add delayed job context into the sampling context (#2148)

* copy delayed job context into the transaction via custom_sampling_context

* add changelog entry

* add spec

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ### Features
 
+- Make additional job context available to traces_sampler for determining sample rate (sentry-delayed_job) [#2148](https://github.com/getsentry/sentry-ruby/pull/2148)
 - Add new `config.rails.active_support_logger_subscription_items` to allow customization breadcrumb data of active support logger [#2139](https://github.com/getsentry/sentry-ruby/pull/2139)
 
   ```rb

sentry-delayed_job/lib/sentry/delayed_job/plugin.rb

@@ -20,7 +20,12 @@ class Plugin < ::Delayed::Plugin
             scope.set_contexts(**contexts)
             scope.set_tags("delayed_job.queue" => job.queue, "delayed_job.id" => job.id.to_s)
 
-            transaction = Sentry.start_transaction(name: scope.transaction_name, source: scope.transaction_source, op: OP_NAME)
+            transaction = Sentry.start_transaction(
+              name: scope.transaction_name,
+              source: scope.transaction_source,
+              op: OP_NAME,
+              custom_sampling_context: contexts
+            )
             scope.set_span(transaction) if transaction
 
             begin

sentry-delayed_job/spec/sentry/delayed_job_spec.rb

@@ -264,6 +264,17 @@ def perform
         expect(transaction.contexts.dig(:trace, :status)).to eq("ok")
       end
 
+      it "passes job context into the sampling context" do
+        expect_any_instance_of(Sentry::Transaction).to receive(:set_initial_sample_decision) do |**args|
+          expect(args.dig(:sampling_context, Sentry::DelayedJob::Plugin::DELAYED_JOB_CONTEXT_KEY, :priority)).to eq(7)
+          expect(args.dig(:sampling_context, Sentry::DelayedJob::Plugin::ACTIVE_JOB_CONTEXT_KEY, :job_class)).to eq('ReportingJob')
+        end
+        ReportingJob.set(priority: 7).perform_later
+
+        enqueued_job = Delayed::Backend::ActiveRecord::Job.last
+        enqueued_job.invoke_job
+      end
+
       it "records transaction with exception" do
         FailedJob.perform_later
         enqueued_job = Delayed::Backend::ActiveRecord::Job.last