Log failure where attempting to use Cylc 8 on installed Cylc 7 workflow.

Tests for cylc.flow.network

response to review

cylc/flow/exceptions.py

@@ -253,3 +253,18 @@ def __str__(self):
             for key, value in data.items():
                 ret += f'\n        {key}: {value}'
         return ret
+
+
+class CylcVersionError(CylcError):
+    """Contact file is for a Cylc Version not supported by this script."""
+    def __init__(self, version=None):
+        self.version = version
+
+    def __str__(self):
+        if self.version is not None:
+            return (
+                f'Installed Cylc {self.version} workflow is not '
+                'compatible with Cylc 8.'
+            )
+        else:
+            return "Installed workflow is not compatible with Cylc 8."

cylc/flow/network/__init__.py

@@ -28,6 +28,7 @@
 from cylc.flow.exceptions import (
     ClientError,
     CylcError,
+    CylcVersionError,
     ServiceFileError,
     WorkflowStopped
 )
@@ -71,6 +72,7 @@ def get_location(workflow: str):
         Tuple[str, int, int]: tuple with the host name and port numbers.
     Raises:
         ClientError: if the workflow is not running.
+        CylcVersionError: if target is a Cylc 7 (or earlier) workflow.
     """
     try:
         contact = load_contact_file(workflow)
@@ -80,7 +82,12 @@ def get_location(workflow: str):
     host = contact[ContactFileFields.HOST]
     host = get_fqdn_by_host(host)
     port = int(contact[ContactFileFields.PORT])
-    pub_port = int(contact[ContactFileFields.PUBLISH_PORT])
+    if ContactFileFields.PUBLISH_PORT in contact:
+        pub_port = int(contact[ContactFileFields.PUBLISH_PORT])
+    else:
+        version = (
+            contact['CYLC_VERSION'] if 'CYLC_VERSION' in contact else None)
+        raise CylcVersionError(version=version)
     return host, port, pub_port
 
 

tests/unit/network/test__init__.py

@@ -0,0 +1,61 @@
+# 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 __init__.py for network interfaces to Cylc scheduler objects."""
+
+import pytest
+
+import cylc
+from cylc.flow.exceptions import CylcVersionError
+from cylc.flow.network import get_location
+from cylc.flow.workflow_files import load_contact_file, ContactFileFields
+
+
+BASE_CONTACT_DATA = {
+    ContactFileFields.HOST: 'foo',
+    ContactFileFields.PORT: '42',
+}
+
+
+@pytest.fixture()
+def mpatch_get_fqdn_by_host(monkeypatch):
+    """Monkeypatch function used the same by all tests."""
+    monkeypatch.setattr(
+        cylc.flow.network, 'get_fqdn_by_host', lambda _ : 'myhost.x.y.z'
+    )
+
+
+def test_get_location_ok(monkeypatch, mpatch_get_fqdn_by_host):
+    """It passes when information is available."""
+    contact_data = BASE_CONTACT_DATA.copy()
+    contact_data[ContactFileFields.PUBLISH_PORT] = '8042'
+    monkeypatch.setattr(
+        cylc.flow.network, 'load_contact_file', lambda _ : contact_data
+    )
+    assert get_location('_') == (
+        'myhost.x.y.z', 42, 8042
+    )
+
+
+def test_get_location_old_contact_file(monkeypatch, mpatch_get_fqdn_by_host):
+    """It Fails because it's not a Cylc 8 workflow."""
+    contact_data = BASE_CONTACT_DATA.copy()
+    contact_data['CYLC_SUITE_PUBLISH_PORT'] = '8042'
+    contact_data['CYLC_VERSION'] = '5.1.2'
+    monkeypatch.setattr(
+        cylc.flow.network, 'load_contact_file', lambda _ : contact_data
+    )
+    with pytest.raises(CylcVersionError, match=r'.*5.1.2.*') as exc:
+        get_location('_')