Better profiler_class setter in config

sentry-ruby/lib/sentry-ruby.rb

@@ -25,6 +25,7 @@
 require "sentry/backpressure_monitor"
 require "sentry/cron/monitor_check_ins"
 require "sentry/metrics"
+require "sentry/vernier/profiler"
 
 [
   "sentry/rake",

sentry-ruby/lib/sentry/configuration.rb

@@ -293,7 +293,7 @@ def capture_exception_frame_locals=(value)
 
     # The profiler class
     # @return [Class]
-    attr_accessor :profiler_class
+    attr_reader :profiler_class
 
     # Take a float between 0.0 and 1.0 as the sample rate for capturing profiles.
     # Note that this rate is relative to traces_sample_rate / traces_sampler,
@@ -504,6 +504,18 @@ def profiles_sample_rate=(profiles_sample_rate)
       @profiles_sample_rate = profiles_sample_rate
     end
 
+    def profiler_class=(profiler_class)
+      if profiler_class == Sentry::Vernier::Profiler
+        begin
+          require "vernier"
+        rescue LoadError
+          raise ArgumentError, "Please add the 'vernier' gem to your Gemfile to use the Vernier profiler with Sentry."
+        end
+      end
+
+      @profiler_class = profiler_class
+    end
+
     def sending_allowed?
       spotlight || sending_to_dsn_allowed?
     end

sentry-ruby/lib/sentry/vernier/profiler.rb

@@ -4,8 +4,6 @@
 require_relative "../profiler/helpers"
 require_relative "output"
 
-begin; require "vernier"; rescue LoadError; return; end
-
 module Sentry
   module Vernier
     class Profiler
@@ -19,7 +17,7 @@ def initialize(configuration)
         @started = false
         @sampled = nil
 
-        @profiling_enabled = configuration.profiling_enabled?
+        @profiling_enabled = defined?(Vernier) && configuration.profiling_enabled?
         @profiles_sample_rate = configuration.profiles_sample_rate
         @project_root = configuration.project_root
         @app_dirs_pattern = configuration.app_dirs_pattern

sentry-ruby/spec/sentry/configuration_spec.rb

@@ -693,4 +693,21 @@ class SentryConfigurationSample < Sentry::Configuration
       expect(subject.enabled_patches).to eq(%i[redis http])
     end
   end
+
+  describe "#profiler_class=" do
+    it "sets the profiler class to Vernier when it's available", when: :vernier_installed? do
+      subject.profiler_class = Sentry::Vernier::Profiler
+      expect(subject.profiler_class).to eq(Sentry::Vernier::Profiler)
+    end
+
+    it "sets the profiler class to StackProf when Vernier is not available", when: { ruby_version?: [:<, "3.2"] } do
+      expect { subject.profiler_class = Sentry::Vernier::Profiler }
+        .to raise_error(
+          ArgumentError,
+          /Please add the 'vernier' gem to your Gemfile/
+        )
+
+      expect(subject.profiler_class).to eq(Sentry::Profiler)
+    end
+  end
 end

sentry-ruby/spec/sentry/rack/capture_exceptions_spec.rb

@@ -706,13 +706,10 @@ def will_be_sampled_by_sdk
       expect(profile[:transaction][:trace_id]).to eq(event.contexts[:trace][:trace_id])
 
       thread_id_mapping = {
-        Sentry::Profiler => "0"
+        Sentry::Profiler => "0",
+        Sentry::Vernier::Profiler => Thread.current.object_id.to_s
       }
 
-      if defined?(Sentry::Vernier::Profiler)
-        thread_id_mapping[Sentry::Vernier::Profiler] = Thread.current.object_id.to_s
-      end
-
       expect(profile[:transaction][:active_thread_id]).to eq(thread_id_mapping[Sentry.configuration.profiler_class])
 
       # detailed checking of content is done in profiler_spec,
@@ -737,7 +734,7 @@ def will_be_sampled_by_sdk
       let(:app) do
          ->(_) do
           [200, {}, "ok"]
-         end
+        end
       end
 
       let(:stackprof_results) do

sentry-ruby/spec/sentry/vernier/profiler_spec.rb

@@ -2,8 +2,8 @@
 
 require "sentry/vernier/profiler"
 
-RSpec.describe "Sentry::Vernier::Profiler", when: { ruby_version?: [:>=, "3.2.1"] } do
-  subject(:profiler) { Sentry::Vernier::Profiler.new(Sentry.configuration) }
+RSpec.describe Sentry::Vernier::Profiler, when: { ruby_version?: [:>=, "3.2.1"] } do
+  subject(:profiler) { described_class.new(Sentry.configuration) }
 
   before do
     # TODO: replace with some public API once available

sentry-ruby/spec/spec_helper.rb

@@ -8,6 +8,7 @@
 require "rspec/retry"
 require "redis"
 require "stackprof" unless RUBY_PLATFORM == "java"
+require "vernier" unless RUBY_PLATFORM == "java" || RUBY_VERSION < "3.2"
 
 SimpleCov.start do
   project_name "sentry-ruby"