engine refactor

internal/api/async/handler.go

@@ -0,0 +1,63 @@
+package async
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"predictor-refactored/internal/api/httpjson"
+	"predictor-refactored/internal/api/v2"
+)
+
+// Handler implements the /api/v1/predictions{,/{id}} endpoints.
+type Handler struct {
+	mgr *Manager
+}
+
+// NewHandler wires a handler.
+func NewHandler(mgr *Manager) *Handler { return &Handler{mgr: mgr} }
+
+// Register installs the async routes on mux.
+func (h *Handler) Register(mux *http.ServeMux) {
+	mux.HandleFunc("POST /api/v1/predictions", h.create)
+	mux.HandleFunc("GET /api/v1/predictions/{id}", h.get)
+	mux.HandleFunc("DELETE /api/v1/predictions/{id}", h.cancel)
+}
+
+func (h *Handler) create(w http.ResponseWriter, r *http.Request) {
+	var req v2.PredictionRequest
+	dec := json.NewDecoder(r.Body)
+	dec.DisallowUnknownFields()
+	if err := dec.Decode(&req); err != nil {
+		writeError(w, http.StatusBadRequest, "invalid body: "+err.Error())
+		return
+	}
+	info, accepted := h.mgr.Enqueue(req)
+	if !accepted {
+		writeJSON(w, http.StatusServiceUnavailable, info)
+		return
+	}
+	w.Header().Set("Location", "/api/v1/predictions/"+info.ID)
+	writeJSON(w, http.StatusAccepted, info)
+}
+
+func (h *Handler) get(w http.ResponseWriter, r *http.Request) {
+	id := r.PathValue("id")
+	info, ok := h.mgr.Get(id)
+	if !ok {
+		writeError(w, http.StatusNotFound, "prediction job not found")
+		return
+	}
+	writeJSON(w, http.StatusOK, info)
+}
+
+func (h *Handler) cancel(w http.ResponseWriter, r *http.Request) {
+	id := r.PathValue("id")
+	if !h.mgr.Cancel(id) {
+		writeError(w, http.StatusConflict, "job not found or already terminal")
+		return
+	}
+	w.WriteHeader(http.StatusNoContent)
+}
+
+var writeJSON = httpjson.Write
+var writeError = httpjson.Error