[API] Add stop upgrade endpoint

cmd/gendoc/docs.go

@@ -824,6 +824,21 @@ Contains a JSON object with the details of an error.
 				{StatusCode: http.StatusNoContent, Reference: "#/components/responses/NoContent"},
 			},
 		},
+		{
+			OperationId: "stopUpdate",
+			Method:      http.MethodPut,
+			Path:        "/v1/system/update/stop",
+			CustomSuccessResponse: &CustomResponseDef{
+				Description: "Successful response",
+				StatusCode:  http.StatusOK,
+			},
+			Description: "Stop the upgrade process.",
+			Summary:     "Stop the upgrade process in background",
+			Tags:        []Tag{SystemTag},
+			PossibleErrors: []ErrorResponse{
+				{StatusCode: http.StatusConflict, Reference: "#/components/responses/Conflict"},
+			},
+		},
 		{
 			OperationId: "applyUpdate",
 			Method:      http.MethodPut,

internal/api/api.go

@@ -66,6 +66,7 @@ func NewHTTPRouter(
 	mux.Handle("GET /v1/system/update/check", handlers.HandleCheckUpgradable(updater))
 	mux.Handle("GET /v1/system/update/events", handlers.HandleUpdateEvents(updater))
 	mux.Handle("PUT /v1/system/update/apply", handlers.HandleUpdateApply(updater))
+	mux.Handle("PUT /v1/system/update/stop", handlers.HandlerUpdateStop(updater))
 	mux.Handle("GET /v1/system/resources", handlers.HandleSystemResources())
 
 	mux.Handle("GET /v1/models", handlers.HandleModelsList(modelsIndex))

internal/api/docs/openapi.yaml

@@ -1080,6 +1080,18 @@ paths:
       summary: SSE stream of the update process
       tags:
       - System
+  /v1/system/update/stop:
+    put:
+      description: Stop the upgrade process.
+      operationId: stopUpdate
+      responses:
+        "200":
+          description: Successful response
+        "409":
+          $ref: '#/components/responses/Conflict'
+      summary: Stop the upgrade process in background
+      tags:
+      - System
   /v1/version:
     get:
       description: returns the application current version

internal/api/handlers/update.go

@@ -107,6 +107,16 @@ func HandleUpdateApply(updater *update.Manager) http.HandlerFunc {
 	}
 }
 
+func HandlerUpdateStop(updater *update.Manager) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if updater.StopUpgrade() {
+			render.EncodeResponse(w, http.StatusOK, "Upgrade operation cancellation requested")
+		} else {
+			render.EncodeResponse(w, http.StatusConflict, models.ErrorResponse{Details: "No upgrade operation in progress"})
+		}
+	}
+}
+
 func HandleUpdateEvents(updater *update.Manager) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		sseStream, err := render.NewSSEStream(r.Context(), w)