Prepare 2.0.0

- Removed optimistic variable resolution for `Fn::GetAtt` as it was not working properly and caused more issues than it solved. If you rely on `Fn::GetAtt` in your environment variables, define a custom resolution using the `getAttMap` [configuration option](#Configuration-Options).
arabold · Jun 4, 2021 · d08ec6c · d08ec6c
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diff --git a/README.md b/README.md
@@ -107,14 +107,14 @@ custom:
 
 ### Configuration Options
 
-| Option         | Default | Description                                                                                          |
-| -------------- | ------- | ---------------------------------------------------------------------------------------------------- |
-| filename       | `.env`  | Target file name where to write the environment variables to, relative to the project root.          |
-| enableOffline  | `true`  | Evaluate the environment variables when running `sls invoke local` or `sls offline start`.           |
-| overwrite      | `false` | Overwrite the file even if it exists already.                                                        |
-| refMap         | `{}`    | A mapping of [resource resolutions](#Custom-Resource-Resoluition) for the `Ref` function             |
-| getAttMap      | `{}`    | A mapping of [resource resolutions](#Custom-Resource-Resoluition) for the `Fn::GetAtt` function      |
-| importValueMap | `{}`    | A mapping of [resource resolutions](#Custom-Resource-Resoluition) for the `Fn::ImportValue` function |
+| Option         | Default | Description                                                                                       |
+| -------------- | ------- | ------------------------------------------------------------------------------------------------- |
+| filename       | `.env`  | Target file name where to write the environment variables to, relative to the project root.       |
+| enableOffline  | `true`  | Evaluate the environment variables when running `sls invoke local` or `sls offline start`.        |
+| overwrite      | `false` | Overwrite the file even if it exists already.                                                     |
+| refMap         | `{}`    | Mapping of [resource resolutions](#Custom-Resource-Resolution) for the `Ref` function             |
+| getAttMap      | `{}`    | Mapping of [resource resolutions](#Custom-Resource-Resolution) for the `Fn::GetAtt` function      |
+| importValueMap | `{}`    | Mapping of [resource resolutions](#Custom-Resource-Resolution) for the `Fn::ImportValue` function |
 
 ### Custom Resource Resolution
 
@@ -128,17 +128,19 @@ The plugin will try its best to resolve resource references like `Ref`, `Fn::Get
 custom:
   export-env:
     refMap:
-      # Resolve `!Ref MyDbTable` as `mock-myTable`
-      MyDbTable: "mock-myTable"
+      # Resolve `!Ref MyDynamoDbTable` as `mock-myTable`
+      MyDynamoDbTable: "mock-myTable"
     getAttMap:
-      # Resolve `!GetAtt ElasticSearchInstance.DomainEndpoint` as `localhost:9200`
-      ElasticSearchInstance:
+      # Resolve `!GetAtt MyElasticSearchInstance.DomainEndpoint` as `localhost:9200`
+      MyElasticSearchInstance:
         DomainEndpoint: "localhost:9200"
     importValueMap:
-      # Resolve `!ImportValue OtherLambdaFunction` as `arn:aws:lambda:us-east-2::function:other-lambda-function`
-      OtherLambdaFunction: "arn:aws:lambda:us-east-2::function:other-lambda-function"
+      # Resolve `!ImportValue MyLambdaFunction` as `arn:aws:lambda:us-east-2::function:my-lambda-function`
+      MyLambdaFunction: "arn:aws:lambda:us-east-2::function:my-lambda-function"
 ```
 
+> 👉 Generally, it is recommended to avoid the use of intrinsic functions in your environment variables. Often, the same can be achieved by simply predefining a resource name and then manually construct the desired variable values. To share resources between different Serverless services, check out the `${cf:stackName.outputKey}` [variable resolution](https://www.serverless.com/framework/docs/providers/aws/guide/variables/) mechanism.
+
 ## Command-Line Options
 
 Running `sls export-env` will, by default, only export _global_ environment variables into your `.env` file (those defined under `provider.environment` in your `serverless.yml`). If you want to generate the `.env` file for a specific function, pass the function name as a command-line argument as follows:
@@ -173,6 +175,8 @@ sls export-env --function hello --filename .env-hello
 
 ### 2.0.0
 
+- Removed optimistic variable resolution for `Fn::GetAtt` as it was not working properly and caused more issues than it solved. If you rely on `Fn::GetAtt` in your environment variables, define a custom resolution using the `getAttMap` [configuration option](#Configuration-Options).
+
 ### alpha.1
 
 - Added `--all` command line parameter to merge the environment variables of all functions into a single `.env` file. Please note that the behavior is _undefined_ if functions use conflicting values for the same environment variable name.

diff --git a/src/lib/collectFunctionEnvVariables.js b/src/lib/collectFunctionEnvVariables.js
@@ -10,10 +10,6 @@ const _ = require("lodash");
  */
 function collectFunctionEnvVariables(serverless) {
   const functions = _.get(serverless, "service.functions", {});
-  // const envVars = _.mapValues(
-  //   _.mapKeys(functions, (func) => func.name),
-  //   (func) => func.environment
-  // );
   const envVars = _.mapValues(functions, (func) => func.environment);
   return envVars;
 }

diff --git a/src/lib/resolveCloudFormationEnvVariables.js b/src/lib/resolveCloudFormationEnvVariables.js
@@ -5,36 +5,43 @@ const BbPromise = require("bluebird"),
   NodeEvaluator = require("cfn-resolver-lib");
 
 function resolveGetAtt(refs, resource) {
-  const Partition = refs["AWS::Partition"];
-  const Region = refs["AWS::Region"];
-  const AccountId = refs["AWS::AccountId"];
-  switch (resource.ResourceType) {
-    case "AWS::Lambda::Function":
-      return {
-        Arn: `arn:${Partition}:lambda:${Region}:${AccountId}:function:${resource.PhysicalResourceId}`,
-        FunctionName: resource.PhysicalResourceId,
-      };
-    case "AWS::SNS::Topic":
-      return { TopicName: _.last(_.split(resource.PhysicalResourceId, ":")) };
-    case "AWS::SQS::Queue":
-      return { QueueName: _.last(_.split(resource.PhysicalResourceId, ":")) };
-    case "AWS::CloudWatch::Alarm":
-      return { AlarmName: _.last(_.split(resource.PhysicalResourceId, ":")) };
-    case "AWS::EC2::Subnet":
-      return { SubnetId: _.last(_.split(resource.PhysicalResourceId, ":")) };
-    case "AWS::EC2::VPC":
-      return { VpcId: _.last(_.split(resource.PhysicalResourceId, ":")) };
-    case "AWS::S3::Bucket":
-      return { BucketName: _.last(_.split(resource.PhysicalResourceId, ":")) };
-    case "AWS::EC2::SecurityGroup":
-      return { SecurityGroupId: _.last(_.split(resource.PhysicalResourceId, ":")) };
-    case "AWS::DynamoDB::Table":
-      return { TableName: _.last(_.split(resource.PhysicalResourceId, ":")) };
-    case "AWS::IAM::Role":
-      return { Arn: `arn:${Partition}:iam::${AccountId}:role/${resource.PhysicalResourceId}` };
-    case "AWS::ApiGateway::RestApi":
-      return { RootResourceId: resource.PhysicalResourceId };
-  }
+  // TODO: While this code was created in good intention (isn't it all?), it doesn't work in the current form.
+  // There's no AWS API that can help resolve !GetAtt automatically and some attributes are impossible to
+  // determine without retrieving additional details of the resource, e.g. using an additional API call.
+  // So, for now, we completely disable this variable resolution mechanism and rely of hardcoding the `getAttMap`
+  // in the config instead.
+  // Please note that the code below doesn't work properly.
+
+  // const Partition = refs["AWS::Partition"];
+  // const Region = refs["AWS::Region"];
+  // const AccountId = refs["AWS::AccountId"];
+  // switch (resource.ResourceType) {
+  //   case "AWS::Lambda::Function":
+  //     return {
+  //       Arn: `arn:${Partition}:lambda:${Region}:${AccountId}:function:${resource.PhysicalResourceId}`,
+  //       FunctionName: resource.PhysicalResourceId,
+  //     };
+  //   case "AWS::SNS::Topic":
+  //     return { TopicName: _.last(_.split(resource.PhysicalResourceId, ":")) };
+  //   case "AWS::SQS::Queue":
+  //     return { QueueName: _.last(_.split(resource.PhysicalResourceId, ":")) };
+  //   case "AWS::CloudWatch::Alarm":
+  //     return { AlarmName: _.last(_.split(resource.PhysicalResourceId, ":")) };
+  //   case "AWS::EC2::Subnet":
+  //     return { SubnetId: _.last(_.split(resource.PhysicalResourceId, ":")) };
+  //   case "AWS::EC2::VPC":
+  //     return { VpcId: _.last(_.split(resource.PhysicalResourceId, ":")) };
+  //   case "AWS::S3::Bucket":
+  //     return { BucketName: _.last(_.split(resource.PhysicalResourceId, ":")) };
+  //   case "AWS::EC2::SecurityGroup":
+  //     return { SecurityGroupId: _.last(_.split(resource.PhysicalResourceId, ":")) };
+  //   case "AWS::DynamoDB::Table":
+  //     return { TableName: _.last(_.split(resource.PhysicalResourceId, ":")) };
+  //   case "AWS::IAM::Role":
+  //     return { Arn: `arn:${Partition}:iam::${AccountId}:role/${resource.PhysicalResourceId}` };
+  //   case "AWS::ApiGateway::RestApi":
+  //     return { RootResourceId: resource.PhysicalResourceId };
+  // }
 
   return resource;
 }