1 files changed, 141 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb b/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb
new file mode 100644
index 0000000000..8acb11f75f
--- /dev/null
+++ b/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb
@@ -0,0 +1,141 @@
+# frozen_string_literal: true
+
+require "tempfile"
+
+module ActiveRecord
+  module Tasks # :nodoc:
+    class PostgreSQLDatabaseTasks # :nodoc:
+      DEFAULT_ENCODING = ENV["CHARSET"] || "utf8"
+      ON_ERROR_STOP_1 = "ON_ERROR_STOP=1"
+      SQL_COMMENT_BEGIN = "--"
+
+      delegate :connection, :establish_connection, :clear_active_connections!,
+        to: ActiveRecord::Base
+
+      def initialize(configuration)
+        @configuration = configuration
+      end
+
+      def create(master_established = false)
+        establish_master_connection unless master_established
+        connection.create_database configuration["database"],
+          configuration.merge("encoding" => encoding)
+        establish_connection configuration
+      rescue ActiveRecord::StatementInvalid => error
+        if error.cause.is_a?(PG::DuplicateDatabase)
+          raise DatabaseAlreadyExists
+        else
+          raise
+        end
+      end
+
+      def drop
+        establish_master_connection
+        connection.drop_database configuration["database"]
+      end
+
+      def charset
+        connection.encoding
+      end
+
+      def collation
+        connection.collation
+      end
+
+      def purge
+        clear_active_connections!
+        drop
+        create true
+      end
+
+      def structure_dump(filename, extra_flags)
+        set_psql_env
+
+        search_path = \
+          case ActiveRecord::Base.dump_schemas
+          when :schema_search_path
+            configuration["schema_search_path"]
+          when :all
+            nil
+          when String
+            ActiveRecord::Base.dump_schemas
+          end
+
+        args = ["-s", "-x", "-O", "-f", filename]
+        args.concat(Array(extra_flags)) if extra_flags
+        unless search_path.blank?
+          args += search_path.split(",").map do |part|
+            "--schema=#{part.strip}"
+          end
+        end
+
+        ignore_tables = ActiveRecord::SchemaDumper.ignore_tables
+        if ignore_tables.any?
+          args += ignore_tables.flat_map { |table| ["-T", table] }
+        end
+
+        args << configuration["database"]
+        run_cmd("pg_dump", args, "dumping")
+        remove_sql_header_comments(filename)
+        File.open(filename, "a") { |f| f << "SET search_path TO #{connection.schema_search_path};\n\n" }
+      end
+
+      def structure_load(filename, extra_flags)
+        set_psql_env
+        args = ["-v", ON_ERROR_STOP_1, "-q", "-X", "-f", filename]
+        args.concat(Array(extra_flags)) if extra_flags
+        args << configuration["database"]
+        run_cmd("psql", args, "loading")
+      end
+
+      private
+
+        attr_reader :configuration
+
+        def encoding
+          configuration["encoding"] || DEFAULT_ENCODING
+        end
+
+        def establish_master_connection
+          establish_connection configuration.merge(
+            "database"           => "postgres",
+            "schema_search_path" => "public"
+          )
+        end
+
+        def set_psql_env
+          ENV["PGHOST"]     = configuration["host"]          if configuration["host"]
+          ENV["PGPORT"]     = configuration["port"].to_s     if configuration["port"]
+          ENV["PGPASSWORD"] = configuration["password"].to_s if configuration["password"]
+          ENV["PGUSER"]     = configuration["username"].to_s if configuration["username"]
+        end
+
+        def run_cmd(cmd, args, action)
+          fail run_cmd_error(cmd, args, action) unless Kernel.system(cmd, *args)
+        end
+
+        def run_cmd_error(cmd, args, action)
+          msg = +"failed to execute:\n"
+          msg << "#{cmd} #{args.join(' ')}\n\n"
+          msg << "Please check the output above for any errors and make sure that `#{cmd}` is installed in your PATH and has proper permissions.\n\n"
+          msg
+        end
+
+        def remove_sql_header_comments(filename)
+          removing_comments = true
+          tempfile = Tempfile.open("uncommented_structure.sql")
+          begin
+            File.foreach(filename) do |line|
+              unless removing_comments && (line.start_with?(SQL_COMMENT_BEGIN) || line.blank?)
+                tempfile << line
+                removing_comments = false
+              end
+            end
+          ensure
+            tempfile.close
+          end
+          FileUtils.cp(tempfile.path, filename)
+        end
+    end
+  end
+end