Merge pull request #24 from ww-daniel-mora/feat/sql-rollback

feat(sql): enable rollback

README.md

@@ -210,6 +210,30 @@ grant select on t to myrole;
 })
 ```
 
+Rollback sql on stack deletion:
+
+```ts
+const sql = new Sql(this, "Sql", {
+  provider: provider,
+  database: database,
+  statement: `
+create table if not exists t (i int);
+grant select on t to myrole;
+`,
+  rollback: `
+DO $$BEGIN
+  IF EXISTS (select from pg_database WHERE datname = 't') THEN
+    IF EXISTS (select from pg_catalog.pg_roles WHERE rolname = 'myrole') THEN
+      revoke select t from myrole;
+    END IF;
+    drop table t;
+  END IF;
+END$$;
+`
+})
+```
+
+
 Note that there is no synchronisation between various `Sql`
 constructs, in particular the order in your code does not determine
 the order in which your SQL is executed. This happens in parallel,
@@ -219,8 +243,8 @@ There are a lot of concerns when using `Sql`:
 
 - When you update your Sql, your previous Sql is not "rolled back",
   the new Sql is simply executed again.
-- The same when you delete your `Sql` construct: nothing is rolled
-  back in the database.
+- When you delete your `Sql` construct the rollback is executed if specified
+- When permission are granted via `Sql` they must be removed via rollback to succesfully remove the role
 - Currently the `Sql` constructs has less than 5 minutes to execute
   its work.
 - It is unknown how large your SQL can be.

src/handler.ts

@@ -68,7 +68,9 @@ const jumpTable: JumpTable = {
     Update: (_: string, __: string, props?: any) => {
       return props.Statement
     },
-    Delete: (_: string) => {},
+    Delete: (_: string, __: string, props?: any) => {
+      return props.Rollback
+    },
   },
   schema: {
     Create: async (resourceId: string) => {

src/sql.ts

@@ -21,6 +21,11 @@ export interface SqlProps {
    * SQL.
    */
   readonly statement?: string
+
+  /**
+   * Optional statment to be executed when the resource is deleted
+   */
+  readonly rollback?: string
 }
 
 export class Sql extends CustomResource {
@@ -32,6 +37,7 @@ export class Sql extends CustomResource {
         SecretArn: props.provider.secret.secretArn,
         DatabaseName: props.database ? props.database.databaseName : undefined,
         Statement: props.statement,
+        Rollback: props.rollback,
       },
     })
     this.node.addDependency(props.provider)

test/serverlessv1-stack.ts

@@ -61,6 +61,7 @@ export class TestStack extends Stack {
       provider: provider,
       database: database,
       statement: "create table t (i int)",
+      rollback: "drop table t",
     })
   }
 }

test/serverlessv2-stack.ts

@@ -75,6 +75,16 @@ export class TestStack extends Stack {
       statement: `
 create table if not exists t (i int);
 grant select on t to myrole;
+`,
+      rollback: `
+DO $$BEGIN
+   IF EXISTS (select from pg_database WHERE datname = 't') THEN
+     IF EXISTS (select from pg_catalog.pg_roles WHERE rolname = 'myrole') THEN
+       revoke select  database t from myrole;
+    END IF;
+    drop table t;
+  END IF;
+END$$;,
 `,
     })
   }