[libvirt] [jenkins-ci PATCH 2/5] lcitool: use subparsers for commands

Currently only a single global parser is used for all commands. This means that every command accepts every argument which is undesirable as users don't know what to pass. It also prevents the parser from generating useful help information. Python's argparse module supports multi-command binaries in a very easy way by adding subparsers, each of which has their own distinct arguments. It can then generate suitable help text on a per command basis. This also means commands can use positional arguments for data items that are always passed. $ ./guests/lcitool -h usage: lcitool [-h] {install,update,build,hosts,projects,dockerfile} ... libvirt CI guest management tool positional arguments: {install,update,build,hosts,projects,dockerfile} commands install perform unattended host installation update prepare hosts and keep them updated build build projects on hosts hosts list all known hosts projects list all known projects dockerfile generate a host docker file optional arguments: -h, --help show this help message and exit $ ./guests/lcitool install -h usage: lcitool install [-h] hosts positional arguments: hosts list of hosts to act on (accepts globs) optional arguments: -h, --help show this help message and exit $ ./guests/lcitool dockerfile -h usage: lcitool dockerfile [-h] hosts projects positional arguments: hosts list of hosts to act on (accepts globs) projects list of projects to consider (accepts globs) optional arguments: -h, --help show this help message and exit Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com&gt; --- guests/lcitool | 135 ++++++++++++++++++++++++++++--------------------- 1 file changed, 78 insertions(+), 57 deletions(-) diff --git a/guests/lcitool b/guests/lcitool index 726e3bb..35a6b68 100755 --- a/guests/lcitool +++ b/guests/lcitool @@ -307,43 +307,72 @@ class Application: conflict_handler="resolve", formatter_class=argparse.RawDescriptionHelpFormatter, description="libvirt CI guest management tool", - epilog=textwrap.dedent(""" - common actions: - install perform unattended host installation - update prepare hosts and keep them updated - build build projects on hosts + ) - informational actions: - hosts list all known hosts - projects list all known projects + subparser = self._parser.add_subparsers(help="commands") + subparser.required = True + subparser.dest = "command" - uncommon actions: - dockerfile generate Dockerfile (doesn't access the host) + def add_hosts_arg(parser): + parser.add_argument( + "hosts", + help="list of hosts to act on (accepts globs)", + ) - glob patterns are supported for HOSTS and PROJECTS - """), - ) - self._parser.add_argument( - "-a", - metavar="ACTION", - required=True, - help="action to perform (see below)", - ) - self._parser.add_argument( - "-h", - metavar="HOSTS", - help="list of hosts to act on", - ) - self._parser.add_argument( - "-p", - metavar="PROJECTS", - help="list of projects to consider", - ) - self._parser.add_argument( - "-g", - metavar="GIT_REVISION", - help="git revision to build (remote/branch)", - ) + def add_projects_arg(parser): + parser.add_argument( + "projects", + help="list of projects to consider (accepts globs)", + ) + + def add_gitrev_arg(parser): + parser.add_argument( + "-g", "--git-revision", + help="git revision to build (remote/branch)", + ) + + installparser = subparser.add_parser( + "install", help="perform unattended host installation", + formatter_class=argparse.RawDescriptionHelpFormatter) + installparser.set_defaults(func=self._action_install) + + add_hosts_arg(installparser) + + updateparser = subparser.add_parser( + "update", help="prepare hosts and keep them updated", + formatter_class=argparse.RawDescriptionHelpFormatter) + updateparser.set_defaults(func=self._action_update) + + add_hosts_arg(updateparser) + add_projects_arg(updateparser) + add_gitrev_arg(updateparser) + + buildparser = subparser.add_parser( + "build", help="build projects on hosts", + formatter_class=argparse.RawDescriptionHelpFormatter) + buildparser.set_defaults(func=self._action_build) + + add_hosts_arg(buildparser) + add_projects_arg(buildparser) + add_gitrev_arg(buildparser) + + hostsparser = subparser.add_parser( + "hosts", help="list all known hosts", + formatter_class=argparse.RawDescriptionHelpFormatter) + hostsparser.set_defaults(func=self._action_hosts) + + projectsparser = subparser.add_parser( + "projects", help="list all known projects", + formatter_class=argparse.RawDescriptionHelpFormatter) + projectsparser.set_defaults(func=self._action_projects) + + dockerfileparser = subparser.add_parser( + "dockerfile", help="generate a host docker file", + formatter_class=argparse.RawDescriptionHelpFormatter) + dockerfileparser.set_defaults(func=self._action_dockerfile) + + add_hosts_arg(dockerfileparser) + add_projects_arg(dockerfileparser) def _execute_playbook(self, playbook, hosts, projects, git_revision): base = Util.get_base() @@ -404,20 +433,20 @@ class Application: raise Error( "Failed to run {} on '{}': {}".format(playbook, hosts, ex)) - def _action_hosts(self, _hosts, _projects, _revision): + def _action_hosts(self, args): for host in self._inventory.expand_pattern("all"): print(host) - def _action_projects(self, _hosts, _projects, _revision): + def _action_projects(self, args): for project in self._projects.expand_pattern("all"): print(project) - def _action_install(self, hosts, _projects, _revision): + def _action_install(self, args): base = Util.get_base() flavor = self._config.get_flavor() - for host in self._inventory.expand_pattern(hosts): + for host in self._inventory.expand_pattern(args.hosts): facts = self._inventory.get_facts(host) # Both memory size and disk size are stored as GiB in the @@ -484,16 +513,18 @@ class Application: except Exception as ex: raise Error("Failed to install '{}': {}".format(host, ex)) - def _action_update(self, hosts, projects, git_revision): - self._execute_playbook("update", hosts, projects, git_revision) + def _action_update(self, args): + self._execute_playbook("update", args.hosts, args.projects, + args.git_revision) - def _action_build(self, hosts, projects, git_revision): - self._execute_playbook("build", hosts, projects, git_revision) + def _action_build(self, args): + self._execute_playbook("build", args.hosts, args.projects, + args.git_revision) - def _action_dockerfile(self, hosts, projects, _revision): + def _action_dockerfile(self, args): mappings = self._projects.get_mappings() - hosts = self._inventory.expand_pattern(hosts) + hosts = self._inventory.expand_pattern(args.hosts) if len(hosts) > 1: raise Error("Can't generate Dockerfile for multiple hosts") host = hosts[0] @@ -507,7 +538,7 @@ class Application: if package_format not in ["deb", "rpm"]: raise Error("Host {} doesn't support Dockerfiles".format(host)) - projects = self._projects.expand_pattern(projects) + projects = self._projects.expand_pattern(args.projects) for project in projects: if project not in facts["projects"]: raise Error( @@ -573,18 +604,8 @@ class Application: """).format(**varmap)) def run(self): - cmdline = self._parser.parse_args() - action = cmdline.a - hosts = cmdline.h - projects = cmdline.p - git_revision = cmdline.g - - method = "_action_{}".format(action.replace("-", "_")) - - if hasattr(self, method): - getattr(self, method).__call__(hosts, projects, git_revision) - else: - raise Error("Invalid action '{}'".format(action)) + args = self._parser.parse_args() + args.func(args) if __name__ == "__main__": -- 2.20.1