package main
import (
"fmt"
"io"
"log"
"net/http"
"os"
"time"
)
func env(key, fallback string) string {
if v := os.Getenv(key); v != "" {
return v
}
return fallback
}
type status struct {
Service string `json:"service"`
OK bool `json:"ok"`
Data string `json:"data"`
}
func fetchUsers(usersURL string) status {
client := &http.Client{Timeout: 5 * time.Second}
resp, err := client.Get(usersURL + "/users")
if err != nil {
return status{"users-api", false, fmt.Sprintf("error: %v", err)}
}
defer resp.Body.Close()
body, _ := io.ReadAll(resp.Body)
if resp.StatusCode != 200 {
return status{"users-api", false, fmt.Sprintf("status %d: %s", resp.StatusCode, body)}
}
return status{"users-api", true, string(body)}
}
func main() {
usersURL := env("USERS_API_URL", "http://users-api:8080")
http.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(200)
})
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
if r.URL.Path == "/healthz" {
w.WriteHeader(200)
return
}
users := fetchUsers(usersURL)
w.Header().Set("Content-Type", "text/html; charset=utf-8")
fmt.Fprintf(w, `
API Gateway
API Gateway
Service-to-service communication test
`)
cls := "ok"
if !users.OK {
cls = "fail"
}
fmt.Fprintf(w, `
`, cls, users.Service, usersURL, users.Data)
fmt.Fprintf(w, ` Checked at %s
`, time.Now().Format(time.RFC3339))
})
port := env("PORT", "8080")
log.Printf("api-gateway listening on :%s", port)
log.Fatal(http.ListenAndServe(":"+port, nil))
}