Clarify metrics SDK limits handling (open-telemetry#2007)

* Clarify metrics SDK limits handling * fix link * Update specification/metrics/sdk.md Co-authored-by: Armin Ruech <[email protected]> * Update specification/metrics/sdk.md Co-authored-by: Armin Ruech <[email protected]> * Apply suggestions from code review Co-authored-by: Armin Ruech <[email protected]> * lowercase * update changelog Co-authored-by: Armin Ruech <[email protected]>
carlosalberto · Oct 15, 2021 · 79cee63 · 79cee63
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -17,6 +17,8 @@ release.
   ([#1915](https://github.com/open-telemetry/opentelemetry-specification/pull/1915))
 - Add exponential histogram to the metrics data model.
   ([#1935](https://github.com/open-telemetry/opentelemetry-specification/pull/1935))
+- Add clarifications on how to handle numerical limits.
+  ([#2007](https://github.com/open-telemetry/opentelemetry-specification/pull/2007))
 
 ### Logs
 

diff --git a/specification/metrics/sdk.md b/specification/metrics/sdk.md
@@ -19,6 +19,7 @@ Table of Contents
   * [Push Metric Exporter](#push-metric-exporter)
   * [Pull Metric Exporter](#pull-metric-exporter)
 * [Defaults and configuration](#defaults-and-configuration)
+* [Numerical limits handling](#numerical-limits-handling)
 * [Compatibility requirements](#compatibility-requirements)
 * [Concurrency requirements](#concurrency-requirements)
 
@@ -775,6 +776,24 @@ modeled to interact with other components in the SDK:
 The SDK MUST provide configuration according to the [SDK environment
 variables](../sdk-environment-variables.md) specification.
 
+## Numerical limits handling
+
+The SDK MUST handle numerical limits in a graceful way according to [Error
+handling in OpenTelemetry](../error-handling.md).
+
+If the SDK receives float/double values from [Instruments](./api.md#instrument),
+it MUST handle all the possible values. For example, if the language runtime
+supports [IEEE 754](https://en.wikipedia.org/wiki/IEEE_754), the SDK needs to
+handle NaNs and Infinites.
+
+It is unspecified _how_ the SDK should handle the input limits. The SDK authors
+MAY leverage/follow the language runtime behavior for better performance, rather
+than perform a check on each value coming from the API.
+
+It is unspecified _how_ the SDK should handle the output limits (e.g. integer
+overflow). The SDK authors MAY rely on the language runtime behavior as long as
+errors/exceptions are taken care of.
+
 ## Compatibility requirements
 
 All the metrics components SHOULD allow new methods to be added to existing