Change rpc.*.duration unit from ms to sec, clarify duration in case of streaming

.chloggen/rpc-duration-seconds.yaml

@@ -0,0 +1,6 @@
+change_type: breaking
+component: rpc
+note: Rename `rpc.client|server.duration` to `rpc.client|server.call.duration`,
+      change RPC duration metrics from milliseconds to seconds,
+      and clarify metric and span duration semantics for streaming.
+issues: [383, 2961]

docs/rpc/connect-rpc.md

@@ -12,7 +12,7 @@ described on this page.
 
 ## Client Span
 
-<!-- semconv span.rpc.connect_rpc.client -->
+<!-- semconv span.rpc.connect_rpc.call.client -->
 <!-- NOTE: THIS TEXT IS AUTOGENERATED. DO NOT EDIT BY HAND. -->
 <!-- see templates/registry/markdown/snippet.md.j2 -->
 <!-- prettier-ignore-start -->
@@ -163,7 +163,7 @@ the `rpc.connect_rpc.response.metadata.my-custom-key` attribute with value `["at
 
 ## Server Span
 
-<!-- semconv span.rpc.connect_rpc.server -->
+<!-- semconv span.rpc.connect_rpc.call.server -->
 <!-- NOTE: THIS TEXT IS AUTOGENERATED. DO NOT EDIT BY HAND. -->
 <!-- see templates/registry/markdown/snippet.md.j2 -->
 <!-- prettier-ignore-start -->

docs/rpc/grpc.md

@@ -12,7 +12,7 @@ described on this page.
 
 ## Client Span
 
-<!-- semconv span.rpc.grpc.client -->
+<!-- semconv span.rpc.grpc.call.client -->
 <!-- NOTE: THIS TEXT IS AUTOGENERATED. DO NOT EDIT BY HAND. -->
 <!-- see templates/registry/markdown/snippet.md.j2 -->
 <!-- prettier-ignore-start -->
@@ -164,7 +164,7 @@ the `rpc.grpc.response.metadata.my-custom-key` attribute with value `["attribute
 
 ## Server Span
 
-<!-- semconv span.rpc.grpc.server -->
+<!-- semconv span.rpc.grpc.call.server -->
 <!-- NOTE: THIS TEXT IS AUTOGENERATED. DO NOT EDIT BY HAND. -->
 <!-- see templates/registry/markdown/snippet.md.j2 -->
 <!-- prettier-ignore-start -->

docs/rpc/json-rpc.md

@@ -12,7 +12,7 @@ described on this page.
 
 ## Client Span
 
-<!-- semconv span.rpc.jsonrpc.client -->
+<!-- semconv span.rpc.jsonrpc.call.client -->
 <!-- NOTE: THIS TEXT IS AUTOGENERATED. DO NOT EDIT BY HAND. -->
 <!-- see templates/registry/markdown/snippet.md.j2 -->
 <!-- prettier-ignore-start -->
@@ -126,7 +126,7 @@ different processes could be listening on TCP port 12345 and UDP port 12345.
 
 ## Server Span
 
-<!-- semconv span.rpc.jsonrpc.server -->
+<!-- semconv span.rpc.jsonrpc.call.server -->
 <!-- NOTE: THIS TEXT IS AUTOGENERATED. DO NOT EDIT BY HAND. -->
 <!-- see templates/registry/markdown/snippet.md.j2 -->
 <!-- prettier-ignore-start -->

docs/rpc/rpc-metrics.md

@@ -16,11 +16,11 @@ metrics can be filtered for finer grain analysis.
 
 - [Metric instruments](#metric-instruments)
   - [RPC server](#rpc-server)
-    - [Metric: `rpc.server.duration`](#metric-rpcserverduration)
+    - [Metric: `rpc.server.call.duration`](#metric-rpcservercallduration)
     - [Metric: `rpc.server.request.size`](#metric-rpcserverrequestsize)
     - [Metric: `rpc.server.response.size`](#metric-rpcserverresponsesize)
   - [RPC client](#rpc-client)
-    - [Metric: `rpc.client.duration`](#metric-rpcclientduration)
+    - [Metric: `rpc.client.call.duration`](#metric-rpcclientcallduration)
     - [Metric: `rpc.client.request.size`](#metric-rpcclientrequestsize)
     - [Metric: `rpc.client.response.size`](#metric-rpcclientresponsesize)
 - [Semantic Conventions for specific RPC technologies](#semantic-conventions-for-specific-rpc-technologies)
@@ -63,11 +63,15 @@ MUST be of the specified type and units.
 
 Below is a list of RPC server metric instruments.
 
-#### Metric: `rpc.server.duration`
+#### Metric: `rpc.server.call.duration`
 
 This metric is [recommended][MetricRecommended].
 
-<!-- semconv metric.rpc.server.duration -->
+This metric SHOULD be specified with
+[`ExplicitBucketBoundaries`](https://github.com/open-telemetry/opentelemetry-specification/blob/v1.50.0/specification/metrics/api.md#instrument-advisory-parameters)
+of `[ 0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, 1, 2.5, 5, 7.5, 10 ]`.
+
+<!-- semconv metric.rpc.server.call.duration -->
 <!-- NOTE: THIS TEXT IS AUTOGENERATED. DO NOT EDIT BY HAND. -->
 <!-- see templates/registry/markdown/snippet.md.j2 -->
 <!-- prettier-ignore-start -->
@@ -76,12 +80,10 @@ This metric is [recommended][MetricRecommended].
 
 | Name     | Instrument Type | Unit (UCUM) | Description    | Stability | Entity Associations |
 | -------- | --------------- | ----------- | -------------- | --------- | ------ |
-| `rpc.server.duration` | Histogram | `ms` | Measures the duration of inbound RPC. [1] | ![Development](https://img.shields.io/badge/-development-blue) |  |
-
-**[1]:** While streaming RPCs may record this metric as start-of-batch
-to end-of-batch, it's hard to interpret in practice.
+| `rpc.server.call.duration` | Histogram | `s` | Measures the duration of inbound remote procedure calls (RPC). [1] | ![Development](https://img.shields.io/badge/-development-blue) |  |
 
-**Streaming**: N/A.
+**[1]:** When this metric is reported alongside an RPC server span, the metric value
+SHOULD be the same as the RPC server span duration.
 
 **Attributes:**
 
@@ -369,13 +371,16 @@ different processes could be listening on TCP port 12345 and UDP port 12345.
 ### RPC client
 
 Below is a list of RPC client metric instruments.
-These apply to traditional RPC usage, not streaming RPCs.
 
-#### Metric: `rpc.client.duration`
+#### Metric: `rpc.client.call.duration`
 
 This metric is [recommended][MetricRecommended].
 
-<!-- semconv metric.rpc.client.duration -->
+This metric SHOULD be specified with
+[`ExplicitBucketBoundaries`](https://github.com/open-telemetry/opentelemetry-specification/blob/v1.50.0/specification/metrics/api.md#instrument-advisory-parameters)
+of `[ 0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, 1, 2.5, 5, 7.5, 10 ]`.
+
+<!-- semconv metric.rpc.client.call.duration -->
 <!-- NOTE: THIS TEXT IS AUTOGENERATED. DO NOT EDIT BY HAND. -->
 <!-- see templates/registry/markdown/snippet.md.j2 -->
 <!-- prettier-ignore-start -->
@@ -384,12 +389,10 @@ This metric is [recommended][MetricRecommended].
 
 | Name     | Instrument Type | Unit (UCUM) | Description    | Stability | Entity Associations |
 | -------- | --------------- | ----------- | -------------- | --------- | ------ |
-| `rpc.client.duration` | Histogram | `ms` | Measures the duration of outbound RPC. [1] | ![Development](https://img.shields.io/badge/-development-blue) |  |
-
-**[1]:** While streaming RPCs may record this metric as start-of-batch
-to end-of-batch, it's hard to interpret in practice.
+| `rpc.client.call.duration` | Histogram | `s` | Measures the duration of outbound remote procedure calls (RPC). [1] | ![Development](https://img.shields.io/badge/-development-blue) |  |
 
-**Streaming**: N/A.
+**[1]:** When this metric is reported alongside an RPC client span, the metric value
+SHOULD be the same as the RPC client span duration.
 
 **Attributes:**
 

docs/rpc/rpc-spans.md

@@ -86,7 +86,7 @@ Generally, a user SHOULD NOT set `peer.service` to a fully qualified RPC service
 
 ### RPC client span
 
-<!-- semconv span.rpc.client -->
+<!-- semconv span.rpc.call.client -->
 <!-- NOTE: THIS TEXT IS AUTOGENERATED. DO NOT EDIT BY HAND. -->
 <!-- see templates/registry/markdown/snippet.md.j2 -->
 <!-- prettier-ignore-start -->
@@ -97,6 +97,16 @@ Generally, a user SHOULD NOT set `peer.service` to a fully qualified RPC service
 
 This span represents an outgoing Remote Procedure Call (RPC).
 
+RPC client spans SHOULD cover the entire client-side lifecycle of an RPC,
+starting when the RPC is initiated and ending when the response is received
+or the RPC is terminated due to an error or cancellation.
+
+For streaming RPCs, the span covers the full lifetime of the request and/or
+response streams until they are closed or terminated.
+
+If a transient issue happened and was retried within this RPC, the corresponding
+span SHOULD cover the duration of the logical call with all retries.
+
 **Span name:** refer to the [Span Name](/docs/rpc/rpc-spans.md#span-name) section.
 
 **Span kind** MUST be `CLIENT`.
@@ -212,7 +222,7 @@ different processes could be listening on TCP port 12345 and UDP port 12345.
 
 ### RPC server span
 
-<!-- semconv span.rpc.server -->
+<!-- semconv span.rpc.call.server -->
 <!-- NOTE: THIS TEXT IS AUTOGENERATED. DO NOT EDIT BY HAND. -->
 <!-- see templates/registry/markdown/snippet.md.j2 -->
 <!-- prettier-ignore-start -->
@@ -223,6 +233,13 @@ different processes could be listening on TCP port 12345 and UDP port 12345.
 
 This span represents an incoming Remote Procedure Call (RPC).
 
+RPC server spans SHOULD cover the entire server-side lifecycle of an RPC,
+starting when the request is received and ending when the response is sent
+or the RPC is terminated due to an error or cancellation.
+
+For streaming RPCs, the span SHOULD cover the full lifetime of the request
+and/or response streams until they are closed or terminated.
+
 **Span name:** refer to the [Span Name](/docs/rpc/rpc-spans.md#span-name) section.
 
 **Span kind** MUST be `SERVER`.

model/rpc/deprecated/metrics-deprecated.yaml

@@ -74,3 +74,43 @@ groups:
     deprecated:
       reason: obsoleted
       note: Removed, no replacement at this time.
+
+  - id: metric.rpc.server.duration
+    type: metric
+    metric_name: rpc.server.duration
+    annotations:
+      code_generation:
+        metric_value_type: double
+    stability: development
+    instrument: histogram
+    unit: "ms"
+    note: |
+      While streaming RPCs may record this metric as start-of-batch
+      to end-of-batch, it's hard to interpret in practice.
+
+      **Streaming**: N/A.
+    extends: attributes.metrics.rpc.server
+    deprecated:
+      reason: uncategorized
+      note: Replaced by `rpc.server.call.duration` with unit `s`.
+    brief: "Deprecated, use `rpc.server.call.duration` instead. Note: the unit also changed from `ms` to `s`."
+
+  - id: metric.rpc.client.duration
+    type: metric
+    metric_name: rpc.client.duration
+    annotations:
+      code_generation:
+        metric_value_type: double
+    stability: development
+    instrument: histogram
+    unit: "ms"
+    note: |
+      While streaming RPCs may record this metric as start-of-batch
+      to end-of-batch, it's hard to interpret in practice.
+
+      **Streaming**: N/A.
+    extends: attributes.metrics.rpc.client
+    deprecated:
+      reason: uncategorized
+      note: Replaced by `rpc.client.call.duration` with unit `s`.
+    brief: "Deprecated, use `rpc.client.call.duration` instead. Note: the unit also changed from `ms` to `s`."

model/rpc/metrics.yaml

@@ -1,20 +1,19 @@
 groups:
   # RPC Server metrics
-  - id: metric.rpc.server.duration
+  - id: metric.rpc.server.call.duration
     type: metric
-    metric_name: rpc.server.duration
+    metric_name: rpc.server.call.duration
     annotations:
       code_generation:
         metric_value_type: double
     stability: development
-    brief: Measures the duration of inbound RPC.
+    brief: Measures the duration of inbound remote procedure calls (RPC).
     instrument: histogram
-    unit: "ms"
+    unit: "s"
     note: |
-      While streaming RPCs may record this metric as start-of-batch
-      to end-of-batch, it's hard to interpret in practice.
+      When this metric is reported alongside an RPC server span, the metric value
+      SHOULD be the same as the RPC server span duration.
 
-      **Streaming**: N/A.
     extends: attributes.metrics.rpc.server
 
   - id: metric.rpc.server.request.size
@@ -47,21 +46,19 @@ groups:
 
 
   # RPC Client metrics
-  - id: metric.rpc.client.duration
+  - id: metric.rpc.client.call.duration
     type: metric
-    metric_name: rpc.client.duration
+    metric_name: rpc.client.call.duration
     annotations:
       code_generation:
         metric_value_type: double
     stability: development
-    brief: Measures the duration of outbound RPC.
+    brief: Measures the duration of outbound remote procedure calls (RPC).
     instrument: histogram
-    unit: "ms"
+    unit: "s"
     note: |
-      While streaming RPCs may record this metric as start-of-batch
-      to end-of-batch, it's hard to interpret in practice.
-
-      **Streaming**: N/A.
+      When this metric is reported alongside an RPC client span, the metric value
+      SHOULD be the same as the RPC client span duration.
     extends: attributes.metrics.rpc.client
 
   - id: metric.rpc.client.request.size

model/rpc/spans.yaml

@@ -1,9 +1,19 @@
 groups:
-  - id: span.rpc.client
+  - id: span.rpc.call.client
     type: span
     stability: development
     brief: This span represents an outgoing Remote Procedure Call (RPC).
     note: |
+      RPC client spans SHOULD cover the entire client-side lifecycle of an RPC,
+      starting when the RPC is initiated and ending when the response is received
+      or the RPC is terminated due to an error or cancellation.
+
+      For streaming RPCs, the span covers the full lifetime of the request and/or
+      response streams until they are closed or terminated.
+
+      If a transient issue happened and was retried within this RPC, the corresponding
+      span SHOULD cover the duration of the logical call with all retries.
+
       **Span name:** refer to the [Span Name](/docs/rpc/rpc-spans.md#span-name) section.
 
       **Span kind** MUST be `CLIENT`.
@@ -14,22 +24,29 @@ groups:
       - ref: rpc.system
         requirement_level: required
 
-  - id: span.rpc.server
+  - id: span.rpc.call.server
     type: span
     stability: development
     extends: rpc_service.server
     span_kind: server
     brief: This span represents an incoming Remote Procedure Call (RPC).
     events: [rpc.message]
     note: |
+      RPC server spans SHOULD cover the entire server-side lifecycle of an RPC,
+      starting when the request is received and ending when the response is sent
+      or the RPC is terminated due to an error or cancellation.
+
+      For streaming RPCs, the span SHOULD cover the full lifetime of the request
+      and/or response streams until they are closed or terminated.
+
       **Span name:** refer to the [Span Name](/docs/rpc/rpc-spans.md#span-name) section.
 
       **Span kind** MUST be `SERVER`.
     attributes:
       - ref: rpc.system
         requirement_level: required
 
-  - id: span.rpc.connect_rpc.client
+  - id: span.rpc.connect_rpc.call.client
     type: span
     stability: development
     brief: This span represents an outgoing Remote Procedure Call (RPC).
@@ -50,7 +67,7 @@ groups:
       - ref: rpc.connect_rpc.response.metadata
         requirement_level: opt_in
 
-  - id: span.rpc.connect_rpc.server
+  - id: span.rpc.connect_rpc.call.server
     type: span
     stability: development
     extends: rpc_service.server
@@ -71,7 +88,7 @@ groups:
       - ref: rpc.connect_rpc.response.metadata
         requirement_level: opt_in
 
-  - id: span.rpc.grpc.client
+  - id: span.rpc.grpc.call.client
     type: span
     stability: development
     brief: This span represents an outgoing Remote Procedure Call (RPC).
@@ -97,7 +114,7 @@ groups:
       - ref: rpc.grpc.response.metadata
         requirement_level: opt_in
 
-  - id: span.rpc.grpc.server
+  - id: span.rpc.grpc.call.server
     type: span
     stability: development
     extends: rpc_service.server
@@ -119,7 +136,7 @@ groups:
       - ref: rpc.grpc.response.metadata
         requirement_level: opt_in
 
-  - id: span.rpc.jsonrpc.client
+  - id: span.rpc.jsonrpc.call.client
     type: span
     stability: development
     brief: This span represents an outgoing Remote Procedure Call (RPC).
@@ -145,7 +162,7 @@ groups:
       - ref: rpc.jsonrpc.error_message
         requirement_level: recommended
 
-  - id: span.rpc.jsonrpc.server
+  - id: span.rpc.jsonrpc.call.server
     type: span
     stability: development
     extends: rpc.server