feat(backend): add HTTP server entrypoint

Wire config, migrations, storage, and the API server into the process main.

backend/cmd/server/main.go

@@ -0,0 +1,110 @@
+package main
+
+import (
+	"context"
+	"io/fs"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"pargar/backend/internal/api"
+	"pargar/backend/internal/config"
+	"pargar/backend/internal/db"
+	"pargar/backend/internal/observability"
+	"pargar/backend/internal/redisdb"
+	"pargar/backend/internal/seed"
+	"pargar/backend/internal/storage"
+	"pargar/backend/internal/store"
+)
+
+func main() {
+	observability.SetupJSONLogger()
+	cfg := config.Load()
+	if err := cfg.Validate(); err != nil {
+		observability.L().Error("configuration", "error", err)
+		os.Exit(1)
+	}
+
+	ctx := context.Background()
+
+	otelShutdown, err := observability.SetupTracing(ctx, observability.Config{
+		ServiceName:  cfg.OTELServiceName,
+		OTLPEndpoint: cfg.OTELEndpoint,
+	})
+	if err != nil {
+		observability.L().Error("otel setup", "error", err)
+		os.Exit(1)
+	}
+	defer func() { _ = otelShutdown(context.Background()) }()
+
+	pool, err := db.Connect(ctx, cfg.DatabaseURL)
+	if err != nil {
+		observability.L().Error("database", "error", err)
+		os.Exit(1)
+	}
+	defer pool.Close()
+
+	sub, _ := fs.Sub(db.MigrationFiles, "migrations")
+	if err := db.Migrate(ctx, pool, sub); err != nil {
+		observability.L().Error("migrate", "error", err)
+		os.Exit(1)
+	}
+
+	rdb, err := redisdb.Connect(ctx, cfg.RedisURL)
+	if err != nil {
+		observability.L().Error("redis", "error", err)
+		os.Exit(1)
+	}
+	defer rdb.RDB().Close()
+
+	st := store.New(pool)
+	if err := seed.Run(ctx, st, cfg.SeedCurriculum); err != nil {
+		observability.L().Error("seed", "error", err)
+		os.Exit(1)
+	}
+
+	var stg storage.Storage
+	if cfg.StorageDriver == "s3" {
+		stg, err = storage.NewS3(ctx, cfg.StorageEndpoint, cfg.StorageRegion, cfg.StorageAccess, cfg.StorageSecret, cfg.StorageBucket, cfg.PublicURL)
+		if err != nil {
+			observability.L().Error("storage", "error", err)
+			os.Exit(1)
+		}
+	} else {
+		stg = storage.NewLocal(cfg.StorageDir, cfg.PublicURL)
+	}
+	if err := storage.EnsureSampleMP4(stg, storage.DefaultSampleCandidates()...); err != nil {
+		observability.L().Warn("sample media", "error", err)
+	}
+
+	srv := api.NewServer(cfg, st, rdb.RDB(), stg)
+
+	scheduler := api.NewScheduler(srv, st, cfg)
+	go scheduler.Run()
+
+	httpSrv := &http.Server{
+		Addr:              ":" + cfg.Port,
+		Handler:           srv.Handler(),
+		ReadHeaderTimeout: 10 * time.Second,
+		IdleTimeout:       120 * time.Second,
+	}
+
+	go func() {
+		observability.L().Info("pargar backend listening", "port", cfg.Port)
+		if err := httpSrv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			observability.L().Error("server", "error", err)
+			os.Exit(1)
+		}
+	}()
+
+	stop := make(chan os.Signal, 1)
+	signal.Notify(stop, os.Interrupt, syscall.SIGTERM)
+	<-stop
+	scheduler.Stop()
+	shutdownCtx, cancel := context.WithTimeout(ctx, 10*time.Second)
+	defer cancel()
+	_ = httpSrv.Shutdown(shutdownCtx)
+	observability.L().Info("shutdown complete")
+}