How can I remove a stack with serverless greengrass plugin?

Question

I am using kepware to collect data and send it to AWS greengrass IoT Core. I deploy my project with serverless and the plugin serverless-plugin-greengrass. Here a part of my serverless file:

[...]
functions:
  opcuaPubSub:
    description: Lambda function for get data from kepware.
    handler: src.opcua_pub_sub.handler
    greengrass:
      subscriptions: 
        - target: cloud
          subject: topic/opcua

custom:
  output:
    file: stack.json
  pythonRequirements:
    usePipenv: true
  greengrass:
    autoDeploy: true
    groupId: ${env:GROUP_ID}
    defaults:
      pinned: true 
      memorySize: 262144
      encodingType: json 

plugins:
  - serverless-python-requirements
  - serverless-stack-output
  - serverless-pseudo-parameters
  - serverless-plugin-greengrass

But I cann't remove the stack with serverless. When I run: serverless remove --stage xxx I have the following error :

Greengrass: Execute reset for group id xxxxx-xxxx-xxxx-xxxx...

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

  That deployment type is not valid.  Please specify one of the following types: {NewDeployment,Redeployment}.

I don't understand because 'serverless' is expecting NewDeployment or Redeployment, but what I would like is to remove the stack. I tried to reset deployement of the greengrass group before run: 'serverless remove...', with the command aws greengrass reset-deployments --group-id $GROUP_ID but I obtain the same error. If I delete manually the stack in cloudformation console, it's work my group greengrass will be deleted. (I run serverless remove --stage xxx when I want to change branch in gitlab-ci). Someone knows why I can not remove this stack with serverless ?

Answer 1

Let's divide your problem into three parts.

1. Deploy Lambdas
2. Associate Lambdas to one or multiple Greengrass groups
3. Deploy the updated Greengrass group to its target devices

I have a similar setup running for last 6-9 months. I did not use serverless alone to achieve all of these.

Rather, I used

• serverless for #1

• serverless & cloudformation for #2

• ci/cd pipelines with aws cli for #3

I prefer this approach due to the fact it allowed me to maintain 'static unchanging' resources and 'dynamically changing' resources next to each other in a mono-repo, yet handle them with care. E.g. you create Greengrass Group once, but you will end up adding/removing Subscriptions to various Topics at a later point in time (multiple times).

TL; DR

#1 serverless Limit it to deploying / re-deploying Lambdas with source code packages and dependency injection etc.

#2 serverless & cloudformation is where I define AWS::Greengrass::FunctionDefinition and AWS::Greengrass::SubscriptionDefinition resources and grab these resources as a part of when I want to create a new Greengrass group definition.

#3 ci/cd pipelines with aws cli is where i call it as 'Flash Greengrass Device' (involves 2 steps, see below). They almost everytime works.

# Retrieve Service Role Arn & grant exclusive permissions to Greengrass to use this role.
echo "Associating Greengrass Service Role to AWS Account.."
export GGG_ROLE_NAME=`aws2 cloudformation list-stack-resources --stack-name XXX | jq ".StackResourceSummaries[].PhysicalResourceId" --raw-output | grep YYY`
export GGG_ROLE_ARN=`aws2 iam get-role --role-name $GGG_ROLE_NAME | jq ".Role.Arn" --raw-output`
aws2 greengrass associate-service-role-to-account --role-arn $GGG_ROLE_ARN --region $AWS_DEFAULT_REGION

# Get Group ID, Group Version & Flash it!
export GGG_ID=`aws2 greengrass list-groups --query  "Groups[?Name=='XXX']" | jq ".[0].Id" --raw-output`
export GGG_VERSION_ID=`aws2 greengrass list-groups --query  "Groups[?Name=='XXX']" | jq ".[0].LatestVersion" --raw-output`
export GGG_DEPL_ID=`aws2 greengrass create-deployment --group-id $GGG_ID --group-version-id $GGG_VERSION_ID --deployment-type NewDeployment | jq ".DeploymentId"  --raw-output`
export GGG_DEPL_STATUS=`aws2 greengrass get-deployment-status --deployment-id $GGG_DEPL_ID --group-id GGG_ID | jq ".DeploymentStatus" --raw-output`

Cheers!