Initial commit

internal/config/config.go

@@ -0,0 +1,85 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/BurntSushi/toml"
+)
+
+type Config struct {
+	Server     ServerConfig     `toml:"server"`
+	EPICS      EPICSConfig      `toml:"datasource.epics"`
+	Synthetic  SyntheticConfig  `toml:"datasource.synthetic"`
+}
+
+type ServerConfig struct {
+	Listen     string `toml:"listen"`
+	StorageDir string `toml:"storage_dir"`
+}
+
+type EPICSConfig struct {
+	Enabled    bool   `toml:"enabled"`
+	CAAddrList string `toml:"ca_addr_list"`
+	ArchiveURL string `toml:"archive_url"`
+}
+
+type SyntheticConfig struct {
+	Enabled         bool   `toml:"enabled"`
+	DefinitionsFile string `toml:"definitions_file"`
+}
+
+func Default() Config {
+	return Config{
+		Server: ServerConfig{
+			Listen:     ":8080",
+			StorageDir: "./interfaces",
+		},
+		EPICS: EPICSConfig{
+			Enabled: true,
+		},
+		Synthetic: SyntheticConfig{
+			Enabled:         true,
+			DefinitionsFile: "./synthetic.json",
+		},
+	}
+}
+
+// Load reads a TOML config file and applies environment variable overrides.
+// Environment variables use the prefix UOPI_ with __ as separator, e.g.
+// UOPI_SERVER_LISTEN=":9090".
+func Load(path string) (Config, error) {
+	cfg := Default()
+
+	if path != "" {
+		if _, err := toml.DecodeFile(path, &cfg); err != nil {
+			return cfg, fmt.Errorf("reading config %q: %w", path, err)
+		}
+	}
+
+	applyEnv(&cfg)
+	return cfg, nil
+}
+
+func applyEnv(cfg *Config) {
+	if v := env("UOPI_SERVER_LISTEN"); v != "" {
+		cfg.Server.Listen = v
+	}
+	if v := env("UOPI_SERVER_STORAGE_DIR"); v != "" {
+		cfg.Server.StorageDir = v
+	}
+	if v := env("UOPI_EPICS_CA_ADDR_LIST"); v != "" {
+		cfg.EPICS.CAAddrList = v
+	}
+	if v := env("UOPI_EPICS_ARCHIVE_URL"); v != "" {
+		cfg.EPICS.ArchiveURL = v
+	}
+	if v := env("UOPI_SYNTHETIC_DEFINITIONS_FILE"); v != "" {
+		cfg.Synthetic.DefinitionsFile = v
+	}
+}
+
+func env(key string) string {
+	return strings.TrimSpace(os.Getenv(key))
+}

internal/server/server.go

@@ -0,0 +1,63 @@
+package server
+
+import (
+	"context"
+	"io/fs"
+	"log/slog"
+	"net/http"
+	"time"
+)
+
+type Server struct {
+	httpServer *http.Server
+	log        *slog.Logger
+}
+
+// New creates an HTTP server that serves the embedded frontend and a health
+// check endpoint. Additional routes (API, WebSocket) will be registered in
+// later phases.
+func New(addr string, webFS fs.FS, log *slog.Logger) *Server {
+	mux := http.NewServeMux()
+
+	// Health check
+	mux.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte("ok"))
+	})
+
+	// Serve embedded frontend for everything else
+	mux.Handle("/", http.FileServerFS(webFS))
+
+	return &Server{
+		httpServer: &http.Server{
+			Addr:         addr,
+			Handler:      mux,
+			ReadTimeout:  10 * time.Second,
+			WriteTimeout: 30 * time.Second,
+			IdleTimeout:  120 * time.Second,
+		},
+		log: log,
+	}
+}
+
+// Start listens and serves until ctx is cancelled.
+func (s *Server) Start(ctx context.Context) error {
+	s.log.Info("listening", "addr", s.httpServer.Addr)
+
+	errCh := make(chan error, 1)
+	go func() {
+		if err := s.httpServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			errCh <- err
+		}
+	}()
+
+	select {
+	case err := <-errCh:
+		return err
+	case <-ctx.Done():
+		shutCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+		s.log.Info("shutting down")
+		return s.httpServer.Shutdown(shutCtx)
+	}
+}