Call a aws Lambda function from another lambda function in C#

Question

I am new to aws lambda functions with c#. I have two lambda functions and I want to call one lambda function from second function, I am using code as below:

public string Function1(JObject input)
{
    string param = input["param"].ToString();
    string param1 = input["param1"].ToString();
    return param.ToUpper()+" "+param1.ToUpper();
}


public string Function2()
{
    try
    {
        using (AmazonLambdaClient client = new AmazonLambdaClient(some region))
        {
            JObject ob = new JObject();
            ob.Add("param", "hello");
            ob.Add("param1", "Lambda");
            var request = new InvokeRequest
            {
                FunctionName = "Function1",
                Payload = ob.ToString()
            };
            var response = client.Invoke(request);
            string result;
            using (var sr = new StreamReader(response.Payload))
            {
                return result = sr.ReadToEnd();
            }
        }
    }
    catch (Exception ex) 
    {
        return ex.Message.ToString();
    }
}

And I am getting an error as below:

{ "errorType": "TypeLoadException", "errorMessage": "Could not load type 'System.Net.HttpStatusCode' from assembly 'System, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e, Retargetable=Yes'.", "stackTrace": [ "at AWSLambdaApp.Function.Function2()", "at lambda_method(Closure , Stream , Stream , ContextInfo )" ] }

And in function 2 application I have added a reference of "AWSSDK.Core" and "AWSSDK.Lambda" dlls. Can any one tell me what I am doing wrong?

Answer 1

I don't have 'netcoreapp1.0' installed on my PC. So I have tried on 'netcoreapp2.0'.

And my code looks like:

public string FunctionHandler(JObject input, ILambdaContext context)
{
    param = input["param"].Value<string>();
    param1 = input["param1"].Value<string>();
    param.ToUpper() + " " + param1.ToUpper();
}

and for Function2:

public async Task<string> FunctionHandler(string input, ILambdaContext context)
{
    try
    {
        using (AmazonLambdaClient client = new AmazonLambdaClient(RegionEndpoint.USEast1))
        {
            JObject ob = new JObject { { "param", "hello" }, { "param1", "Lambda" } };

            var request = new InvokeRequest
            {
                FunctionName = "Function1",//Function1:v1 if you use alias
                Payload = ob.ToString()
            };

            var response = await client.InvokeAsync(request);

            using (var sr = new StreamReader(response.Payload))
            {
                return await sr.ReadToEndAsync();
            }
        }
    }
    catch (Exception ex)
    {
        return ex.Message;
    }
}

And the result of execution is "\"HELLO LAMBDA\"".

The reason for work of my code could be:

• How I get parameter from input in Function1. It is most probably.
• My async code. I can't use the synchronous code for call lambda with the latest SDK.
• The version of .net core.

Also, I need send a simple string as the parameter of Function2.