Improve error reporting.

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

diff --git a/services/dhcp/__init__.py b/services/dhcp/__init__.py
index 3d956f94a7152c895c5057a6f2fe3e92a88eef62..d7c185c278bdb22ccacc99b19349954d6552685e 100644 (file)
--- a/services/dhcp/__init__.py
+++ b/services/dhcp/__init__.py
@@ -22,6 +22,81 @@ config_filename = 'dhcpd.conf'
 
 template_dir = path.join(path.dirname(__file__), 'templates')
 
+class Error(RuntimeError):
+    r"""
+    Error(command) -> Error instance :: Base DhcpHandler exception class.
+
+    All exceptions raised by the DhcpHandler inherits from this one, so you can
+    easily catch any DhcpHandler exception.
+
+    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:
     r"""Host(name, ip, mac) -> Host instance :: Class representing a host.
 
@@ -52,16 +127,15 @@ class HostHandler:
     @handler
     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)
 
     @handler
     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:
@@ -71,7 +145,7 @@ class HostHandler:
     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]
 
     @handler
@@ -134,7 +208,7 @@ class DhcpHandler:
     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
 
     @handler
@@ -218,7 +292,9 @@ class DhcpHandler:
     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)
+        pkl_file = file(self._pickle_filename(name), 'wb')
+        pickle.dump(var, pkl_file, 2)
+        pkl_file.close()
 
     def _load_var(self, name):
         r"_load_var() -> object :: Load a especific pickle file."
@@ -232,6 +308,7 @@ class DhcpHandler:
         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)
+        out_file.close()
 
 if __name__ == '__main__':