Deprecate Zipkin exporter

CHANGELOG.md

@@ -11,6 +11,9 @@ release.
 
 ### Traces
 
+- Deprecate Zipkin exporter document and make exporter implementation optional.
+  ([#4715](https://github.com/open-telemetry/opentelemetry-specification/pull/4715/))
+
 ### Metrics
 
 ### Logs

spec-compliance-matrix.md

@@ -334,8 +334,8 @@ Disclaimer: Declarative configuration is currently in Development status - work
 | **[Zipkin](specification/trace/sdk_exporters/zipkin.md)** | Optional | Go | Java | JS | Python | Ruby | Erlang | PHP | Rust | C++ | .NET | Swift |
 | Zipkin V1 JSON | X | - | + |  | + | - | - | - | - | - | - | - |
 | Zipkin V1 Thrift | X | - | + |  | [-][py1174] | - | - | - | - | - | - | - |
-| Zipkin V2 JSON | * | + | + |  | + | + | - | + | + | + | + | + |
-| Zipkin V2 Protobuf | * | - | + |  | + | - | + | - | - | - | - | - |
+| Zipkin V2 JSON | X | + | + |  | + | + | - | + | + | + | + | + |
+| Zipkin V2 Protobuf | X | - | + |  | + | - | + | - | - | - | - | - |
 | Service name mapping |  | + | + | + | + | + | + | + | + | + | + | + |
 | SpanKind mapping |  | + | + | + | + | + | + | + | + | + | + | + |
 | InstrumentationLibrary mapping |  | + | + | - | + | + | - | + | + | + | + | + |

spec-compliance-matrix/template.yaml

@@ -375,9 +375,9 @@ sections:
           - name: Zipkin V1 Thrift
             optional: true
           - name: Zipkin V2 JSON
-            optional_one_of_group_is_required: true
+            optional: true
           - name: Zipkin V2 Protobuf
-            optional_one_of_group_is_required: true
+            optional: true
           - name: Service name mapping
           - name: SpanKind mapping
           - name: InstrumentationLibrary mapping

specification/configuration/sdk-environment-variables.md

@@ -15,32 +15,33 @@ aliases:
 
 <!-- toc -->
 
-- [Implementation guidelines](#implementation-guidelines)
-- [Parsing empty value](#parsing-empty-value)
-- [Configuration types](#configuration-types)
-  * [Boolean](#boolean)
-  * [Numeric](#numeric)
-    + [Integer](#integer)
-    + [Duration](#duration)
-    + [Timeout](#timeout)
-  * [String](#string)
-    + [Enum](#enum)
-- [General SDK Configuration](#general-sdk-configuration)
-- [Batch Span Processor](#batch-span-processor)
-- [Batch LogRecord Processor](#batch-logrecord-processor)
-- [Attribute Limits](#attribute-limits)
-- [Span Limits](#span-limits)
-- [LogRecord Limits](#logrecord-limits)
-- [OTLP Exporter](#otlp-exporter)
-- [Zipkin Exporter](#zipkin-exporter)
-- [Prometheus Exporter](#prometheus-exporter)
-- [Exporter Selection](#exporter-selection)
-  * [In-development Exporter Selection](#in-development-exporter-selection)
-- [Metrics SDK Configuration](#metrics-sdk-configuration)
-  * [Exemplar](#exemplar)
-  * [Periodic exporting MetricReader](#periodic-exporting-metricreader)
-- [Declarative configuration](#declarative-configuration)
-- [Language Specific Environment Variables](#language-specific-environment-variables)
+- [OpenTelemetry Environment Variable Specification](#opentelemetry-environment-variable-specification)
+  - [Implementation guidelines](#implementation-guidelines)
+  - [Parsing empty value](#parsing-empty-value)
+  - [Configuration types](#configuration-types)
+    - [Boolean](#boolean)
+    - [Numeric](#numeric)
+      - [Integer](#integer)
+      - [Duration](#duration)
+      - [Timeout](#timeout)
+    - [String](#string)
+      - [Enum](#enum)
+  - [General SDK Configuration](#general-sdk-configuration)
+  - [Batch Span Processor](#batch-span-processor)
+  - [Batch LogRecord Processor](#batch-logrecord-processor)
+  - [Attribute Limits](#attribute-limits)
+  - [Span Limits](#span-limits)
+  - [LogRecord Limits](#logrecord-limits)
+  - [OTLP Exporter](#otlp-exporter)
+  - [Zipkin Exporter](#zipkin-exporter)
+  - [Prometheus Exporter](#prometheus-exporter)
+  - [Exporter Selection](#exporter-selection)
+    - [In-development Exporter Selection](#in-development-exporter-selection)
+  - [Metrics SDK Configuration](#metrics-sdk-configuration)
+    - [Exemplar](#exemplar)
+    - [Periodic exporting MetricReader](#periodic-exporting-metricreader)
+  - [Declarative configuration](#declarative-configuration)
+  - [Language Specific Environment Variables](#language-specific-environment-variables)
 
 <!-- tocstop -->
 
@@ -270,6 +271,8 @@ See [OpenTelemetry Protocol Exporter Configuration Options](../protocol/exporter
 
 ## Zipkin Exporter
 
+**Status**: [Deprecated](../document-status.md)
+
 | Name                          | Description                                                                        | Default                              | Type        |
 |-------------------------------|------------------------------------------------------------------------------------|--------------------------------------|-------------|
 | OTEL_EXPORTER_ZIPKIN_ENDPOINT | Endpoint for Zipkin traces                                                         | `http://localhost:9411/api/v2/spans` | [String][]  |

specification/trace/sdk_exporters/zipkin.md

@@ -4,7 +4,14 @@ linkTitle: Zipkin
 
 # OpenTelemetry to Zipkin Transformation
 
-**Status**: [Stable](../../document-status.md)
+**Status**: [Deprecated](../../document-status.md)
+
+> Note: This document remains here for backwards compatibility and
+> will be removed in a future version. SDKs MAY include Zipkin exporters,
+> but Zipkin exporter is not required.
+>
+> Users may export to Zipkin using [zipkin exporter](https://github.com/open-telemetry/opentelemetry-collector->contrib/tree/main/exporter/zipkinexporter) collector component or [zipkin-otel](https://github.com/openzipkin-contrib/zipkin-otel)
+> Zipkin server module.
 
 This document defines the transformation between OpenTelemetry and Zipkin Spans.
 The generic transformation [rules specified here](../../common/mapping-to-non-otlp.md) also apply. If a
@@ -69,7 +76,7 @@ not work properly. OpenTelemetry doesn't provide this consistency guarantee.
 Exporter may chose to override the value for service name based on a local root
 span to improve Zipkin user experience.
 
-*Note*, the attribute `service.namespace` MUST NOT be used for the Zipkin
+Note that the attribute `service.namespace` MUST NOT be used for the Zipkin
 service name and should be sent as a Zipkin tag.
 
 ### SpanKind