Start by writing a simple Go web server application. This is very similar to the app in the Container basics scenario, but this time the response content is read from a file rather than being hard-coded.
Hello world
Write a basic web server in Go that will respond to a request on port 8080 with a simple message like "hello world". The editor pane on the top right of this screen is already set up to edit a file called hello.go. You can click the button below to copy the code into that file.
package main
import (
"fmt"
"io/ioutil"
"net/http"
"os"
)
func main() {
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
response, err := ioutil.ReadFile("./text/response")
if err != nil {
fmt.Printf("reading file: %v\n", err)
os.Exit(1)
}
fmt.Printf("response: %s\n", response)
w.Write(response)
})
err := http.ListenAndServe(":8080", nil)
if err != nil {
fmt.Printf("serving: %v\n", err)
os.Exit(1)
}
}
Compile this app:
CGO_ENABLED=0 go build -o hello hello.go
You'll need to define the response file that this application code reads from. First let's open the file in the editor:
text/response
And copy the message into that text file. (Feel free to change it to make it your own!)
Here's a response
Run your app
Run the app in the background (using the ampersand) so that you can still type into the terminal.
./hello &
Check you get the response you expect when making a request to your application using curl:
curl localhost:8080
You should see
- the output from the call to
fmt.Printfwhich displays the contents of the response file, and - the text message returned to your request.
It should look something like this:
$ curl localhost:8080
response: Here's a response
Here's a response
Stop the application
When you're satisfied that this application works, let's stop it:
kill %1
Next step
At this stage you have a compiled Go binary and a text file that it reads from. In the next step we'll build a container image that includes both the binary and the text file.
