Build a Go Web App

Talks about building a basic web app in Go using net/http and goes over some of the available Go frameworks for building web apps. Finally wraps up with the necessary steps needed to build and deploy a Go Web App on the Heroku Platform.

Transcript

1. BUILD YOUR WEB APP IN GO & DEPLOY IT ON HEROKU Naga Sowjanya Mudunuri Senior Software Engineer @heroku @gritncompassion
2. Acknowledgements ▪ Bryan Vanderhoof (@bjvhoof) ▪ Jacob Vorreuter (@jkvor) ▪ Dane Harrigan (@daneharrigan) ▪ Bernerd Schaefer (@bjschaefer) ▪ Ed Muller (@freeformz) @gritncompassion
3. References ▪ https://golang.org/doc/articles/wiki/ ▪ https://golang.org/pkg/net/http/ ▪ http://www.gorillatoolkit.org/ ▪ https://github.com/gin-gonic/gin ▪ https://github.com/revel ▪ https://beego.me/ ▪ https://github.com/kardianos/govendor @gritncompassion
4. Agenda ▪ Build a web app with net/http ▪ Available web frameworks for Go ▪ Deployments on Heroku @gritncompassion
5. Web packages/toolkits/frameworks Ø net/http ▪ Gorilla ▪ Gin ▪ Revel ▪ Beego @gritncompassion
6. net/http package ▪ provides HTTP client and server implementations ▪ HTTP Server – ListenAndServe starts an HTTP Server with a given address and handler – Handle – HandleFunc – ServeFile @gritncompassion
7. http.HandlerFunc type HandlerFunc func(ResponseWriter, *Request) http.HandleFunc("/foo", func(w http.ResponseWriter, r *http.Request) { fmt.Fprint(w, "Hello World!") }) @gritncompassion
8. http.Request ▪ Context ▪ Cookie ▪ Cookies ▪ Referer @gritncompassion
9. http.ServeMux ▪ HTTP request multiplexer ▪ matches the URL of each incoming request against a list of registered patterns & calls the handler for the pattern – mux := http.NewServeMux() – mux.HandleFunc("/", homeHandler) @gritncompassion
10. Response ▪ Write: – func (r *Response) Write(w io.Writer) error ▪ JSON: – json.Marshal from encoding/json – w.Header().Set(“Content-type”, “application/json”) – w.write(jsonData) ▪ Static Assets: – http.Fileserver @gritncompassion
11. Demo of skeleton net/http web app @gritncompassion Example of a basic web app using net/http Ø https://github.com/sowjumn/web-net-http-go
12. Web packages/toolkits/frameworks ▪ net/http Ø Gorilla ▪ Gin ▪ Revel ▪ Beego @gritncompassion
13. Gorilla ▪ https://github.com/gorilla ▪ Web toolkit in Go ▪ Requests can be matched based on URL host, path, path prefix, schemes, header and query values, HTTP methods or using custom matchers. ▪ URL hosts, paths and query values can have variables with an optional regular expression. @gritncompassion
14. Gorilla/mux ▪ Routes can be used as subrouters: nested routes are only tested if the parent route matches. ▪ It implements the http.Handler interface so it is compatible with the standard http.ServeMux. @gritncompassion
15. Gorilla ▪ Routes can also be restricted to a domain or subdomain. – r := mux.NewRouter() – r.Host("www.foobar.com") // Only matches if domain is www.foobar.com – r.Host("{subdomain:[a-z]+}.domain.com") // Matches a dynamic subdomain @gritncompassion
16. Upgrade to Gorilla ▪ http://www.gorillatoolkit.org/pkg/mux ▪ go get github.com/gorilla/mux – `r := mux.NewRouter()` – r.HandleFunc("/products/{key}", ProductHandler) @gritncompassion
17. Web packages/toolkits/frameworks ▪ net/http ▪ Gorilla Ø Gin ▪ Revel ▪ Beego @gritncompassion
18. GIN @gritncompassion
19. GIN ▪ go get github.com/gin-gonic/gin ▪ import "github.com/gin-gonic/gin” @gritncompassion
20. Routing with GIN ▪ router := gin.Default() – router.GET("/someGet", getHandler) – router.POST("/somePost", postHandler) – router.PUT("/somePut", putHandler) – router.DELETE("/someDelete", deleteHandler) – router.PATCH("/somePatch", patchHandler) – router.HEAD("/someHead", headHandler) @gritncompassion
21. Params in URL using GIN Parameters in path: router.GET("/user/:name", func(c *gin.Context) { name := c.Param("name") c.String(http.StatusOK, "Hello %s", name) }) @gritncompassion
22. Query Params ▪ router.GET("/welcome", func(c *gin.Context) { firstname := c.DefaultQuery("firstname", "Guest") lastname := c.Query("lastname") c.String(http.StatusOK, "Hello %s %s", firstname, lastname) }) ▪ router.Run(":8080") @gritncompassion
23. Grouping Routes ▪ v1 := router.Group("/v1") – v1.POST("/login", loginEndpoint) – v1.POST("/submit", submitEndpoint) – v1.POST("/read", readEndpoint) @gritncompassion
24. Sending JSON back in GIN ▪ router.POST("/form_post", func(c *gin.Context) { message := c.PostForm("message") nick := c.DefaultPostForm(”sowju", "anonymous") c.JSON(200, gin.H{ ”foo": ”bar", "message": “created”, }) }) @gritncompassion
25. Model Binding and Validation ▪ Uses https://github.com/go-playground/validator ▪ Bind ▪ BindJson @gritncompassion
26. Serving Static Assets in GIN ▪ router.Static("/assets", "./assets") ▪ router.StaticFS("/more_static", http.Dir("my_file_system")) ▪ router.StaticFile("/favicon.ico", "./resources/favicon.ico") @gritncompassion
27. Web packages/toolkits/frameworks ▪ net/http ▪ Gorilla ▪ Gin Ø Revel ▪ Beego @gritncompassion
28. REVEL @gritncompassion
29. Getting Started with Revel ▪ Get the executable `go get -u github.com/revel/cmd/revel` ▪ Create an app with Revel `revel new <app_name>` ▪ Spin up the Server `revel run <app_name>` ▪ References: – https://github.com/revel/revel – https://revel.github.io/tutorial/requestflow.html @gritncompassion
30. Rendering Views in Revel ▪ Templating: html/template package ▪ Which view does revel render? – The application app/views/ directory and subdirectories. – revel core templates/ directory. – Otherwise a 500 error as template not found References: ▪ https://revel.github.io/manual/templates.html @gritncompassion
31. Responses in Revel ▪ Actions must return a revel.Result – Render() – RenderJSON() – Redirect() – RenderError() @gritncompassion
32. Validating your Model using Revel ▪ Revel has validations in the Model. Similar to Active Record Validations. ▪ revel.Validation has a couple of methods that could be useful to you – required – Max – Min – Range – MinSize – MaxSize – Length @gritncompassion
33. ▪ Uses BootStrap by default ▪ i18n ▪ Supports Websockets ▪ Standard way to send JSON back Revel @gritncompassion
34. Web packages/toolkits/frameworks ▪ net/http ▪ Gorilla ▪ Revel ▪ Gin Ø Beego @gritncompassion
35. Beego ▪ RESTful HTTP framework ▪ go get github.com/astaxie/beego ▪ go get github.com/beego/bee ▪ cd $GOPATH/src/github.com/<github_username>/ ▪ bee new <project_name> ▪ cd <project_name> @gritncompassion
36. Beego Controllers ▪ Restful Routing ▪ XSRF Filtering ▪ Easier parsing ▪ Form Validation @gritncompassion
37. Beego Models ▪ Custom ORM ▪ Supports MySQL, PostgreSQL, Sqlite ▪ Supports RawSQL query mapping ▪ Supports transactions @gritncompassion
38. Beego Views ▪ Uses html/template ▪ Supports Pagination ▪ Static Assets: Wrapper around http.ServeFile @gritncompassion
39. More of Beego ▪ Supports Sessions ▪ Supports Memcache and Redis caching ▪ Logging ▪ i18n @gritncompassion
40. Deploying on Heroku ▪ Procfile ▪ Dependency management file – govendor – Also supported: godep, glide, gb – dep(community supported) – https://devcenter.heroku.com/categories/managing-go-dependencies ▪ The main file shouldnot set the port . It should only set the port for local deployments @gritncompassion
41. Deploying on Heroku: vendor.json ▪ Specify your Go version if you want a particular go version ▪ Install all packages ▪ The supported go versions are – https://devcenter.heroku.com/articles/go-support#go-versions ▪ References: – https://devcenter.heroku.com/articles/getting-started-with-go @gritncompassion
42. References: Deploying on Heroku ▪ https://devcenter.heroku.com/articles/dynos#web-dynos ▪ https://devcenter.heroku.com/articles/dynos#common-runtime-networking ▪ https://devcenter.heroku.com/articles/procfile ▪ https://devcenter.heroku.com/articles/go-dependencies-via-govendor#build- configuration @gritncompassion
43. Thanks! Naga Sowjanya Mudunuri Senior Software Engineer @Heroku @gritncompassion @gritncompassion