Fix argparser incompatibilities with newer python 3

[libvirt] [PATCH sandbox] Fix argparser incompatibilities with newer python 3

Posted by Daniel P. Berrangé 6 years ago

Python 3 changes such that if no subparser command is listed, it just
throws an error. To get back the old behavior we need to set the
'required'  attribute and a dest name.

Since we treat 'debug' as a global attribute we need to set that on the
top level parser too, otherwise we get a missing attribute error with
newish python 3 too.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 libvirt-sandbox/image/cli.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/libvirt-sandbox/image/cli.py b/libvirt-sandbox/image/cli.py
index 490c5e0..d2035de 100644
--- a/libvirt-sandbox/image/cli.py
+++ b/libvirt-sandbox/image/cli.py
@@ -202,7 +202,6 @@ Example supported URI formats:
 def gen_purge_args(subparser):
     parser = gen_command_parser(subparser, "purge",
                                 _("Purge cached template"))
-    requires_debug(parser)
     requires_template(parser)
     requires_template_dir(parser)
     parser.set_defaults(func=purge)
@@ -210,7 +209,6 @@ def gen_purge_args(subparser):
 def gen_prepare_args(subparser):
     parser = gen_command_parser(subparser, "prepare",
                                 _("Prepare local template"))
-    requires_debug(parser)
     requires_template(parser)
     requires_connect(parser)
     requires_template_dir(parser)
@@ -219,7 +217,6 @@ def gen_prepare_args(subparser):
 def gen_run_args(subparser):
     parser = gen_command_parser(subparser, "run",
                                 _("Run an instance of a template"))
-    requires_debug(parser)
     requires_name(parser)
     requires_template(parser)
     requires_connect(parser)
@@ -238,7 +235,6 @@ def gen_run_args(subparser):
 def gen_list_args(subparser):
     parser = gen_command_parser(subparser, "list",
                                 _("List locally cached images"))
-    requires_debug(parser)
     requires_template_dir(parser)
 
     parser.add_argument("-s","--source",
@@ -249,7 +245,11 @@ def gen_list_args(subparser):
 def main():
     parser = argparse.ArgumentParser(description="Sandbox Container Image Tool")
 
+    requires_debug(parser)
+
     subparser = parser.add_subparsers(help=_("commands"))
+    subparser.required = True
+    subparser.dest = "command"
     gen_purge_args(subparser)
     gen_prepare_args(subparser)
     gen_run_args(subparser)
-- 
2.14.3

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Re: [libvirt] [PATCH sandbox] Fix argparser incompatibilities with newer python 3

Posted by Cedric Bosdonnat 6 years ago

On Fri, 2018-03-23 at 16:44 +0000, Daniel P. Berrangé wrote:
> Python 3 changes such that if no subparser command is listed, it just
> throws an error. To get back the old behavior we need to set the
> 'required'  attribute and a dest name.
> 
> Since we treat 'debug' as a global attribute we need to set that on the
> top level parser too, otherwise we get a missing attribute error with
> newish python 3 too.
> 
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>  libvirt-sandbox/image/cli.py | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/libvirt-sandbox/image/cli.py b/libvirt-sandbox/image/cli.py
> index 490c5e0..d2035de 100644
> --- a/libvirt-sandbox/image/cli.py
> +++ b/libvirt-sandbox/image/cli.py
> @@ -202,7 +202,6 @@ Example supported URI formats:
>  def gen_purge_args(subparser):
>      parser = gen_command_parser(subparser, "purge",
>                                  _("Purge cached template"))
> -    requires_debug(parser)
>      requires_template(parser)
>      requires_template_dir(parser)
>      parser.set_defaults(func=purge)
> @@ -210,7 +209,6 @@ def gen_purge_args(subparser):
>  def gen_prepare_args(subparser):
>      parser = gen_command_parser(subparser, "prepare",
>                                  _("Prepare local template"))
> -    requires_debug(parser)
>      requires_template(parser)
>      requires_connect(parser)
>      requires_template_dir(parser)
> @@ -219,7 +217,6 @@ def gen_prepare_args(subparser):
>  def gen_run_args(subparser):
>      parser = gen_command_parser(subparser, "run",
>                                  _("Run an instance of a template"))
> -    requires_debug(parser)
>      requires_name(parser)
>      requires_template(parser)
>      requires_connect(parser)
> @@ -238,7 +235,6 @@ def gen_run_args(subparser):
>  def gen_list_args(subparser):
>      parser = gen_command_parser(subparser, "list",
>                                  _("List locally cached images"))
> -    requires_debug(parser)
>      requires_template_dir(parser)
>  
>      parser.add_argument("-s","--source",
> @@ -249,7 +245,11 @@ def gen_list_args(subparser):
>  def main():
>      parser = argparse.ArgumentParser(description="Sandbox Container Image Tool")
>  
> +    requires_debug(parser)
> +
>      subparser = parser.add_subparsers(help=_("commands"))
> +    subparser.required = True
> +    subparser.dest = "command"
>      gen_purge_args(subparser)
>      gen_prepare_args(subparser)
>      gen_run_args(subparser)

ACK
--
Cedric

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