python: Added a simple module for daemon management.

diff --git a/python/ashd/pdm.py b/python/ashd/pdm.py
new file mode 100644 (file)
index 0000000..de4ac7a
--- /dev/null
+++ b/python/ashd/pdm.py
@@ -0,0 +1,147 @@
+"""Management for daemon processes
+
+This module contains a utility to listen for management commands on a
+socket, lending itself to managing daemon processes.
+"""
+
+import os, sys, socket, threading, grp, select
+import types, pprint, traceback
+
+class repl(object):
+    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.sk.send("+REPL\n")
+
+    def echo(self, ob):
+        self.cl.sk.send(self.printer.pformat(ob) + "\n")
+
+    def command(self, cmd):
+        try:
+            try:
+                ccode = compile(cmd, "PDM Input", "eval")
+            except SyntaxError:
+                ccode = compile(cmd, "PDM Input", "exec")
+                exec ccode in self.mod.__dict__
+                self.cl.sk.send("+OK\n")
+            else:
+                self.echo(eval(ccode, self.mod.__dict__))
+                self.cl.sk.send("+OK\n")
+        except:
+            for line in traceback.format_exception(*sys.exc_info()):
+                self.cl.sk.send(line)
+            self.cl.sk.send("+EXC\n")
+
+    def handle(self, buf):
+        p = buf.find("\n\n")
+        if p < 0:
+            return buf
+        cmd = buf[:p + 1]
+        self.command(cmd)
+        return buf[p + 2:]
+
+class client(threading.Thread):
+    def __init__(self, sk):
+        super(client, self).__init__(name = "Management client")
+        self.setDaemon(True)
+        self.sk = sk
+        self.handler = self
+
+    def choose(self, proto):
+        if proto == "repl":
+            self.handler = repl(self)
+        else:
+            self.sk.send("-ERR Unknown protocol: %s\n" % proto)
+            raise Exception()
+
+    def handle(self, buf):
+        p = buf.find("\n")
+        if p >= 0:
+            proto = buf[:p]
+            buf = buf[p + 1:]
+            self.choose(proto)
+        return buf
+
+    def run(self):
+        try:
+            buf = ""
+            self.sk.send("+PDM1\n")
+            while True:
+                ret = self.sk.recv(1024)
+                if ret == "":
+                    return
+                buf += ret
+                while True:
+                    try:
+                        nbuf = self.handler.handle(buf)
+                    except:
+                        return
+                    if nbuf == buf:
+                        break
+                    buf = nbuf
+        finally:
+            self.sk.close()
+
+class listener(threading.Thread):
+    def __init__(self):
+        super(listener, self).__init__(name = "Management listener")
+        self.setDaemon(True)
+
+    def listen(self, sk):
+        self.running = True
+        while self.running:
+            rfd, wfd, efd = select.select([sk], [], [sk], 1)
+            for fd in rfd:
+                if fd == sk:
+                    nsk, addr = sk.accept()
+                    self.accept(nsk, addr)
+
+    def stop(self):
+        self.running = False
+        self.join()
+
+    def accept(self, sk, addr):
+        cl = client(sk)
+        cl.start()
+
+class unixlistener(listener):
+    def __init__(self, name, mode = 0600, group = None):
+        super(unixlistener, self).__init__()
+        self.name = name
+        self.mode = mode
+        self.group = group
+
+    def run(self):
+        sk = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+        ul = False
+        try:
+            if os.path.exists(self.name) and os.path.stat.S_ISSOCK(os.stat(self.name).st_mode):
+                os.unlink(self.name)
+            sk.bind(self.name)
+            ul = True
+            os.chmod(self.name, self.mode)
+            if self.group is not None:
+                os.chown(self.name, os.getuid(), grp.getgrnam(self.group).gr_gid)
+            sk.listen(16)
+            self.listen(sk)
+        finally:
+            sk.close()
+            if ul:
+                os.unlink(self.name)
+
+class tcplistener(listener):
+    def __init__(self, port, bindaddr = "127.0.0.1"):
+        super(tcplistener, self).__init__()
+        self.port = port
+        self.bindaddr = bindaddr
+
+    def run(self):
+        sk = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        try:
+            sk.bind((self.bindaddr, self.port))
+            sk.listen(16)
+            self.listen(sk)
+        finally:
+            sk.close()