added readme,basic handlers and build scripts

Author: JayJamieson

.gitignore

@@ -13,3 +13,6 @@
 
 # Dependency directories (remove the comment below to include it)
 # vendor/
+bin/main
+bin/main.local
+function.zip

Dockerfile

@@ -0,0 +1,15 @@
+FROM amazonlinux:latest
+
+RUN yum install -y tar xz gzip gcc
+
+RUN curl -L -o golang.tar.gz https://go.dev/dl/go1.18.3.linux-amd64.tar.gz
+
+RUN  rm -rf /usr/local/go && tar -C /usr/local -xzf golang.tar.gz
+
+WORKDIR /project
+
+COPY go.mod go.sum ./
+
+RUN /usr/local/go/bin/go mod download -x
+
+ENV PATH="${PATH}:/usr/local/go/bin"

README.md

@@ -1 +1,26 @@
-# go-lambda
+# go-lambda
+
+## Requirements
+
+- go 1.18
+- zip
+- docker
+- terraform
+
+## Setup (optional)
+
+Although not require specifically to run go in lambdas, can be useful to avoid compatibility issues
+when using cgo bindings or third party libraries using cgo such as sqlite3.
+
+- build docker container for building lambda function binary fully compatible with aws lambda runtime
+- `docker build -t lambda-build .`
+
+## Build
+
+- `go build -o ./bin/main.local ./cmd/handler/main.go` for locally running lambda handler
+- `go build -o ./bin/main ./main.go` for lambda binary. Can be run locally if `_LAMBDA_SERVER_PORT` and `AWS_LAMBDA_RUNTIME_API` are defined
+but this is not tested and behaviour is undefined
+
+## Deploy
+
+- `aws lambda update-function-code --function-name go-lambda --zip-file fileb://function.zip`

build.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+docker run -it -v $(pwd):/project lambda-build go build -o ./bin/main.local ./cmd/handler/main.go
+docker run -it -v $(pwd):/project lambda-build go build -o ./bin/main ./main.go
+
+rm function.zip
+
+zip -j function.zip ./bin/main

cmd/handler/main.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"context"
+	"log"
+	"os"
+	"time"
+
+	"github.com/JayJamieson/go-lambda/handler"
+)
+
+func main() {
+	//this lambda setup is used for testing/running locally without deployment
+	//if specific events are required we can read in json event samples or
+	//command line flags to help build the events
+
+	lambdaMaxRuntime := time.Now().Add(15 * time.Minute)
+
+	ctx, cancel := context.WithDeadline(context.Background(), lambdaMaxRuntime)
+	defer cancel()
+
+	handler := handler.NewHandler()
+
+	err := handler(ctx)
+
+	if err != nil {
+		log.Fatal(err.Error())
+		os.Exit(0)
+	}
+
+	os.Exit(0)
+}

go.mod

@@ -0,0 +1,10 @@
+module github.com/JayJamieson/go-lambda
+
+go 1.18
+
+require (
+	github.com/aws/aws-lambda-go v1.32.0
+	github.com/aws/aws-sdk-go-v2 v1.16.5
+	github.com/aws/aws-sdk-go-v2/config v1.15.10
+	github.com/aws/aws-sdk-go-v2/service/s3 v1.26.11
+)

go.sum

@@ -0,0 +1,6 @@
+github.com/aws/aws-lambda-go v1.32.0 h1:i8MflawW1hoyYp85GMH7LhvAs4cqzL7LOS6fSv8l2KM=
+github.com/aws/aws-lambda-go v1.32.0/go.mod h1:IF5Q7wj4VyZyUFnZ54IQqeWtctHQ9tz+KhcbDenr220=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0=
+gopkg.in/yaml.v3 v3.0.0-20200615113413-eeeca48fe776 h1:tQIYjPdBoyREyB9XMu+nnTclpTYkz2zFM+lzLJFO4gQ=

handler/handler.go

@@ -0,0 +1,16 @@
+package handler
+
+import (
+	"context"
+	"log"
+)
+
+func NewHandler() func(ctx context.Context) error {
+	// similar to http middlewares, initialize dependencies here and use in
+	// returned handler function.
+	return func(ctx context.Context) error {
+		log.Print("Running lambda")
+		defer log.Print("Lambda complete")
+		return nil
+	}
+}

main.go

@@ -0,0 +1,14 @@
+package main
+
+import (
+	"github.com/JayJamieson/go-lambda/handler"
+	"github.com/aws/aws-lambda-go/lambda"
+)
+
+func main() {
+	//https://docs.aws.amazon.com/lambda/latest/dg/golang-handler.html
+	//NewHandler returns handler function this is useful for passing
+	//in environment configurations and dependencies
+	handler := handler.NewHandler()
+	lambda.Start(handler)
+}