api-gateway with depends_on users-api

2026-04-09 16:53:42 +03:00
commit eae5f6165d
4 changed files with 127 additions and 0 deletions
--- a/main.go
+++ b/main.go
@@ -0,0 +1,95 @@
+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, `<!DOCTYPE html>
+<html>
+<head>
+  <title>API Gateway</title>
+  <style>
+    body { font-family: 'JetBrains Mono', monospace; background: #0a0a0a; color: #e5e5e5; padding: 40px; }
+    h1 { color: #60a5fa; }
+    .svc { margin: 16px 0; padding: 16px; border-radius: 8px; border: 1px solid #333; }
+    .ok { border-color: #166534; background: #052e16; }
+    .fail { border-color: #7f1d1d; background: #1c0a0a; }
+    .label { font-size: 14px; color: #9ca3af; }
+    .url { font-size: 11px; color: #6b7280; margin-top: 2px; }
+    .data { font-size: 13px; margin-top: 8px; color: #d1d5db; }
+    .ok .data { color: #4ade80; }
+    .fail .data { color: #f87171; }
+    .time { color: #6b7280; font-size: 12px; margin-top: 24px; }
+  </style>
+</head>
+<body>
+  <h1>API Gateway</h1>
+  <p style="color:#9ca3af">Service-to-service communication test</p>
+`)
+		cls := "ok"
+		if !users.OK {
+			cls = "fail"
+		}
+		fmt.Fprintf(w, `  <div class="svc %s">
+    <div class="label">%s</div>
+    <div class="url">→ %s</div>
+    <div class="data">%s</div>
+  </div>
+`, cls, users.Service, usersURL, users.Data)
+
+		fmt.Fprintf(w, `  <div class="time">Checked at %s</div>
+</body></html>`, time.Now().Format(time.RFC3339))
+	})
+
+	port := env("PORT", "8080")
+	log.Printf("api-gateway listening on :%s", port)
+	log.Fatal(http.ListenAndServe(":"+port, nil))
+}