feat(schedules): add the ability to list tasks from snapshots (#2458)

* feat(schedules): add the ability to list tasks from snapshots

* feat(schedules): update schedules

* refactor(schedules): fix linting issue

api/http/handler/schedules/schedule_tasks.go

@@ -0,0 +1,87 @@
+package schedules
+
+import (
+	"encoding/json"
+	"errors"
+	"net/http"
+	"strconv"
+
+	httperror "github.com/portainer/libhttp/error"
+	"github.com/portainer/libhttp/request"
+	"github.com/portainer/libhttp/response"
+	"github.com/portainer/portainer"
+)
+
+type taskContainer struct {
+	ID         string               `json:"Id"`
+	EndpointID portainer.EndpointID `json:"EndpointId"`
+	Status     string               `json:"Status"`
+	Created    float64              `json:"Created"`
+	Labels     map[string]string    `json:"Labels"`
+}
+
+// GET request on /api/schedules/:id/tasks
+func (handler *Handler) scheduleTasks(w http.ResponseWriter, r *http.Request) *httperror.HandlerError {
+	scheduleID, err := request.RetrieveNumericRouteVariableValue(r, "id")
+	if err != nil {
+		return &httperror.HandlerError{http.StatusBadRequest, "Invalid schedule identifier route variable", err}
+	}
+
+	schedule, err := handler.ScheduleService.Schedule(portainer.ScheduleID(scheduleID))
+	if err == portainer.ErrObjectNotFound {
+		return &httperror.HandlerError{http.StatusNotFound, "Unable to find a schedule with the specified identifier inside the database", err}
+	} else if err != nil {
+		return &httperror.HandlerError{http.StatusInternalServerError, "Unable to find a schedule with the specified identifier inside the database", err}
+	}
+
+	if schedule.JobType != portainer.ScriptExecutionJobType {
+		return &httperror.HandlerError{http.StatusBadRequest, "Unable to retrieve schedule tasks", errors.New("This type of schedule do not have any associated tasks")}
+	}
+
+	tasks := make([]taskContainer, 0)
+
+	for _, endpointID := range schedule.ScriptExecutionJob.Endpoints {
+		endpoint, err := handler.EndpointService.Endpoint(endpointID)
+		if err == portainer.ErrObjectNotFound {
+			continue
+		} else if err != nil {
+			return &httperror.HandlerError{http.StatusInternalServerError, "Unable to find an endpoint with the specified identifier inside the database", err}
+		}
+
+		endpointTasks, err := extractTasksFromContainerSnasphot(endpoint, schedule.ID)
+		if err != nil {
+			return &httperror.HandlerError{http.StatusInternalServerError, "Unable to find extract schedule tasks from endpoint snapshot", err}
+		}
+
+		tasks = append(tasks, endpointTasks...)
+	}
+
+	return response.JSON(w, tasks)
+}
+
+func extractTasksFromContainerSnasphot(endpoint *portainer.Endpoint, scheduleID portainer.ScheduleID) ([]taskContainer, error) {
+	endpointTasks := make([]taskContainer, 0)
+	if len(endpoint.Snapshots) == 0 {
+		return endpointTasks, nil
+	}
+
+	b, err := json.Marshal(endpoint.Snapshots[0].SnapshotRaw.Containers)
+	if err != nil {
+		return nil, err
+	}
+
+	var containers []taskContainer
+	err = json.Unmarshal(b, &containers)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, container := range containers {
+		if container.Labels["io.portainer.schedule.id"] == strconv.Itoa(int(scheduleID)) {
+			container.EndpointID = endpoint.ID
+			endpointTasks = append(endpointTasks, container)
+		}
+	}
+
+	return endpointTasks, nil
+}