Initial experiments with schema_triggers

README.md

@@ -2,3 +2,9 @@ cartodb-postgresql
 ==================
 
 PostgreSQL extension for CartoDB
+
+Depdenencies
+------------
+
+ * PostgreSQL 9.3+ 
+ * [Schema triggers extension](https://bitbucket.org/malloclabs/pg_schema_triggers)

cartodb_hooks.sql

@@ -0,0 +1,160 @@
+LOAD 'schema_triggers.so';
+CREATE EXTENSION IF NOT EXISTS schema_triggers;
+
+GRANT EXECUTE ON ALL FUNCTIONS IN SCHEMA schema_triggers TO public;
+
+BEGIN;
+
+-- Table creation
+-- {
+CREATE OR REPLACE FUNCTION cdb_handle_create_table ()
+RETURNS event_trigger SECURITY DEFINER LANGUAGE plpgsql AS $$
+DECLARE
+  event_info RECORD;
+BEGIN
+  event_info := schema_triggers.get_relation_create_eventinfo();
+
+  -- We're only interested in real relations
+  IF (event_info.new).relkind != 'r' THEN RETURN; END IF;
+
+  RAISE NOTICE 'Relation % of kind % created in namespace oid %',
+	 event_info.relation, (event_info.new).relkind, (event_info.new).relnamespace;
+
+  -- We don't want to react to alters triggered by superuser,
+  -- or we'd enter an infinite loop here
+  IF current_setting('is_superuser') = 'on' THEN
+    RAISE DEBUG 'no ddl trigger for superuser';
+    RETURN;
+  END IF;
+
+  -- CDB_CartodbfyTable must not create tables, or infinite loop will happen
+  PERFORM public.CDB_CartodbfyTable(event_info.relation);
+
+END; $$;
+-- }
+
+-- Column alter
+-- {
+CREATE OR REPLACE FUNCTION cdb_handle_alter_column ()
+RETURNS event_trigger SECURITY DEFINER LANGUAGE plpgsql AS $$
+DECLARE
+  event_info RECORD;
+  rel RECORD;
+BEGIN
+  event_info := schema_triggers.get_column_alter_eventinfo();
+
+  SELECT oid,* FROM pg_class WHERE oid = event_info.relation INTO rel;
+
+  RAISE NOTICE 'Column % altered by % (superuser? %) in relation % of kind %',
+	 (event_info.old).attname, current_user, current_setting('is_superuser'), event_info.relation::regclass, rel.relkind;
+
+  -- We're only interested in real relations
+  IF rel.relkind != 'r' THEN RETURN; END IF;
+
+  -- We don't want to react to alters triggered by superuser,
+  -- or we'd enter an infinite loop here
+  IF current_setting('is_superuser') = 'on' THEN
+    RAISE DEBUG 'no ddl trigger for superuser';
+    RETURN;
+  END IF;
+
+  PERFORM cdb_disable_ddl_hooks();
+
+  PERFORM public.CDB_CartodbfyTable(event_info.relation);
+
+  PERFORM cdb_enable_ddl_hooks();
+
+  -- TODO: invalidate varnish ?
+
+END; $$;
+-- }
+
+-- Column drop
+-- {
+CREATE OR REPLACE FUNCTION cdb_handle_drop_column ()
+RETURNS event_trigger SECURITY DEFINER LANGUAGE plpgsql AS $$
+DECLARE
+  event_info RECORD;
+  rel RECORD;
+BEGIN
+  event_info := schema_triggers.get_column_drop_eventinfo();
+
+  SELECT oid,* FROM pg_class WHERE oid = event_info.relation INTO rel;
+
+  RAISE NOTICE 'Column % drop by % (superuser? %) in relation % of kind %',
+	 (event_info.old).attname, current_user, current_setting('is_superuser'), event_info.relation::regclass, rel.relkind;
+
+  -- We're only interested in real relations
+  IF rel.relkind != 'r' THEN RETURN; END IF;
+
+  -- We don't want to react to drops triggered by superuser,
+  -- or we'd enter an infinite loop here
+  IF current_setting('is_superuser') = 'on' THEN
+    RAISE DEBUG 'no ddl trigger for superuser';
+    RETURN;
+  END IF;
+
+  PERFORM cdb_disable_ddl_hooks();
+
+  PERFORM public.CDB_CartodbfyTable(event_info.relation);
+
+  PERFORM cdb_enable_ddl_hooks();
+
+  -- TODO: invalidate varnish ?
+
+END; $$;
+-- }
+
+-- Column add
+-- {
+CREATE OR REPLACE FUNCTION cdb_handle_add_column ()
+RETURNS event_trigger SECURITY DEFINER LANGUAGE plpgsql AS $$
+DECLARE
+  event_info RECORD;
+  rel RECORD;
+BEGIN
+  event_info := schema_triggers.get_column_add_eventinfo();
+
+  SELECT oid,* FROM pg_class WHERE oid = event_info.relation INTO rel;
+
+  RAISE NOTICE 'Column % add by % (superuser? %) in relation % of kind %',
+	 (event_info.old).attname, current_user, current_setting('is_superuser'), event_info.relation::regclass, rel.relkind;
+
+  -- We're only interested in real relations
+  IF rel.relkind != 'r' THEN RETURN; END IF;
+
+  -- We don't want to react to drops triggered by superuser,
+  -- or we'd enter an infinite loop here
+  IF current_setting('is_superuser') = 'on' THEN
+    RAISE DEBUG 'no ddl trigger for superuser';
+    RETURN;
+  END IF;
+
+  --PERFORM cdb_disable_ddl_hooks();
+  --PERFORM public.CDB_CartodbfyTable(event_info.relation);
+  --PERFORM cdb_enable_ddl_hooks();
+
+  -- TODO: invalidate varnish ?
+
+END; $$;
+-- }
+
+CREATE OR REPLACE FUNCTION cdb_disable_ddl_hooks() returns void AS $$
+ DROP EVENT TRIGGER IF EXISTS cdb_on_relation_create;
+ DROP EVENT TRIGGER IF EXISTS cdb_on_alter_column;
+ DROP EVENT TRIGGER IF EXISTS cdb_on_drop_column;
+ DROP EVENT TRIGGER IF EXISTS cdb_on_add_column;
+$$ LANGUAGE sql;
+
+CREATE OR REPLACE FUNCTION cdb_enable_ddl_hooks() returns void AS $$
+ SELECT cdb_disable_ddl_hooks();
+ CREATE EVENT TRIGGER cdb_on_relation_create ON "relation_create" EXECUTE PROCEDURE cdb_handle_create_table();
+ CREATE EVENT TRIGGER cdb_on_alter_column ON "column_alter" EXECUTE PROCEDURE cdb_handle_alter_column();
+ CREATE EVENT TRIGGER cdb_on_drop_column ON "column_drop" EXECUTE PROCEDURE cdb_handle_drop_column();
+ CREATE EVENT TRIGGER cdb_on_add_column ON "column_drop" EXECUTE PROCEDURE cdb_handle_add_column();
+$$ LANGUAGE sql;
+
+SELECT cdb_enable_ddl_hooks();
+
+END;
+

hook_on_table_create.sql

@@ -0,0 +1,19 @@
+\i cartodb_hooks.sql
+\set VERBOSITY terse
+
+SET SESSION AUTHORIZATION 'development_cartodb_user_1';
+
+SELECT session_user, current_user;
+
+
+create schema c;
+--create table c.t3(a int);
+select 1 as i INTO c.t3;
+select * from c.t3;
+alter table c.t3 rename column the_geom_webmercator to webmerc;
+select * from c.t3;
+alter table c.t3 rename column the_geom_webmercator to webmerc2;
+select * from c.t3;
+alter table c.t3 drop column the_geom_webmercator;
+select * from c.t3;
+drop schema c cascade;