fix: allow postgres role to allow granting usage on graphql and graphql_public schemas (#761)

* fix: allow postgres role to allow granting usage on graphql and graphql_public schemas to custom roles

* fix: commit schema.sql file

* fix: add missing comment

* fix: add missing newline

Author: imor

migrations/db/migrations/20231017062225_grant_pg_graphql_permissions_for_custom_roles.sql

@@ -0,0 +1,78 @@
+-- migrate:up
+
+create or replace function extensions.grant_pg_graphql_access()
+    returns event_trigger
+    language plpgsql
+AS $func$
+DECLARE
+    func_is_graphql_resolve bool;
+BEGIN
+    func_is_graphql_resolve = (
+        SELECT n.proname = 'resolve'
+        FROM pg_event_trigger_ddl_commands() AS ev
+        LEFT JOIN pg_catalog.pg_proc AS n
+        ON ev.objid = n.oid
+    );
+
+    IF func_is_graphql_resolve
+    THEN
+        -- Update public wrapper to pass all arguments through to the pg_graphql resolve func
+        DROP FUNCTION IF EXISTS graphql_public.graphql;
+        create or replace function graphql_public.graphql(
+            "operationName" text default null,
+            query text default null,
+            variables jsonb default null,
+            extensions jsonb default null
+        )
+            returns jsonb
+            language sql
+        as $$
+            select graphql.resolve(
+                query := query,
+                variables := coalesce(variables, '{}'),
+                "operationName" := "operationName",
+                extensions := extensions
+            );
+        $$;
+
+        -- This hook executes when `graphql.resolve` is created. That is not necessarily the last
+        -- function in the extension so we need to grant permissions on existing entities AND
+        -- update default permissions to any others that are created after `graphql.resolve`
+        grant usage on schema graphql to postgres, anon, authenticated, service_role;
+        grant select on all tables in schema graphql to postgres, anon, authenticated, service_role;
+        grant execute on all functions in schema graphql to postgres, anon, authenticated, service_role;
+        grant all on all sequences in schema graphql to postgres, anon, authenticated, service_role;
+        alter default privileges in schema graphql grant all on tables to postgres, anon, authenticated, service_role;
+        alter default privileges in schema graphql grant all on functions to postgres, anon, authenticated, service_role;
+        alter default privileges in schema graphql grant all on sequences to postgres, anon, authenticated, service_role;
+
+        -- Allow postgres role to allow granting usage on graphql and graphql_public schemas to custom roles
+        grant usage on schema graphql_public to postgres with grant option;
+        grant usage on schema graphql to postgres with grant option;
+    END IF;
+
+END;
+$func$;
+
+-- Cycle the extension off and back on to apply the permissions update.
+
+drop extension if exists pg_graphql;
+-- Avoids limitation of only being able to load the extension via dashboard
+-- Only install as well if the extension is actually installed
+DO $$
+DECLARE
+  graphql_exists boolean;
+BEGIN
+  graphql_exists = (
+      select count(*) = 1 
+      from pg_available_extensions 
+      where name = 'pg_graphql'
+  );
+
+  IF graphql_exists 
+  THEN
+  create extension if not exists pg_graphql;
+  END IF;
+END $$;
+
+-- migrate:down

migrations/schema.sql

@@ -298,6 +298,10 @@ BEGIN
         alter default privileges in schema graphql grant all on tables to postgres, anon, authenticated, service_role;
         alter default privileges in schema graphql grant all on functions to postgres, anon, authenticated, service_role;
         alter default privileges in schema graphql grant all on sequences to postgres, anon, authenticated, service_role;
+
+        -- Allow postgres role to allow granting usage on graphql and graphql_public schemas to custom roles
+        grant usage on schema graphql_public to postgres with grant option;
+        grant usage on schema graphql to postgres with grant option;
     END IF;
 
 END;