Merge pull request #724 from bugsnag/aws-lambda-response

Fix issue with AWS lambda response output regex not being restrictive enough

CHANGELOG.md

@@ -1,3 +1,9 @@
+# 9.23.1 - 2025/02/19
+
+## Fixes
+
+- Fix issue with the method used to parse the lambda response line [724](https://github.com/bugsnag/maze-runner/pull/724)
+
 # 9.23.0 - 2025/02/18
 
 ## Enhancements

lib/maze.rb

@@ -8,7 +8,7 @@
 # providing an alternative to the proliferation of global variables or singletons.
 module Maze
 
-  VERSION = '9.23.0'
+  VERSION = '9.23.1'
 
   class << self
     attr_accessor :check, :driver, :internal_hooks, :mode, :start_time, :dynamic_retry, :public_address,

lib/maze/aws/sam.rb

@@ -62,6 +62,7 @@ def build_invoke_command(lambda, event)
         #
         # @return [Hash]
         def parse(output)
+
           unless valid?(output)
             message = <<-WARNING
               The lambda function did not successfully complete.
@@ -76,14 +77,10 @@ def parse(output)
           end
 
           # Attempt to parse response line of the output.
-          # It's possible for a Lambda to output nothing,
-          # e.g. if it forcefully exited, so we allow JSON parse failures here
-          begin
-            response_line = output.find { |line| /{.*}/.match(line.strip) }
-            parsed_output = JSON.parse(response_line)
-          rescue JSON::ParserError
-            return {}
-          end
+          # We can assume that the output is the last line present that is JSON parsable
+          response_lines = output.find_all { |line| /^{.*}$/.match(line.strip) }
+          response_line = response_lines.last
+          parsed_output = response_line.nil? ? {} : JSON.parse(response_line)
 
           # Error output has no "body" of additional JSON so we can stop here
           return parsed_output unless parsed_output.key?('body')

test/e2e/aws-sam/features/fixtures/node-app/template.yaml

@@ -37,6 +37,19 @@ Resources:
             Path: /process-exit
             Method: get
 
+  ThrownErrorFunction:
+    Type: AWS::Serverless::Function
+    Properties:
+      CodeUri: thrown-error/
+      Handler: app.lambdaHandler
+      Runtime: nodejs20.x
+      Events:
+        ThrownError:
+          Type: Api
+          Properties:
+            Path: /thrown-error
+            Method: get
+
 Outputs:
   # ServerlessRestApi is an implicit API created out of Events key under Serverless::Function
   # Find out more about other implicit resources you can reference within SAM

test/e2e/aws-sam/features/fixtures/node-app/thrown-error/app.js

@@ -0,0 +1,4 @@
+exports.lambdaHandler = (event, context, callback) => {
+    throw new Error('Oh no!')
+}
+

test/e2e/aws-sam/features/fixtures/ruby-app/no_response/app.rb

@@ -0,0 +1,5 @@
+def lambda_handler(event:, context:)
+  {
+    statusCode: 200
+  }
+end

test/e2e/aws-sam/features/fixtures/ruby-app/template.yaml

@@ -23,6 +23,18 @@ Resources:
           Properties:
             Path: /hello
             Method: get
+  NoResponseFunction:
+    Type: AWS::Serverless::Function # More info about Function Resource: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#awsserverlessfunction
+    Properties:
+      CodeUri: no_response/
+      Handler: app.lambda_handler
+      Runtime: ruby3.3
+      Events:
+        HelloWorld:
+          Type: Api # More info about API Event Source: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#api
+          Properties:
+            Path: /no_response
+            Method: get
 
 Outputs:
   # ServerlessRestApi is an implicit API created out of Events key under Serverless::Function

test/e2e/aws-sam/features/invoke.feature

@@ -73,9 +73,22 @@ Scenario: Executing a lambda function that returns a HTML body
   And the lambda response "statusCode" equals 200
   And the SAM exit code equals 0
 
-Scenario: Executing a lambda function that does not respond
+Scenario: Executing a lambda function that returns nothing
+  Given I invoke the "NoResponseFunction" lambda in "features/fixtures/ruby-app"
+  And the lambda response "body" is null
+  And the lambda response "statusCode" equals 200
+  And the SAM exit code equals 0
+
+Scenario: Executing a lambda function that fails with no internal errors
   Given I invoke the "ProcessExitFunction" lambda in "features/fixtures/node-app"
   Then the lambda response "errorMessage" contains "Error: Runtime exited with error: exit status 1"
   And the lambda response "errorType" equals "Runtime.ExitError"
   And the lambda response "body" is null
   And the SAM exit code equals 0
+
+Scenario: Executing a lambda function that fails with an internal error
+  Given I invoke the "ThrownErrorFunction" lambda in "features/fixtures/node-app"
+  Then the lambda response "errorMessage" contains "Oh no!"
+  And the lambda response "errorType" equals "Error"
+  And the lambda response "body" is null
+  And the SAM exit code equals 0