Call aws Lambda function without using API Gateway and EC2 Instance

Question

Can we call lambda function from outside aws without using API Gateway? I want to call lambda function directly from outside aws services is it possible?

Answer 1

This is how call AWS lambda function without API GateWay in Android.

Interface Class

 @LambdaFunction(functionName = "lambdafunctionName", invocationType = "RequestResponse")
 String lambdafunctionName(String str);

Android Code (Java)

  new AsyncTask() {
   @Override
    protected String doInBackground(Response... params) {
    try{
        CognitoCachingCredentialsProvider cognitoProvider = new 
        CognitoCachingCredentialsProvider(MainActivity.this, "#identitypoolID", #Region);     
    // creates an invocation factory
         LambdaInvokerFactory factory = new LambdaInvokerFactory(MainActivity.this,
                                    #Region, cognitoProvider);

    // create a proxied object of lambdafunctionName
          MyInterface lambdaFuction = factory.build(MyInterface.class,
                                    new LambdaJsonBinder());

   // invoke it just like a regular method
         String AWSResponse = lambdaFuction.lambdafunctionName(#Parameter to AWS lambda) ;
                            return AWSResponse;

     }catch(Exception e){

     Toast.makeText(MainActivity.this, e.getMessage(), Toast.LENGTH_LONG).show();
                          return null;
                        }

                    }
 @Override
  protected void onPostExecute(String result) {
   if (result == null) {
   Toast.makeText(MainActivity.this,"Error !", Toast.LENGTH_LONG).show();
   return;
   }
  Toast.makeText(MainActivity.this,"Response From AWS " +  result, Toast.LENGTH_LONG).show();
                    }
                }.execute();