Add bash completion support for ironic cli

This commit adds the 'bash-completion' option to
ironic cli which prints all sub-commands and
options, and bash_completion scripts for bash
auto completion.

Change-Id: Ide5b29e262b4217046f124d86902cd0abfdab1b6
Closes-Bug: 1332408

doc/source/cli.rst

@@ -42,6 +42,16 @@ supplying an auth token using :option:`--ironic-url` and
     export IRONIC_URL=http://ironic.example.org:6385/
     export OS_AUTH_TOKEN=3bcc3d3a03f44e3d8377f9247b0ad155
 
+Ironic cli supports bash completion. The command-line tool can automatically
+fill partially typed commands. To use this feature, source the below file to
+your terminal and then bash completion should work::
+
+    source tools/ironic.bash_completion
+
+To avoid doing this everytime, add this to your ``.bashrc`` or copy the
+ironic.bash_completion file to the default bash completion scripts directory
+on your linux distribution.
+
 OPTIONS
 =======
 

ironicclient/shell.py

@@ -195,6 +195,16 @@ class IronicShell(object):
                     format="%(levelname)s %(message)s",
                     level=logging.CRITICAL)
 
+    def _bash_completion(self):
+        """Prints all of the commands and options for bash-completion."""
+        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)
+        print(' '.join(commands | options))
+
     def main(self, argv):
         # Parse args once to find version
         parser = self.get_base_parser()
@@ -211,6 +221,9 @@ class IronicShell(object):
         if options.help or not argv:
             self.do_help(options)
             return 0
+        elif argv[0] == 'bash-completion':
+            self._bash_completion()
+            return 0
 
         # Parse args again and call whatever callback was selected
         args = subcommand_parser.parse_args(argv)

ironicclient/tests/test_shell.py

@@ -93,3 +93,16 @@ class ShellTest(utils.BaseTestCase):
     def test_auth_param(self):
         self.make_env(exclude='OS_USERNAME')
         self.test_help()
+
+    def test_bash_completion(self):
+        stdout = self.shell('bash-completion')
+        # just check we have some output
+        required = [
+            '.*--driver_info',
+            '.*--chassis_uuid',
+            '.*help',
+            '.*node-create',
+            '.*chassis-create']
+        for r in required:
+            self.assertThat(stdout,
+                            matchers.MatchesRegex(r, self.re_options))

tools/ironic.bash_completion

@@ -0,0 +1,27 @@
+_ironic_opts="" # lazy init
+_ironic_flags="" # lazy init
+_ironic_opts_exp="" # lazy init
+_ironic()
+{
+    local cur prev nbc cflags
+    COMPREPLY=()
+    cur="${COMP_WORDS[COMP_CWORD]}"
+    prev="${COMP_WORDS[COMP_CWORD-1]}"
+
+    if [ "x$_ironic_opts" == "x" ] ; then
+        nbc="`ironic bash-completion | sed -e "s/  *-h  */ /" -e "s/  *-i  */ /"`"
+        _ironic_opts="`echo "$nbc" | sed -e "s/--[a-z0-9_-]*//g" -e "s/  */ /g"`"
+        _ironic_flags="`echo " $nbc" | sed -e "s/ [^-][^-][a-z0-9_-]*//g" -e "s/  */ /g"`"
+        _ironic_opts_exp="`echo "$_ironic_opts" | tr ' ' '|'`"
+    fi
+
+    if [[ " ${COMP_WORDS[@]} " =~ " "($_ironic_opts_exp)" " && "$prev" != "help" ]] ; then
+        COMPLETION_CACHE=$HOME/.cache/python-ironicclient/*/*-cache
+        cflags="$_ironic_flags "$(cat $COMPLETION_CACHE 2> /dev/null | tr '\n' ' ')
+        COMPREPLY=($(compgen -W "${cflags}" -- ${cur}))
+    else
+        COMPREPLY=($(compgen -W "${_ironic_opts}" -- ${cur}))
+    fi
+    return 0
+}
+complete -F _ironic ironic