Serverless Go Webservices Using AWS, Revisited

Now that AWS supports Go natively, I have updated my shim that allows API Gateway Requests to be handled as if they were regular http.Handler calls.

Here is a quick rundown on how to use this:

1. Separate your configuration of your web service muxer from your call to http.ListenAndServe.

   package hello
   
   import (
       "net/http"
       ...
   )
   
   func InitHandler() (http.Handler, error) {
       mux := http.NewServeMux()
       mux.HandleFunc("/hello/", func(w http.ResponseWriter, req *http.Request) {
         // Handle your requests here ...
       })
       return mux, nil
   }
   

2. Create your main() for your web service:
    ```go
    package main

    import (
      "github.com/danapsimer/aws-lambda-shim/examples/helloWorld/hello"
      "log"
      "net/http"
    )

    func main() {
      handler, _ := hello.InitHandler()
      log.Fatal(http.ListenAndServe(":8080", handler))
    }

3. Create your main() for your lambda handler:

   package main
   
   import (
       "github.com/danapsimer/aws-lambda-shim/examples/helloWorld/hello"
       "github.com/danapsimer/aws-lambda-shim/aws"
   )
   
   func init() {
       shim.NewHttpHandlerShim(hello.InitHandler)
   }
   
   func main() {
   }
   

4. Make your executable:
    ```Makefile
    build:
      GOOS=linux go build -o handler

    pack:
      zip handler.zip handler

5. Create your lambda function in AWS: (in the directory your handler was built)

   aws lambda create-function \
       --function-name hello-world-api \
       --runtime go1.x --handler handler --zip-file fileb://handler.zip \
       --role arn:aws:iam::${AWS_ACCOUNT_ID}:role/lambda_basic_execution
   

6. Create your API Gateway API:
    ```bash
    aws apigateway import-rest-api \
      --body file://examples/helloWorld/swagger.json --region us-east-1
    aws lambda add-permission --region us-east-1 \
      --function-name hello-world-api --statement-id 5 \
      --principal apigateway.amazonaws.com --action lambda:InvokeFunction \
      --source-arn 'arn:aws:execute-api:us-east-1:${AWS_ACCOUNT_ID}:3l3za8xwnd/*/*/*'