Commit | Line | Data |
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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: | |
c30be9c9 FT |
22 | if ":" in spec: |
23 | p = spec.rindex(":") | |
24 | first, second = spec[:p], spec[p + 1:] | |
25 | if "/" in second: | |
26 | import sshsock | |
27 | sk = sshsock.sshsocket(first, second) | |
28 | else: | |
29 | sk = socket.socket(socket.AF_INET, socket.SOCK_STREAM) | |
30 | sk.connect((first, second)) | |
31 | elif "/" in spec: | |
7f97a47e FT |
32 | sk = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) |
33 | sk.connect(spec) | |
34 | elif spec.isdigit(): | |
35 | sk = socket.socket(socket.AF_INET, socket.SOCK_STREAM) | |
36 | sk.connect(("localhost", int(spec))) | |
7f97a47e FT |
37 | else: |
38 | raise Exception("Unknown target specification %r" % spec) | |
39 | rv = sk | |
40 | sk = None | |
41 | finally: | |
42 | if sk is not None: sk.close() | |
43 | return rv | |
44 | ||
45 | class client(object): | |
73c1ef8b FT |
46 | """PDM client |
47 | ||
48 | This class provides general facilities to speak to PDM servers, | |
49 | and is mainly intended to be subclassed to provide for the | |
50 | specific protocols, such as replclient and perfclient do. | |
51 | ||
52 | `client' instances can be passed as arguments to select.select(), | |
53 | and can be used in `with' statements. | |
54 | """ | |
7f97a47e | 55 | def __init__(self, sk, proto = None): |
73c1ef8b FT |
56 | """Create a client object connected to the specified |
57 | server. `sk' can either be a socket object, which is used as | |
58 | it is, or a string specification very similar to the | |
57808152 FT |
59 | specification for L{pdm.srv.listen}, so see its documentation |
60 | for details. The differences are only that this function does | |
61 | not take arguments specific to socket creation, like the mode | |
62 | and group arguments for Unix sockets. If `proto' is given, | |
63 | that subprotocol will negotiated with the server (by calling | |
64 | the select() method). | |
73c1ef8b | 65 | """ |
7f97a47e FT |
66 | self.sk = resolve(sk) |
67 | self.buf = "" | |
68 | line = self.readline() | |
69 | if line != "+PDM1": | |
70 | raise protoerr("Illegal protocol signature") | |
71 | if proto is not None: | |
72 | self.select(proto) | |
73 | ||
74 | def close(self): | |
73c1ef8b | 75 | """Close this connection""" |
7f97a47e FT |
76 | self.sk.close() |
77 | ||
9928d247 | 78 | def fileno(self): |
73c1ef8b | 79 | """Return the file descriptor of the underlying socket.""" |
9928d247 FT |
80 | return self.sk.fileno() |
81 | ||
7f97a47e | 82 | def readline(self): |
73c1ef8b | 83 | """Read a single NL-terminated line and return it.""" |
7f97a47e FT |
84 | while True: |
85 | p = self.buf.find("\n") | |
86 | if p >= 0: | |
87 | ret = self.buf[:p] | |
88 | self.buf = self.buf[p + 1:] | |
89 | return ret | |
90 | ret = self.sk.recv(1024) | |
91 | if ret == "": | |
92 | return None | |
93 | self.buf += ret | |
94 | ||
95 | def select(self, proto): | |
73c1ef8b | 96 | """Negotiate the given subprotocol with the server""" |
7f97a47e FT |
97 | if "\n" in proto: |
98 | raise Exception("Illegal protocol specified: %r" % proto) | |
99 | self.sk.send(proto + "\n") | |
100 | rep = self.readline() | |
101 | if len(rep) < 1 or rep[0] != "+": | |
102 | raise protoerr("Error reply when selecting protocol %s: %s" % (proto, rep[1:])) | |
103 | ||
104 | def __enter__(self): | |
105 | return self | |
106 | ||
107 | def __exit__(self, *excinfo): | |
108 | self.close() | |
109 | return False | |
110 | ||
111 | class replclient(client): | |
73c1ef8b FT |
112 | """REPL protocol client |
113 | ||
57808152 FT |
114 | Implements the client side of the REPL protocol; see |
115 | L{pdm.srv.repl} for details on the protocol and its functionality. | |
73c1ef8b | 116 | """ |
7f97a47e | 117 | def __init__(self, sk): |
73c1ef8b | 118 | """Create a connected client as documented in the `client' class.""" |
7f97a47e FT |
119 | super(replclient, self).__init__(sk, "repl") |
120 | ||
121 | def run(self, code): | |
73c1ef8b | 122 | """Run a single block of Python code on the server. Returns |
57808152 FT |
123 | the output of the command (as documented in L{pdm.srv.repl}) |
124 | as a string. | |
73c1ef8b | 125 | """ |
7f97a47e FT |
126 | while True: |
127 | ncode = code.replace("\n\n", "\n") | |
128 | if ncode == code: break | |
129 | code = ncode | |
130 | while len(code) > 0 and code[-1] == "\n": | |
131 | code = code[:-1] | |
132 | self.sk.send(code + "\n\n") | |
133 | buf = "" | |
134 | while True: | |
135 | ln = self.readline() | |
136 | if ln[0] == " ": | |
137 | buf += ln[1:] + "\n" | |
138 | elif ln[0] == "+": | |
139 | return buf | |
140 | elif ln[0] == "-": | |
141 | raise protoerr("Error reply: %s" % ln[1:]) | |
142 | else: | |
143 | raise protoerr("Illegal reply: %s" % ln) | |
144 | ||
145 | class perfproxy(object): | |
146 | def __init__(self, cl, id, proto): | |
147 | self.cl = cl | |
148 | self.id = id | |
149 | self.proto = proto | |
150 | self.subscribers = set() | |
151 | ||
152 | def lookup(self, name): | |
153 | self.cl.lock.acquire() | |
154 | try: | |
155 | id = self.cl.nextid | |
156 | self.cl.nextid += 1 | |
157 | finally: | |
158 | self.cl.lock.release() | |
159 | (proto,) = self.cl.run("lookup", id, self.id, name) | |
160 | proxy = perfproxy(self.cl, id, proto) | |
161 | self.cl.proxies[id] = proxy | |
162 | return proxy | |
163 | ||
164 | def listdir(self): | |
165 | return self.cl.run("ls", self.id)[0] | |
166 | ||
167 | def readattr(self): | |
168 | return self.cl.run("readattr", self.id)[0] | |
169 | ||
170 | def attrinfo(self): | |
171 | return self.cl.run("attrinfo", self.id)[0] | |
172 | ||
173 | def invoke(self, method, *args, **kwargs): | |
174 | return self.cl.run("invoke", self.id, method, args, kwargs)[0] | |
175 | ||
176 | def subscribe(self, cb): | |
177 | if cb in self.subscribers: | |
178 | raise ValueError("Already subscribed") | |
179 | if len(self.subscribers) == 0: | |
180 | self.cl.run("subs", self.id) | |
181 | self.subscribers.add(cb) | |
182 | ||
441160a2 | 183 | def unsubscribe(self, cb): |
7f97a47e FT |
184 | if cb not in self.subscribers: |
185 | raise ValueError("Not subscribed") | |
186 | self.subscribers.remove(cb) | |
187 | if len(self.subscribers) == 0: | |
188 | self.cl.run("unsubs", self.id) | |
189 | ||
190 | def notify(self, ev): | |
191 | for cb in self.subscribers: | |
192 | try: | |
193 | cb(ev) | |
194 | except: pass | |
195 | ||
196 | def close(self): | |
4fcf3c74 FT |
197 | if self.id is not None: |
198 | self.cl.run("unbind", self.id) | |
199 | del self.cl.proxies[self.id] | |
200 | self.id = None | |
201 | ||
202 | def __del__(self): | |
203 | self.close() | |
7f97a47e FT |
204 | |
205 | def __enter__(self): | |
206 | return self | |
207 | ||
208 | def __exit__(self, *excinfo): | |
209 | self.close() | |
210 | return False | |
211 | ||
212 | class perfclient(client): | |
73c1ef8b FT |
213 | """PERF protocol client |
214 | ||
57808152 FT |
215 | Implements the client side of the PERF protocol; see |
216 | L{pdm.srv.perf} for details on the protocol and its functionality. | |
73c1ef8b FT |
217 | |
218 | This client class implements functions for finding PERF objects on | |
219 | the server, and returns, for each server-side object looked up, a | |
220 | proxy object that mimics exactly the PERF interfaces that the | |
221 | object implements. As the proxy objects reference live objects on | |
222 | the server, they should be released when they are no longer used; | |
223 | they implement a close() method for that purpose, and can also be | |
224 | used in `with' statements. | |
225 | ||
57808152 FT |
226 | See L{pdm.srv.perf} for details on the various PERF interfaces |
227 | that the proxy objects might implement. | |
73c1ef8b | 228 | """ |
7f97a47e | 229 | def __init__(self, sk): |
73c1ef8b | 230 | """Create a connected client as documented in the `client' class.""" |
7f97a47e FT |
231 | super(perfclient, self).__init__(sk, "perf") |
232 | self.nextid = 0 | |
233 | self.lock = threading.Lock() | |
234 | self.proxies = {} | |
235 | self.names = {} | |
236 | ||
237 | def send(self, ob): | |
238 | buf = pickle.dumps(ob) | |
239 | buf = struct.pack(">l", len(buf)) + buf | |
240 | self.sk.send(buf) | |
241 | ||
242 | def recvb(self, num): | |
243 | buf = "" | |
244 | while len(buf) < num: | |
245 | data = self.sk.recv(num - len(buf)) | |
246 | if data == "": | |
247 | raise EOFError() | |
248 | buf += data | |
249 | return buf | |
250 | ||
251 | def recv(self): | |
252 | return pickle.loads(self.recvb(struct.unpack(">l", self.recvb(4))[0])) | |
253 | ||
254 | def event(self, id, ev): | |
255 | proxy = self.proxies.get(id) | |
256 | if proxy is None: return | |
257 | proxy.notify(ev) | |
258 | ||
259 | def dispatch(self, timeout = None): | |
73c1ef8b FT |
260 | """Wait for an incoming notification from the server, and |
261 | dispatch it to the callback functions that have been | |
262 | registered for it. If `timeout' is specified, wait no longer | |
263 | than so many seconds; otherwise, wait forever. This client | |
264 | object may also be used as argument to select.select(). | |
265 | """ | |
7f97a47e FT |
266 | rfd, wfd, efd = select.select([self.sk], [], [], timeout) |
267 | if self.sk in rfd: | |
268 | msg = self.recv() | |
269 | if msg[0] == "*": | |
270 | self.event(msg[1], msg[2]) | |
271 | else: | |
272 | raise ValueError("Unexpected non-event message: %r" % msg[0]) | |
273 | ||
274 | def recvreply(self): | |
275 | while True: | |
276 | reply = self.recv() | |
277 | if reply[0] in ("+", "-"): | |
278 | return reply | |
279 | elif reply[0] == "*": | |
280 | self.event(reply[1], reply[2]) | |
281 | else: | |
282 | raise ValueError("Illegal reply header: %r" % reply[0]) | |
283 | ||
284 | def run(self, cmd, *args): | |
285 | self.lock.acquire() | |
286 | try: | |
287 | self.send((cmd,) + args) | |
288 | reply = self.recvreply() | |
289 | if reply[0] == "+": | |
290 | return reply[1:] | |
291 | else: | |
292 | raise reply[1] | |
293 | finally: | |
294 | self.lock.release() | |
295 | ||
296 | def lookup(self, module, obnm): | |
73c1ef8b FT |
297 | """Look up a single server-side object by the given name in |
298 | the given module. Will return a new proxy object for each | |
299 | call when called multiple times for the same name. | |
300 | """ | |
7f97a47e FT |
301 | self.lock.acquire() |
302 | try: | |
303 | id = self.nextid | |
304 | self.nextid += 1 | |
305 | finally: | |
306 | self.lock.release() | |
307 | (proto,) = self.run("bind", id, module, obnm) | |
308 | proxy = perfproxy(self, id, proto) | |
309 | self.proxies[id] = proxy | |
310 | return proxy | |
311 | ||
312 | def find(self, name): | |
73c1ef8b FT |
313 | """Convenience function for looking up server-side objects |
314 | through PERF directories and for multiple uses. The object | |
315 | name can be given as "MODULE.OBJECT", which will look up the | |
316 | named OBJECT in the named MODULE, and can be followed by any | |
317 | number of slash-separated names, which will assume that the | |
318 | object to the left of the slash is a PERF directory, and will | |
319 | return the object in that directory by the name to the right | |
320 | of the slash. For instance, find("pdm.perf.sysres/cputime") | |
321 | will return the built-in attribute for reading the CPU time | |
322 | used by the server process. | |
ebd7a8ba FT |
323 | |
324 | The proxy objects returned by this function are cached and the | |
325 | same object are returned the next time the same name is | |
326 | requested, which means that they are kept live until the | |
327 | client connection is closed. | |
73c1ef8b | 328 | """ |
7f97a47e FT |
329 | ret = self.names.get(name) |
330 | if ret is None: | |
331 | if "/" in name: | |
332 | p = name.rindex("/") | |
333 | ret = self.find(name[:p]).lookup(name[p + 1:]) | |
334 | else: | |
335 | p = name.rindex(".") | |
336 | ret = self.lookup(name[:p], name[p + 1:]) | |
337 | self.names[name] = ret | |
338 | return ret |