title: Invoke an AWS lambda across regions
body: <p>I have three lambda functions: boss, worker1, worker2. When using boto3.client.invoke I am able to call worker1 from boss. These two are in the same region.<br>
  worker2 is in a separate region. When attempting to call worker2 from boss the following error returns:<br>
  "An error occurred (ResourceNotFoundException) when calling the Invoke operation: Functions from 'us-east-1' are not reachable in this region ('us-west-2')" . 
  boss has an execution role with the following permission:  </p>
  
  <pre><code>{
  "Version": "2012-10-17",
  "Statement": [
      {
          "Action": [
              "lambda:InvokeFunction"
          ],
          "Effect": "Allow",
          "Resource": "arn:aws:lambda:*:*:*"
      }
  ]
  }
  </code></pre>
  
  <p>Please help clarify how permissions need to be conveyed for this to work.
  Thanks</p>
  
  <p>Edit:
  master and worker1 are in us-west-2 and worker1 is in us-east-1.<br>
  Here is the code used to invoke worker from master:  </p>
  
  <pre><code>def lambda_handler(event, context):
  function_name = "arn:aws:lambda:us-east-1-...:function:worker_2"
  lambda_client = boto3.client('lambda')
  payload = json.dumps({"body-json": "payload string")
  response = lambda_client.invoke(
      FunctionName = function_name,
      Payload = payload
  )
  response_payload = response['Payload'].read()
  response_arr = json.loads(response_payload)
  return response_arr['answer']
  </code></pre>