X-Git-Url: https://scripts.mit.edu/gitweb/wizard.git/blobdiff_plain/4c3a9a2e00d17447baaaa8fd71531ce9362e0a6e..8264ae4501b4e3ca5e7fef548bebb33c16a62a65:/wizard/shell.py diff --git a/wizard/shell.py b/wizard/shell.py index 8748b93..8660d1a 100644 --- a/wizard/shell.py +++ b/wizard/shell.py @@ -25,16 +25,18 @@ def is_python(args): """Detects whether or not an argument list invokes a Python program.""" return args[0] == "python" or args[0] == "wizard" -def drop_priviledges(options): +def drop_priviledges(dir, log_file): """ Checks if we are running as root. If we are, attempt to drop - priviledges to the user who owns the current directory, by re-calling + priviledges to the user who owns ``dir``, by re-calling itself using sudo with exec, such that the new process subsumes our - current one. + current one. If ``log_file`` is passed, the file is chown'ed + to the user we are dropping priviledges to, so the subprocess + can write to it. """ if os.getuid(): return - uid = util.get_dir_uid('.') + uid = util.get_dir_uid(dir) if not uid: return args = [] @@ -43,7 +45,7 @@ def drop_priviledges(options): args.append("%s=%s" % (k,v)) args += sys.argv logging.debug("Dropping priviledges") - if options.log_file: os.chown(options.log_file, uid, -1) + if log_file: os.chown(log_file, uid, -1) os.execlp('sudo', 'sudo', '-u', '#' + str(uid), *args) class Shell(object): @@ -71,6 +73,11 @@ class Shell(object): removed. This emulates the behavior of backticks and ``$()`` in Bash. Prefer to use :meth:`eval` instead (you should only need to explicitly specify this if you are using another wrapper around this function). + :param log: if True, we log the call as INFO, if False, we log the call + as DEBUG, otherwise, we detect based on ``strip``. + :param stdout: + :param stderr: + :param stdin: a file-type object that will be written to or read from as a pipe. :returns: a tuple of strings ``(stdout, stderr)``, or a string ``stdout`` if ``strip`` is specified. @@ -80,15 +87,24 @@ class Shell(object): >>> sh.call("cat", input='Foobar') ('Foobar', '') """ + if hasattr(self, "_wait"): + self._wait() kwargs.setdefault("interactive", False) kwargs.setdefault("strip", False) kwargs.setdefault("python", None) - if kwargs["strip"]: - logging.debug("Evaluating `" + ' '.join(args) + "`") + kwargs.setdefault("log", None) + kwargs.setdefault("stdout", subprocess.PIPE) + kwargs.setdefault("stdin", subprocess.PIPE) + kwargs.setdefault("stderr", subprocess.PIPE) + msg = "Running `" + ' '.join(args) + "`" + if kwargs["strip"] and not kwargs["log"] is True or kwargs["log"] is False: + logging.debug(msg) else: - logging.info("Running `" + ' '.join(args) + "`") + logging.info(msg) if self.dry: - return + if kwargs["strip"]: + return '' + return None, None if kwargs["python"] is None and is_python(args): kwargs["python"] = True if args[0] == "wizard": @@ -100,9 +116,9 @@ class Shell(object): stdin=sys.stdin stderr=sys.stderr else: - stdout=subprocess.PIPE - stdin=subprocess.PIPE - stderr=subprocess.PIPE + stdout=kwargs["stdout"] + stdin=kwargs["stdin"] + stderr=kwargs["stderr"] # XXX: There is a possible problem here where we can fill up # the kernel buffer if we have 64KB of data. This shouldn't # be a problem, and the fix for such case would be to write to @@ -197,19 +213,10 @@ class ParallelShell(Shell): with ``max`` subprocesses, and result in callback execution when they finish. - Before enqueueing a system call with :meth:`call` or :meth:`callAsUser`, - you should wait for an open slot using :meth:`wait`; otherwise, - ``max`` rate limiting will have no effect. For example:: - - sh = ParallelShell() - for command in commands_to_execute_in_parallel: - sh.wait() - sh.call(*command) - sh.join() - .. method:: call(*args, **kwargs) - Enqueues a system call for parallel processing. Keyword arguments + Enqueues a system call for parallel processing. If there are + no openings in the queue, this will block. Keyword arguments are the same as :meth:`Shell.call` with the following additions: :param on_success: Callback function for success (zero exit status). @@ -245,20 +252,23 @@ class ParallelShell(Shell): super(ParallelShell, self).__init__(dry=dry) self.running = {} self.max = max # maximum of commands to run in parallel + @staticmethod + def make(no_parallelize, max): + """Convenience method oriented towards command modules.""" + if no_parallelize: + return DummyParallelShell() + else: + return ParallelShell(max=max) def _async(self, proc, args, python, on_success, on_error, **kwargs): """ Gets handed a :class:`subprocess.Proc` object from our deferred execution. See :meth:`Shell.call` source code for details. """ self.running[proc.pid] = (proc, args, python, on_success, on_error) - def wait(self): + def _wait(self): """ - Blocking call that waits for an open subprocess slot. You should - call this before enqueuing. - - .. note:: - - This method may become unnecessary in the future. + Blocking call that waits for an open subprocess slot. This is + automatically called by :meth:`Shell.call`. """ # XXX: This API sucks; the actuall call/callAsUser call should # probably block automatically (unless I have a good reason not to) @@ -321,7 +331,8 @@ class CallError(Error): self.stdout = stdout self.stderr = stderr def __str__(self): - return "CallError [%d]" % self.code + compact = self.stderr.rstrip().split("\n")[-1] + return "%s (exited with %d)\n%s" % (compact, self.code, self.stderr) class PythonCallError(CallError): """ @@ -335,7 +346,7 @@ class PythonCallError(CallError): CallError.__init__(self, code, args, stdout, stderr) def __str__(self): if self.name: - return "PythonCallError [%s]" % self.name + return "PythonCallError [%s]\n%s" % (self.name, self.stderr) else: - return "PythonCallError" + return "PythonCallError\n%s" % self.stderr