.
+  ([#2078](https://github.com/open-telemetry/opentelemetry-specification/pull/2078))
 - Clarify difference between container.name and k8s.container.name
   ([#1980](https://github.com/open-telemetry/opentelemetry-specification/pull/1980))
 

semantic_conventions/trace/http.yaml

@@ -104,6 +104,13 @@ groups:
         brief: >
           The size of the uncompressed response payload body after transport decoding. Not set if transport encoding not used.
         examples: 5493
+      - id: retry_count
+        type: int
+        brief: >
+          The ordinal number of request re-sending attempt.
+        required:
+          conditional: If and only if a request was retried.
+        examples: 3
       - ref: net.peer.name
         sampling_relevant: true
       - ref: net.peer.ip

specification/trace/semantic_conventions/http.md

@@ -14,6 +14,7 @@ and various HTTP versions like 1.1, 2 and SPDY.
 - [Status](#status)
 - [Common Attributes](#common-attributes)
   * [HTTP request and response headers](#http-request-and-response-headers)
+  * [HTTP request retries and redirects](#http-request-retries-and-redirects)
 - [HTTP client](#http-client)
 - [HTTP server](#http-server)
   * [HTTP server definitions](#http-server-definitions)
@@ -70,6 +71,7 @@ Don't set the span status description if the reason can be inferred from `http.s
 | `http.request_content_length_uncompressed` | int | The size of the uncompressed request payload body after transport decoding. Not set if transport encoding not used. | `5493` | No |
 | `http.response_content_length` | 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://tools.ietf.org/html/rfc7230#section-3.3.2) header. For requests using transport encoding, this should be the compressed size. | `3495` | No |
 | `http.response_content_length_uncompressed` | int | The size of the uncompressed response payload body after transport decoding. Not set if transport encoding not used. | `5493` | No |
+| `http.retry_count` | int | The ordinal number of request re-sending attempt. | `3` | If and only if a request was retried. |
 | [`net.peer.ip`](span-general.md) | string | Remote address of the peer (dotted decimal for IPv4 or [RFC5952](https://tools.ietf.org/html/rfc5952) for IPv6) | `127.0.0.1` | No |
 | [`net.peer.name`](span-general.md) | string | Remote hostname or similar, see note below. | `example.com` | No |
 | [`net.peer.port`](span-general.md) | int | Remote port number. | `80`; `8080`; `443` | No |
@@ -121,6 +123,12 @@ Users MAY explicitly configure instrumentations to capture them even though it i
 
 [network attributes]: span-general.md#general-network-connection-attributes
 
+### HTTP request retries and redirects
+
+A span for each subsequent HTTP request re-sending attempt MUST be created and it SHOULD be linked with a previous one by creating a single `Link`. `http.retry_count` attribute SHOULD be added to each retry span with the value that reflects the ordinal number of request retry attempt.
+
+A span for each subsequent HTTP request redirect MUST be created and it SHOULD be linked with a span for initial request or previous redirect by creating a single `Link`.
+
 ## HTTP client
 
 This span type represents an outbound HTTP request.