Remove redundant sidekiq exception logger

config/initializers/sidekiq.rb

@@ -31,9 +31,9 @@ Sidekiq.configure_server do |config|
     Sidekiq.logger.formatter = Gitlab::SidekiqLogging::JSONFormatter.new
     config.options[:job_logger] = Gitlab::SidekiqLogging::StructuredLogger
 
-    # Remove the default-provided handler
+    # Remove the default-provided handler. The exception is logged inside
+    # Gitlab::SidekiqLogging::StructuredLogger
     config.error_handlers.reject! { |handler| handler.is_a?(Sidekiq::ExceptionHandler::Logger) }
-    config.error_handlers << Gitlab::SidekiqLogging::ExceptionHandler.new
   end
 
   config.redis = queues_config_hash

lib/gitlab/sidekiq_logging/exception_handler.rb

-# frozen_string_literal: true
-
-module Gitlab
-  module SidekiqLogging
-    class ExceptionHandler
-      def call(job_exception, context)
-        data = {
-          error_class: job_exception.class.name,
-          error_message: job_exception.message
-        }
-
-        if context.is_a?(Hash)
-          data.merge!(context)
-          # correlation_id, jid, and class are available inside the job
-          # Hash, so promote these arguments to the root tree so that
-          # can be searched alongside other Sidekiq log messages.
-          job_data = data.delete(:job)
-          data.merge!(job_data) if job_data.present?
-        end
-
-        data[:error_backtrace] = Rails.backtrace_cleaner.clean(job_exception.backtrace) if job_exception.backtrace.present?
-
-        Sidekiq.logger.warn(data)
-      end
-    end
-  end
-end

spec/lib/gitlab/sidekiq_logging/exception_handler_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-RSpec.describe Gitlab::SidekiqLogging::ExceptionHandler do
-  describe '#call' do
-    let(:job) do
-      {
-        "class" => "TestWorker",
-        "args" => [1234, 'hello'],
-        "retry" => false,
-        "queue" => "cronjob:test_queue",
-        "queue_namespace" => "cronjob",
-        "jid" => "da883554ee4fe414012f5f42",
-        "correlation_id" => 'cid'
-      }
-    end
-
-    let(:exception_message) { 'An error was thrown' }
-    let(:backtrace) { caller }
-    let(:exception) { RuntimeError.new(exception_message) }
-    let(:logger) { double }
-
-    before do
-      allow(Sidekiq).to receive(:logger).and_return(logger)
-      allow(exception).to receive(:backtrace).and_return(backtrace)
-    end
-
-    subject { described_class.new.call(exception, { context: 'Test', job: job }) }
-
-    it 'logs job data into root tree' do
-      expected_data = job.merge(
-        error_class: 'RuntimeError',
-        error_message: exception_message,
-        context: 'Test',
-        error_backtrace: Rails.backtrace_cleaner.clean(backtrace)
-      )
-
-      expect(logger).to receive(:warn).with(expected_data)
-
-      subject
-    end
-  end
-end