Add hub stats function

sample-functions/DockerHubStats/main.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"os"
+	"strings"
+)
+
+type dockerHubStatsType struct {
+	Count int `json:"count"`
+}
+
+func sanitizeInput(input string) string {
+	parts := strings.Split(input, "\n")
+	return strings.Trim(parts[0], " ")
+}
+
+func requestHubStats(org string) dockerHubStatsType {
+	client := http.Client{}
+	res, err := client.Get("https://hub.docker.com/v2/repositories/" + org)
+	if err != nil {
+		log.Fatalln("Unable to reach Docker Hub server.")
+	}
+
+	body, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		log.Fatalln("Unable to parse response from server.")
+	}
+
+	dockerHubStats := dockerHubStatsType{}
+	json.Unmarshal(body, &dockerHubStats)
+	return dockerHubStats
+}
+
+func main() {
+	input, err := ioutil.ReadAll(os.Stdin)
+	if err != nil {
+		log.Fatal("Unable to read standard input:", err)
+	}
+	org := string(input)
+	if len(input) == 0 {
+		log.Fatalln("A username or organisation is required.")
+	}
+
+	org = sanitizeInput(org)
+	dockerHubStats := requestHubStats(org)
+
+	fmt.Printf("The organisation or user %s has %d repositories on the Docker hub.\n", org, dockerHubStats.Count)
+}