Factored out a lot of common code.

[software/pymin.git] / services / dhcp / __init__.py

diff --git a/services/dhcp/__init__.py b/services/dhcp/__init__.py
index 3d956f94a7152c895c5057a6f2fe3e92a88eef62..7ffadcf7a4dc424a421bb6d77fc2b71d8df8f76e 100644 (file)
--- a/services/dhcp/__init__.py
+++ b/services/dhcp/__init__.py
@@ -1,28 +1,91 @@
 # vim: set encoding=utf-8 et sw=4 sts=4 :
 
 # vim: set encoding=utf-8 et sw=4 sts=4 :
 

-from mako.template import Template
-from mako.runtime import Context

 from os import path
 from os import path

-try:
-    import cPickle as pickle
-except ImportError:
-    import pickle
-try:
-    from dispatcher import handler
-except ImportError:
-    def handler(f): return f # NOP for testing

 
 

-__ALL__ = ('DhcpHandler',)
+from seqtools import Sequence
+from dispatcher import Handler, handler, HandlerError
+from services.util import Restorable, ConfigWriter
+from services.util import InitdHandler, TransactionalHandler

 
 

-pickle_ext = '.pkl'
-pickle_vars = 'vars'
-pickle_hosts = 'hosts'
+__ALL__ = ('DhcpHandler', 'Error', 'HostError', 'HostAlreadyExistsError',
+            'HostNotFoundError', 'ParameterError', 'ParameterNotFoundError')

 
 

-config_filename = 'dhcpd.conf'
+class Error(HandlerError):
+    r"""
+    Error(message) -> Error instance :: Base DhcpHandler exception class.

 
 

-template_dir = path.join(path.dirname(__file__), 'templates')
+    All exceptions raised by the DhcpHandler inherits from this one, so you can
+    easily catch any DhcpHandler exception.

 
 

-class Host:
+    message - A descriptive error message.
+    """
+
+    def __init__(self, message):
+        r"Initialize the Error object. See class documentation for more info."
+        self.message = message
+
+    def __str__(self):
+        return self.message
+
+class HostError(Error, KeyError):
+    r"""
+    HostError(hostname) -> HostError instance
+
+    This is the base exception for all host related errors.
+    """
+
+    def __init__(self, hostname):
+        r"Initialize the object. See class documentation for more info."
+        self.message = 'Host error: "%s"' % hostname
+
+class HostAlreadyExistsError(HostError):
+    r"""
+    HostAlreadyExistsError(hostname) -> HostAlreadyExistsError instance
+
+    This exception is raised when trying to add a hostname that already exists.
+    """
+
+    def __init__(self, hostname):
+        r"Initialize the object. See class documentation for more info."
+        self.message = 'Host already exists: "%s"' % hostname
+
+class HostNotFoundError(HostError):
+    r"""
+    HostNotFoundError(hostname) -> HostNotFoundError instance
+
+    This exception is raised when trying to operate on a hostname that doesn't
+    exists.
+    """
+
+    def __init__(self, hostname):
+        r"Initialize the object. See class documentation for more info."
+        self.message = 'Host not found: "%s"' % hostname
+
+class ParameterError(Error, KeyError):
+    r"""
+    ParameterError(paramname) -> ParameterError instance
+
+    This is the base exception for all DhcpHandler parameters related errors.
+    """
+
+    def __init__(self, paramname):
+        r"Initialize the object. See class documentation for more info."
+        self.message = 'Parameter error: "%s"' % paramname
+
+class ParameterNotFoundError(ParameterError):
+    r"""
+    ParameterNotFoundError(hostname) -> ParameterNotFoundError instance
+
+    This exception is raised when trying to operate on a parameter that doesn't
+    exists.
+    """
+
+    def __init__(self, paramname):
+        r"Initialize the object. See class documentation for more info."
+        self.message = 'Parameter not found: "%s"' % paramname
+
+
+class Host(Sequence):

     r"""Host(name, ip, mac) -> Host instance :: Class representing a host.
 
     name - Host name, should be a fully qualified name, but no checks are done.
     r"""Host(name, ip, mac) -> Host instance :: Class representing a host.
 
     name - Host name, should be a fully qualified name, but no checks are done.


@@ -36,7 +99,11 @@ class Host:
         self.ip = ip
         self.mac = mac
 
         self.ip = ip
         self.mac = mac
 

-class HostHandler:
+    def as_tuple(self):
+        r"Return a tuple representing the host."
+        return (self.name, self.ip, self.mac)
+
+class HostHandler(Handler):

     r"""HostHandler(hosts) -> HostHandler instance :: Handle a list of hosts.
 
     This class is a helper for DhcpHandler to do all the work related to hosts
     r"""HostHandler(hosts) -> HostHandler instance :: Handle a list of hosts.
 
     This class is a helper for DhcpHandler to do all the work related to hosts


@@ -49,50 +116,48 @@ class HostHandler:
         r"Initialize HostHandler object, see class documentation for details."
         self.hosts = hosts
 
         r"Initialize HostHandler object, see class documentation for details."
         self.hosts = hosts
 

-    @handler
+    @handler(u'Add a new host.')

     def add(self, name, ip, mac):
         r"add(name, ip, mac) -> None :: Add a host to the hosts list."
     def add(self, name, ip, mac):
         r"add(name, ip, mac) -> None :: Add a host to the hosts list."

-        # XXX deberia indexar por hostname o por ip? o por mac? :)
-        # o por nada... Puedo tener un nombre con muchas IPs? Una IP con muchos
-        # nombres? Una MAC con muchas IP? una MAC con muchos nombre? Etc...
+        if name in self.hosts:
+            raise HostAlreadyExistsError(name)

         self.hosts[name] = Host(name, ip, mac)
 
         self.hosts[name] = Host(name, ip, mac)
 

-    @handler
+    @handler(u'Update a host.')

     def update(self, name, ip=None, mac=None):
         r"update(name[, ip[, mac]]) -> None :: Update a host of the hosts list."
         if not name in self.hosts:
     def update(self, name, ip=None, mac=None):
         r"update(name[, ip[, mac]]) -> None :: Update a host of the hosts list."
         if not name in self.hosts:

-            raise KeyError('Host not found')
+            raise HostNotFoundError(name)

         if ip is not None:
             self.hosts[name].ip = ip
         if mac is not None:
             self.hosts[name].mac = mac
 
         if ip is not None:
             self.hosts[name].ip = ip
         if mac is not None:
             self.hosts[name].mac = mac
 

-    @handler
+    @handler(u'Delete a host.')

     def delete(self, name):
         r"delete(name) -> None :: Delete a host of the hosts list."
         if not name in self.hosts:
     def delete(self, name):
         r"delete(name) -> None :: Delete a host of the hosts list."
         if not name in self.hosts:

-            raise KeyError('Host not found')
+            raise HostNotFoundError(name)

         del self.hosts[name]
 
         del self.hosts[name]
 

-    @handler
-    def list(self):
-        r"""list() -> CSV string :: List all the hostnames.
+    @handler(u'Get information about a host.')
+    def get(self, name):
+        r"get(name) -> Host :: List all the information of a host."
+        if not name in self.hosts:
+            raise HostNotFoundError(name)
+        return self.hosts[name]

 
 

-        The list is returned as a single CSV line with all the hostnames.
-        """
-        return ','.join(self.hosts)
+    @handler(u'List hosts.')
+    def list(self):
+        r"list() -> tuple :: List all the hostnames."
+        return self.hosts.keys()

 
 

-    @handler
+    @handler(u'Get information about all hosts.')

     def show(self):
     def show(self):

-        r"""show() -> CSV string :: List all the complete hosts information.
-
-        The hosts are returned as a CSV list with each host in a line, like:
-        hostname,ip,mac
-        """
-        hosts = self.hosts.values()
-        return '\n'.join('%s,%s,%s' % (h.name, h.ip, h.mac) for h in hosts)
+        r"show() -> list of Hosts :: List all the complete hosts information."
+        return self.hosts.values()

 
 

-class DhcpHandler:
+class DhcpHandler(Restorable, ConfigWriter, InitdHandler, TransactionalHandler):

     r"""DhcpHandler([pickle_dir[, config_dir]]) -> DhcpHandler instance.
 
     Handles DHCP service commands for the dhcpd program.
     r"""DhcpHandler([pickle_dir[, config_dir]]) -> DhcpHandler instance.
 
     Handles DHCP service commands for the dhcpd program.


@@ -104,19 +169,13 @@ class DhcpHandler:
     Both defaults to the current working directory.
     """
 
     Both defaults to the current working directory.
     """
 

-    def __init__(self, pickle_dir='.', config_dir='.'):
-        r"Initialize DhcpHandler object, see class documentation for details."
-        self.pickle_dir = pickle_dir
-        self.config_dir = config_dir
-        filename = path.join(template_dir, config_filename)
-        self.template = Template(filename=filename)
-        try:
-            self._load()
-        except IOError:
-            # This is the first time the handler is used, create a basic
-            # setup using some nice defaults
-            self.hosts = dict()
-            self.vars = dict(
+    _initd_name = 'dhcpd'
+
+    _persistent_vars = ('vars', 'hosts')
+
+    _restorable_defaults = dict(
+            hosts = dict(),
+            vars  = dict(

                 domain_name = 'example.com',
                 dns_1       = 'ns1.example.com',
                 dns_2       = 'ns2.example.com',
                 domain_name = 'example.com',
                 dns_1       = 'ns1.example.com',
                 dns_2       = 'ns2.example.com',


@@ -125,149 +184,80 @@ class DhcpHandler:
                 net_start   = '192.168.0.100',
                 net_end     = '192.168.0.200',
                 net_gateway = '192.168.0.1',
                 net_start   = '192.168.0.100',
                 net_end     = '192.168.0.200',
                 net_gateway = '192.168.0.1',

-            )
-            self._dump()
-            self._write_config()
+            ),
+    )
+
+    _config_writer_files = 'dhcpd.conf'
+    _config_writer_tpl_dir = path.join(path.dirname(__file__), 'templates')
+
+    def __init__(self, pickle_dir='.', config_dir='.'):
+        r"Initialize DhcpHandler object, see class documentation for details."
+        self._persistent_dir = pickle_dir
+        self._config_writer_cfg_dir = config_dir
+        self._config_build_templates()
+        self._restore()

         self.host = HostHandler(self.hosts)
 
         self.host = HostHandler(self.hosts)
 

-    @handler
+    def _get_config_vars(self, config_file):
+        return dict(hosts=self.hosts.values(), **self.vars)
+
+    @handler(u'Set a DHCP parameter.')

     def set(self, param, value):
         r"set(param, value) -> None :: Set a DHCP parameter."
         if not param in self.vars:
     def set(self, param, value):
         r"set(param, value) -> None :: Set a DHCP parameter."
         if not param in self.vars:

-            raise KeyError('Parameter ' + param + ' not found')
+            raise ParameterNotFoundError(param)

         self.vars[param] = value
 
         self.vars[param] = value
 

-    @handler
-    def list(self):
-        r"""list() -> CSV string :: List all the parameter names.
+    @handler(u'Get a DHCP parameter.')
+    def get(self, param):
+        r"get(param) -> None :: Get a DHCP parameter."
+        if not param in self.vars:
+            raise ParameterNotFoundError(param)
+        return self.vars[param]

 
 

-        The list is returned as a single CSV line with all the names.
-        """
-        return ','.join(self.vars)
+    @handler(u'List all available DHCP parameters.')
+    def list(self):
+        r"list() -> tuple :: List all the parameter names."
+        return self.vars.keys()

 
 

-    @handler
+    @handler(u'Get all DHCP parameters, with their values.')

     def show(self):
     def show(self):

-        r"""show() -> CSV string :: List all the parameters (with their values).
-
-        The parameters are returned as a CSV list with each parameter in a
-        line, like:
-        name,value
-        """
-        return '\n'.join(('%s,%s' % (k, v) for (k, v) in self.vars.items()))
-
-    @handler
-    def start(self):
-        r"start() -> None :: Start the DHCP service."
-        #esto seria para poner en una interfaz
-        #y seria el hook para arrancar el servicio
-        pass
-
-    @handler
-    def stop(self):
-        r"stop() -> None :: Stop the DHCP service."
-        #esto seria para poner en una interfaz
-        #y seria el hook para arrancar el servicio
-        pass
-
-    @handler
-    def restart(self):
-        r"restart() -> None :: Restart the DHCP service."
-        #esto seria para poner en una interfaz
-        #y seria el hook para arrancar el servicio
-        pass
-
-    @handler
-    def reload(self):
-        r"reload() -> None :: Reload the configuration of the DHCP service."
-        #esto seria para poner en una interfaz
-        #y seria el hook para arrancar el servicio
-        pass
-
-    @handler
-    def commit(self):
-        r"commit() -> None :: Commit the changes and reload the DHCP service."
-        #esto seria para poner en una interfaz
-        #y seria que hace el pickle deberia llamarse
-        #al hacerse un commit
-        self._dump()
-        self._write_config()
-        self.reload()
-
-    @handler
-    def rollback(self):
-        r"rollback() -> None :: Discard the changes not yet commited."
-        self._load()
-
-    def _dump(self):
-        r"_dump() -> None :: Dump all persistent data to pickle files."
-        # XXX podría ir en una clase base
-        self._dump_var(self.vars, pickle_vars)
-        self._dump_var(self.hosts, pickle_hosts)
-
-    def _load(self):
-        r"_load() -> None :: Load all persistent data from pickle files."
-        # XXX podría ir en una clase base
-        self.vars = self._load_var(pickle_vars)
-        self.hosts = self._load_var(pickle_hosts)
-
-    def _pickle_filename(self, name):
-        r"_pickle_filename() -> string :: Construct a pickle filename."
-        # XXX podría ir en una clase base
-        return path.join(self.pickle_dir, name) + pickle_ext
-
-    def _dump_var(self, var, name):
-        r"_dump_var() -> None :: Dump a especific variable to a pickle file."
-        # XXX podría ir en una clase base
-        pickle.dump(var, file(self._pickle_filename(name), 'wb'), 2)
-
-    def _load_var(self, name):
-        r"_load_var() -> object :: Load a especific pickle file."
-        # XXX podría ir en una clase base
-        return pickle.load(file(self._pickle_filename(name)))
-
-    def _write_config(self):
-        r"_write_config() -> None :: Generate all the configuration files."
-        # XXX podría ir en una clase base, ver como generalizar variables a
-        # reemplazar en la template
-        out_file = file(path.join(self.config_dir, config_filename), 'w')
-        ctx = Context(out_file, hosts=self.hosts.values(), **self.vars)
-        self.template.render_context(ctx)
+        r"show() -> (key, value) tuples :: List all the parameters."
+        return self.vars.items()

 
 if __name__ == '__main__':
 
     import os
 
 
 if __name__ == '__main__':
 
     import os
 

-    dhcp_handler = DhcpHandler()
+    h = DhcpHandler()

 
     def dump():
         print '-' * 80
 
     def dump():
         print '-' * 80

-        print 'Variables:', dhcp_handler.list()
-        print dhcp_handler.show()
+        print 'Variables:', h.list()
+        print h.show()

         print
         print

-        print 'Hosts:', dhcp_handler.host.list()
-        print dhcp_handler.host.show()
+        print 'Hosts:', h.host.list()
+        print h.host.show()

         print '-' * 80
 
     dump()
 
         print '-' * 80
 
     dump()
 

-    dhcp_handler.host.add('my_name','192.168.0.102','00:12:ff:56')
+    h.host.add('my_name','192.168.0.102','00:12:ff:56')

 
 

-    dhcp_handler.host.update('my_name','192.168.0.192','00:12:ff:56')
+    h.host.update('my_name','192.168.0.192','00:12:ff:56')

 
 

-    dhcp_handler.host.add('nico','192.168.0.188','00:00:00:00')
+    h.host.add('nico','192.168.0.188','00:00:00:00')

 
 

-    dhcp_handler.set('domain_name','baryon.com.ar')
+    h.set('domain_name','baryon.com.ar')

 
     try:
 
     try:

-        dhcp_handler.set('sarasa','baryon.com.ar')
+        h.set('sarasa','baryon.com.ar')

     except KeyError, e:
         print 'Error:', e
 
     except KeyError, e:
         print 'Error:', e
 

-    dhcp_handler.commit()
+    h.commit()

 
     dump()
 
 
     dump()
 

-    for f in (pickle_vars + pickle_ext, pickle_hosts + pickle_ext,
-                                                            config_filename):
-        os.unlink(f)
+    os.system('rm -f *.pkl ' + ' '.join(h._config_writer_files))