complete implementation

lib/outboxer/messages.rb

@@ -44,6 +44,32 @@ def unpublished!(limit: 1, order: :asc)
       end
     end
 
+    def republish_all_failed!
+      ActiveRecord::Base.connection_pool.with_connection do
+        Models::Message
+          .where(status: Models::Message::Status::FAILED)
+          .order(updated_at: :asc)
+          .pluck(:id)
+          .each_slice(1000) { |message_ids| republish_batch_failed!(message_ids) }
+      end
+    end
+
+    def republish_batch_failed!(message_ids)
+      ActiveRecord::Base.transaction do
+        message_ids.each do |message_id|
+          message = Models::Message.lock.find(message_id)
+
+          if message.status != Models::Message::Status::FAILED
+            raise InvalidTransition,
+              "cannot transition outboxer message #{message.id} " \
+              "from #{message.status} to #{Models::Message::Status::UNPUBLISHED}"
+          end
+
+          message.update!(status: Models::Message::Status::UNPUBLISHED)
+        end
+      end
+    end
+
     def delete_all!
       ActiveRecord::Base.connection_pool.with_connection do
         ActiveRecord::Base.transaction do

spec/lib/outboxer/messages/republish_all_failed_spec.rb

@@ -0,0 +1,40 @@
+require 'spec_helper'
+
+module Outboxer
+  RSpec.describe Messages do
+    describe '.republish_all_failed!' do
+      let!(:message_1) { create(:outboxer_message, :unpublished) }
+      let!(:exception_1) { create(:outboxer_exception, message: message_1) }
+      let!(:frame_1) { create(:outboxer_frame, exception: exception_1) }
+
+      let!(:message_2) { create(:outboxer_message, :publishing) }
+      let!(:exception_2) { create(:outboxer_exception, message: message_2) }
+      let!(:frame_2) { create(:outboxer_frame, exception: exception_2) }
+
+      let!(:message_3) { create(:outboxer_message, :failed) }
+      let!(:exception_3) { create(:outboxer_exception, message: message_3) }
+      let!(:frame_3) { create(:outboxer_frame, exception: exception_3) }
+
+      let!(:message_4) { create(:outboxer_message, :failed) }
+      let!(:exception_4) { create(:outboxer_exception, message: message_4) }
+      let!(:frame_4) { create(:outboxer_frame, exception: exception_4) }
+
+      let!(:result) { Messages.republish_all_failed! }
+
+      it 'sets failed messages to unpublished' do
+        expect(
+          Models::Message.where(
+            id: [message_1, message_3.id, message_4.id],
+            status: Models::Message::Status::UNPUBLISHED
+          ).count
+        ).to eq(3)
+      end
+
+      it 'does not change messages that are publishing' do
+        expect(
+          Models::Message.where(id: [message_2], status: Models::Message::Status::PUBLISHING).count
+        ).to eq(1)
+      end
+    end
+  end
+end