Optionally trim attribute keys & values?

[fbogsany]

Related to open-telemetry/opentelemetry-specification#504

Java provides optional attribute value truncation: https://github.com/open-telemetry/opentelemetry-java/blob/a021a59b9433691c06ab2265b4c574eab825b0ed/sdk/tracing/src/main/java/io/opentelemetry/sdk/trace/SpanBuilderSdk.java#L195-L197

    if (traceConfig.shouldTruncateStringAttributeValues()) {
      value = StringUtils.truncateToSize(value, traceConfig.getMaxLengthOfAttributeValues());
    }

We have some ad-hoc truncation and UTF8 validation in the Redis instrumentation, for example:

opentelemetry-ruby/instrumentation/redis/lib/opentelemetry/instrumentation/redis/utils.rb

Lines 60 to 80 in 1a680bb

	def truncate(string, size)
	string.size > size ? "#{string[0...size - 3]}..." : string
	end
	def utf8_encode(str, options = {})
	str = str.to_s
	if options[:binary]
	# This option is useful for "gracefully" displaying binary data that
	# often contains text such as marshalled objects
	str.encode('UTF-8', 'binary', invalid: :replace, undef: :replace, replace: '')
	elsif str.encoding == ::Encoding::UTF_8
	str
	else
	str.encode(::Encoding::UTF_8)
	end
	rescue StandardError => e
	OpenTelemetry.logger.debug("Error encoding string in UTF-8: #{e}")
	options.fetch(:placeholder, STRING_PLACEHOLDER)
	end

It is likely worth extracting this into a common utility module, and implementing attribute truncation in a single place with a configurable limit (most likely in the SDK Span class).

[plantfansam]

I believe this issue has been addressed. Should we close or is there more to do here?

[fbogsany]

I think #1136 is relevant here.

[github-actions]

👋 This issue has been marked as stale because it has been open with no activity. You can: comment on the issue or remove the stale label to hold stale off for a while, add the keep label to hold stale off permanently, or do nothing. If you do nothing this issue will be closed eventually by the stale bot.