New Command module

code/python/echomesh/util/Importer.py

@@ -9,5 +9,6 @@ def importer(classpath):
     except ImportError:
         # Try to import a function out of a module.
         parts = classpath.split('.')
-        function = classpath.pop()
-        return getattr(importlib.import_module(classpath), function)
+        function = parts.pop()
+
+        return getattr(importlib.import_module('.'.join(parts)), function)

code/python/echomesh/util/command/Command.py

@@ -0,0 +1,53 @@
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import six
+
+from echomesh.base.GetPrefix import PrefixDict
+from echomesh.util.Importer import importer
+from echomesh.util.string.Formatted import Formatted
+
+class Command(Formatted):
+    FORMAT_MEMBERS = 'name', 'help'
+
+    def __init__(self, classpath, name, importer=importer):
+        self.classpath = classpath
+        self.name = name
+        self.importer = importer
+        self._load()
+
+    def _load(self):
+        mod = self.importer('%s.%s' % (self.classpath, self.name))
+        get = lambda key: getattr(mod, key, None)
+
+        self.call = get('COMMAND') or get(self.name.lower())
+        assert (self.call)
+        self.help = get('HELP')
+        self._loaded = True
+
+    def __call__(self, *args, **kwds):
+        return self.call(*args, **kwds)
+
+
+class Registry(PrefixDict):
+    def __init__(self, name, base_path, more_paths,
+                 allow_prefixes=True, importer=importer):
+        super(Registry, self).__init__()
+        self.allow_prefixes = allow_prefixes
+        self.name = name
+        if isinstance(more_paths, six.string_types):
+            classpaths = (c.strip() for c in more_paths.split(':'))
+            classpaths = [c for c in classpaths if c]
+        else:
+            classpaths = list(more_paths)
+        classpaths.append(base_path)
+
+        self.help_table = PrefixDict(name=name, allow_prefixes=allow_prefixes)
+        for cp in reversed(classpaths):
+            module = importer(cp)
+            for name in getattr(module, '__all__'):
+                command = Command(cp, name)
+                self[name.lower()] = command
+            self.help_table.update(getattr(module, 'HELP', {}))
+
+    def help(self, key):
+        return self.help_table.get(key) or getattr(self[key], 'HELP', '')

code/python/echomesh/util/command/Command_test.py

@@ -0,0 +1,23 @@
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+from echomesh.util.command import Command
+from echomesh.util.TestCase import TestCase
+
+class Command_test(TestCase):
+    def test_simple(self):
+        registry = Command.Registry('test', 'echomesh.util.command.test', '')
+        foo = registry['f']
+        self.assertEquals(foo(), 'foo')
+        self.assertEquals(registry.help('foo'), '')
+
+    def test_two(self):
+        registry = Command.Registry('test', 'echomesh.util.command.test',
+                                    'echomesh.util.command.test.Baz')
+        foo = registry['f']
+        self.assertEquals(foo(), 'foo')
+        with self.assertRaises(KeyError) as cm:
+            b = registry['ba']
+        self.assertEquals(
+            str(cm.exception),
+            'In table test, "ba" matches more than one: bar and baz')
+        self.assertEquals(registry['baz'](), 'baz')

code/python/echomesh/util/command/test/Bar.py

@@ -0,0 +1,4 @@
+def foo():
+    return 'bar'
+
+COMMAND = foo

code/python/echomesh/util/command/test/Baz.py

@@ -0,0 +1,10 @@
+__all__ = 'Baz', 'Bing'
+
+class Class(object): pass
+
+Baz = Class()
+Baz.baz = lambda: 'baz'
+Baz.HELP = 'Baz help'
+
+Bing = Class()
+Bing.COMMAND = lambda: 'bing'

code/python/echomesh/util/command/test/Foo.py

@@ -0,0 +1,4 @@
+def foo():
+    return 'foo'
+
+HELP = 'Some help text'

code/python/echomesh/util/command/test/__init__.py

@@ -0,0 +1 @@
+__all__ = 'Foo', 'Bar'