dump: restrict window to n=0 (#5600)

This restores the old `cylc dump` behaviour of displaying only the pool contents.

changes.d/5600.break.md

@@ -0,0 +1,3 @@
+The `cylc dump` command now only shows active tasks (e.g. running & queued
+tasks). This restores its behaviour of only showing the tasks which currently
+exist in the pool as it did in Cylc 7 and earlier versions of Cylc 8.

cylc/flow/scripts/dump.py

@@ -20,6 +20,9 @@
 
 Print information about a running workflow.
 
+This command can provide information about active tasks, e.g. running or queued
+tasks. For more detailed view of the workflow see `cylc tui` or `cylc gui`.
+
 For command line monitoring:
 * `cylc tui`
 * `watch cylc dump WORKFLOW_ID` works for small simple workflows
@@ -28,20 +31,21 @@
 its prerequisites and outputs, see 'cylc show'.
 
 Examples:
-  # Display the state of all running tasks, sorted by cycle point:
+  # Display the state of all active tasks, sorted by cycle point:
   $ cylc dump --tasks --sort WORKFLOW_ID | grep running
 
-  # Display the state of all tasks in a particular cycle point:
+  # Display the state of all active in a particular cycle point:
   $ cylc dump -t WORKFLOW_ID | grep 2010082406
 """
 
-from graphene.utils.str_converters import to_snake_case
+import asyncio
 import json
-import sys
 from typing import TYPE_CHECKING
 
+from graphene.utils.str_converters import to_snake_case
+
 from cylc.flow.exceptions import CylcError
-from cylc.flow.id_cli import parse_id
+from cylc.flow.id_cli import parse_id_async
 from cylc.flow.option_parsers import (
     WORKFLOW_ID_ARG_DOC,
     CylcOptionParser as COP,
@@ -59,6 +63,7 @@
   name
   cyclePoint
   state
+  graphDepth
   isHeld
   isQueued
   isRunahead
@@ -179,7 +184,11 @@ def get_option_parser():
 
 @cli_function(get_option_parser)
 def main(_, options: 'Values', workflow_id: str) -> None:
-    workflow_id, *_ = parse_id(
+    asyncio.run(dump(workflow_id, options))
+
+
+async def dump(workflow_id, options, write=print):
+    workflow_id, *_ = await parse_id_async(
         workflow_id,
         constraint='workflows',
     )
@@ -195,6 +204,9 @@ def main(_, options: 'Values', workflow_id: str) -> None:
     else:
         sort_args = {'keys': ['name', 'cyclePoint']}
 
+    # retrict to the n=0 window
+    graph_depth = 0
+
     if options.disp_form == "raw":
         query = f'''
             {TASK_SUMMARY_FRAGMENT}
@@ -203,10 +215,10 @@ def main(_, options: 'Values', workflow_id: str) -> None:
             query ($wFlows: [ID]!, $sortBy: SortArgs) {{
               workflows (ids: $wFlows, stripNull: false) {{
                 ...wFlow
-                taskProxies (sort: $sortBy) {{
+                taskProxies (sort: $sortBy, graphDepth: {graph_depth}) {{
                   ...tProxy
                 }}
-                familyProxies (sort: $sortBy) {{
+                familyProxies (sort: $sortBy, graphDepth: {graph_depth}) {{
                   ...fProxy
                 }}
               }}
@@ -224,7 +236,7 @@ def main(_, options: 'Values', workflow_id: str) -> None:
             {TASK_SUMMARY_FRAGMENT}
             query ($wFlows: [ID]!, $sortBy: SortArgs) {{
               workflows (ids: $wFlows, stripNull: false) {{
-                taskProxies (sort: $sortBy) {{
+                taskProxies (sort: $sortBy, graphDepth: {graph_depth}) {{
                   ...tProxy
                 }}
               }}
@@ -235,15 +247,15 @@ def main(_, options: 'Values', workflow_id: str) -> None:
         'variables': {'wFlows': [workflow_id], 'sortBy': sort_args}
     }
 
-    workflows = pclient('graphql', query_kwargs)
+    workflows = await pclient.async_request('graphql', query_kwargs)
 
     try:
         for summary in workflows['workflows']:
             if options.disp_form == "raw":
                 if options.pretty:
-                    sys.stdout.write(json.dumps(summary, indent=4) + '\n')
+                    write(json.dumps(summary, indent=4))
                 else:
-                    print(summary)
+                    write(summary)
             else:
                 if options.disp_form != "tasks":
                     node_urls = {
@@ -261,7 +273,7 @@ def main(_, options: 'Values', workflow_id: str) -> None:
                     del summary['families']
                     del summary['meta']
                     for key, value in sorted(summary.items()):
-                        print(
+                        write(
                             f'{to_snake_case(key).replace("_", " ")}={value}')
                 else:
                     for item in summary['taskProxies']:
@@ -282,7 +294,7 @@ def main(_, options: 'Values', workflow_id: str) -> None:
                                       else 'not-runahead')
                         if options.show_flows:
                             values.append(item['flowNums'])
-                        print(', '.join(values))
+                        write(', '.join(values))
     except Exception as exc:
         raise CylcError(
             json.dumps(workflows, indent=4) + '\n' + str(exc) + '\n')

tests/functional/runahead/06-release-update.t

@@ -35,7 +35,6 @@ sleep 10
 # (gratuitous use of --flows for test coverage)
 cylc dump --flows -t "${WORKFLOW_NAME}" | awk '{print $1 $2 $3 $7}' >'log'
 cmp_ok 'log' - <<__END__
-bar,$NEXT1,waiting,[1]
 foo,$NEXT1,waiting,[1]
 __END__
 

tests/integration/scripts/test_dump.py

@@ -0,0 +1,52 @@
+# THIS FILE IS PART OF THE CYLC WORKFLOW ENGINE.
+# Copyright (C) NIWA & British Crown (Met Office) & Contributors.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Test the "cylc dump" command."""
+
+from cylc.flow.option_parsers import (
+    Options,
+)
+from cylc.flow.scripts.dump import (
+    dump,
+    get_option_parser,
+)
+
+
+DumpOptions = Options(get_option_parser())
+
+
+async def test_dump_tasks(flow, scheduler, start):
+    """It should show n=0 tasks.
+
+    See: https://github.com/cylc/cylc-flow/pull/5600
+    """
+    id_ = flow({
+        'scheduler': {
+            'allow implicit tasks': 'true',
+        },
+        'scheduling': {
+            'graph': {
+                'R1': 'a => b => c',
+            },
+        },
+    })
+    schd = scheduler(id_)
+    async with start(schd):
+        # schd.release_queued_tasks()
+        await schd.update_data_structure()
+        ret = []
+        await dump(id_, DumpOptions(disp_form='tasks'), write=ret.append)
+        assert ret == ['a, 1, waiting, not-held, queued, not-runahead']