Merge branch 'main' into enum-values-headings

.chloggen/1440.yaml

@@ -0,0 +1,6 @@
+change_type: breaking
+component: feature_flag
+note: >
+  Rename `feature_flag` event to `feature_flag.evaluation` event, define new feature flag attributes and provide body definition.
+  Remove `feature_flag` span event definition in favor of log-based event.
+issues: [1440]

.chloggen/1548.yaml

@@ -0,0 +1,4 @@
+change_type: enhancement
+component: kestrel
+note: Add .NET 9 error reasons to Kestrel connection metric.
+issues: [1582]

docs/attributes-registry/feature-flag.md

@@ -6,21 +6,47 @@
 
 # Feature Flag
 
+- [Feature Flag Attributes](#feature-flag-attributes)
+- [Deprecated Feature Flag Attributes](#deprecated-feature-flag-attributes)
+
 ## Feature Flag Attributes
 
 This document defines attributes for Feature Flags.
 
 | Attribute | Type | Description | Examples | Stability |
 |---|---|---|---|---|
-| <a id="feature-flag-key" href="#feature-flag-key">`feature_flag.key`</a> | string | The unique identifier of the feature flag. | `logo-color` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
-| <a id="feature-flag-provider-name" href="#feature-flag-provider-name">`feature_flag.provider_name`</a> | string | The name of the service provider that performs the flag evaluation. | `Flag Manager` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
-| <a id="feature-flag-variant" href="#feature-flag-variant">`feature_flag.variant`</a> | string | SHOULD be a semantic identifier for a value. If one is unavailable, a stringified version of the value can be used. [1] | `red`; `true`; `on` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| <a id="feature-flag-context-id" href="#feature-flag-context-id">`feature_flag.context.id`</a> | string | The unique identifier for the flag evaluation context. For example, the targeting key. | `5157782b-2203-4c80-a857-dbbd5e7761db` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| <a id="feature-flag-evaluation-error-message" href="#feature-flag-evaluation-error-message">`feature_flag.evaluation.error.message`</a> | string | A message explaining the nature of an error occurring during flag evaluation. | `Flag `header-color` expected type `string` but found type `number`` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| <a id="feature-flag-evaluation-reason" href="#feature-flag-evaluation-reason">`feature_flag.evaluation.reason`</a> | string | The reason code which shows how a feature flag value was determined. | `static`; `targeting_match`; `error`; `default` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| <a id="feature-flag-key" href="#feature-flag-key">`feature_flag.key`</a> | string | The lookup key of the feature flag. | `logo-color` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| <a id="feature-flag-set-id" href="#feature-flag-set-id">`feature_flag.set.id`</a> | string | The identifier of the [flag set](https://openfeature.dev/specification/glossary/#flag-set) to which the feature flag belongs. | `proj-1`; `ab98sgs`; `service1/dev` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| <a id="feature-flag-system" href="#feature-flag-system">`feature_flag.system`</a> | string | Identifies the feature flag provider. | `Flag Manager` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| <a id="feature-flag-variant" href="#feature-flag-variant">`feature_flag.variant`</a> | string | A semantic identifier for an evaluated flag value. [1] | `red`; `true`; `on` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| <a id="feature-flag-version" href="#feature-flag-version">`feature_flag.version`</a> | string | The version of the ruleset used during the evaluation. This may be any stable value which uniquely identifies the ruleset. | `1`; `01ABCDEF` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
 
 **[1]:** A semantic identifier, commonly referred to as a variant, provides a means
 for referring to a value without including the value itself. This can
 provide additional context for understanding the meaning behind a value.
 For example, the variant `red` maybe be used for the value `#c05543`.
 
-A stringified version of the value can be used in situations where a
-semantic identifier is unavailable. String representation of the value
-should be determined by the implementer.
+`feature_flag.evaluation.reason` 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 |
+|---|---|---|
+| `cached` | The resolved value was retrieved from cache. | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| `default` | The resolved value fell back to a pre-configured value (no dynamic evaluation occurred or dynamic evaluation yielded no result). | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| `disabled` | The resolved value was the result of the flag being disabled in the management system. | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| `error` | The resolved value was the result of an error. | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| `split` | The resolved value was the result of pseudorandom assignment. | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| `stale` | The resolved value is non-authoritative or possibly out of date | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| `static` | The resolved value is static (no dynamic evaluation). | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| `targeting_match` | The resolved value was the result of a dynamic evaluation, such as a rule or specific user-targeting. | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| `unknown` | The reason for the resolved value could not be determined. | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+
+## Deprecated Feature Flag Attributes
+
+Describes deprecated Feature Flag attributes.
+
+| Attribute | Type | Description | Examples | Stability |
+|---|---|---|---|---|
+| <a id="feature-flag-provider-name" href="#feature-flag-provider-name">`feature_flag.provider_name`</a> | string | Deprecated, use `feature_flag.system` instead. | `Flag Manager` | ![Deprecated](https://img.shields.io/badge/-deprecated-red)<br>Replaced by `feature_flag.system`. |

docs/dotnet/dotnet-kestrel-metrics.md

@@ -138,7 +138,57 @@ of `[ 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 1, 2, 5, 10, 30, 60, 120, 300 ]`.
 | [`server.port`](/docs/attributes-registry/server.md) | int | Server port number. [7] | `80`; `8080`; `443` | `Recommended` | ![Stable](https://img.shields.io/badge/-stable-lightgreen) |
 | [`tls.protocol.version`](/docs/attributes-registry/tls.md) | string | Numeric part of the version parsed from the original string of the negotiated [SSL/TLS protocol version](https://www.openssl.org/docs/man1.1.1/man3/SSL_get_version.html#RETURN-VALUES) | `1.2`; `3` | `Recommended` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
 
-**[1]:** Captures the exception type when a connection fails.
+**[1]:** Starting from .NET 9, Kestrel `kestrel.connection.duration` metric reports
+the following errors types when a corresponding error occurs:
+
+| Value  | Description | Stability |
+|---|---|---|
+| `aborted_by_app` | The HTTP/1.1 connection was aborted when app code aborted an HTTP request with `HttpContext.Abort()`. |
+| `app_shutdown_timeout` | The connection was aborted during app shutdown. During shutdown, the server stops accepting new connections and HTTP requests, and it is given time for active requests to complete. If the app shutdown timeout is exceeded, all remaining connections are aborted. |
+| `closed_critical_stream` | A critical control stream for an HTTP/3 connection was closed. |
+| `connection_reset` | The connection was reset while there were active HTTP/2 or HTTP/3 streams on the connection. |
+| `error_after_starting_response` | An error such as an unhandled application exception or invalid request body occurred after the response was started, causing an abort of the HTTP/1.1 connection. |
+| `error_reading_headers` | An error occurred when decoding HPACK headers in an HTTP/2 `HEADERS` frame. |
+| `error_writing_headers` | An error occurred when encoding HPACK headers in an HTTP/2 `HEADERS` frame. |
+| `flow_control_queue_size_exceeded` | The connection exceeded the outgoing flow control maximum queue size and was closed with `INTERNAL_ERROR`. This can be caused by an excessive number of HTTP/2 stream resets. For more information, see [Microsoft Security Advisory CVE-2023-44487](https://github.com/dotnet/runtime/issues/93303). |
+| `flow_control_window_exceeded` | The client sent more data than allowed by the current flow-control window. |
+| `frame_after_stream_close` | An HTTP/2 frame was received on a closed stream. |
+| `insufficient_tls_version` | The connection doesn't have TLS 1.2 or greater, as required by HTTP/2. |
+| `invalid_body_reader_state` | An error occurred when draining the request body, aborting the HTTP/1.1 connection. This could be caused by app code reading the request body and missing a call to `PipeReader.AdvanceTo` in a finally block. |
+| `invalid_data_padding` | An HTTP/2 `HEADER` or `DATA` frame has an invalid amount of padding. |
+| `invalid_frame_length` | An HTTP/2 frame was received with an invalid frame payload length. The frame could contain a payload that is not valid for the type, or a `DATA` frame payload does not match the length specified in the frame header. |
+| `invalid_handshake` | An invalid HTTP/2 handshake was received. |
+| `invalid_http_version` | The connection received an HTTP request with the wrong version. For example, a browser sends an HTTP/1.1 request to a plain-text HTTP/2 connection. |
+| `invalid_request_headers` | The HTTP request contains invalid headers. This error can occur in a number of scenarios: a header might not be allowed by the HTTP protocol, such as a pseudo-header in the `HEADERS` frame of an HTTP/2 request. A header could also have an invalid value, such as a non-integer `content-length`, or a header name or value might contain invalid characters. |
+| `invalid_request_line` | The first line of an HTTP/1.1 request was invalid, potentially due to invalid content or exceeding the allowed limit. Configured by `KestrelServerLimits.MaxRequestLineSize`. |
+| `invalid_settings` | The connection received an HTTP/2 or HTTP/3 `SETTINGS` frame with invalid settings. |
+| `invalid_stream_id` | An HTTP/2 stream with an invalid stream ID was received. |
+| `invalid_window_update_size` | The server received an HTTP/2 `WINDOW_UPDATE` frame with a zero increment, or an increment that caused a flow-control window to exceed the maximum size. |
+| `io_error` | An `IOException` occurred while reading or writing HTTP/2 or HTTP/3 connection data. |
+| `keep_alive_timeout` | There was no activity on the connection, and the keep-alive timeout configured by `KestrelServerLimits.KeepAliveTimeout` was exceeded. |
+| `max_concurrent_connections_exceeded` | The connection exceeded the maximum concurrent connection limit. Configured by `KestrelServerLimits.MaxConcurrentConnections`. |
+| `max_frame_length_exceeded` | The connection received an HTTP/2 frame that exceeded the size limit specified by `Http2Limits.MaxFrameSize`. |
+| `max_request_body_size_exceeded` | The HTTP request body exceeded the maximum request body size limit. Configured by `KestrelServerLimits.MaxRequestBodySize`. |
+| `max_request_header_count_exceeded` | The HTTP request headers exceeded the maximum count limit. Configured by `KestrelServerLimits.MaxRequestHeaderCount`. |
+| `max_request_headers_total_size_exceeded` | The HTTP request headers exceeded the maximum total size limit. Configured by `KestrelServerLimits.MaxRequestHeadersTotalSize`. |
+| `min_request_body_data_rate` | Reading the request body timed out due to data arriving too slowly. Configured by `KestrelServerLimits.MinRequestBodyDataRate`. |
+| `min_response_data_rate` | Writing the response timed out because the client did not read it at the specified minimum data rate. Configured by `KestrelServerLimits.MinResponseDataRate`. |
+| `missing_stream_end` | The connection received an HTTP/2 `HEADERS` frame for trailers without a stream end flag. |
+| `output_queue_size_exceeded` | The connection exceeded the output queue size and was closed with `INTERNAL_ERROR`. This can be caused by an excessive number of HTTP/2 stream resets. For more information, see [Microsoft Security Advisory CVE-2023-44487](https://github.com/dotnet/runtime/issues/93303). |
+| `request_headers_timeout` | Request headers timed out while waiting for headers to be received after the request started. Configured by `KestrelServerLimits.RequestHeadersTimeout`. |
+| `response_content_length_mismatch` | The HTTP response body sent data that didn't match the response's `content-length` header. |
+| `server_timeout` | The connection timed out with the `IConnectionTimeoutFeature`. |
+| `stream_creation_error` | The HTTP/3 connection received a stream that it wouldn't accept. For example, the client created duplicate control streams. |
+| `stream_reset_limit_exceeded` | The connection received an excessive number of HTTP/2 stream resets and was closed with `ENHANCE_YOUR_CALM`. For more information, see [Microsoft Security Advisory CVE-2023-44487](https://github.com/dotnet/runtime/issues/93303). |
+| `stream_self_dependency` | The connection received an HTTP/2 frame that caused a frame to depend on itself. |
+| `tls_handshake_failed` | An error occurred during the TLS handshake for a connection. Only reported for HTTP/1.1 and HTTP/2 connections. The TLS handshake for HTTP/3 is internal to QUIC transport. | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| `tls_not_supported` | A TLS handshake was received by an endpoint that isn't configured to support TLS. |
+| `unexpected_end_of_request_content` | The HTTP/1.1 request body ended before the data specified by the `content-length` header or chunked transfer encoding mechanism was received. |
+| `unexpected_frame` | An unexpected HTTP/2 or HTTP/3 frame type was received. The frame type is either unknown, unsupported, or invalid for the current stream state. |
+| `unknown_stream` | An HTTP/2 frame was received on an unknown stream. |
+| `write_canceled` | The cancellation of a response body write aborted the HTTP/1.1 connection. |
+
+In other cases, `error.type` contains the fully qualified type name of the exception.
 
 **[2]:** The value SHOULD be normalized to lowercase.
 

docs/feature-flags/README.md

@@ -14,7 +14,6 @@ evaluations in spans and logs.
 
 Semantic conventions for feature flags are defined for the following signals:
 
-* [Feature Flags in Spans](feature-flags-spans.md): Semantic Conventions for recording feature flags in *spans*.
 * [Feature Flags in Logs](feature-flags-logs.md): Semantic Conventions for recording feature flags in *logs*.
 
 [DocumentStatus]: https://opentelemetry.io/docs/specs/otel/document-status