Host select

.travis.yml

@@ -124,7 +124,9 @@ jobs:
 
   - <<: *flakytest
     python: "3.7"
-    env: FLAKYTESTS="./flakytests"
+    env: 
+      FLAKYTESTS="./flakytests"
+      CYLC_TEST_DEBUG=true
 
   # TODO: run shortlist of regression tests with the
   #       least contemporary Python version

.travis/cover.py

@@ -36,6 +36,7 @@ def main():
     if flakytests:
         command.append(flakytests)
         command.append('--jobs=1')
+        command.append('-v')
     else:
         command.append('--jobs=5')
     # Safe here - only used in Travis CI for tests with predefined environment

cylc/flow/cfgspec/globalcfg.py

@@ -272,11 +272,7 @@
         'run ports': [VDR.V_INTEGER_LIST, list(range(43001, 43101))],
         'condemned hosts': [VDR.V_ABSOLUTE_HOST_LIST],
         'auto restart delay': [VDR.V_INTERVAL],
-        'run host select': {
-            'rank': [VDR.V_STRING, 'random', 'load:1', 'load:5', 'load:15',
-                     'memory', 'disk-space'],
-            'thresholds': [VDR.V_STRING],
-        },
+        'ranking': [VDR.V_STRING]
     },
 }
 

cylc/flow/exceptions.py

@@ -172,3 +172,19 @@ class CylcMissingFinalCyclePointError(CyclingError):
 class PlatformLookupError(CylcConfigError):
     """Unable to determine the correct job platform from the information
     given"""
+
+
+class HostSelectException(CylcError):
+    """No hosts could be selected from the provided configuration."""
+
+    def __init__(self, data):
+        self.data = data
+        CylcError.__init__(self)
+
+    def __str__(self):
+        ret = f'Could not select host from:'
+        for host, data in sorted(self.data.items()):
+            ret += f'\n    {host}:'
+            for key, value in data.items():
+                ret += f'\n        {key}: {value}'
+        return ret