pinterb / google-cloud-functions-go

Google Cloud Function tutorial and hacks enable to use Go.

Google Cloud Functions Go

This project contains a collection of tutorials and hacks for using Go with Google Cloud Functions.

Usage

Save the following source code to a file named function.go:

package main

import (
    "encoding/json"
    "io/ioutil"
    "net/http"
)

type response struct {
     Message string `json:"message"`
}

func F(w http.ResponseWriter, r *http.Request) {
    d, err := ioutil.ReadAll(r.Body)
    if err != nil {
        w.WriteHeader(500)
        return
    }
    if err := json.NewEncoder(w).Encode(response{Message: string(d)}); err != nil {
        w.WriteHeader(500)
        return
    }
}

Build the function binary:

cp cmd/go-http-shim/main.go . 
go build -o function .

Testing your function

cat request.json | function

{"body":"{\"message\":\"Go Serverless!\"}\n","header":{"Content-Type":"text/plain; charset=utf-8"},"status_code":200}

At this point everything is working. Now we need to package our function and the shim for use with Google Cloud Functions.

Google Cloud Functions

Package the function binary and the index.js shim:

GOOS=linux go build -o function .
zip -r go-serverless.zip function index.js

updating: function (deflated 65%)
updating: index.js (deflated 53%)

Upload go-serverless.zip and set the function to execute to helloGET

Once the function is deployed invoke it with an HTTP trigger

Example:

curl -X POST https://us-central1-hightowerlabs.cloudfunctions.net/go-serverless \
  -H "Content-Type: text/plain" \
  --data 'Go Serverless!'

{"message":"Go Serverless!"}