def main():
"""
Main command-line execution loop.
"""
try:
# Parse command line options
parser, options, arguments = parse_options()
# Handle regular args vs -- args
arguments = parser.largs
remainder_arguments = parser.rargs
# Update env with any overridden option values
# NOTE: This needs to remain the first thing that occurs
# post-parsing, since so many things hinge on the values in env.
for option in env_options:
state.env[option.dest] = getattr(options, option.dest)
# Handle --hosts, --roles, --exclude-hosts (comma separated string =>
# list)
for key in ['hosts', 'roles', 'exclude_hosts']:
if key in state.env and isinstance(state.env[key], basestring):
state.env[key] = state.env[key].split(',')
# Handle output control level show/hide
update_output_levels(show=options.show, hide=options.hide)
# Handle version number option
if options.show_version:
print("Fabric %s" % state.env.version)
sys.exit(0)
# Load settings from user settings file, into shared env dict.
state.env.update(load_settings(state.env.rcfile))
# Find local fabfile path or abort
fabfile = find_fabfile()
if not fabfile and not remainder_arguments:
abort("""Couldn't find any fabfiles!
Remember that -f can be used to specify fabfile path, and use -h for help.""")
# Store absolute path to fabfile in case anyone needs it
state.env.real_fabfile = fabfile
# Load fabfile (which calls its module-level code, including
# tweaks to env values) and put its commands in the shared commands
# dict
if fabfile:
docstring, callables, default = load_fabfile(fabfile)
state.commands.update(callables)
# Handle case where we were called bare, i.e. just "fab", and print
# a help message.
actions = (options.list_commands, options.shortlist, options.display,
arguments, remainder_arguments, default)
if not any(actions):
parser.print_help()
sys.exit(1)
# Abort if no commands found
if not state.commands and not remainder_arguments:
abort("Fabfile didn't contain any commands!")
# Now that we're settled on a fabfile, inform user.
if state.output.debug:
if fabfile:
print("Using fabfile '%s'" % fabfile)
else:
print("No fabfile loaded -- remainder command only")
# Shortlist is now just an alias for the "short" list format;
# it overrides use of --list-format if somebody were to specify both
if options.shortlist:
options.list_format = 'short'
options.list_commands = True
# List available commands
if options.list_commands:
print("\n".join(list_commands(docstring, options.list_format)))
sys.exit(0)
# Handle show (command-specific help) option
if options.display:
display_command(options.display)
# If user didn't specify any commands to run, show help
if not (arguments or remainder_arguments or default):
parser.print_help()
sys.exit(0) # Or should it exit with error (1)?
# Parse arguments into commands to run (plus args/kwargs/hosts)
commands_to_run = parse_arguments(arguments)
# Parse remainders into a faux "command" to execute
remainder_command = parse_remainder(remainder_arguments)
# Figure out if any specified task names are invalid
unknown_commands = []
for tup in commands_to_run:
if crawl(tup[0], state.commands) is None:
unknown_commands.append(tup[0])
# Abort if any unknown commands were specified
if unknown_commands:
abort("Command(s) not found:\n%s" \
% indent(unknown_commands))
# Generate remainder command and insert into commands, commands_to_run
if remainder_command:
r = '<remainder>'
state.commands[r] = lambda: api.run(remainder_command)
commands_to_run.append((r, [], {}, [], [], []))
# Ditto for a default, if found
if not commands_to_run and default:
commands_to_run.append((default.name, [], {}, [], [], []))
if state.output.debug:
names = ", ".join(x[0] for x in commands_to_run)
print("Commands to run: %s" % names)
# Import multiprocessing if needed, erroring out usefully if it can't.
if state.env.parallel or _parallel_tasks(commands_to_run):
try:
import multiprocessing
except ImportError, e:
msg = "At least one task needs to be run in parallel, but the\nmultiprocessing module cannot be imported:"
msg += "\n\n\t%s\n\n" % e
msg += "Please make sure the module is installed or that the above ImportError is\nfixed."
abort(msg)
# At this point all commands must exist, so execute them in order.
for name, args, kwargs, cli_hosts, cli_roles, cli_exclude_hosts in commands_to_run:
# Get callable by itself
task = crawl(name, state.commands)
# Set current task name (used for some error messages)
state.env.command = name
# Set host list (also copy to env)
state.env.all_hosts = hosts = get_hosts(
task, cli_hosts, cli_roles, cli_exclude_hosts)
# Get pool size for this task
pool_size = _get_pool_size(task, hosts)
# Set up job queue in case parallel is needed
jobs = JobQueue(pool_size)
if state.output.debug:
jobs._debug = True
# If hosts found, execute the function on each host in turn
for host in hosts:
# Preserve user
prev_user = state.env.user
# Split host string and apply to env dict
username, hostname, port = interpret_host_string(host)
# Log to stdout
if state.output.running and not hasattr(task, 'return_value'):
print("[%s] Executing task '%s'" % (host, name))
# Handle parallel execution
if requires_parallel(task):
# Grab appropriate callable (func or instance method)
to_call = task
if hasattr(task, 'run') and callable(task.run):
to_call = task.run
# Wrap in another callable that nukes the child's cached
# connection object, if needed, to prevent shared-socket
# problems.
def inner(*args, **kwargs):
key = normalize_to_string(state.env.host_string)
state.connections.pop(key, "")
to_call(*args, **kwargs)
# Stuff into Process wrapper
p = multiprocessing.Process(target=inner, args=args,
kwargs=kwargs)
# Name/id is host string
p.name = state.env.host_string
# Add to queue
jobs.append(p)
# Handle serial execution
else:
_run_task(task, args, kwargs)
# Put old user back
state.env.user = prev_user
# If running in parallel, block until job queue is emptied
if jobs:
jobs.close()
jobs.start()
# If no hosts found, assume local-only and run once
if not hosts:
_run_task(task, args, kwargs)
# If we got here, no errors occurred, so print a final note.
if state.output.status:
print("\nDone.")
