fix(ruby): keep OTel auto-instrumentation working on Rails 7.0#643
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fix(ruby): keep OTel auto-instrumentation working on Rails 7.0#643ccschmitz-launchdarkly wants to merge 6 commits into
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…lure (red) Reproduces the CardFlight failure: on Rails 7.0 with the current gem, opentelemetry-instrumentation-all resolves to the latest (0.94 -> instrumentation-rails 0.42), whose Rails-family members raised their floor to Rails 7.1. They fail their runtime compatible? check, log a flurry of 'failed to install' warnings, and never attach, so no autoinstrumented HTTP server span is produced. - e2e/ruby/rails/demo-rails70: copy of demo pinned to rails ~> 7.0 (Ruby 3.3.4 kept so bundler still resolves the latest instrumentation, faithfully matching a current-Ruby Rails 7.0 customer). - test/support/otlp_sink.rb: in-process OTLP/protobuf sink (pure Ruby, decodes via the exporter gems' proto classes) so the e2e test asserts telemetry over the real export path under bundle exec rake (no Docker/Node). - test/integration/otlp_export_e2e_test.rb: asserts traces (server span), a log record, and a captured exception all reach the sink. RED here. Boot logs show 8 Rails-family 'failed to install' warnings; the new test and the existing observability_instrumentation_test both fail (missing server span).
The observability plugin depended on opentelemetry-instrumentation-all, whose Rails-family members raised their floor to Rails 7.1. On Rails 7.0 every Rails-family instrumentation failed its compatible? check, logged a flurry of 'failed to install' warnings, and never attached — so apps lost all Rails auto-instrumentation (no HTTP server spans, DB spans, etc.) and got only manual instrumentation. The meta gem couples versions, so the only fix is to stop using it. - Replace opentelemetry-instrumentation-all with individual instrumentation gems (lib/launchdarkly_observability/instrumentations.rb). The Rails family is capped below each member's Rails-7.1-enforcing release (rails <0.42, action_pack <0.18, active_record/action_view <0.13, active_support <0.12, active_job <0.12, action_mailer <0.8, active_storage <0.5); everything else tracks the latest. These capped releases still work on Rails 7.1+, so modern apps are unaffected, and use_all still activates any extra instrumentation gem a consumer adds. - Replace the per-instrumentation 'failed to install' log flurry with a single actionable summary via a logger filter (InstrumentationLogFilter), naming the instrumentations that could not attach and how to resolve it. Verified on the demo-rails70 repro: 0 'failed to install', all 13 instrumentations install, and traces (server span) + a log + a captured exception are exported to the OTLP sink. 5 runs, 16 assertions, 0 failures.
…lures correctly - Move the log-suppression filter into its own file (instrumentation_log_filter.rb) with class-level capture_failures/ failure_warning helpers (keeps OpenTelemetryConfig under the class-length limit and is unit-testable). - Wrap the whole OpenTelemetry::SDK.configure call rather than just use_all: the SDK installs instrumentations AFTER the configure block returns, so the earlier placement around use_all never saw the install logging. Now the per-instrumentation 'failed to install' / 'successfully installed' chatter is actually suppressed and failures are collected for the single summary. - rails.rb: Railtie#otel_logger_provider_available? now returns an explicit boolean instead of nil when the logs constant is absent. Fixes a pre-existing order-dependent failure in rails_railtie_test (verified failing identically on the unmodified gem at the same seed). Updated e2e Gemfile.locks for the new individual-gem resolution. demo (7.2) and api-only (7.2) suites pass; demo-rails70 (7.0) passes with 0 'failed to install'.
Adds e2e-rails-legacy to ruby-plugin.yml, running e2e/ruby/rails/demo-rails70 (Rails 7.0) under bundle exec rake. The existing e2e jobs run Rails 7.2 — above the floor the OTel Rails-family instrumentations enforce — so they cannot catch an old-Rails compatibility break. This job fails if Rails-family auto-instrumentation stops attaching on Rails 7.0. Demonstrated red-then-green with the job's exact command: - pre-fix gemspec (instrumentation-all -> instrumentation-rails 0.42.0): 5 runs, 9 assertions, 4 failures (ActionPack not installed, no server span) - fixed gemspec (instrumentation-rails 0.41.0): 5 runs, 16 assertions, 0 failures
- README: replace the opentelemetry-instrumentation-all dependency note with a 'Ruby & Rails compatibility' section (Ruby >= 3.0, Rails >= 7.0 matrix, the individual-gem rationale, the single-warning behavior, and the per-gem pin escape hatch). Update the auto-instrumentation list to the curated set. - CHANGELOG: add an Unreleased Bug Fixes entry for the Rails 7.0 fix. - demo-rails70/README: explain what the repro proves and how to run it.
…ncies) rubocop's Gemspec/OrderedDependencies (run by the build CI job) requires alphabetical order within each section. No functional change.
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Cool! Test app features
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Summary
The observability plugin depended on
opentelemetry-instrumentation-all, whose Rails-family members raised their minimum to Rails 7.1. On Rails 7.0 every Rails-family instrumentation fails its runtimecompatible?check, logs a flurry of"... failed to install"warnings, and never attaches — so the app loses all Rails auto-instrumentation (no HTTP server spans, DB spans, etc.) and gets only manual instrumentation. The meta-gem couples every instrumentation to a single version, so the fix is to stop using it.Changes
opentelemetry-instrumentation-allfor individual gems (instrumentations.rb). The Rails family is capped below each member's Rails-7.1-enforcing release (rails <0.42,action_pack <0.18,action_view/active_record<0.13,active_support <0.12,active_job <0.12,action_mailer <0.8,active_storage <0.5); everything else tracks the latest. These capped releases still work on Rails 7.1+, so modern apps are unaffected and keep the latest non-Rails instrumentations.use_allstill activates any extra instrumentation gem a consumer adds.InstrumentationLogFilterreplaces the per-instrumentation "failed to install" flurry with one actionable summary. It wraps the wholeSDK.configurecall, since the SDK installs instrumentations after the configure block returns.e2e/ruby/rails/demo-rails70(Rails 7.0) with a pure-Ruby in-process OTLP protobuf sink that asserts traces (a server span), a log, and a captured exception are exported over the wire — no Docker/Node, runs underbundle exec rake. (The JSmock-otel-serveris JSON-only and gated onhighlight.session_id, so it can't verify Ruby's protobuf export.)e2e-rails-legacyjob inruby-plugin.yml— a regression guard, since the other e2e apps run Rails 7.2 (above the floor) and can't catch this class of break.Built on top of #582 (boot auto-instrumentation) — base branch is
feat/ruby-rails-boot-instrumentation, so the diff here is just the 6 old-Rails commits. It referencesinstall_instrumentation_onlyfrom #582 and should merge after it; GitHub will retarget tomainonce #582 lands.Context
CardFlight (the original report) has since upgraded Rails, so this no longer blocks them — but it remains a valuable general regression guard so a future instrumentation-gem bump can't silently re-break Rails 7.0.
Testing
Red→green with the CI job's exact command (
bundle exec rakeindemo-rails70):5 runs, 9 assertions, 4 failures(ActionPack not installed, no server span)5 runs, 16 assertions, 0 failures, 0 "failed to install"Modern apps verified:
demo(7.2) andapi-only(7.2) pass and still resolve the latest non-Rails instrumentations (rack 0.31, redis 0.29, pg 0.36, …). Gem unit tests + rubocop green.🤖 Generated with Claude Code