This is a Bug Report

Description

I accidentally configured the plugin incorrectly and instead of failing gracefully, a cloudformation upload was attempted and failed spectacularly.

For bug reports:

• What went wrong?

• What did you expect should have happened? An error message saying the config was invalid should be printed

• What was the config you used?

+    alerts: {
+        alarms: [
+          'functionThrottles',
+          'functionErrors',
+          'functionInvocations',
+          'functionDuration',
+        ],
+        dashboards: true,
+        topics: '${self:custom.service}-${self:custom.stage}-alerts-alarm',
+   }

(note that topics should have alarm nested underneath but it doesn't.

• What stacktrace or error message from your provider did you see? Many AWS::SNS::Topic objects were attempted to be created, it looks like one per alarm if it were operating correctly. It then fails to create these topics saying they "already exist":

  Serverless Error ---------------------------------------

  An error occurred: AwsAlerts43 - r already exists in stack arn:aws:cloudformation:us-west-2:12345678910:stack/servicename-my-api-my-env/5c073420-d0c9-11e8-9030-0254f5c7f298.

Additional Data

• Serverless Framework Version: 1.32.0
• Stack Trace:
• Provider Error messages: