bug: eventbridge input transformer does not work with json object as a result #10287
Description
Is there an existing issue for this?
- I have searched the existing issues
Current Behavior
Recently added localstack feature to enable input transformation works fine to get a string, but fails on trying to create a JSON input. Localstack logs contain this error message - exception during call chain: replace() argument 2 must be str, not dict.
I believe the issue is with this line - link.
Expected Behavior
JSON as input for target is created
How are you starting LocalStack?
With a docker-compose file
Steps To Reproduce
Given localstack is running from docker compose.yml
version: "3.8"
services:
localstack:
image: localstack/localstack:latest
ports:
- "127.0.0.1:4566:4566" # LocalStack Gateway
- "127.0.0.1:4510-4559:4510-4559" # external services port range
volumes:
- "${LOCALSTACK_VOLUME_DIR:-./temp/localstack}:/var/lib/localstack"
- "/var/run/docker.sock:/var/run/docker.sock"
And given resources are created from Cloudformation template
Resources:
LogGroup:
Type: AWS::Logs::LogGroup
Properties:
LogGroupName: /aws/lambda/AwsLambdaMinimalExample
LambdaFunction:
Type: AWS::Lambda::Function
Properties:
FunctionName: AwsLambdaMinimalExample
Handler: index.handler
Runtime: nodejs20.x
Role: !GetAtt LambdaFunctionRole.Arn
MemorySize: 256
Code:
ZipFile: |
exports.handler = async (event) => {
console.log(event);
return {
statusCode: 200,
body: JSON.stringify(event),
}
}
LambdaFunctionRole:
Type: AWS::IAM::Role
Properties:
AssumeRolePolicyDocument:
Version: '2012-10-17'
Statement:
- Effect: Allow
Principal:
Service:
- lambda.amazonaws.com
Action:
- sts:AssumeRole
Path: "/"
Policies:
- PolicyName: AppendToLogsPolicy
PolicyDocument:
Version: '2012-10-17'
Statement:
- Effect: Allow
Action:
- logs:CreateLogGroup
- logs:CreateLogStream
- logs:PutLogEvents
Resource: "*"
EventRule:
Type: AWS::Events::Rule
Properties:
Name: input-transformer-rule
EventPattern:
detail-type:
- "ExampleEvent"
Targets:
- Id: transform-and-invoke-lambda
Arn: !GetAtt LambdaFunction.Arn
InputTransformer:
InputPathsMap:
"detail" : "$.detail"
InputTemplate: |
{
"method" : "POST",
"path" : "my/custom/path",
"body": <detail>
}
PermissionForEventToInvokeLambda:
Type: AWS::Lambda::Permission
Properties:
FunctionName: !GetAtt LambdaFunction.Arn
Action: "lambda:InvokeFunction"
Principal: "events.amazonaws.com"
SourceArn: !GetAtt EventRule.Arn
And deployed using aws cloudformation create-stack --stack-name minimal-example --template-body file://cloudformation.yaml --endpoint-url http://localhost:4566 --region us-east-1 command.
On dispatching eventbridge events - aws events put-events --endpoint-url http://localhost:4566 --region us-east-1 --entries file://event.json with event.json containing
[
{
"Source": "acme.com",
"Detail": "{ \"key1\": \"value1\", \"key2\": \"value2\" }",
"DetailType": "ExampleEvent"
}
]
Validation is done using lambda function with simple log and monitored by watching tail of a log group via
aws logs tail /aws/lambda/AwsLambdaMinimalExample --endpoint-url http://localhost:4566 --region us-east-1 --follow command.
Expected result is JSON object presented in logs
{
"method" : "POST",
"path" : "my/custom/path",
"body": {
"key1": "value1",
"key2": "value2"
}
}
Actual behavior - 500 error in localstack log.
Environment
- OS: Ubuntu 20.04
- LocalStack: latestAnything else?
Provided above is working on actual AWS platform.