add Message.truncate(...)

lib/outboxer/database.rb

@@ -67,5 +67,48 @@ def disconnect(logger: nil)
       ActiveRecord::Base.connection_handler.connection_pool_list.each(&:disconnect!)
       logger&.info "Outboxer disconnected from database"
     end
+
+    # Truncates all Outboxer tables.
+    #
+    # - Runs inside a transaction for atomicity where supported.
+    # - Works across PostgreSQL and MySQL without adapter branching.
+    # - Automatically resets auto-increment / identity sequences.
+    #
+    # @param logger [#info, #warn, #error, nil] optional logger
+    # @return [void]
+    def truncate(logger: nil)
+      logger&.warn("Outboxer truncating tables...")
+
+      ActiveRecord::Base.connection_pool.with_connection do |connection|
+        if connection.adapter_name.downcase.include?("postgres")
+          connection.execute(<<~SQL)
+            TRUNCATE TABLE
+              outboxer_message_counts,
+              outboxer_message_totals,
+              outboxer_frames,
+              outboxer_exceptions,
+              outboxer_messages,
+              outboxer_signals,
+              outboxer_publishers
+            RESTART IDENTITY;
+          SQL
+        else
+          foreign_key_checks = connection.select_value("SELECT @@FOREIGN_KEY_CHECKS;").to_i
+
+          begin
+            connection.execute("SET FOREIGN_KEY_CHECKS = 0;")
+            connection.execute("TRUNCATE TABLE outboxer_message_counts;")
+            connection.execute("TRUNCATE TABLE outboxer_message_totals;")
+            connection.execute("TRUNCATE TABLE outboxer_frames;")
+            connection.execute("TRUNCATE TABLE outboxer_exceptions;")
+            connection.execute("TRUNCATE TABLE outboxer_messages;")
+            connection.execute("TRUNCATE TABLE outboxer_signals;")
+            connection.execute("TRUNCATE TABLE outboxer_publishers;")
+          ensure
+            connection.execute("SET FOREIGN_KEY_CHECKS = #{foreign_key_checks};")
+          end
+        end
+      end
+    end
   end
 end

spec/lib/outboxer/database/truncate_spec.rb

@@ -0,0 +1,49 @@
+require "rails_helper"
+
+module Outboxer
+  RSpec.describe Database, type: :service do
+    describe ".truncate" do
+      before do
+        message = Models::Message.create!(
+          status: Models::Message::Status::QUEUED,
+          messageable_type: "Event",
+          messageable_id: "1",
+          queued_at: Time.now.utc)
+
+        Models::MessageCount.create!(status: "queued", partition: 0, value: 1)
+        Models::MessageTotal.create!(status: "queued", partition: 0, value: 1)
+
+        exception = Models::Exception.create!(message_id: message.id, message_text: "Example error")
+        Models::Frame.create!(exception_id: exception.id, text: "frame", index: 0)
+
+        publisher = Models::Publisher.create!(name: "pub-1", settings: {}, metrics: {})
+        Models::Signal.create!(publisher_id: publisher.id, name: "SIG1", created_at: Time.now.utc)
+      end
+
+      it "removes all records from all tables" do
+        Database.truncate
+
+        expect(Models::Message.count).to eq(0)
+        expect(Models::MessageCount.count).to eq(0)
+        expect(Models::MessageTotal.count).to eq(0)
+        expect(Models::Exception.count).to eq(0)
+        expect(Models::Frame.count).to eq(0)
+        expect(Models::Publisher.count).to eq(0)
+        expect(Models::Signal.count).to eq(0)
+      end
+
+      it "resets auto-increment IDs" do
+        Database.truncate
+
+        message = Models::Message.create!(
+          status: Models::Message::Status::QUEUED,
+          messageable_type: "Event",
+          messageable_id: "1",
+          queued_at: Time.now.utc
+        )
+
+        expect(message.id).to eq(1)
+      end
+    end
+  end
+end