More applicable command template

With the command being in a dedicated file.

Now also include standard logger naming suggestions.

Fixes datalad/datalad-extension-template#27

datalad_helloworld/__init__.py

@@ -2,17 +2,8 @@
 
 __docformat__ = 'restructuredtext'
 
-from os.path import curdir
-from os.path import abspath
-
-from datalad.interface.base import Interface
-from datalad.interface.base import build_doc
-from datalad.support.param import Parameter
-from datalad.distribution.dataset import datasetmethod
-from datalad.interface.utils import eval_results
-from datalad.support.constraints import EnsureChoice
-
-from datalad.interface.results import get_status_dict
+import logging
+lgr = logging.getLogger('datalad.helloworld')
 
 # Defines a datalad command suite.
 # This variable must be bound as a setuptools entrypoint
@@ -24,7 +15,7 @@
         # specification of a command, any number of commands can be defined
         (
             # importable module that contains the command implementation
-            'datalad_helloworld',
+            'datalad_helloworld.hello_cmd',
             # name of the command class implementation in above module
             'HelloWorld',
             # optional name of the command in the cmdline API
@@ -35,64 +26,6 @@
     ]
 )
 
-
-# decoration auto-generates standard help
-@build_doc
-# all commands must be derived from Interface
-class HelloWorld(Interface):
-    # first docstring line is used a short description in the cmdline help
-    # the rest is put in the verbose help and manpage
-    """Short description of the command
-
-    Long description of arbitrary volume.
-    """
-
-    # parameters of the command, must be exhaustive
-    _params_ = dict(
-        # name of the parameter, must match argument name
-        language=Parameter(
-            # cmdline argument definitions, incl aliases
-            args=("-l", "--language"),
-            # documentation
-            doc="""language to say "hello" in""",
-            # type checkers, constraint definition is automatically
-            # added to the docstring
-            constraints=EnsureChoice('en', 'de')),
-    )
-
-    @staticmethod
-    # decorator binds the command to the Dataset class as a method
-    @datasetmethod(name='hello_cmd')
-    # generic handling of command results (logging, rendering, filtering, ...)
-    @eval_results
-    # signature must match parameter list above
-    # additional generic arguments are added by decorators
-    def __call__(language='en'):
-        if language == 'en':
-            msg = 'Hello!'
-        elif language == 'de':
-            msg = 'Tachchen!'
-        else:
-            msg = ("unknown language: '%s'", language)
-
-        # commands should be implemented as generators and should
-        # report any results by yielding status dictionaries
-        yield get_status_dict(
-            # an action label must be defined, the command name make a good
-            # default
-            action='demo',
-            # most results will be about something associated with a dataset
-            # (component), reported paths MUST be absolute
-            path=abspath(curdir),
-            # status labels are used to identify how a result will be reported
-            # and can be used for filtering
-            status='ok' if language in ('en', 'de') else 'error',
-            # arbitrary result message, can be a str or tuple. in the latter
-            # case string expansion with arguments is delayed until the
-            # message actually needs to be rendered (analog to exception messages)
-            message=msg)
-
-
 from datalad import setup_package
 from datalad import teardown_package
 

datalad_helloworld/hello_cmd.py

@@ -0,0 +1,76 @@
+"""DataLad demo command"""
+
+__docformat__ = 'restructuredtext'
+
+from os.path import curdir
+from os.path import abspath
+
+from datalad.interface.base import Interface
+from datalad.interface.base import build_doc
+from datalad.support.param import Parameter
+from datalad.distribution.dataset import datasetmethod
+from datalad.interface.utils import eval_results
+from datalad.support.constraints import EnsureChoice
+
+from datalad.interface.results import get_status_dict
+
+import logging
+lgr = logging.getLogger('datalad.helloworld.hello_cmd')
+
+
+# decoration auto-generates standard help
+@build_doc
+# all commands must be derived from Interface
+class HelloWorld(Interface):
+    # first docstring line is used a short description in the cmdline help
+    # the rest is put in the verbose help and manpage
+    """Short description of the command
+
+    Long description of arbitrary volume.
+    """
+
+    # parameters of the command, must be exhaustive
+    _params_ = dict(
+        # name of the parameter, must match argument name
+        language=Parameter(
+            # cmdline argument definitions, incl aliases
+            args=("-l", "--language"),
+            # documentation
+            doc="""language to say "hello" in""",
+            # type checkers, constraint definition is automatically
+            # added to the docstring
+            constraints=EnsureChoice('en', 'de')),
+    )
+
+    @staticmethod
+    # decorator binds the command to the Dataset class as a method
+    @datasetmethod(name='hello_cmd')
+    # generic handling of command results (logging, rendering, filtering, ...)
+    @eval_results
+    # signature must match parameter list above
+    # additional generic arguments are added by decorators
+    def __call__(language='en'):
+        if language == 'en':
+            msg = 'Hello!'
+        elif language == 'de':
+            msg = 'Tachchen!'
+        else:
+            msg = ("unknown language: '%s'", language)
+
+        # commands should be implemented as generators and should
+        # report any results by yielding status dictionaries
+        yield get_status_dict(
+            # an action label must be defined, the command name make a good
+            # default
+            action='demo',
+            # most results will be about something associated with a dataset
+            # (component), reported paths MUST be absolute
+            path=abspath(curdir),
+            # status labels are used to identify how a result will be reported
+            # and can be used for filtering
+            status='ok' if language in ('en', 'de') else 'error',
+            # arbitrary result message, can be a str or tuple. in the latter
+            # case string expansion with arguments is delayed until the
+            # message actually needs to be rendered (analog to exception
+            # messages)
+            message=msg)