From 66958f7c21c5124ce2eac056a3e52199213278d9 Mon Sep 17 00:00:00 2001
From: Ross McFarland <rwmcfa1@gmail.com>
Date: Mon, 28 Mar 2022 13:33:32 -0700
Subject: [PATCH] Manager._try_version with 3.7 noop (for now)

---
 octodns/manager.py            | 33 ++++++++++++++++++++++++++++++---
 tests/test_octodns_manager.py | 24 ++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 3 deletions(-)

diff --git a/octodns/manager.py b/octodns/manager.py
index f3da6a3..e640a8d 100644
--- a/octodns/manager.py
+++ b/octodns/manager.py
@@ -20,6 +20,18 @@ from .yaml import safe_load
 from .zone import Zone
 
 
+# TODO: this can go away once we no longer support python 3.7
+try:
+    from importlib.metadata import PackageNotFoundError, \
+        version as module_version
+except ModuleNotFoundError:  # pragma: no cover
+    class PackageNotFoundError(Exception):
+        pass
+
+    def module_version(*args, **kargs):
+        raise PackageNotFoundError('placeholder')
+
+
 class _AggregateTarget(object):
     id = 'aggregate'
 
@@ -85,8 +97,9 @@ class Manager(object):
         return len(plan.changes[0].record.zone.name) if plan.changes else 0
 
     def __init__(self, config_file, max_workers=None, include_meta=False):
+        version = self._try_version('octodns', version=__VERSION__)
         self.log.info('__init__: config_file=%s (octoDNS %s)', config_file,
-                      __VERSION__)
+                      version)
 
         # Read our config file
         with open(config_file, 'r') as fh:
@@ -197,18 +210,32 @@ class Manager(object):
                 raise ManagerException('Incorrect plan_output config for ' +
                                        plan_output_name)
 
+    def _try_version(self, module_name, module=None, version=None):
+        try:
+            # Always try and use the official lookup first
+            return module_version(module_name)
+        except PackageNotFoundError:
+            pass
+        # If we were passed a version that's next in line
+        if version is not None:
+            return version
+        # finally try and import the module and see if it has a __VERSION__
+        if module is None:
+            module = import_module(module_name)
+        return getattr(module, '__VERSION__', None)
+
     def _import_module(self, module_name):
         current = module_name
         _next = current.rsplit('.', 1)[0]
         module = import_module(current)
-        version = getattr(module, '__VERSION__', None)
+        version = self._try_version(current, module=module)
         # If we didn't find a version in the specific module we're importing,
         # we'll try walking up the hierarchy, as long as there is one (`.`),
         # looking for it.
         while version is None and current != _next:
             current = _next
             _next = current.rsplit('.', 1)[0]
-            version = getattr(import_module(current), '__VERSION__', None)
+            version = self._try_version(current)
         return module, version or 'n/a'
 
     def _get_named_class(self, _type, _class):
diff --git a/tests/test_octodns_manager.py b/tests/test_octodns_manager.py
index 51c47eb..6d85924 100644
--- a/tests/test_octodns_manager.py
+++ b/tests/test_octodns_manager.py
@@ -8,6 +8,7 @@ from __future__ import absolute_import, division, print_function, \
 from os import environ
 from os.path import dirname, join
 
+from octodns import __VERSION__
 from octodns.manager import _AggregateTarget, MainThreadExecutor, Manager, \
     ManagerException
 from octodns.processor.base import BaseProcessor
@@ -524,6 +525,29 @@ class TestManager(TestCase):
         # no plans
         self.assertFalse(plans)
 
+    def test_try_version(self):
+        manager = Manager(get_config_filename('simple.yaml'))
+
+        class DummyModule(object):
+            __VERSION__ = '2.3.4'
+
+        dummy_module = DummyModule()
+
+        # use importlib.metadata.version
+        self.assertTrue(__VERSION__,
+                        manager._try_version('octodns',
+                                             module=dummy_module,
+                                             version='1.2.3'))
+
+        # use module
+        self.assertTrue(manager._try_version('doesnt-exist',
+                                             module=dummy_module))
+
+        # fall back to version, preferred over module
+        self.assertEqual('1.2.3', manager._try_version('doesnt-exist',
+                                                       module=dummy_module,
+                                                       version='1.2.3', ))
+
 
 class TestMainThreadExecutor(TestCase):