X-Git-Url: http://dolda2000.com/gitweb/?a=blobdiff_plain;f=pdm%2Fsrv.py;h=80f9a260d688a438e0000a248f805c6129e64ef2;hb=HEAD;hp=9f6869e9305e21e4c5ef7100341c7c2ebd1af6eb;hpb=cfc372bf6dba593333f2ff5ba226cf7fb71afa12;p=pdm.git diff --git a/pdm/srv.py b/pdm/srv.py index 9f6869e..80f9a26 100644 --- a/pdm/srv.py +++ b/pdm/srv.py @@ -1,50 +1,75 @@ -"""Management for daemon processes +"""Python Daemon Management -- Server functions -This module contains a utility to listen for management commands on a -socket, lending itself to managing daemon processes. +This module implements the server part of the PDM protocols. The +primary object of interest herein is the listen() function, which is +the most generic way to create PDM listeners based on user +configuration, and the documentation for the repl and perf classes, +which describes the functioning of the REPL and PERF protocols. """ import os, sys, socket, threading, grp, select import types, pprint, traceback import pickle, struct -__all__ = ["listener", "unixlistener", "tcplistener", "listen"] +__all__ = ["repl", "perf", "listener", "unixlistener", "tcplistener", "listen"] protocols = {} class repl(object): + """REPL protocol handler + + Provides a read-eval-print loop. The primary client-side interface + is the L{pdm.cli.replclient} class. Clients can send arbitrary + code, which is compiled and run on its own thread in the server + process, and output responses that are echoed back to the client. + + Each client is provided with its own module, in which the code + runs. The module is prepared with a function named `echo', which + takes a single object and pretty-prints it as part of the command + response. If a command can be parsed as an expression, the value + it evaluates to is automatically echoed to the client. If the + evalution of the command terminates with an exception, its + traceback is echoed to the client. + + The REPL protocol is only intended for interactive usage. In order + to interact programmatically with the server process, see the PERF + protocol instead. + """ def __init__(self, cl): self.cl = cl self.mod = types.ModuleType("repl") self.mod.echo = self.echo self.printer = pprint.PrettyPrinter(indent = 4, depth = 6) - cl.send("+REPL\n") + cl.send(b"+REPL\n") def sendlines(self, text): for line in text.split("\n"): - self.cl.send(" " + line + "\n") + self.cl.send(b" " + line.encode("utf-8") + b"\n") def echo(self, ob): self.sendlines(self.printer.pformat(ob)) def command(self, cmd): + cmd = cmd.decode("utf-8") try: try: ccode = compile(cmd, "PDM Input", "eval") except SyntaxError: ccode = compile(cmd, "PDM Input", "exec") - exec ccode in self.mod.__dict__ - self.cl.send("+OK\n") + exec(ccode, self.mod.__dict__) + self.cl.send(b"+OK\n") else: self.echo(eval(ccode, self.mod.__dict__)) - self.cl.send("+OK\n") + self.cl.send(b"+OK\n") except: - for line in traceback.format_exception(*sys.exc_info()): - self.cl.send(" " + line) - self.cl.send("+EXC\n") + lines = ("".join(traceback.format_exception(*sys.exc_info()))).split("\n") + while len(lines) > 0 and lines[-1] == "": lines = lines[:-1] + for line in lines: + self.cl.send(b" " + line.encode("utf-8") + b"\n") + self.cl.send(b"+EXC\n") def handle(self, buf): - p = buf.find("\n\n") + p = buf.find(b"\n\n") if p < 0: return buf cmd = buf[:p + 1] @@ -53,16 +78,107 @@ class repl(object): protocols["repl"] = repl class perf(object): + """PERF protocol handler + + The PERF protocol provides an interface for program interaction + with the server process. It allows limited remote interactions + with Python objects over a few defined interfaces. + + All objects that wish to be available for interaction need to + implement a method named `pdm_protocols' which, when called with + no arguments, should return a list of strings, each indicating a + PERF interface that the object implements. For each such + interface, the object must implement additional methods as + described below. + + A client can find PERF objects to interact with either by + specifying the name of such an object in an existing module, or by + using the `dir' interface, described below. Thus, to make a PERF + object available for clients, it needs only be bound to a global + variable in a module and implement the `pdm_protocols' + method. When requesting an object from a module, the module must + already be imported. PDM will not import new modules for clients; + rather, the daemon process needs to import all modules that + clients should be able to interact with. PDM itself always imports + the L{pdm.perf} module, which contains a few basic PERF + objects. See its documentation for details. + + The following interfaces are currently known to PERF. + + - attr: + An object that implements the `attr' interface models an + attribute that can be read by clients. The attribute can be + anything, as long as its representation can be + pickled. Examples of attributes could be such things as the CPU + time consumed by the server process, or the number of active + connections to whatever clients the program serves. To + implement the `attr' interface, an object must implement + methods called `readattr' and `attrinfo'. `readattr' is called + with no arguments to read the current value of the attribute, + and `attrinfo' is called with no arguments to read a + description of the attribute. Both should be + idempotent. `readattr' can return any pickleable object, and + `attrinfo' should return either None to indicate that it has no + description, or an instance of the L{pdm.perf.attrinfo} class. + + - dir: + The `dir' interface models a directory of other PERF + objects. An object implementing it must implement methods + called `lookup' and `listdir'. `lookup' is called with a single + string argument that names an object, and should either return + another PERF object based on the name, or raise KeyError if it + does not recognize the name. `listdir' is called with no + arguments, and should return a list of known names that can be + used as argument to `lookup', but the list is not required to + be exhaustive and may also be empty. + + - invoke: + The `invoke' interface allows a more arbitrary form of method + calls to objects implementing it. Such objects must implement a + method called `invoke', which is called with one positional + argument naming a method to be called (which it is free to + interpret however it wishes), and with any additional + positional and keyword arguments that the client wishes to pass + to it. Whatever `invoke' returns is pickled and sent back to + the client. In case the method name is not recognized, `invoke' + should raise an AttributeError. + + - event: + The `event' interface allows PERF objects to notify clients of + events asynchronously. Objects implementing it must implement + methods called `subscribe' and `unsubscribe'. `subscribe' will + be called with a single argument, which is a callable of one + argument, which should be registered to be called when an event + pertaining to the `event' object in question occurs. The + `event' object should then call all such registered callables + with a single argument describing the event. The argument could + be any object that can be pickled, but should be an instance of + a subclass of the L{pdm.perf.event} class. If `subscribe' is + called with a callback object that it has already registered, + it should raise a ValueError. `unsubscribe' is called with a + single argument, which is a previously registered callback + object, which should then be unregistered to that it is no + longer called when an event occurs. If the given callback + object is not, in fact, registered, a ValueError should be + raised. + + The L{pdm.perf} module contains a few convenience classes which + implements the interfaces, but PERF objects are not required to be + instances of them. Any object can implement a PERF interface, as + long as it does so as described above. + + The L{pdm.cli.perfclient} class is the client-side implementation. + """ def __init__(self, cl): self.cl = cl self.odtab = {} - cl.send("+PERF1\n") + cl.send(b"+PERF1\n") self.buf = "" self.lock = threading.Lock() self.subscribed = {} def closed(self): - for id, recv in self.subscribed.iteritems(): + for id, recv in self.subscribed.items(): ob = self.odtab[id] if ob is None: continue ob, protos = ob @@ -84,7 +200,7 @@ class perf(object): raise ValueError("Object does not support PDM introspection") try: proto = ob.pdm_protocols() - except Exception, exc: + except Exception as exc: raise ValueError("PDM introspection failed", exc) self.odtab[id] = ob, proto return proto @@ -101,7 +217,7 @@ class perf(object): return try: proto = self.bindob(id, ob) - except Exception, exc: + except Exception as exc: self.send("-", exc) return self.send("+", proto) @@ -123,12 +239,12 @@ class perf(object): return try: ob = src.lookup(obnm) - except KeyError, exc: + except KeyError as exc: self.send("-", exc) return try: proto = self.bindob(tgtid, ob) - except Exception, exc: + except Exception as exc: self.send("-", exc) return self.send("+", proto) @@ -158,7 +274,7 @@ class perf(object): return try: ret = ob.readattr() - except Exception, exc: + except Exception as exc: self.send("-", Exception("Could not read attribute")) return self.send("+", ret) @@ -175,7 +291,7 @@ class perf(object): return try: self.send("+", ob.invoke(method, *args, **kwargs)) - except Exception, exc: + except Exception as exc: self.send("-", exc) def event(self, id, ob, ev): @@ -241,7 +357,7 @@ protocols["perf"] = perf class client(threading.Thread): def __init__(self, sk): - super(client, self).__init__(name = "Management client") + super().__init__(name = "Management client") self.setDaemon(True) self.sk = sk self.handler = self @@ -250,6 +366,10 @@ class client(threading.Thread): return self.sk.send(data) def choose(self, proto): + try: + proto = proto.decode("ascii") + except UnicodeError: + proto = None if proto in protocols: self.handler = protocols[proto](self) else: @@ -257,7 +377,7 @@ class client(threading.Thread): raise Exception() def handle(self, buf): - p = buf.find("\n") + p = buf.find(b"\n") if p >= 0: proto = buf[:p] buf = buf[p + 1:] @@ -266,24 +386,24 @@ class client(threading.Thread): def run(self): try: - buf = "" - self.send("+PDM1\n") + buf = b"" + self.send(b"+PDM1\n") while True: ret = self.sk.recv(1024) - if ret == "": + if ret == b"": return buf += ret while True: try: nbuf = self.handler.handle(buf) except: + #for line in traceback.format_exception(*sys.exc_info()): + # print(line) return if nbuf == buf: break buf = nbuf finally: - #for line in traceback.format_exception(*sys.exc_info()): - # print line try: self.sk.close() finally: @@ -292,11 +412,19 @@ class client(threading.Thread): class listener(threading.Thread): + """PDM listener + + This subclass of a thread listens to PDM connections and handles + client connections properly. It is intended to be subclassed by + providers of specific domains, such as unixlistener and + tcplistener. + """ def __init__(self): - super(listener, self).__init__(name = "Management listener") + super().__init__(name = "Management listener") self.setDaemon(True) def listen(self, sk): + """Listen for and accept connections.""" self.running = True while self.running: rfd, wfd, efd = select.select([sk], [], [sk], 1) @@ -306,6 +434,11 @@ class listener(threading.Thread): self.accept(nsk, addr) def stop(self): + """Stop listening for client connections + + Tells the listener thread to stop listening, and then waits + for it to terminate. + """ self.running = False self.join() @@ -314,8 +447,15 @@ class listener(threading.Thread): cl.start() class unixlistener(listener): - def __init__(self, name, mode = 0600, group = None): - super(unixlistener, self).__init__() + """Unix socket listener""" + def __init__(self, name, mode = 0o600, group = None): + """Create a listener that will bind to the Unix socket named + by `name'. The socket will not actually be bound until the + listener is started. The socket will be chmodded to `mode', + and if `group' is given, the named group will be set as the + owner of the socket. + """ + super().__init__() self.name = name self.mode = mode self.group = group @@ -339,8 +479,13 @@ class unixlistener(listener): os.unlink(self.name) class tcplistener(listener): + """TCP socket listener""" def __init__(self, port, bindaddr = "127.0.0.1"): - super(tcplistener, self).__init__() + """Create a listener that will bind to the given TCP port, and + the given local interface. The socket will not actually be + bound until the listener is started. + """ + super().__init__() self.port = port self.bindaddr = bindaddr @@ -354,6 +499,22 @@ class tcplistener(listener): sk.close() def listen(spec): + """Create and start a listener according to a string + specification. The string specifications can easily be passed from + command-line options, user configuration or the like. Currently, + the two following specification formats are recognized: + + PATH[:MODE[:GROUP]] -- PATH must contain at least one slash. A + Unix socket listener will be created listening to that path, and + the socket will be chmodded to MODE and owned by GROUP. If MODE is + not given, it defaults to 0600, and if GROUP is not given, the + process' default group is used. + + ADDRESS:PORT -- PORT must be entirely numeric. A TCP socket + listener will be created listening to that port, bound to the + given local interface address. Since PDM has no authentication + support, ADDRESS should probably be localhost. + """ if ":" in spec: first = spec[:spec.index(":")] last = spec[spec.rindex(":") + 1:] @@ -362,7 +523,7 @@ def listen(spec): last = spec if "/" in first: parts = spec.split(":") - mode = 0600 + mode = 0o600 group = None if len(parts) > 1: mode = int(parts[1], 8)