Tasks in the GUI/Tui

Task & Job States

Tasks are a workflow abstraction; they represent future and past jobs as well as current active jobs. In the Cylc UI, task states have monochromatic icons like this: .

Jobs represent real job scripts submitted to run on a job platform. In the Cylc UI, job states have coloured icons like this: .

A single task can have multiple jobs, by automatic retry or manual triggering.

State	Task Icon	Job Icon	Description
waiting			waiting on prerequisites
preparing			job being prepared for submission
submitted			job submitted
running			job running
succeeded			job succeeded
failed			job failed
submit-failed			job submission failed
expired			will not submit job (too far behind)

The running task icon contains a clock face which shows the time elapsed as a proportion of the average runtime.

Task Modifiers

Tasks are run as soon as their dependencies are satisfied, however, there are some other conditions which can prevent tasks from being run. These are given “modifier” icons which appear to the top-left of the task icon:

	Held: Task has been manually held back from running.
	Runahead: Task is held back by the runahead limit.
	Skip Mode: Task has/will be run in skip mode.
	Queued: Task has been held back by an internal queue.
	Retry: Task is waiting to retry.
	Wallclock: Task is waiting for a clock trigger.
	Xtriggered: Task is waiting for an xtrigger.

The “n” Window

Changed in version 8.0.0.

Cylc workflow graphs can be very large, or infinite in extent for cycling workflows with no final cycle point.

Consequently the GUI often can’t display “all of the tasks” at once. Instead it displays all tasks in a configurable n-window around the current active tasks.

n=0:

The n=0 window contains current active tasks: those that are near ready to run, running, or which may require user intervention.

n=1:

The n=1 window contains the n=0 tasks plus those out to one graph edge around them in the graph.

n=2:

The n=2 window extends out to two graph edges from n=0.

This animation shows how the n-window advances as a workflow runs, tasks are colour coded according to their n-window value with the colours changing from n=0 (blue) to n=8 (pink):

By default the GUI/Tui displays the n=1 window. You can change this using the “Set Graph Window Extent” command which is currently only available in the GUI.

Note

The “graph window extent” is a property of the workflow not a property of the GUI so persists between sessions. Better visibility and easier control over the n-window are planned in future releases of Cylc.

Warning

High “graph window extent” values can cause a Cylc scheduler and the GUI to run slowly.

Dimmed Tasks

Changed in version cylc-ui: 2.15.0

Previously only tasks in the none flow were dimmed. Now all tasks outside of the n=0 window are dimmed.

In the GUI’s tree, table and graph views, tasks (and families) which are not in the n=0 window, i.e. those with an n value greater than zero, are displayed dimmed (greyed out):

• Tasks shown at full opacity are active tasks (n=0). These are the tasks the scheduler is currently managing, e.g. running jobs, or tasks waiting on a prerequisite, xtrigger, internal queue, the runahead limit, or on being resumed.

• Tasks shown dimmed are inactive tasks (n>0). These are past or future tasks, pulled into the view to provide context. The scheduler is not currently managing them, although you can still act on them, e.g. by triggering them.

In this example (the tree view), eventually_succeeded, succeeded and waiting lie outside of the active window so are dimmed. The tasks left at full opacity — failed, retrying, checkpoint and sleepy — are the n=0 tasks that Cylc is actively managing.

This makes it easy to see, at a glance, which part of the workflow Cylc is actually working on.

Note

Dimming is based on a task’s position in the n-window, not on its flow numbers. Tasks triggered in the none flow are typically outside of the n=0 window, so they will usually appear dimmed too. To check a task’s flows, click on it and look at the “Flows” field in the info view.