AWS API Gateway to Lambda Shim using http.Handler

This software is based, in part, on the work done by eawsy Their terrific idea was to use the Python 2.7 runtime available in AWS Lambda to run go programs. I was in the midst of creating a new API using goa and it dawned on me that if I could somehow trick goa into responding to AWS Api Gateway requests, I could have a service that could both run standalone and serverless on AWS's API Gateway and Lambda.

So I created this.

Now that AWS Lambda supports GO programs natively there is no reason to use eawsy but I have maintained support for it. I have updated the usage instructions to include examples for both AWS Native and eAWSy.

Usage

AWS Native

For complete details checkout the helloWorld example

The basic steps for usage are as follows:

NOTE: you need to replace the '${AWS_ACCOUNT_ID}' place holder in the swagger.json and the aws commands above with your account id.

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) {
         ...
       })
       return mux, nil
   }

2. Create your main() for your web service:

   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 aws:

   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:

   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:

   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/*/*/*'

Eawsy

For complete details checkout the helloWorld example

The basic steps for usage are as follows:

NOTE: you need to replace the '${AWS_ACCOUNT_ID}' place holder in the swagger.json and the aws commands above with your account id.

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) {
         ...
       })
       return mux, nil
   }

2. Create your main() for your web service:

   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 eawsy:

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

4. Make your eawsy:

   build:
   	go build -buildmode=c-shared -ldflags="-w -s" -o handler.so
   
   pack:
   	zip handler.zip handler.so

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

   aws lambda create-function \
       --function-name hello-world-api \
       --runtime python2.7 --handler handler.handle --zip-file fileb://handler.zip \
       --role arn:aws:iam::${AWS_ACCOUNT_ID}:role/lambda_basic_execution

6. Create your API Gateway API:

   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/*/*/*'