tui: add estimatedFinishTime field

* Add new field.
* Abstract back-compat logic to make it easier to add and maintain
  support for older scheduler versions.

Author: oliver-sanders

cylc/flow/tui/data.py

@@ -17,6 +17,8 @@
 from functools import partial
 from subprocess import Popen, PIPE
 
+from packaging.specifiers import SpecifierSet
+
 from cylc.flow.exceptions import (
     ClientError,
     ClientTimeout,
@@ -31,7 +33,7 @@
 
 # the GraphQL query which Tui runs against each of the workflows
 # is is subscribed to
-QUERY = '''
+_QUERY = '''
   query cli($taskStates: [String]){
     workflows {
       id
@@ -63,6 +65,7 @@
           jobRunnerName
           jobId
           startedTime
+          estimatedFinishTime
           finishedTime
         }
         task {
@@ -105,24 +108,32 @@
   }
 '''
 
-# BACK COMPAT: isRetry, isWallclock, isXtriggered
-# url:
-#     https://github.com/cylc/cylc-flow/pull/6671
-# from:
-#     Cylc 8.4.0
-# to:
-#     Cylc 8.5.0
-# remove at:
-#     Cylc 8.7.0
-#     * set min Cylc version requirement in the updater scan pipeline
-#     * replace `data.get('isRetry', False)` with 1data['isRetry']`, etc
-COMPAT_QUERY = (
-    QUERY
-    .replace('isRetry', '')
-    .replace('isWallclock', '')
-    .replace('isXtriggered', '')
+
+# graphql queries for every version of Cylc that Tui supports:
+_COMPAT_QUERIES = (
+    (
+        # regular query for current and future scheduler versions
+        SpecifierSet('>=8.6.dev'), _QUERY
+    ),
+    (
+        # BACK COMPAT
+        # estimatedFinishTime field added at 8.6.0
+        SpecifierSet('>=8.5.0, <8.6'),
+        _QUERY.replace('estimatedFinishTime', '')
+    ),
+    (
+        # BACK COMPAT
+        # isRetry, isWallclock and isXtriggered fields added at 8.5.0
+        SpecifierSet('>=8, <8.5'),
+        _QUERY
+        .replace('isRetry', '')
+        .replace('isWallclock', '')
+        .replace('isXtriggered', '')
+        .replace('estimatedFinishTime', ''),
+    ),
 )
 
+
 # the list of mutations we can call on a running scheduler
 MUTATIONS = {
     'workflow': [
@@ -160,6 +171,32 @@
 }
 
 
+class VersionIncompat(Exception):
+    ...
+
+
+def get_query(scheduler_version: str) -> str:
+    """Return a GraphQL query compatibile with the provided scheduler version.
+
+    Args:
+        scheduler_version: The version of the scheduler we are connecting to.
+
+    Returns:
+        The GraphQL query string.
+
+    Raises:
+        VersionIncompat:
+            If the scheduler version is not supported.
+
+    """
+    for query_version_range, query in _COMPAT_QUERIES:
+        if scheduler_version in query_version_range:
+            return query
+    raise VersionIncompat(
+        f'Scheduler version {scheduler_version} is not supported'
+    )
+
+
 def cli_cmd(*cmd, ret=False):
     """Issue a CLI command.
 

cylc/flow/tui/updater.py

@@ -28,7 +28,6 @@
 from multiprocessing import Queue
 from time import time
 
-from packaging.version import parse as parse_version
 from zmq.error import ZMQError
 
 from cylc.flow.exceptions import (
@@ -49,7 +48,8 @@
     TASK_STATUSES_ORDERED,
 )
 from cylc.flow.tui.data import (
-    QUERY, COMPAT_QUERY
+    VersionIncompat,
+    get_query,
 )
 from cylc.flow.tui.util import (
     NaturalSort,
@@ -271,15 +271,9 @@ async def _update_workflow(self, w_id, client, data):
             return
 
         try:
-            if (
-                parse_version(client.scheduler_version)
-                < parse_version('8.5.0.dev')
-            ):
-                # BACK COMPAT: isRetry, isWallclock, isXtriggered
-                # (see comment in cylc.flow.tui.data)
-                query = COMPAT_QUERY
-            else:
-                query = QUERY
+            # get a graphql query compatible with this workflow
+            query = get_query(client.scheduler_version)
+
             # fetch the data from the workflow
             workflow_update = await client.async_request(
                 'graphql',
@@ -318,6 +312,12 @@ async def _update_workflow(self, w_id, client, data):
                 'Timeout communicating with workflow.'
                 ' Use "--comms-timeout" to increase the timeout',
             )
+        except VersionIncompat as exc:
+            set_message(
+                data,
+                w_id,
+                str(exc),
+            )
         except (CylcError, ZMQError) as exc:
             # something went wrong :(
             # remove the client on any error, we'll reconnect next time

tests/integration/tui/test_app.py

@@ -22,13 +22,14 @@
 
 from cylc.flow.cycling.integer import IntegerPoint
 from cylc.flow.id import TaskTokens
+from cylc.flow.network import get_location
 from cylc.flow.task_outputs import TASK_OUTPUT_SUCCEEDED
 from cylc.flow.task_state import (
     TASK_STATUS_EXPIRED,
     TASK_STATUS_FAILED,
     TASK_STATUS_RUNNING,
-    TASK_STATUS_SUBMITTED,
     TASK_STATUS_SUBMIT_FAILED,
+    TASK_STATUS_SUBMITTED,
     TASK_STATUS_SUCCEEDED,
     TASK_STATUS_WAITING,
 )
@@ -630,3 +631,39 @@ async def test_states(flow, scheduler, start, rakiura):
                 'the task should show as waiting+runahead in the context menu,'
                 ' the task should be marked as flows=None'
             )
+
+
+async def test_incompat_scheduler_version(
+    one_conf,
+    flow,
+    scheduler,
+    start,
+    rakiura,
+    monkeypatch,
+):
+    """It should handle workflows it cannot subscribe to."""
+    # make it look like the scheduler is reallllyyyy old
+    def patched_get_location(*args, **kwargs):
+        *_, _scheduler_version = get_location(*args, **kwargs)
+        return *_, '6.11.4'
+
+    monkeypatch.setattr(
+        'cylc.flow.network.client.get_location', patched_get_location
+    )
+
+    schd = scheduler(flow(one_conf, name='one'))
+    with rakiura(size='80,20') as rk:
+        async with start(schd):
+            await schd.update_data_structure()
+            # wait for the workflow to appear (collapsed)
+            rk.wait_until_loaded('#spring')
+
+            # expand the workflow (subscribes to updates from it)
+            rk.force_update()
+            rk.user_input('down', 'right')
+
+            # it should be marked as incompatible
+            rk.compare_screenshot(
+                'on-load',
+                'the workflow should be marked as incompatible',
+            )

tests/unit/tui/test_data.py

@@ -15,8 +15,16 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 
+import pytest
+
+from cylc.flow import __version__
 import cylc.flow.tui.data
-from cylc.flow.tui.data import generate_mutation
+from cylc.flow.tui.data import (
+    _QUERY,
+    VersionIncompat,
+    generate_mutation,
+    get_query,
+)
 
 
 def test_generate_mutation(monkeypatch):
@@ -36,3 +44,13 @@ def test_generate_mutation(monkeypatch):
             }
         }
     '''
+
+
+def test_query_compat():
+    """It should return a query or raise an exception."""
+    # old version - unsupported
+    with pytest.raises(VersionIncompat, match='6.11.4'):
+        get_query('6.11.4')
+
+    # current version - supported
+    assert get_query(__version__) == _QUERY