Since the program is self-contained and not exposing a library API there is no reason to subclass the Exception object. Removing ensures that the try/except block around the application execution will catch all exceptions and print a pretty message. Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com&gt; --- guests/lcitool | 58 ++++++++++++++++++++++---------------------------- 1 file changed, 26 insertions(+), 32 deletions(-) diff --git a/guests/lcitool b/guests/lcitool index 1d17c04..487b67d 100755 --- a/guests/lcitool +++ b/guests/lcitool @@ -35,13 +35,6 @@ except ImportError: import ConfigParser as configparser -class Error(Exception): - - def __init__(self, message): - super(Error, self).__init__() - self.message = message - - class Util: @staticmethod @@ -57,7 +50,7 @@ class Util: @staticmethod def expand_pattern(pattern, source, name): if pattern is None: - raise Error("Missing {} list".format(name)) + raise Exception("Missing {} list".format(name)) if pattern == "all": pattern = "*" @@ -74,7 +67,7 @@ class Util: partial_matches += [item] if not partial_matches: - raise Error("Invalid {} list '{}'".format(name, pattern)) + raise Exception("Invalid {} list '{}'".format(name, pattern)) matches += partial_matches @@ -142,7 +135,7 @@ class Config: try: os.mkdir(config_dir) except Exception as ex: - raise Error( + raise Exception( "Can't create configuration directory ({}): {}".format( config_dir, ex, ) @@ -164,14 +157,14 @@ class Config: with open(flavor_file, "w") as infile: infile.write("{}\n".format(flavor)) except Exception as ex: - raise Error( + raise Exception( "Can't write flavor file ({}): {}".format( flavor_file, ex ) ) if flavor not in ["test", "jenkins"]: - raise Error("Invalid flavor '{}'".format(flavor)) + raise Exception("Invalid flavor '{}'".format(flavor)) return flavor @@ -188,7 +181,7 @@ class Config: if not infile.readline().strip(): raise ValueError except Exception as ex: - raise Error( + raise Exception( "Missing or invalid vault password file ({}): {}".format( vault_pass_file, ex ) @@ -204,7 +197,7 @@ class Config: if not infile.readline().strip(): raise ValueError except Exception as ex: - raise Error( + raise Exception( "Missing or invalid root password file ({}): {}".format( root_pass_file, ex ) @@ -224,7 +217,7 @@ class Inventory: parser.read(ansible_cfg_path) inventory_path = parser.get("defaults", "inventory") except Exception as ex: - raise Error( + raise Exception( "Can't read inventory location in ansible.cfg: {}".format(ex)) inventory_path = os.path.join(base, inventory_path) @@ -239,7 +232,7 @@ class Inventory: host = line.strip() self._facts[host] = {} except Exception as ex: - raise Error( + raise Exception( "Missing or invalid inventory ({}): {}".format( inventory_path, ex ) @@ -250,7 +243,8 @@ class Inventory: self._facts[host] = self._read_all_facts(host) self._facts[host]["inventory_hostname"] = host except Exception as ex: - raise Error("Can't load facts for '{}': {}".format(host, ex)) + raise Exception("Can't load facts for '{}': {}".format( + host, ex)) @staticmethod def _add_facts_from_file(facts, yaml_path): @@ -302,7 +296,7 @@ class Projects: mappings = yaml.load(infile) self._mappings = mappings["mappings"] except Exception as ex: - raise Error("Can't load mappings: {}".format(ex)) + raise Exception("Can't load mappings: {}".format(ex)) source = os.path.join(base, "vars", "projects") @@ -321,7 +315,7 @@ class Projects: packages = yaml.load(infile) self._packages[project] = packages["packages"] except Exception as ex: - raise Error( + raise Exception( "Can't load packages for '{}': {}".format(project, ex)) def expand_pattern(self, pattern): @@ -434,7 +428,7 @@ class Application: if git_revision is not None: tokens = git_revision.split("/") if len(tokens) < 2: - raise Error( + raise Exception( "Missing or invalid git revision '{}'".format(git_revision) ) git_remote = tokens[0] @@ -477,7 +471,7 @@ class Application: try: subprocess.check_call(cmd) except Exception as ex: - raise Error( + raise Exception( "Failed to run {} on '{}': {}".format(playbook, hosts, ex)) def _action_hosts(self, args): @@ -519,7 +513,7 @@ class Application: elif facts["os_name"] in ["CentOS", "Fedora"]: install_config = "kickstart.cfg" else: - raise Error( + raise Exception( "Host {} doesn't support installation".format(host) ) initrd_inject = os.path.join(base, "configs", install_config) @@ -558,7 +552,7 @@ class Application: try: subprocess.check_call(cmd) except Exception as ex: - raise Error("Failed to install '{}': {}".format(host, ex)) + raise Exception("Failed to install '{}': {}".format(host, ex)) def _action_update(self, args): self._execute_playbook("update", args.hosts, args.projects, @@ -573,7 +567,7 @@ class Application: hosts = self._inventory.expand_pattern(args.hosts) if len(hosts) > 1: - raise Error("Can't generate Dockerfile for multiple hosts") + raise Exception("Can't generate Dockerfile for multiple hosts") host = hosts[0] facts = self._inventory.get_facts(host) @@ -583,18 +577,18 @@ class Application: os_full = os_name + os_version if package_format not in ["deb", "rpm"]: - raise Error("Host {} doesn't support Dockerfiles".format(host)) + raise Exception("Host {} doesn't support Dockerfiles".format(host)) if args.cross_arch: if os_name != "Debian": - raise Error("Cannot cross compile on {}".format(os_name)) + raise Exception("Cannot cross compile on {}".format(os_name)) if args.cross_arch == self._native_arch: - raise Error("Cross arch {} should differ from native {}". + raise Exception("Cross arch {} should differ from native {}". format(args.cross_arch, self._native_arch)) projects = self._projects.expand_pattern(args.projects) for project in projects: if project not in facts["projects"]: - raise Error( + raise Exception( "Host {} doesn't support project {}".format( host, project, @@ -620,8 +614,8 @@ class Application: if key in mappings[package]: cross_policy = mappings[package][key] if cross_policy not in ["native", "foreign", "skip"]: - raise Error("Unexpected cross arch policy {} for {}", - cross_policy, package) + raise Exception("Unexpected cross arch policy {} for {}", + cross_policy, package) for key in keys: if key in mappings[package]: @@ -702,6 +696,6 @@ class Application: if __name__ == "__main__": try: Application().run() - except Error as err: - sys.stderr.write("{}: {}\n".format(sys.argv[0], err.message)) + except Exception as err: + sys.stderr.write("{}: {}\n".format(sys.argv[0], err)) sys.exit(1) -- 2.20.1

Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com&gt; --- guests/lcitool | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/guests/lcitool b/guests/lcitool index 487b67d..2c86d07 100755 --- a/guests/lcitool +++ b/guests/lcitool @@ -690,12 +690,12 @@ class Application: def run(self): args = self._parser.parse_args() - args.func(args) + try: + args.func(args) + except Exception as err: + sys.stderr.write("{}: {}\n".format(sys.argv[0], err)) + sys.exit(1) if __name__ == "__main__": - try: - Application().run() - except Exception as err: - sys.stderr.write("{}: {}\n".format(sys.argv[0], err)) - sys.exit(1) + Application().run() -- 2.20.1

Introduce a --debug / -d argument that allows the display of information relevant to developers debugging problems. Initially this just displays the top level exception catch, so that full stack traces are shown. Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com&gt; --- guests/lcitool | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/guests/lcitool b/guests/lcitool index 2c86d07..d8a3aca 100755 --- a/guests/lcitool +++ b/guests/lcitool @@ -350,6 +350,9 @@ class Application: description="libvirt CI guest management tool", ) + self._parser.add_argument("--debug", "-d", action="store_true", + help="display debugging information") + subparsers = self._parser.add_subparsers(metavar="ACTION") subparsers.required = True @@ -690,11 +693,14 @@ class Application: def run(self): args = self._parser.parse_args() - try: + if args.debug: args.func(args) - except Exception as err: - sys.stderr.write("{}: {}\n".format(sys.argv[0], err)) - sys.exit(1) + else: + try: + args.func(args) + except Exception as err: + sys.stderr.write("{}: {}\n".format(sys.argv[0], err)) + sys.exit(1) if __name__ == "__main__": -- 2.20.1