Fn::GetAtt not resolving

[Tiago]

I've tried to use this lib (very useful, btw) to generate my .env to run migrations in continuous deployment. However, the database is postgresql, which means that getting the address involves a look-up using Fn::GetAtt:

Fn::GetAtt:
   - MyDB
   - Endpoint.Address

From what I got in the README, it's still to be implemented. Could you share the timeline for the feature, and eventually what's the stumbling block?

[devops hipster in training.]

Hi - I was interested in the same feature

Having a look through how resolveCloudFormationEnvVariables.js it doesn't seem easy as there is no AWS API Cloudformation call to replicate the behaviour of what Fn:GetAtt does at stack deployment time?

@arabold I've taken the approach of falling through any unknown CF types to already set env variables here that works for our team.

We then use direnv to set these dynamically into the local shell environment using AWS cli + jq.

So far working well for both

serverless offline start
serverless invoke local -f function

[Andre Rabold]

I've also taken a look and it's not straight forward to support GetAtt::. If you can, you should use Ref: MyDB instead as that should resolve without issues. You can also try using Fn::ImportValue as an alternative.

[Andre Rabold]

@herebebogans I'm not sure if I'm a fan of falling back to global environment variables. It might have unforeseen consequences as things aren't fully predictable anymore. I wanted to have the .env file resemble your Lambda configuration as closely as possible.

[Esben von Buchwald]

Does anybody have a suggestion for a decent workaround, until this is implemented? My .env file currently looks like this

companiesTableName=dev-companies
vehiclesTableName=dev-vehicles
region=eu-west-1
searchIndexEndpoint=[object Object]

The search index is defined like

Resources:
  SearchIndex:
    Type: AWS::Elasticsearch::Domain
    Properties:

And my serverless.yml looks like this

provider:
  name: aws
  runtime: nodejs8.10
  stage: dev
  region: eu-west-1
  environment:
    companiesTableName:
      Ref: CompaniesTable
    vehiclesTableName:
      Ref: VehiclesTable
    region: ${self:provider.region}
    searchIndexEndpoint:
      Fn::GetAtt: [SearchIndex, DomainEndpoint]

And of course I want to have access to it in my lambda functions without hardcoding the endpoint. What's the best solution?

[Esben von Buchwald]

I temporarily solved it like this:

in serverless.yml

custom:
  searchIndexEndpoint:
    Fn::GetAtt: [SearchIndex, DomainEndpoint]

provider:
    searchIndexEndpoint: ${opt:searchIndexEndpoint, self:custom.searchIndexEndpoint}

Then I can do like this when I test locally.

$ sls invoke local -f myFunction --path mocks/myFunction.json --searchIndexEndpoint="some-url.es.amazonaws.com"

[Andre Rabold]

v1.4.0 contains a new feature to read environment variables directly from the CloudFormation output. This can work as a workaround to this issue. See the conversation here: #21

[Paweł Zubkiewicz]

Unfortunately, this workaround solution does not work for the new HTTP API in API Gateway.

my config:

custom:
  ...
  apiGatewayEndpointUrl: 
    Fn::GetAtt: [HttpApi, ApiEndpoint]
    #HttpApi is a logical name of a resource that is created by SF under the hood

functions:
  createItem:
    handler: src/createItem/function.handler
    description: Create Item in repository
    memorySize: 128
    timeout: 5
    environment:
      tableName: ${self:custom.tableName}
      createItemEndpoint: ${self:custom.apiGatewayEndpointUrl}/item
    events:
      - httpApi:
          method: POST
          path: /item

Trying to deploy this I get following error

 Trying to populate non string value into a string for variable ${self:custom.apiGatewayEndpointUrl}. Please make sure the value of the property is a string.

[Andre Rabold]

v2.0.0 (not released to npm yet) will support Fn::GetAtt and other intrinsic functions.

https://github.com/arabold/serverless-export-env/tree/v2.0.0

[Andre Rabold]

To simplify testing the new version, I've published 2.0.0-alpha.0 as alpha release to npm:

npm install serverless-export-env@2.0.0-alpha.0 --save-dev

I'm closing this task. Please open a new one (or comment on this one) if your problems are still not solved.