Use generic `error.message` in feature flag evaluation event (#1994)

Co-authored-by: Liudmila Molkova <limolkova@microsoft.com>

.chloggen/ff-generic-error.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: breaking
+
+# The name of the area of concern in the attributes-registry, (e.g. http, cloud, db)
+component: feature_flag
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Use generic `error.message` in feature flag evaluation event
+
+# 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: [1994]
+
+# (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/feature-flag.md

@@ -13,7 +13,6 @@ This document defines attributes for Feature Flags.
 | Attribute | Type | Description | Examples | Stability |
 |---|---|---|---|---|
 | <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` | ![Development](https://img.shields.io/badge/-development-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`` | ![Development](https://img.shields.io/badge/-development-blue) |
 | <a id="feature-flag-key" href="#feature-flag-key">`feature_flag.key`</a> | string | The lookup key of the feature flag. | `logo-color` | ![Development](https://img.shields.io/badge/-development-blue) |
 | <a id="feature-flag-provider-name" href="#feature-flag-provider-name">`feature_flag.provider_name`</a> | string | Identifies the feature flag provider. | `Flag Manager` | ![Development](https://img.shields.io/badge/-development-blue) |
 | <a id="feature-flag-result-reason" href="#feature-flag-result-reason">`feature_flag.result.reason`</a> | string | The reason code which shows how a feature flag value was determined. | `static`; `targeting_match`; `error`; `default` | ![Development](https://img.shields.io/badge/-development-blue) |
@@ -48,6 +47,7 @@ Describes deprecated feature flag attributes.
 
 | Attribute | Type | Description | Examples | Stability |
 |---|---|---|---|---|
+| <a id="feature-flag-evaluation-error-message" href="#feature-flag-evaluation-error-message">`feature_flag.evaluation.error.message`</a> | string | Deprecated, use `error.message` instead. | `Flag `header-color` expected type `string` but found type `number`` | ![Deprecated](https://img.shields.io/badge/-deprecated-red)<br>Replaced by `error.message`. |
 | <a id="feature-flag-evaluation-reason" href="#feature-flag-evaluation-reason">`feature_flag.evaluation.reason`</a> | string | Deprecated, use `feature_flag.result.reason` instead. | `static`; `targeting_match`; `error`; `default` | ![Deprecated](https://img.shields.io/badge/-deprecated-red)<br>Replaced by `feature_flag.result.reason`. |
 | <a id="feature-flag-variant" href="#feature-flag-variant">`feature_flag.variant`</a> | string | Deprecated, use `feature_flag.result.variant` instead. | `red`; `true`; `on` | ![Deprecated](https://img.shields.io/badge/-deprecated-red)<br>Replaced by `feature_flag.result.variant`. |
 

docs/feature-flags/feature-flags-logs.md

@@ -61,8 +61,8 @@ A `feature_flag.evaluation` event SHOULD be emitted whenever a feature flag valu
 | [`feature_flag.key`](/docs/attributes-registry/feature-flag.md) | string | The lookup key of the feature flag. | `logo-color` | `Required` | ![Development](https://img.shields.io/badge/-development-blue) |
 | [`error.type`](/docs/attributes-registry/error.md) | string | Describes a class of error the operation ended with. [1] | `provider_not_ready`; `targeting_key_missing`; `provider_fatal`; `general` | `Conditionally Required` [2] | ![Stable](https://img.shields.io/badge/-stable-lightgreen) |
 | [`feature_flag.result.variant`](/docs/attributes-registry/feature-flag.md) | string | A semantic identifier for an evaluated flag value. [3] | `red`; `true`; `on` | `Conditionally Required` [4] | ![Development](https://img.shields.io/badge/-development-blue) |
+| [`error.message`](/docs/attributes-registry/error.md) | string | A message providing more detail about an error in human-readable form. [5] | `Unexpected input type: string`; `The user has exceeded their storage quota` | `Recommended` [6] | ![Development](https://img.shields.io/badge/-development-blue) |
 | [`feature_flag.context.id`](/docs/attributes-registry/feature-flag.md) | string | The unique identifier for the flag evaluation context. For example, the targeting key. | `5157782b-2203-4c80-a857-dbbd5e7761db` | `Recommended` | ![Development](https://img.shields.io/badge/-development-blue) |
-| [`feature_flag.evaluation.error.message`](/docs/attributes-registry/feature-flag.md) | string | A message explaining the nature of an error occurring during flag evaluation. | `Flag `header-color` expected type `string` but found type `number`` | `Recommended` [5] | ![Development](https://img.shields.io/badge/-development-blue) |
 | [`feature_flag.provider_name`](/docs/attributes-registry/feature-flag.md) | string | Identifies the feature flag provider. | `Flag Manager` | `Recommended` | ![Development](https://img.shields.io/badge/-development-blue) |
 | [`feature_flag.result.reason`](/docs/attributes-registry/feature-flag.md) | string | The reason code which shows how a feature flag value was determined. | `static`; `targeting_match`; `error`; `default` | `Recommended` | ![Development](https://img.shields.io/badge/-development-blue) |
 | [`feature_flag.set.id`](/docs/attributes-registry/feature-flag.md) | 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` | `Recommended` | ![Development](https://img.shields.io/badge/-development-blue) |
@@ -90,7 +90,9 @@ For example, the variant `red` maybe be used for the value `#c05543`.
 
 **[4] `feature_flag.result.variant`:** If feature flag provider supplies a variant or equivalent concept.
 
-**[5] `feature_flag.evaluation.error.message`:** If and only if an error occurred. It's NOT RECOMMENDED to duplicate the value of `error.type` in `feature_flag.evaluation.error.message`.
+**[5] `error.message`:** Should not simply duplicate the value of `error.type`, but should provide more context. For example, if `error.type` is `invalid_context` the `error.message` may enumerate which context keys are missing or invalid.
+
+**[6] `error.message`:** If and only if an error occurred during flag evaluation and `error.type` does not sufficiently describe the error.
 
 ---
 

model/feature-flags/deprecated/registry-deprecated.yaml

@@ -53,3 +53,9 @@ groups:
         stability: development
         deprecated: "Replaced by `feature_flag.result.variant`."
         examples: ["red", "true", "on"]
+      - id: feature_flag.evaluation.error.message
+        type: string
+        brief: 'Deprecated, use `error.message` instead.'
+        stability: development
+        deprecated: "Replaced by `error.message`."
+        examples: ["Flag `header-color` expected type `string` but found type `number`"]

model/feature-flags/events.yaml

@@ -46,9 +46,12 @@ groups:
           | `targeting_key_missing` | The provider requires a targeting key and one was not provided in the evaluation context. | ![Development](https://img.shields.io/badge/-development-blue) |
           | `type_mismatch` | The type of the flag value does not match the expected type. | ![Development](https://img.shields.io/badge/-development-blue) |
           | `general` | The error was for a reason not enumerated above. | ![Development](https://img.shields.io/badge/-development-blue) |
-      - ref: feature_flag.evaluation.error.message
+      - ref: error.message
         requirement_level:
-          recommended: If and only if an error occurred. It's NOT RECOMMENDED to duplicate the value of `error.type` in `feature_flag.evaluation.error.message`.
+          recommended: If and only if an error occurred during flag evaluation and `error.type` does not sufficiently describe the error.
+        note: >
+          Should not simply duplicate the value of `error.type`, but should provide more context.
+          For example, if `error.type` is `invalid_context` the `error.message` may enumerate which context keys are missing or invalid.
     body:
       id: feature_flag.evaluation
       type: map

model/feature-flags/registry.yaml

@@ -88,8 +88,3 @@ groups:
         examples: ["static", "targeting_match", "error", "default"]
         brief: >
           The reason code which shows how a feature flag value was determined.
-      - id: feature_flag.evaluation.error.message
-        type: string
-        stability: development
-        examples: ["Flag `header-color` expected type `string` but found type `number`"]
-        brief: A message explaining the nature of an error occurring during flag evaluation.

schema-next.yaml

@@ -2,6 +2,12 @@ file_format: 1.1.0
 schema_url: https://opentelemetry.io/schemas/1.31.0
 versions:
   next:
+    all:
+      changes:
+        # https://github.com/open-telemetry/semantic-conventions/pull/1994
+        - rename_attributes:
+            attribute_map:
+              feature_flag.evaluation.error.message: error.message
   1.32.0:
     all:
       changes: