Support functions

lib/active_record/connection_adapters/clickhouse/schema_statements.rb

@@ -57,6 +57,16 @@ def tables(name = nil)
           result['data'].flatten
         end
 
+        def functions
+          result = do_system_execute("SELECT name FROM system.functions WHERE origin = 'SQLUserDefined'")
+          return [] if result.nil?
+          result['data'].flatten
+        end
+
+        def show_create_function(function)
+          do_execute("SELECT create_query FROM system.functions WHERE origin = 'SQLUserDefined' AND name = '#{function}'", format: nil)
+        end
+
         def table_options(table)
           sql = show_create_table(table)
           { options: sql.gsub(/^(?:.*?)(?:ENGINE = (.*?))?( AS SELECT .*?)?$/, '\\1').presence, as: sql.match(/^CREATE (?:.*?) AS (SELECT .*?)$/).try(:[], 1) }.compact

lib/active_record/connection_adapters/clickhouse_adapter.rb

@@ -308,6 +308,11 @@ def create_table(table_name, **options, &block)
         end
       end
 
+      def create_function(name, body)
+        fd = "CREATE FUNCTION #{apply_cluster(quote_table_name(name))} AS #{body}"
+        do_execute(fd, format: nil)
+      end
+
       # Drops a ClickHouse database.
       def drop_database(name) #:nodoc:
         sql = apply_cluster "DROP DATABASE IF EXISTS #{quote_table_name(name)}"
@@ -317,6 +322,12 @@ def drop_database(name) #:nodoc:
         end
       end
 
+      def drop_functions
+        functions.each do |function|
+          drop_function(function)
+        end
+      end
+
       def rename_table(table_name, new_name)
         do_execute apply_cluster "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
       end
@@ -336,6 +347,16 @@ def drop_table(table_name, options = {}) # :nodoc:
         end
       end
 
+      def drop_function(name, options = {})
+        query = "DROP FUNCTION"
+        query = "#{query} IF EXISTS " if options[:if_exists]
+        query = "#{query} #{quote_table_name(name)}"
+        query = apply_cluster(query)
+        query = "#{query} SYNC" if options[:sync]
+
+        do_execute(query, format: nil)
+      end
+
       def add_column(table_name, column_name, type, **options)
         return if options[:if_not_exists] == true && column_exists?(table_name, column_name, type)
 

lib/clickhouse-activerecord/schema_dumper.rb

@@ -34,8 +34,12 @@ def header(stream)
     end
 
     def tables(stream)
+      functions = @connection.functions
+      functions.each do |function|
+        function(function, stream)
+      end
+
       sorted_tables = @connection.tables.sort {|a,b| @connection.show_create_table(a).match(/^CREATE\s+(MATERIALIZED\s+)?VIEW/) ? 1 : a <=> b }
-
       sorted_tables.each do |table_name|
         table(table_name, stream) unless ignored?(table_name)
       end
@@ -119,6 +123,13 @@ def table(table, stream)
       end
     end
 
+    def function(function, stream)
+      stream.puts "  # FUNCTION: #{function}"
+      sql = @connection.show_create_function(function)
+      stream.puts "  # SQL: #{sql}" if sql
+      stream.puts "  create_function \"#{function}\", \"#{sql.gsub(/^CREATE FUNCTION (.*?) AS/, '').strip}\"" if sql
+    end
+
     def format_options(options)
       if options && options[:options]
         options[:options] = options[:options].gsub(/^Replicated(.*?)\('[^']+',\s*'[^']+',?\s?([^\)]*)?\)/, "\\1(\\2)")

lib/clickhouse-activerecord/tasks.rb

@@ -42,8 +42,15 @@ def structure_dump(*args)
       # sort view to last
       tables.sort_by! {|table| table.match(/^CREATE\s+(MATERIALIZED\s+)?VIEW/) ? 1 : 0}
 
+      # get all functions
+      functions = connection.execute("SELECT create_query FROM system.functions WHERE origin = 'SQLUserDefined'")['data'].flatten
+
       # put to file
       File.open(args.first, 'w:utf-8') do |file|
+        functions.each do |function|
+          file.puts function + ";\n\n"
+        end
+
         tables.each do |table|
           file.puts table + ";\n\n"
         end

spec/fixtures/migrations/dsl_create_function/1_create_some_function.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class CreateSomeFunction < ActiveRecord::Migration[5.0]
+  def up
+    create_function :some_fun, "(x,y) -> x + y"
+  end
+end

spec/fixtures/migrations/plain_function_creation/1_create_some_function.rb

@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class CreateSomeFunction < ActiveRecord::Migration[5.0]
+  def up
+    sql = <<~SQL
+      CREATE FUNCTION some_fun AS (x,y) -> x + y
+    SQL
+    do_execute(sql, format: nil)
+  end
+end

spec/single/migration_spec.rb

@@ -267,5 +267,29 @@
         expect(current_schema['date'].sql_type).to eq('Date')
       end
     end
+
+    context 'function creation' do
+      after do
+        ActiveRecord::Base.connection.drop_functions
+      end
+
+      context 'plain' do
+        let(:directory) { 'plain_function_creation' }
+        it 'creates a function' do
+          subject
+
+          expect(ActiveRecord::Base.connection.functions).to match_array(['some_fun'])
+        end
+      end
+
+      context 'dsl' do
+        let(:directory) { 'dsl_create_function' }
+        it 'creates a function' do
+          subject
+
+          expect(ActiveRecord::Base.connection.functions).to match_array(['some_fun'])
+        end
+      end
+    end
   end
 end