Question:
I am working with a serverless project and I have only the access to aws cli, so I want to get the trigger information of a function such as event and since I am using a sns topic to trigger the function, I want to get the topic infomation and arn, I tried diffrent options, such as,
list-event-source-mapping – which returns a empty array
get-function: which doesn’t hold that value
Do I have means to get the trigger information of a function with aws cli?
Answer:
In this case, I believe the only way to get that information would be from the get-policy API call as that will contain the resource based policy(AKA trigger) which allows the other service to invoke the Lambda.
The get-event-source-mappings API returns the stream based event sources in the region such as:
- Kinesis
- Dynamo
- SQS
So for example, if I have a lambda function which is configured to be invoked from SNS then the policy returned would be similar to:
aws lambda get-policy --function-name arn:aws:lambda:us-east-1:111122223333:function:YOUR_LAMBDA_NAME_HERE --query Policy --output text | jq '.Statement[0].Condition.ArnLike["AWS:SourceArn"]'
OUTPUT:
“arn:aws:sns:REGION:111122223333:TOPIC_NAME”
Though that assumes that the policy in the Lambda function only has that one statement but if you know the specific statement id then you should be able to select it in jq using a filter