Greengrass V2: LegacySubscriptionRouter component target LambdaNotFoundException

Question

I have a Greengrass Lambda component subscribed to the `aws.greengrass.SNS` output topic `sns/message/status` using the `aws.greengrass.LegacySubscriptionRouter` component with the following configuration: 
```
        {
            "subscriptions": {
                "GreengrassSnsOutput": {
                    "id": "GreengrassSnsOutput",
                    "source": "component:aws.greengrass.SNS",
                    "subject": "sns/message/status",
                    "target": f"component:MyComponentName",
                }
            }
        }
```
That works as expected, but if I update the Lambda corresponding to `MyComponentName`, I get the following error message in the main Greengrass log file: 
```
com.aws.greengrass.lambdamanager.LambdaNotFoundException: Lambda arn:aws:lambda:region:account:function:my-function-name:# does not exist
```
The [developer guide](https://docs.aws.amazon.com/greengrass/v2/developerguide/legacy-subscription-router-component.html#legacy-subscription-router-component-configuration) suggests that v2.1.0...
>Adds support to specify component names instead of ARNs for source and target. If you specify a component name for a subscription, you don't need to reconfigure the subscription each time the version of the Lambda function changes.

I took that to mean nothing needs to happen with respect to the subscription after a new component version with the same name but a new Lambda ARN is deployed. Is that right or is there something else that needs to be done?

I'm using the following component versions:
```
  "aws.greengrass.LegacySubscriptionRouter": {
    "componentVersion": "2.1.4"
  },
  "aws.greengrass.Nucleus": {
    "componentVersion": "2.5.5"
  },
  "aws.greengrass.SNS": {
    "componentVersion": "2.1.0"
  },
```

Answer

Hi,

Please use a RESET configuration update to ensure that the configuration used is what you expect it to be for the subscription router component. Use `RESET: [""]` to reset all of the configuration of that component to the default; then use MERGE to merge in your desired configuration. https://docs.aws.amazon.com/greengrass/v2/developerguide/update-component-configurations.html#reset-configuration-update

The error message does not match the configuration, so I think you still have configuration deployed from a previous attempt, using RESET will remove it.

Greengrass V2: LegacySubscriptionRouter component target LambdaNotFoundException

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