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ebd7a8ba | 1 | """Python Daemon Management -- Client functions |
7f97a47e | 2 | |
ebd7a8ba FT |
3 | This module implements the client part of the PDM protocols. The |
4 | primary objects of interest are the replclient and perfclient classes, | |
5 | which implement support for their respective protocols. See their | |
6 | documentation for details. | |
7f97a47e FT |
7 | """ |
8 | ||
9 | import socket, pickle, struct, select, threading | |
10 | ||
ac4f5166 | 11 | __all__ = ["client", "replclient", "perfclient"] |
7f97a47e FT |
12 | |
13 | class protoerr(Exception): | |
73c1ef8b | 14 | """Raised on protocol errors""" |
7f97a47e FT |
15 | pass |
16 | ||
17 | def resolve(spec): | |
18 | if isinstance(spec, socket.socket): | |
19 | return spec | |
20 | sk = None | |
21 | try: | |
22 | if "/" in spec: | |
23 | sk = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) | |
24 | sk.connect(spec) | |
25 | elif spec.isdigit(): | |
26 | sk = socket.socket(socket.AF_INET, socket.SOCK_STREAM) | |
27 | sk.connect(("localhost", int(spec))) | |
28 | elif ":" in spec: | |
29 | sk = socket.socket(socket.AF_INET, socket.SOCK_STREAM) | |
30 | p = spec.rindex(":") | |
31 | sk.connect((spec[:p], int(spec[p + 1:]))) | |
32 | else: | |
33 | raise Exception("Unknown target specification %r" % spec) | |
34 | rv = sk | |
35 | sk = None | |
36 | finally: | |
37 | if sk is not None: sk.close() | |
38 | return rv | |
39 | ||
40 | class client(object): | |
73c1ef8b FT |
41 | """PDM client |
42 | ||
43 | This class provides general facilities to speak to PDM servers, | |
44 | and is mainly intended to be subclassed to provide for the | |
45 | specific protocols, such as replclient and perfclient do. | |
46 | ||
47 | `client' instances can be passed as arguments to select.select(), | |
48 | and can be used in `with' statements. | |
49 | """ | |
7f97a47e | 50 | def __init__(self, sk, proto = None): |
73c1ef8b FT |
51 | """Create a client object connected to the specified |
52 | server. `sk' can either be a socket object, which is used as | |
53 | it is, or a string specification very similar to the | |
57808152 FT |
54 | specification for L{pdm.srv.listen}, so see its documentation |
55 | for details. The differences are only that this function does | |
56 | not take arguments specific to socket creation, like the mode | |
57 | and group arguments for Unix sockets. If `proto' is given, | |
58 | that subprotocol will negotiated with the server (by calling | |
59 | the select() method). | |
73c1ef8b | 60 | """ |
7f97a47e FT |
61 | self.sk = resolve(sk) |
62 | self.buf = "" | |
63 | line = self.readline() | |
64 | if line != "+PDM1": | |
65 | raise protoerr("Illegal protocol signature") | |
66 | if proto is not None: | |
67 | self.select(proto) | |
68 | ||
69 | def close(self): | |
73c1ef8b | 70 | """Close this connection""" |
7f97a47e FT |
71 | self.sk.close() |
72 | ||
9928d247 | 73 | def fileno(self): |
73c1ef8b | 74 | """Return the file descriptor of the underlying socket.""" |
9928d247 FT |
75 | return self.sk.fileno() |
76 | ||
7f97a47e | 77 | def readline(self): |
73c1ef8b | 78 | """Read a single NL-terminated line and return it.""" |
7f97a47e FT |
79 | while True: |
80 | p = self.buf.find("\n") | |
81 | if p >= 0: | |
82 | ret = self.buf[:p] | |
83 | self.buf = self.buf[p + 1:] | |
84 | return ret | |
85 | ret = self.sk.recv(1024) | |
86 | if ret == "": | |
87 | return None | |
88 | self.buf += ret | |
89 | ||
90 | def select(self, proto): | |
73c1ef8b | 91 | """Negotiate the given subprotocol with the server""" |
7f97a47e FT |
92 | if "\n" in proto: |
93 | raise Exception("Illegal protocol specified: %r" % proto) | |
94 | self.sk.send(proto + "\n") | |
95 | rep = self.readline() | |
96 | if len(rep) < 1 or rep[0] != "+": | |
97 | raise protoerr("Error reply when selecting protocol %s: %s" % (proto, rep[1:])) | |
98 | ||
99 | def __enter__(self): | |
100 | return self | |
101 | ||
102 | def __exit__(self, *excinfo): | |
103 | self.close() | |
104 | return False | |
105 | ||
106 | class replclient(client): | |
73c1ef8b FT |
107 | """REPL protocol client |
108 | ||
57808152 FT |
109 | Implements the client side of the REPL protocol; see |
110 | L{pdm.srv.repl} for details on the protocol and its functionality. | |
73c1ef8b | 111 | """ |
7f97a47e | 112 | def __init__(self, sk): |
73c1ef8b | 113 | """Create a connected client as documented in the `client' class.""" |
7f97a47e FT |
114 | super(replclient, self).__init__(sk, "repl") |
115 | ||
116 | def run(self, code): | |
73c1ef8b | 117 | """Run a single block of Python code on the server. Returns |
57808152 FT |
118 | the output of the command (as documented in L{pdm.srv.repl}) |
119 | as a string. | |
73c1ef8b | 120 | """ |
7f97a47e FT |
121 | while True: |
122 | ncode = code.replace("\n\n", "\n") | |
123 | if ncode == code: break | |
124 | code = ncode | |
125 | while len(code) > 0 and code[-1] == "\n": | |
126 | code = code[:-1] | |
127 | self.sk.send(code + "\n\n") | |
128 | buf = "" | |
129 | while True: | |
130 | ln = self.readline() | |
131 | if ln[0] == " ": | |
132 | buf += ln[1:] + "\n" | |
133 | elif ln[0] == "+": | |
134 | return buf | |
135 | elif ln[0] == "-": | |
136 | raise protoerr("Error reply: %s" % ln[1:]) | |
137 | else: | |
138 | raise protoerr("Illegal reply: %s" % ln) | |
139 | ||
140 | class perfproxy(object): | |
141 | def __init__(self, cl, id, proto): | |
142 | self.cl = cl | |
143 | self.id = id | |
144 | self.proto = proto | |
145 | self.subscribers = set() | |
146 | ||
147 | def lookup(self, name): | |
148 | self.cl.lock.acquire() | |
149 | try: | |
150 | id = self.cl.nextid | |
151 | self.cl.nextid += 1 | |
152 | finally: | |
153 | self.cl.lock.release() | |
154 | (proto,) = self.cl.run("lookup", id, self.id, name) | |
155 | proxy = perfproxy(self.cl, id, proto) | |
156 | self.cl.proxies[id] = proxy | |
157 | return proxy | |
158 | ||
159 | def listdir(self): | |
160 | return self.cl.run("ls", self.id)[0] | |
161 | ||
162 | def readattr(self): | |
163 | return self.cl.run("readattr", self.id)[0] | |
164 | ||
165 | def attrinfo(self): | |
166 | return self.cl.run("attrinfo", self.id)[0] | |
167 | ||
168 | def invoke(self, method, *args, **kwargs): | |
169 | return self.cl.run("invoke", self.id, method, args, kwargs)[0] | |
170 | ||
171 | def subscribe(self, cb): | |
172 | if cb in self.subscribers: | |
173 | raise ValueError("Already subscribed") | |
174 | if len(self.subscribers) == 0: | |
175 | self.cl.run("subs", self.id) | |
176 | self.subscribers.add(cb) | |
177 | ||
441160a2 | 178 | def unsubscribe(self, cb): |
7f97a47e FT |
179 | if cb not in self.subscribers: |
180 | raise ValueError("Not subscribed") | |
181 | self.subscribers.remove(cb) | |
182 | if len(self.subscribers) == 0: | |
183 | self.cl.run("unsubs", self.id) | |
184 | ||
185 | def notify(self, ev): | |
186 | for cb in self.subscribers: | |
187 | try: | |
188 | cb(ev) | |
189 | except: pass | |
190 | ||
191 | def close(self): | |
4fcf3c74 FT |
192 | if self.id is not None: |
193 | self.cl.run("unbind", self.id) | |
194 | del self.cl.proxies[self.id] | |
195 | self.id = None | |
196 | ||
197 | def __del__(self): | |
198 | self.close() | |
7f97a47e FT |
199 | |
200 | def __enter__(self): | |
201 | return self | |
202 | ||
203 | def __exit__(self, *excinfo): | |
204 | self.close() | |
205 | return False | |
206 | ||
207 | class perfclient(client): | |
73c1ef8b FT |
208 | """PERF protocol client |
209 | ||
57808152 FT |
210 | Implements the client side of the PERF protocol; see |
211 | L{pdm.srv.perf} for details on the protocol and its functionality. | |
73c1ef8b FT |
212 | |
213 | This client class implements functions for finding PERF objects on | |
214 | the server, and returns, for each server-side object looked up, a | |
215 | proxy object that mimics exactly the PERF interfaces that the | |
216 | object implements. As the proxy objects reference live objects on | |
217 | the server, they should be released when they are no longer used; | |
218 | they implement a close() method for that purpose, and can also be | |
219 | used in `with' statements. | |
220 | ||
57808152 FT |
221 | See L{pdm.srv.perf} for details on the various PERF interfaces |
222 | that the proxy objects might implement. | |
73c1ef8b | 223 | """ |
7f97a47e | 224 | def __init__(self, sk): |
73c1ef8b | 225 | """Create a connected client as documented in the `client' class.""" |
7f97a47e FT |
226 | super(perfclient, self).__init__(sk, "perf") |
227 | self.nextid = 0 | |
228 | self.lock = threading.Lock() | |
229 | self.proxies = {} | |
230 | self.names = {} | |
231 | ||
232 | def send(self, ob): | |
233 | buf = pickle.dumps(ob) | |
234 | buf = struct.pack(">l", len(buf)) + buf | |
235 | self.sk.send(buf) | |
236 | ||
237 | def recvb(self, num): | |
238 | buf = "" | |
239 | while len(buf) < num: | |
240 | data = self.sk.recv(num - len(buf)) | |
241 | if data == "": | |
242 | raise EOFError() | |
243 | buf += data | |
244 | return buf | |
245 | ||
246 | def recv(self): | |
247 | return pickle.loads(self.recvb(struct.unpack(">l", self.recvb(4))[0])) | |
248 | ||
249 | def event(self, id, ev): | |
250 | proxy = self.proxies.get(id) | |
251 | if proxy is None: return | |
252 | proxy.notify(ev) | |
253 | ||
254 | def dispatch(self, timeout = None): | |
73c1ef8b FT |
255 | """Wait for an incoming notification from the server, and |
256 | dispatch it to the callback functions that have been | |
257 | registered for it. If `timeout' is specified, wait no longer | |
258 | than so many seconds; otherwise, wait forever. This client | |
259 | object may also be used as argument to select.select(). | |
260 | """ | |
7f97a47e FT |
261 | rfd, wfd, efd = select.select([self.sk], [], [], timeout) |
262 | if self.sk in rfd: | |
263 | msg = self.recv() | |
264 | if msg[0] == "*": | |
265 | self.event(msg[1], msg[2]) | |
266 | else: | |
267 | raise ValueError("Unexpected non-event message: %r" % msg[0]) | |
268 | ||
269 | def recvreply(self): | |
270 | while True: | |
271 | reply = self.recv() | |
272 | if reply[0] in ("+", "-"): | |
273 | return reply | |
274 | elif reply[0] == "*": | |
275 | self.event(reply[1], reply[2]) | |
276 | else: | |
277 | raise ValueError("Illegal reply header: %r" % reply[0]) | |
278 | ||
279 | def run(self, cmd, *args): | |
280 | self.lock.acquire() | |
281 | try: | |
282 | self.send((cmd,) + args) | |
283 | reply = self.recvreply() | |
284 | if reply[0] == "+": | |
285 | return reply[1:] | |
286 | else: | |
287 | raise reply[1] | |
288 | finally: | |
289 | self.lock.release() | |
290 | ||
291 | def lookup(self, module, obnm): | |
73c1ef8b FT |
292 | """Look up a single server-side object by the given name in |
293 | the given module. Will return a new proxy object for each | |
294 | call when called multiple times for the same name. | |
295 | """ | |
7f97a47e FT |
296 | self.lock.acquire() |
297 | try: | |
298 | id = self.nextid | |
299 | self.nextid += 1 | |
300 | finally: | |
301 | self.lock.release() | |
302 | (proto,) = self.run("bind", id, module, obnm) | |
303 | proxy = perfproxy(self, id, proto) | |
304 | self.proxies[id] = proxy | |
305 | return proxy | |
306 | ||
307 | def find(self, name): | |
73c1ef8b FT |
308 | """Convenience function for looking up server-side objects |
309 | through PERF directories and for multiple uses. The object | |
310 | name can be given as "MODULE.OBJECT", which will look up the | |
311 | named OBJECT in the named MODULE, and can be followed by any | |
312 | number of slash-separated names, which will assume that the | |
313 | object to the left of the slash is a PERF directory, and will | |
314 | return the object in that directory by the name to the right | |
315 | of the slash. For instance, find("pdm.perf.sysres/cputime") | |
316 | will return the built-in attribute for reading the CPU time | |
317 | used by the server process. | |
ebd7a8ba FT |
318 | |
319 | The proxy objects returned by this function are cached and the | |
320 | same object are returned the next time the same name is | |
321 | requested, which means that they are kept live until the | |
322 | client connection is closed. | |
73c1ef8b | 323 | """ |
7f97a47e FT |
324 | ret = self.names.get(name) |
325 | if ret is None: | |
326 | if "/" in name: | |
327 | p = name.rindex("/") | |
328 | ret = self.find(name[:p]).lookup(name[p + 1:]) | |
329 | else: | |
330 | p = name.rindex(".") | |
331 | ret = self.lookup(name[:p], name[p + 1:]) | |
332 | self.names[name] = ret | |
333 | return ret |