Add bash completion to glance client

Currently glance client does not support command completion.
The intention is to add this functionality to the client

blueprint add-bash-completion

Change-Id: I725dd308118b101e87182acf0cee6dbfd214e0e4

glanceclient/shell.py

@@ -286,6 +286,8 @@ class OpenStackImagesShell(object):
         self._find_actions(subparsers, submodule)
         self._find_actions(subparsers, self)
 
+        self._add_bash_completion_subparser(subparsers)
+
         return parser
 
     def _find_actions(self, subparsers, actions_module):
@@ -312,6 +314,13 @@ class OpenStackImagesShell(object):
                 subparser.add_argument(*args, **kwargs)
             subparser.set_defaults(func=callback)
 
+    def _add_bash_completion_subparser(self, subparsers):
+        subparser = subparsers.add_parser('bash_completion',
+                                          add_help=False,
+                                          formatter_class=HelpFormatter)
+        self.subcommands['bash_completion'] = subparser
+        subparser.set_defaults(func=self.do_bash_completion)
+
     def _get_image_url(self, args):
         """Translate the available url-related options into a single string.
 
@@ -567,6 +576,9 @@ class OpenStackImagesShell(object):
         if args.func == self.do_help:
             self.do_help(args)
             return 0
+        elif args.func == self.do_bash_completion:
+            self.do_bash_completion(args)
+            return 0
 
         LOG = logging.getLogger('glanceclient')
         LOG.addHandler(logging.StreamHandler())
@@ -605,6 +617,22 @@ class OpenStackImagesShell(object):
         else:
             self.parser.print_help()
 
+    def do_bash_completion(self, _args):
+        """
+        Prints all of the commands and options to stdout so that the
+        glance.bash_completion script doesn't have to hard code them.
+        """
+        commands = set()
+        options = set()
+        for sc_str, sc in self.subcommands.items():
+            commands.add(sc_str)
+            for option in sc._optionals._option_string_actions.keys():
+                options.add(option)
+
+        commands.remove('bash_completion')
+        commands.remove('bash-completion')
+        print(' '.join(commands | options))
+
 
 class HelpFormatter(argparse.HelpFormatter):
     def start_section(self, heading):

tests/test_shell.py

@@ -16,8 +16,10 @@
 
 import argparse
 import os
+import sys
 
 import mock
+import six
 
 from glanceclient import exc
 from glanceclient import shell as openstack_shell
@@ -79,6 +81,26 @@ class ShellTest(utils.TestCase):
         global _old_env
         os.environ = _old_env
 
+    def shell(self, argstr, exitcodes=(0,)):
+        orig = sys.stdout
+        orig_stderr = sys.stderr
+        try:
+            sys.stdout = six.StringIO()
+            sys.stderr = six.StringIO()
+            _shell = openstack_shell.OpenStackImagesShell()
+            _shell.main(argstr.split())
+        except SystemExit:
+            exc_type, exc_value, exc_traceback = sys.exc_info()
+            self.assertIn(exc_value.code, exitcodes)
+        finally:
+            stdout = sys.stdout.getvalue()
+            sys.stdout.close()
+            sys.stdout = orig
+            stderr = sys.stderr.getvalue()
+            sys.stderr.close()
+            sys.stderr = orig_stderr
+        return (stdout, stderr)
+
     def test_help_unknown_command(self):
         shell = openstack_shell.OpenStackImagesShell()
         argstr = 'help foofoo'
@@ -285,6 +307,22 @@ class ShellTestWithKeystoneV3Auth(ShellTest):
         glance_shell = openstack_shell.OpenStackImagesShell()
         self.assertRaises(exc.CommandError, glance_shell.main, args.split())
 
+    def test_bash_completion(self):
+        stdout, stderr = self.shell('bash_completion')
+        # just check we have some output
+        required = [
+            '--status',
+            'image-create',
+            'help',
+            '--size']
+        for r in required:
+            self.assertIn(r, stdout.split())
+        avoided = [
+            'bash_completion',
+            'bash-completion']
+        for r in avoided:
+            self.assertNotIn(r, stdout.split())
+
 
 class ShellCacheSchemaTest(utils.TestCase):
     def setUp(self):

tools/glance.bash_completion

@@ -0,0 +1,25 @@
+_glance_opts="" # lazy init
+_glance_flags="" # lazy init
+_glance_opts_exp="" # lazy init
+_glance()
+{
+    local cur prev nbc cflags
+    COMPREPLY=()
+    cur="${COMP_WORDS[COMP_CWORD]}"
+    prev="${COMP_WORDS[COMP_CWORD-1]}"
+
+    if [ "x$_glance_opts" == "x" ] ; then
+        nbc="`glance bash-completion | sed -e "s/  *-h  */ /" -e "s/  *-i  */ /"`"
+        _glance_opts="`echo "$nbc" | sed -e "s/--[a-z0-9_-]*//g" -e "s/  */ /g"`"
+        _glance_flags="`echo " $nbc" | sed -e "s/ [^-][^-][a-z0-9_-]*//g" -e "s/  */ /g"`"
+        _glance_opts_exp="`echo "$_glance_opts" | sed 's/^ *//' | tr ' ' '|'`"
+    fi
+
+    if [[ " ${COMP_WORDS[@]} " =~ " "($_glance_opts_exp)" " && "$prev" != "help" ]] ; then
+        COMPREPLY=($(compgen -W "${_glance_flags}" -- ${cur}))
+    else
+        COMPREPLY=($(compgen -W "${_glance_opts}" -- ${cur}))
+    fi
+    return 0
+}
+complete -F _glance glance