Prototype with single host server and no admin panel (#2)

Reviewed-on: wrenn/sandbox#2
Co-authored-by: pptx704 <rafeed@omukk.dev>
Co-committed-by: pptx704 <rafeed@omukk.dev>

internal/api/middleware.go

@@ -0,0 +1,122 @@
+package api
+
+import (
+	"bufio"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"log/slog"
+	"net"
+	"net/http"
+	"strings"
+	"time"
+
+	"connectrpc.com/connect"
+)
+
+type errorResponse struct {
+	Error errorDetail `json:"error"`
+}
+
+type errorDetail struct {
+	Code    string `json:"code"`
+	Message string `json:"message"`
+}
+
+func writeJSON(w http.ResponseWriter, status int, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	_ = json.NewEncoder(w).Encode(v)
+}
+
+func writeError(w http.ResponseWriter, status int, code, message string) {
+	writeJSON(w, status, errorResponse{
+		Error: errorDetail{Code: code, Message: message},
+	})
+}
+
+// agentErrToHTTP maps a Connect RPC error to an HTTP status, error code, and message.
+func agentErrToHTTP(err error) (int, string, string) {
+	switch connect.CodeOf(err) {
+	case connect.CodeNotFound:
+		return http.StatusNotFound, "not_found", err.Error()
+	case connect.CodeInvalidArgument:
+		return http.StatusBadRequest, "invalid_request", err.Error()
+	case connect.CodeFailedPrecondition:
+		return http.StatusConflict, "conflict", err.Error()
+	default:
+		return http.StatusBadGateway, "agent_error", err.Error()
+	}
+}
+
+// requestLogger returns middleware that logs each request.
+func requestLogger() func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			start := time.Now()
+			sw := &statusWriter{ResponseWriter: w, status: http.StatusOK}
+			next.ServeHTTP(sw, r)
+			slog.Info("request",
+				"method", r.Method,
+				"path", r.URL.Path,
+				"status", sw.status,
+				"duration", time.Since(start),
+			)
+		})
+	}
+}
+
+func decodeJSON(r *http.Request, v any) error {
+	return json.NewDecoder(r.Body).Decode(v)
+}
+
+// serviceErrToHTTP maps a service-layer error to an HTTP status, code, and message.
+// It inspects the underlying Connect RPC error if present, otherwise returns 500.
+func serviceErrToHTTP(err error) (int, string, string) {
+	msg := err.Error()
+
+	// Check for Connect RPC errors wrapped by the service layer.
+	var connectErr *connect.Error
+	if errors.As(err, &connectErr) {
+		return agentErrToHTTP(connectErr)
+	}
+
+	// Map well-known service error patterns.
+	switch {
+	case strings.Contains(msg, "not found"):
+		return http.StatusNotFound, "not_found", msg
+	case strings.Contains(msg, "not running"), strings.Contains(msg, "not paused"):
+		return http.StatusConflict, "invalid_state", msg
+	case strings.Contains(msg, "forbidden"):
+		return http.StatusForbidden, "forbidden", msg
+	case strings.Contains(msg, "invalid"):
+		return http.StatusBadRequest, "invalid_request", msg
+	default:
+		return http.StatusInternalServerError, "internal_error", msg
+	}
+}
+
+type statusWriter struct {
+	http.ResponseWriter
+	status int
+}
+
+func (w *statusWriter) WriteHeader(status int) {
+	w.status = status
+	w.ResponseWriter.WriteHeader(status)
+}
+
+// Hijack implements http.Hijacker, required for WebSocket upgrade.
+func (w *statusWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	if hj, ok := w.ResponseWriter.(http.Hijacker); ok {
+		return hj.Hijack()
+	}
+	return nil, nil, fmt.Errorf("underlying ResponseWriter does not implement http.Hijacker")
+}
+
+// Flush implements http.Flusher, required for streaming responses.
+func (w *statusWriter) Flush() {
+	if fl, ok := w.ResponseWriter.(http.Flusher); ok {
+		fl.Flush()
+	}
+}