calling-sam-local-from-aws-sdk.md

When using AWS SAM it is possible to call your local lambdas using the AWS SDK, just as you would lambdas running in AWS. I found this very useful when building acceptance tests that would work on local as well as against our AWS staging environment.

To do it, just run sam local as a service on a specific port:

sam local start-lambda -p 8035

Then you can run your code which calls the lambda.

invoke-lambda.js

const invokeLambda = async (lambdaName, payload) => {
  AWS.config = {
    region: 'eu-west-1',
    lambda: { endpoint: http://127.0.0.1:8035 }, // whatever port you're running SAM on
  };

  const lambda = new AWS.Lambda();
  return lambda
    .invoke({
      FunctionName: lambdaName,
      InvocationType: 'RequestResponse',
      Payload: JSON.stringify(payload),
    })
    .promise();
};