Log severity numbers will be wrong once opentelemetry-exporter-otlp-logs ships opentelemetry-ruby#2434 #116

Summary

scout_apm_logging translates Ruby Logger severities into OTLP severity numbers by patching OpenTelemetry::Exporter::OTLP::Logs::LogsExporter#as_otlp_log_record, in lib/scout_apm/logging/loggers/opentelemetry/log_record_patch.rb.

open-telemetry/opentelemetry-ruby#2434 removes that method from LogsExporter. It was merged on 2026-10-07 but isn't released yet; the latest opentelemetry-exporter-otlp-logs is 0.6.0. The PR moves log encoding into OpenTelemetry::Exporter::OTLP::Common.as_encoded_elsr, which has its own as_otlp_log_record. Once a release includes it, Scout's patch will never be called. The gemspec allows opentelemetry-exporter-otlp-logs >= 0.2.0, so apps will pick that release up on a routine bundle update.

Effect

Formatter#emit_log passes severity_number: ::Logger::Severity.const_get(severity), which is Ruby's Logger numbering. Without the patch, the exporter sends those numbers unchanged, and OTLP reads them as different levels:

severity_text stays correct.

Where this is in upstream main

• exporter/otlp-logs/lib/opentelemetry/exporter/otlp/logs/logs_exporter.rb encodes with OpenTelemetry::Exporter::OTLP::Common.as_encoded_elsr(log_record_data). LogsExporter no longer defines as_otlp_log_record.
• exporter/otlp-common/lib/opentelemetry/exporter/otlp/common.rb defines as_otlp_log_record with severity_number: log_record_data.severity_number, unchanged.

This comes from reading upstream source. It hasn't been run against a release, because none includes it yet.

Suggestion

Map the severity where the record is created. Formatter#emit_log could pass OTLP numbers to on_emit:

That works with any exporter that passes severity_number through: 0.6.0 does, and so does the upstream main code above. The exporter patch would then no longer be needed for severity. Older exporters that dropped the severity number may need a higher minimum opentelemetry-exporter-otlp-logs in the gemspec. Upper bounds on the pre-1.0 OpenTelemetry gems would also stop changes like this from arriving through a routine update.

Written by Claude, an AI assistant made by Anthropic, on behalf of @rpearce.