This page contains a summary of significant changes across all Cylc components for each release.
For more detail see the component changelogs:
- cylc-flow-changelog
- cylc-uiserver-changelog
- cylc-ui-changelog
- cylc-rose-changelog
- metomi-rose-changelog
- metomi-isodatetime-changelog
Various Cylc commands (e.g. cylc trigger, cylc set and cylc hold)
allow us to select the tasks we want to operate on using cycle points,
family names or globs, e.g:
# trigger active tasks in cycle "2000"
cylc trigger workflow//2000
# trigger active tasks in "FAMILY" in cycle "2000"
cylc trigger workflow//2000/FAMILY
# trigger all tasks in cycle "2000" with names starting with "foo"
cylc trigger workflow//2000/foo*However, prior to 8.6 family names and globs would only match :term:`active tasks <active task>`. So, if you attempted to hold a family of tasks, Cylc would only hold the members of the family which were active at the time.
As of Cylc 8.6.0, this restriction has been lifted, so for example, holding a family will now hold all tasks within the family, irrespective of whether they are active or not.
# hold all tasks in "FAMILY" at cycle "2000"
cylc hold workflow//2000/FAMILY
# re-run all tasks in cycle "2000" (in order)
cylc trigger workflow//2000
# mark all tasks beginning with "foo" in cycle "2000" as "succeeded"
cylc set workflow//2000/foo* --out=succeededBecause Cylc workflows can be infinite, if a cycle includes a "glob" pattern
(e.g. *), this will only match :term:`active cycles <active cycle>`
(any cycle which contains at least one :term:`active task`), e.g:
# remove the task "foo" from all active cycles of the workflow
cylc remove workflow//*/foo
# release all tasks in "FAMILY" in all active cycles of the workflow
cylc release workflow//*/FAMILYThis (combined with :ref:`changes.8.5.0.triggering_multiple_tasks`) makes Cylc 7 "reset to waiting" use cases much easier:
| Cylc 7 | Cylc 8 |
cylc insert workflow FAMILY.cycle cylc reset workflow FAMILY.cycle --state=waiting # Trigger the task(s) that start the FAMILY sub-graph cylc trigger workflow member1.cycle |
cylc trigger workflow//cycle/FAMILY |
For more information on Cylc IDs, run cylc help id.
The initial and final cycle points in a workflow can now be referenced in
commands using the ^ and $ symbols, e.g:
```bash # trigger "mytask" at the initial cycle point cylc trigger myworkflow//^/mytask
# set required outputs for "mytask" at the final cycle point cylc set myworkflow//$/mytask
# remove all tasks at the final cycle point cylc remove myworkflow//$
The minimum supported Python version is now 3.12.
Task now icons in the GUI and TUI have badges for tasks waiting for:
- retries |task-retry|
- xtriggers |task-xtriggered|
- wallclock |task-wallclock|
Xtriggers, wallclock triggers, retry triggers and task run mode are now shown in the information view:
Cylc now respects the dependencies between tasks when triggering multiple tasks at the same time. This provides an easy way to re-run a group of tasks in order:
This is generally easier than :ref:`using a new flow <interventions.reflow>`.
Technical details:
- Prerequisites on any tasks that are outside of the group of tasks being triggered are automatically satisfied.
- Any tasks which have already run within the group will be automatically
removed (i.e.
cylc remove) to allow them to be re-run without intervention. - Any preparing, submitted or running tasks within the group will also be removed if necessary to allow the tasks to re-run in order.
The GUI now has warning triangles, these "light up" whenever warnings occur in the workflow.
- Cylc logs warnings for various things such as task failures, stalled workflows, and command errors. You can see these in the workflow log files.
- When warnings occur, the warning triangle will illuminate for the corresponding workflow.
- Hover over the icon to reveal the warning.
- Click on the icon to dismiss the warning.
- If workflows are installed hierarchically, (e.g. the "development" and "live" groups in this example), warnings will trickle up the hierarchy to make it easier to monitor groups of workflows.
- A log of all warnings can be found on the Dashboard page (last 10 warnings for each workflow).
The GUI and Tui now present some tasks in grey:
These are "ghost" tasks, they indicate something is that isn't presently there:
- Waiting tasks that the scheduler hasn't moved onto yet (i.e. :term:`inactive tasks <active task>` that are waiting).
- Tasks which have been removed (i.e.
cylc remove). - Tasks which have been triggered in the
noneflow, so don't influence the evolution of the workflow.
They appear in grey, if you click on these tasks, you will see the text "Flows: None".
This helps to identify waiting :term:`active tasks <active task>` (which aren't ghosts). These are the tasks which Cylc is currently trying to schedule, but are waiting for something, typically:
- A task prerequisite to be satisfied.
- An xtrigger or ext-trigger to be satisfied.
- Someone to :term:`resume <held task>` them.
:ref:`Cylc 7 compatibility mode <cylc_7_compat_mode>` has been deprecated, it will be removed in Cylc 8.7.0 which is expected to be released some time in the first half of 2026.
Any workflows that are still using suite.rc files will need to be upgraded
to flow.cylc before they are able to run with 8.7.0.
The Cylc GUI now preserves tab layout between sessions.
When working on a workflow, we can open multiple tabs (tree, table, graph, etc) and tile them up in a layout. If you switch to another workflow, switch back, your layout will be restored.
However, with Cylc 8.4, if you refreshed the browser or opened the GUI in a new tab, the layout would be lost.
With Cylc 8.5, the layout will always be restored.
The GUI now picks the default job log file to display based on the task state:
- failed ->
job.err - submit-failed ->
job-activity.log - otherwise ->
job.out
This speeds up the loading of the log file because the GUI doesn't have to wait for a listing of available log files before picking one to view.
Additionally, the log view now has an auto scroll feature which follows the end of the file (useful for viewing the file whilst it is being written), and a scroll-to-top button.
cylc tui can now open log files in external tools.
Configure your $EDITOR, $GEDITOR and $PAGER environment variables
to change which tool is used.
Note
Make sure your configured command waits for the tool to be closed before
exiting, e.g. use GEDITOR=gvim -f rather than EDITOR=gvim.
Additionally, Tui now displays task states and :term:`flow` numbers in context menus for improved clarity / accessibility.
cylc reload now has a --global option to reload the global
configuration while the server is running. This can be used to update platform
settings for an in-progress workflow.
.. seealso::
:ref:`global-configuration`
The cylc set command can now be used to satisfy xtrigger prerequisites.
For example if the task 2026/get_data is
:term:`clock triggered <clock trigger>`, you might satisfy this prerequisite
like so:
$ cylc set myworkflow//2026/get_data --pre xtrigger/wall_clockThe default behaviour of the cylc set command has also changed for tasks
where success is :term:`optional <optional output>`, it will now set the
succeeded output (and any other outputs that are required in the event of
task success) which is more consistent with the behaviour for tasks where
success is required.
A new per-cycle share directory has been added, share/cycle/<cycle>.
This directory is now automatically created and provides a convenient location for tasks to share cycle-specific data. See also :ref:`Shared Task IO Paths`.
This largely replicates the functionality of the Rose :envvar:`ROSE_DATAC`
environment variable, but does not require the use of rose task-env.
The dependency stack of the Cylc UI Server (used to serve the Cylc GUI) has been overhauled.
This allows the UI Server to be installed with newer versions of Python then the old dependency stack allowed.
- Previously the UI Server worked with Python 3.8-3.9.
- It now works with Python 3.9 or higher.
This will likely bring efficiency improvements.
Additionally, the Cylc UI Server has now been configured to send "heartbeat" pings down its open websocket connections. This helps to prevent web proxies from closing Cylc GUI connections when workflows are idle, preventing erroneous GUI disconnects.
For more information see the
Cylc configuration
and the docs for the websocket_ping_interval and websocket_ping_timeout
configurations in
tornado.
.. versionadded:: cylc-flow 8.4.1
Fixed wrapper script $PATH override preventing selection of Cylc version
when playing workflows in the GUI on :ref:`Cylc Hub`.
Important
Sites with existing wrapper scripts should update them with this change: https://github.com/cylc/cylc-flow/pull/6616/files.
.. seealso:: :ref:`managing environments`
cylc remove now allows removing tasks which are no longer active, making
it look like they never ran. Removing a running task will now kill that task.
The cylc remove command now has the --flow option, allowing removal
of a task from specific flows.
Tasks removed from all flows are retained in the workflow database with
flow=none for provenance.
.. seealso:: See :ref:`interventions.remove_tasks` to see an example of this feature in action.
Tasks can now be run in "skip" mode where they complete their required outputs instantly. Tasks can be configured to run in skip mode either in the workflow configuration or by broadcasting.
cylc set --out skip will set outputs for a task as if the task has run
in skip mode. The task outputs delivered by skip mode can be customized using
:cylc:conf:`[runtime][<namespace>][skip]outputs` or defaults to behaviour
described in :ref:`skip_mode.task_outputs`.
This can be used to skip a cycle or a task (for a full example see :ref:`interventions.skip_cycle`).
It may also be useful for :ref:`EfficientInterFamilyTriggering` and for :ref:`skip_mode.parameter_exclusion`.
.. seealso:: :ref:`task-run-modes.skip`
Tasks can now be triggered and will run immediately while the workflow is paused.
.. seealso:: :ref:`interventions.trigger_while_paused` for an example of this feature.
Support for the EmPy template processor (an alternative to Jinja2) has been removed.
An info view has been added, displaying
- :cylc:conf:`[runtime][<namespace>][meta]`.
- :ref:`task ouputs<required outputs>`.
- Task :term:`prerequisite`.
- Task :term:`output completion condition`.
At Cylc 8.3.0, the cylc set-outputs command has been replaced by the new
cylc set command.
The cylc set-outputs command made it look like an output had been generated
to downstream tasks, but did not update the task status to match. As a result,
it was often necessary to use cylc remove in combination with cylc
set-outputs.
The new cylc set command is able to directly set task outputs as if they
had completed naturally, making the command more intuitive and avoiding the
need for cylc remove. It can also set prerequisites, as if they were satisfied naturally.
For example, say there's a failed task holding up your workflow and you want Cylc to continue as if the task had succeeded. Here are the interventions you would need to perform with Cylc 8.2 and 8.3 side-by-side.
| Cylc 8.2 (set-outputs) | Cylc 8.3 (set) |
# let downstream tasks run:
cylc set-outputs <task>
# remove the failed task:
cylc remove <task> |
# tell Cylc that the task succeeded:
cylc set <task> |
|
|
The Tui (terminal user interface) is a command line version of the Gui. You can use it to monitor and control your workflows.
There has been a major update to Tui at Cylc 8.3.0:
- Larger workflows will no longer cause Tui to time out.
- You can now browse all your workflows including stopped workflows.
- You can monitor multiple workflows at the same time.
- The workflow and job logs are now available from within Tui.
The :term:`n-window` determines how much of a workflow is visible in the GUI / Tui.
You can change the n-window extent in the GUI with a toolbar button, to display more or less of the graph around current :term:`active tasks <active task>`. This affects all GUI views equally, not just the graph view.
The n=0 window contains only the active tasks.
The n=1 window displays tasks out to one graph edge around the active
tasks; n=2 out to two graph edges; and so on.
Note
This is currently a per-workflow setting so changing the n-window in one browser tab will also change it in other browser tabs and Tui sessions.
Warning
Using high n-window values with complex workflows may have performance impacts.
The graph view now has an option to group tasks by cycle point.
The GUI now has a Gantt view option:
New Analysis added - a layout which plots run times against cycle points.
When a task achieves a final status, its outputs are validated against a "completion expression" to ensure that it has produced all of its :term:`required outputs <required output>`. If a task fails this validation check it is said to have "incomplete outputs" and will be retained in the :term:`n=0 window <n-window>` pending user intervention.
This completion expression is generated automatically from the graph. By default, tasks are expected to succeed, if you register any additional required output in the graph, then these must also be produced.
At Cylc 8.3.0 it is now possible to manually configure this completion expression for finer control. This is particularly useful for anyone using :term:`custom outputs <custom output>`.
For example, mytask must produce one of the outputs x or y to pass
the completion expression configured here:
[runtime]
[[mytask]]
completion = succeeded and (x or y)
[[[outputs]]]
x = output-x
y = output-yFor more information, see the reference for the :cylc:conf:`[runtime][<namespace>]completion` configuration.
Workflow state xtriggers and command now take Cylc universal IDs instead of separate arguments:
For example, you can (and should) now write:
# On the command line
- cylc workflow-state my-workflow --point 20240101 --task mytask --message "succeeded"
+ cylc workflow-state my-workflow//20240101/mytask:succeeded --triggers
# In the flow.cylc file
- my_xtrigger = workflow_state(
- workflow="my-workflow",
- task="mytask",
- point="20240101",
- message="succeeded"
- )
+ my_xtrigger = workflow_state('my-workflow//20240101/mytask:succeeded', is_trigger=True)Important
The new workflow state trigger syntax can use either the trigger or message from
trigger=message in :cylc:conf:`[runtime][<namespace>][outputs]`.
The trigger and message are the same for the most common use cases (succeeded and started)
but may differ for other outputs, namely :term:`custom outputs <custom output>`.
Note
The suite-state xtrigger has been reimplemented for compatibility with
Cylc 7 workflows.
.. versionadded:: cylc-uiserver 1.4.4
The UI now remembers the layout of your workspace tabs when you navigate away from that workflow. Note that this only applies per browser session.
Cylc now ignores $PYTHONPATH to make it more robust to task
environments which set this value. If you want to add to the Cylc
environment itself, e.g. to install a Cylc extension,
use a custom xtrigger, or event handler use $CYLC_PYTHONPATH.
.. versionadded:: cylc-uiserver 1.4.0
The Cylc UI Server has been updated to work with the latest releases of `Jupyter Server`_ and `Jupyter Hub`_.
If you are utilising Cylc's multi-user functionality then your configuration will require some changes to work with these releases.
See :ref:`cylc.uiserver.multi-user` for more details
.. versionadded:: cylc-uiserver 1.3.0
You can now configure the view which is opened by default when you navigate to a new workflow in the GUI. Navigate to the settings page to select your chosen view.
In the future we plan to support configuring a layout of multiple views and configuring certain options on those views.
.. versionadded:: cylc-flow 8.2.0
When workflows are
:ref:`reloaded <Reloading The Workflow Configuration At Runtime>`,
(e.g. by cylc reload), Cylc will now pause the workflow and wait for any
preparing tasks to be submitted before proceeding with the reload.
Once the reload has been completed, the workflow will be resumed.
You can now see more information about the status of the reload in the workflow status message which appears at the top of the GUI and Tui interfaces.
Warning
Workflows started with Cylc 8.0 which contain multiple :term:`flows <flow>` cannot be restarted with Cylc 8.1 due to database changes.
.. versionadded:: cylc-uiserver 1.2.2
The web UI also has a new view for displaying task queue & run time statistics.
.. versionadded:: cylc-uiserver 1.2.0
The web UI now has a graph view which displays a visualisation of a workflow's graph:
Family & cycle grouping as well as the ability to view graphs for stopped workflows will be added in later releases.
.. versionadded:: cylc-uiserver 1.2.0
The web UI now has a log view which displays workflow and job log files:
Support for viewing more log files, syntax highlighting, searching and line numbers are planned for future releases.
.. versionadded:: cylc-uiserver 1.2.0
The web UI now has a command for editing the :cylc:conf:`[runtime]` section of a task or family.
Any changes made are :ref:`broadcast <cylc-broadcast>` to the running workflow.
.. versionadded:: cylc-flow 8.1.0
Two new commands have been added as short-cuts for common working patterns:
cylc vipValidate, install and plays a workflow, equivalent to:
cylc validate <path> cylc install <path> cylc play <id>
cylc vr- Validate and reinstall a workflow, then either: - reload the workflow if it is running. - restart the workflow if it is stopped.
For more information see the command line help:
cylc vip --help
cylc vr --help.. versionadded:: cylc-flow 8.1.0
Cylc now provides a high performance Bash completion script which saves you typing:
- Cylc commands & options
- Workflow IDs
- Cycle points
- Task names
- Job numbers
:ref:`Installation instructions <installation.shell_auto_completion>`.
The first official release of Cylc 8.
For a summary of changes see the :ref:`migration guide<728.overview>`.