feat: bootstrap control plane app skeleton

internal/app/app.go

@@ -0,0 +1,77 @@
+package app
+
+import (
+	"context"
+	"errors"
+	"net"
+	"net/http"
+	"time"
+)
+
+type ListenerFactory func(network, address string) (net.Listener, error)
+
+type Server struct {
+	server *http.Server
+	listen ListenerFactory
+}
+
+func NewServer(listenAddr string, listenerFactory ListenerFactory) *Server {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/healthz", func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte("ok"))
+	})
+
+	server := &Server{
+		server: &http.Server{
+			Addr:    listenAddr,
+			Handler: mux,
+		},
+		listen: net.Listen,
+	}
+
+	if listenerFactory != nil {
+		server.listen = listenerFactory
+	}
+
+	return server
+}
+
+func (s *Server) Addr() string {
+	return s.server.Addr
+}
+
+func (s *Server) Run(ctx context.Context) error {
+	listener, err := s.listen("tcp", s.server.Addr)
+	if err != nil {
+		return err
+	}
+
+	return s.Serve(ctx, listener)
+}
+
+func (s *Server) Serve(ctx context.Context, listener net.Listener) error {
+	errCh := make(chan error, 1)
+
+	go func() {
+		err := s.server.Serve(listener)
+		if errors.Is(err, http.ErrServerClosed) {
+			err = nil
+		}
+		errCh <- err
+	}()
+
+	select {
+	case <-ctx.Done():
+		shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+
+		if err := s.server.Shutdown(shutdownCtx); err != nil {
+			return err
+		}
+
+		return <-errCh
+	case err := <-errCh:
+		return err
+	}
+}

internal/app/app_test.go

@@ -0,0 +1,128 @@
+package app
+
+import (
+	"context"
+	"errors"
+	"io"
+	"net"
+	"net/http"
+	"testing"
+	"time"
+)
+
+func TestServeExposesHealthz(t *testing.T) {
+	server := NewServer("127.0.0.1:0", nil)
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("net.Listen() error = %v", err)
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	errCh := make(chan error, 1)
+	go func() {
+		errCh <- server.Serve(ctx, listener)
+	}()
+
+	response := waitForHealthz(t, "http://"+listener.Addr().String()+"/healthz")
+	defer response.Body.Close()
+
+	body, err := io.ReadAll(response.Body)
+	if err != nil {
+		t.Fatalf("ReadAll() error = %v", err)
+	}
+
+	if string(body) != "ok" {
+		t.Fatalf("healthz body = %q, want %q", string(body), "ok")
+	}
+
+	cancel()
+
+	if err := <-errCh; err != nil {
+		t.Fatalf("Serve() error = %v, want nil", err)
+	}
+}
+
+func TestRunReturnsAfterContextCancellation(t *testing.T) {
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("net.Listen() error = %v", err)
+	}
+
+	server := NewServer("127.0.0.1:0", func(string, string) (net.Listener, error) {
+		return listener, nil
+	})
+
+	ctx, cancel := context.WithCancel(context.Background())
+	errCh := make(chan error, 1)
+	go func() {
+		errCh <- server.Run(ctx)
+	}()
+
+	response := waitForHealthz(t, "http://"+listener.Addr().String()+"/healthz")
+	response.Body.Close()
+
+	cancel()
+
+	select {
+	case err := <-errCh:
+		if err != nil {
+			t.Fatalf("Run() error = %v, want nil", err)
+		}
+	case <-time.After(2 * time.Second):
+		t.Fatal("Run() did not return after context cancellation")
+	}
+}
+
+func TestRunReturnsListenError(t *testing.T) {
+	wantErr := errors.New("listen failed")
+	server := NewServer("127.0.0.1:0", func(string, string) (net.Listener, error) {
+		return nil, wantErr
+	})
+
+	err := server.Run(context.Background())
+	if !errors.Is(err, wantErr) {
+		t.Fatalf("Run() error = %v, want %v", err, wantErr)
+	}
+}
+
+func TestServeReturnsListenerError(t *testing.T) {
+	server := NewServer("127.0.0.1:0", nil)
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("net.Listen() error = %v", err)
+	}
+
+	if err := listener.Close(); err != nil {
+		t.Fatalf("listener.Close() error = %v", err)
+	}
+
+	err = server.Serve(context.Background(), listener)
+	if err == nil {
+		t.Fatal("Serve() error = nil, want listener startup error")
+	}
+}
+
+func waitForHealthz(t *testing.T, url string) *http.Response {
+	t.Helper()
+
+	client := &http.Client{Timeout: 100 * time.Millisecond}
+	deadline := time.Now().Add(2 * time.Second)
+
+	for time.Now().Before(deadline) {
+		response, err := client.Get(url)
+		if err == nil && response.StatusCode == http.StatusOK {
+			return response
+		}
+
+		if response != nil {
+			response.Body.Close()
+		}
+
+		time.Sleep(20 * time.Millisecond)
+	}
+
+	t.Fatalf("health endpoint %q was not reachable before deadline", url)
+	return nil
+}

internal/app/bootstrap.go

@@ -0,0 +1,16 @@
+package app
+
+import (
+	"context"
+
+	"sub2api-cn-relay-manager/internal/config"
+)
+
+func Bootstrap(_ context.Context) (*Server, error) {
+	cfg, err := config.LoadStartupFromEnv()
+	if err != nil {
+		return nil, err
+	}
+
+	return NewServer(cfg.Server.ListenAddr, nil), nil
+}

internal/config/config.go

@@ -0,0 +1,82 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"strings"
+)
+
+const (
+	EnvListenAddr = "SUB2API_CRM_LISTEN_ADDR"
+	EnvSQLiteDSN  = "SUB2API_CRM_SQLITE_DSN"
+	EnvAdminToken = "SUB2API_CRM_ADMIN_TOKEN"
+
+	DefaultListenAddr = ":8080"
+	DefaultSQLiteDSN  = "file:sub2api-cn-relay-manager.db?_foreign_keys=on&_busy_timeout=5000"
+)
+
+type ServerConfig struct {
+	ListenAddr string
+}
+
+type DatabaseConfig struct {
+	SQLiteDSN string
+}
+
+type StartupConfig struct {
+	Server   ServerConfig
+	Database DatabaseConfig
+}
+
+func LoadStartupFromEnv() (StartupConfig, error) {
+	return loadStartupFromLookupEnv(os.LookupEnv)
+}
+
+func loadStartupFromLookupEnv(lookup func(string) (string, bool)) (StartupConfig, error) {
+	cfg := StartupConfig{
+		Server: ServerConfig{
+			ListenAddr: readOptionalEnv(lookup, EnvListenAddr, DefaultListenAddr),
+		},
+		Database: DatabaseConfig{
+			SQLiteDSN: readOptionalEnv(lookup, EnvSQLiteDSN, DefaultSQLiteDSN),
+		},
+	}
+
+	return cfg, nil
+}
+
+func LoadAdminTokenFromEnv() (string, error) {
+	return loadAdminTokenFromLookupEnv(os.LookupEnv)
+}
+
+func loadAdminTokenFromLookupEnv(lookup func(string) (string, bool)) (string, error) {
+	token := strings.TrimSpace(readRequiredEnv(lookup, EnvAdminToken))
+	if token == "" {
+		return "", fmt.Errorf("%s is required", EnvAdminToken)
+	}
+
+	return token, nil
+}
+
+func readOptionalEnv(lookup func(string) (string, bool), key string, defaultValue string) string {
+	value, ok := lookup(key)
+	if !ok {
+		return defaultValue
+	}
+
+	value = strings.TrimSpace(value)
+	if value == "" {
+		return defaultValue
+	}
+
+	return value
+}
+
+func readRequiredEnv(lookup func(string) (string, bool), key string) string {
+	value, ok := lookup(key)
+	if !ok {
+		return ""
+	}
+
+	return value
+}