How to retrieve the schema.graphql file from @aws-cdk/aws-appsync before deployment

Question

I am using the code-first approach in @aws-cdk/aws-appsync for generating my graphql schema. For Typescript code generation purposes I need a way to retrieve the schema.graphql before deployment (maybe somehow extracting it from the cdk synth command?).

Answer 1

For getting the automatically created schema before deployment, use this script:

readFile('cdk.out/<YOUR-APP-NAME>.template.json', 'utf8', (err, data) => {
  if (err) {
    throw err;
  }
  const definition = JSON.parse(data)
    .Resources
    .<YOUR-SCHEMA-ID> // replace with your schema id
    .Properties
    .Definition;
  writeFile('lib/domain/generated.graphql', definition, (error) => {
    if (error) throw error;
  });
});