[Kimchi-devel] [PATCH] plugin: fix dynamic import mechanism

[Mark Wu]

On 12/31/2013 08:21 PM, Zhou Zheng Sheng wrote:
> The current kimchi plugin subsystem implement a dynamic discovery and
> import mechanism. It uses the Python builtin function __import__() to
> actually import a plugin module by name. However it turns out it only
> works when we start kimchi from the project source directory, not work
> when it is started from the installed path.
>
> This is because the __import__() accepts a "global" arugment and it
> needs "__name__", "__path__" and "__package__" in this "global" dict to
> determine the package context [1][2]. When in kimchi/utils.py it runs
> "import plugins.XXX", it actually fetch the "__package__" from utils.py,
> which is "kimchi", then it imports "kimchi.plugins.XXX" under the hood
> [3].
>
> The current import_module() function calls __import__() without giving a
> global dict. When kimchid is started from /usr/bin, without the package
> context, __import__() can not find "plugins.sample".
>
> This patch provides the full package context to __import__() to mimic
> the standard "import" statement behavior.
>
> [1] http://docs.python.org/2/library/functions.html#__import__
> [2] http://hg.python.org/cpython/file/990d7647ea51/Python/import.c
> [3] http://docs.python.org/2/reference/simple_stmts.html#import
>
> Signed-off-by: Zhou Zheng Sheng <zhshzhou at linux.vnet.ibm.com>
> ---
>   src/kimchi/utils.py | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/kimchi/utils.py b/src/kimchi/utils.py
> index f7eda93..b6d84fd 100644
> --- a/src/kimchi/utils.py
> +++ b/src/kimchi/utils.py
> @@ -83,4 +83,4 @@ def import_class(class_path):
>
>
>   def import_module(module_name):
> -    return __import__(module_name, fromlist=[''])
> +    return __import__(module_name, globals(), locals(), [''])
Reviewed-by: Mark Wu<wudxw at linux.vnet.ibm.com>

Thanks for the fix!