vr: plugin options not respected when workflow is running

[oliver-sanders]

The -S option does not take effect with the cylc vr command in the situation where the workflow is already running (i.e. the reload case).

Reproducible Example:

#!Jinja2

[scheduling]
    [[graph]]
        R1 = a

[runtime]
    [[a]]
        script = echo {{ VAR }}

$ cylc vip --pause -S VAR=1
$ cylc vr <id> -S VAR=2
$ cd ~/cylc-run/<id>

VAR is updated in the Rose files:

$ cat opt/rose-suite-cylc-install.conf
...
[template variables]
VAR=2

But not in the Cylc files:

$ cat log/config/02-reload-01.cylc
...
[runtime]
    [[a]]
        script = echo 1
$ cat log/config/flow-processed.cylc
...
[runtime]
    [[a]]
        script = echo 1

Example derived from: https://cylc.discourse.group/t/jinja2-variable-differences-in-config-files-new-ones-are-not-being-respected/885/6

How it's supposed to work:

• The -S option is provided by cylc-rose and applies to (re)install.
• When you provide the -S option, it writes the input to the cylc-install optional config (~/cylc-run/<workflow>/opt/rose-suite-cylc-install.conf).
• When the workflow is reloaded, the cylc-rose plugin is automatically invoked.
• It reads these inputs from the cylc-install optional config and makes them available for the parsing of the workflow configuration.

Ongoing Work

Note, there have been recent changes (unreleased) to the reinstall code and there are pending changes to the way the plugins are run: #5868

Suggest reproducing and fixing on top of that branch.

[oliver-sanders]

The root cause of this bug is that the CLI options are held in memory, they are subsequently re-used to re-load the workflow config:

cylc-flow/cylc/flow/scheduler.py

Lines 1272 to 1287 in 8ab57ad

	return WorkflowConfig(
	self.workflow,
	self.flow_file,
	self.options,
	self.template_vars,
	xtrigger_mgr=self.xtrigger_mgr,
	mem_log_func=self.profiler.log_memory,
	output_fname=os.path.join(
	self.workflow_run_dir, 'log', 'config',
	workflow_files.WorkflowFiles.FLOW_FILE_PROCESSED
	),
	run_dir=self.workflow_run_dir,
	log_dir=self.workflow_log_dir,
	work_dir=self.workflow_work_dir,
	share_dir=self.workflow_share_dir,
	)

Inspecting the options at this point will reveal the previous value:

opts.rose_template_vars
['VAR=1', 'ROSE_ORIG_HOST=vld601.cmpd1.metoffice.gov.uk']

This makes it look like the plugin as if -S VAR=1 had been specified on the command line which overrides the VAR=2 value present in the optional configuration.

This diff fixes the problem:

diff --git a/cylc/flow/scheduler.py b/cylc/flow/scheduler.py
index ec3ba6f0c..f6bda8ca6 100644
--- a/cylc/flow/scheduler.py
+++ b/cylc/flow/scheduler.py
@@ -1269,6 +1269,7 @@ class Scheduler:
     def load_flow_file(self, is_reload=False):
         """Load, and log the workflow definition."""
         # Local workflow environment set therein.
+        self.options.rose_template_vars = []
         return WorkflowConfig(
             self.workflow,
             self.flow_file,

But it's a bit ugly!

Not sure what nicer options might be available, things to consider:

• Do any other cylc-rose options need clearing?
• Do any cylc-rose options need to be preserved, e.g. for auto-restart?

[wxtim]

• Do any other cylc-rose options need clearing?

I'd guess that -D should be checked, although I suspect that from Cylc's point of view it might well be stored in the same place as -S & Should be fixed by this change.

Worth checking, but logically -O shouldn't be a problem, since that works entirely in the plugin layer, and isn't really used by Cylc.

• Do any cylc-rose options need to be preserved, e.g. for auto-restart?

I should check whether -O is preserved on restart. It ought to be.

[oliver-sanders]

I should check whether -O is preserved on restart. It ought to be.

This will be tested in cylc-rose.

[wxtim]

Have checked. Definately need to do the same with -D

[oliver-sanders]

Closed by #5996 and cylc-rose changes.