If you are working on AWS Lambda Dotnet with C# and find out that you are getting something like an error like below.

Error message
Could not find the specified handler assembly with the file name ‘LambdaTest, Culture=neutral, PublicKeyToken=null’. The assembly should be located in the root of your uploaded .zip file.: LambdaException
[WARN] (invoke@invoke.c:331 errno: No such file or directory) run_dotnet(dotnet_path, &args) failed
START RequestId: b7bb069b-3f44-4cd6-8b63-43a37098cd5e Version: $LATEST
Could not find the specified handler assembly with the file name ‘LambdaTest, Culture=neutral, PublicKeyToken=null’. The assembly should be located in the root of your uploaded .zip file.: LambdaException

The main reason is that you most likely created the lambda on the console first and then tried to upload the code using dotnet cli e.g dotnet lambda deploy-function “functionName”.

In order to fix it, its quite simple you have to go back on the console and into the configuration section of the lambda function in console. Find the Runtime Settings and click on Edit and change the Handler to the function name you are using. E.g MyTransformFunc::MyTransformFunc.Function::ProcessFile as you can see the ProcessFile is my method that I have in my code that needs to be executed based on the namespace I am using.

I hope this helps 🙂