# The missing Cloud Endpoints for Go
This package will let you write Cloud Endpoints backends in Go.
If you're not familiar with Cloud Endpoints, see Google App Engine official documentation for Python or Java.
Start with go get github.com/crhym3/go-endpoints/endpoints.
Declare structs which describe your data. For instance:
// Greeting is a datastore entity that represents a single greeting.
// It also serves as (a part of) a response of GreetingService.
type Greeting struct {
Id string `json:"id,omitempty" datastore:"-"`
Author string `json:"author"`
Content string `json:"content" datastore:",noindex"`
Date time.Time `json:"date"`
}
// GreetingsList is a response type of GreetingService.List method
type GreetingsList struct {
Items []*Greeting `json:"items"`
}
// Request type for GreetingService.List
type GreetingsListReq struct {
Limit int
}Then, a service:
// GreetingService can sign the guesbook, list all greetings and delete
// a greeting from the guestbook.
type GreetingService struct {
}
// List responds with a list of all greetings ordered by Date field.
// Most recent greets come first.
func (gs *GreetingService) List(
r *http.Request, req *GreetingsListReq, resp *GreetingsList) error {
ctx := appengine.NewContext(r)
q := datastore.NewQuery("Greeting").Order("-Date").Limit(req.Limit)
greets := make([]*Greeting, 0, req.Limit)
keys, err := q.GetAll(ctx, &greets)
if err != nil {
return err
}
for i, k := range keys {
greets[i].Id = k.Encode()
}
resp.Items = greets
return nil
}Last step is to make the above available as a discoverable API and leverage all the juicy stuff Cloud Endpoints are great at.
import "github.com/crhym3/go-endpoints/endpoints"
func init() {
greetService := &GreetingService{}
api, err := endpoints.RegisterService(greetService,
"greeting", "v1", "Greetings API", true)
if err != nil {
panic(err.Error())
}
info := api.MethodByName("List").Info()
info.Name, info.HttpMethod, info.Path, info.Desc =
"greets.list", "GET", "greetings", "List most recent greetings."
endpoints.HandleHttp()Don't forget to add URL matching in app.yaml:
application: my-app-id
version: v1
threadsafe: true
runtime: go
api_version: go1
handlers:
- url: /.*
script: _go_app
# Important! Even though there's a catch all routing above,
# without these two lines it's not going to work.
# Make sure you have this:
- url: /_ah/spi/.*
script: _go_appThat's it. It is time to start dev server and enjoy the discovery doc at localhost:8080/_ah/api/discovery/v1/apis/greeting/v1/rest
Naturally, API Explorer works too: localhost:8080/_ah/api/explorer
Time to deploy the app on appengine.appspot.com!
Check out the famous TicTacToe app. It has its own readme file.
We currently use aet tool to simplify running tests on files that have "appengine" or "appengine_internal" imports.
Check out the readme of that tool but, assuming you cloned this repo (so you can reach ./endpoints dir), the initial setup process is pretty simple:
go get github.com/crhym3/aegot/aetaet init ./endpoints
That's it. You should be able to run tests with "aet test ./endpoints" now.