add managed schema for subscription management

Author: encima

migrations/db/migrations/20250915105031_add_subscription_mgmt_schema.sql

@@ -0,0 +1,100 @@
+-- migrate:up
+create schema if not exists supabase_subscription_mgmt;
+    
+create or replace function supabase_subscription_mgmt.pg_create_subscription(
+    arg_subscription_name text,
+    arg_connection_string text,
+    arg_publication_name text,
+    arg_slot_name text,
+    arg_copy_data boolean = true,
+    arg_origin text = 'any'
+)
+returns void language plpgsql
+security definer
+set search_path = pg_catalog, supabase_subscription_mgmt
+as $$
+declare
+  pg_version int;
+  create_subscription_cmd text;
+begin
+  -- get the postgresql version
+  select current_setting('server_version_num')::int into pg_version;
+
+  if pg_version < 160000 and arg_origin <> 'any' then
+    raise exception 'postgresql version must be 16 or higher to specify origin other than "any". current version: %', pg_version;
+  end if;
+
+  if arg_origin <> 'any' and arg_origin <> 'none' then
+    raise exception 'invalid origin: %. origin must be either "any" or "none".', arg_origin;
+  end if;
+
+  -- pg16 and later: include the origin parameter only if it's 'none', as its default is any
+  if pg_version >= 160000 and arg_origin = 'none' then
+      create_subscription_cmd := pg_catalog.format(
+        'create subscription %I connection %L publication %I with (slot_name=%L, create_slot=false, copy_data=%s, origin=%L)',
+        arg_subscription_name, arg_connection_string, arg_publication_name, arg_slot_name, arg_copy_data::text, arg_origin);
+ else
+      create_subscription_cmd := pg_catalog.format(
+        'create subscription %I connection %L publication %I with (slot_name=%L, create_slot=false, copy_data=%s)',
+        arg_subscription_name, arg_connection_string, arg_publication_name, arg_slot_name, arg_copy_data::text);
+  end if;
+
+  -- execute the create subscription command
+  execute create_subscription_cmd;
+end;
+$$;
+
+
+create or replace function supabase_subscription_mgmt.pg_alter_subscription_disable(
+  arg_subscription_name text
+)
+  returns void language plpgsql
+  security definer
+  set search_path = pg_catalog
+as $$
+begin
+    execute pg_catalog.format('alter subscription %I disable', arg_subscription_name);
+end;
+$$;
+
+create or replace function supabase_subscription_mgmt.pg_alter_subscription_enable(
+  arg_subscription_name text
+)
+  returns void language plpgsql
+  security definer
+  set search_path = pg_catalog, supabase_subscription_mgmt
+as $$
+begin
+    execute pg_catalog.format('alter subscription %I enable', arg_subscription_name);
+end;
+$$;
+
+create or replace function supabase_subscription_mgmt.pg_drop_subscription(
+    arg_subscription_name text
+)
+  returns void language plpgsql
+  security definer
+  set search_path = pg_catalog, supabase_subscription_mgmt
+as $$
+declare
+    l_slot_name text;
+    l_subconninfo text;
+begin
+    select subslotname, subconninfo
+        into l_slot_name, l_subconninfo
+        from pg_catalog.pg_subscription
+        where subname = arg_subscription_name;
+    if l_slot_name is null and l_subconninfo is null then
+        raise exception 'no subscription found for name: %', arg_subscription_name;
+    end if;
+    execute pg_catalog.format('alter subscription %I disable', arg_subscription_name);
+    execute pg_catalog.format('alter subscription %I set (slot_name = none)', arg_subscription_name);
+    execute pg_catalog.format('drop subscription %I', arg_subscription_name);
+end;
+$$;
+
+grant usage on schema supabase_subscription_mgmt to postgres;
+grant execute on all functions in schema supabase_subscription_mgmt to postgres;
+
+-- migrate:down
+