PYRO - Errors and Troubleshooting

Pyro Manual

8. Errors and Troubleshooting

The Pyro Errors section describes the various errors that can occur when using Pyro. It only describes Pyro's custom exceptions - other Python exceptions may occur due to other runtime problems.

The Troubleshooting section provides various hints and tips when you can't get things to work as expected.

Pyro Errors

Pyro Exception Hierarchy

Exception
- PyroError
  - URIError
  - DaemonError
  - NamingError
  - ProtocolError
    - SocketClosedError
    - ServerFullError

Initialization

OSError-- is raised when Pyro can't create or open the storage directory specified by PYRO_STORAGE.

Naming Server

NamingError-- The naming service responds with the following kinds of NamingError exceptions (raised by the remote NS object):

Error string	raised by	description
name already exists	register	The name you're trying to register is already present in the NS database
name not found	unregister	You're trying to unregister an unknown name.
name not found	resolve	The name you're trying to resolve is unknown by the NS.
invalid name	various methods	The object name is invalid. It must be a string with no whitespaces and only 7-bit ASCII characters.
invalid URI	various methods	The object URI that was passed is invalid.
parent is no group	register	A new name can only be registered within a group. The name is not in a correct group.
attempt to resolve groupname	resolve	A resolve was done on a group name, only object names can be resolved.
group not found	various methods	The name contains an unknown group.
is no group	deleteGroup, list	An operation was done that can only be performed on a group, not on an object name.
(parent)group not found	various methods	The name contains an unknown (parent) group.
name is not absolute	nearly all methods	Object names have to be absolute (i.e. fully specified in the namespace).
default group name is not absolute	nearly all methods	The default group name has to be absolute (i.e. fully specified in the namespace).

PyroError-- The NameServerLocator raises PyroError "Naming Service not responding" if it failed to discover the naming service (via the getNS method).

Pyro Core

URIError-- The PyroURI object raises URIError "illegal URI format" when you try to create a PyroURI object from an illegal URI.

DaemonError-- The Daemon object raises DaemonError "Couldn't start Pyro daemon" if it was unable to start. This usually means that the required network port (socket) is temporarily unavailable because another Pyro daemon is already running on it.

PYRO Protocol adapter

Various exceptions may be raised by the PYRO protocol code:

Exception	Error string	raised by	description
`SocketClosedError`	connection lost	receive code	The network connection was lost while receiving data.
`SocketClosedError`	connection lost	send code	The network connection was lost while sending data.
`ProtocolError`	incompatible protocol in URI	`bindToURI` method of `PYROAdapter`	You supplied an incompatible protocol ID. Use 'PYRO'.
`ProtocolError`	connection failed	`bindToURI` method of `PYROAdapter`	Network problems caused the connection to fail.
`ProtocolError`	invalid header	receive code	A message with an invalid header has been received.
`ProtocolError`	incompatible version	receive code	A message from an incompatible Pyro version has been received.
`ProtocolError`	unsupported protocol	`getProtocolAdapter`	You tried to get a protocol adapter for an unsupported protocol. Currently only the 'PYRO' protocol is supported.
`ServerFullError`	connection denied, too busy	`bindToURI` method of `PYROAdapter`	The Pyro server has too many connections at this time so your request for another connection was denied.

Util

KeyError-- The ArgParser will raise KeyError "no such option" if you try to getOpt an option that has nog been detected in the option string and you have not supplied a default value to getOpt (otherwise that default value is returned).

Troubleshooting

Problem	Possible cause	Hint/tip
The naming service or my own Pyro server refuses to start, aborts with `DaemonError`	The daemon can't set up the network port (socket), probably because another daemon is already running, or another process occupies the resource.	Wait a little while and try again (sometimes it takes a while for resources to become available again). If this doesn't work, find the other daemon that is probably running and shut it down, or specify another port for the new daemon. Sorry, but your new process can't yet use the daemon of another running process - perhaps in a future Pyro version.
Pyro refuses to initialise, aborts with `IOError` and/or things saying 'permission denied' or similar	You probably specified a wrong location for Pyro's storage directory and/or logfiles. Perhaps you don't have permission to write in those locations.	Fix those locations by changing the configuration items. Make sure you have permission to write to those locations. Usually `PYRO_STORAGE` must be changed to point to a correct directory.
My code can't find the Naming Service, it aborts with "Naming Service not responding"	The Pyro Naming Service is not running or it can't be discovered automatically. The latter may be the case if your network doesn't support broadcasts or if the NS is running on a different subnet which cannot be reached by a broadcast.	Start the NS if it's not running. If the problem persists, you have to help the `NameServerLocator` by specifying the host and perhaps even the port number where the NS is running. You can also try to obtain the NS' URI string and create a proxy directly from this string, bypassing the `NameServerLocator`.
Naming server responds with 'group not found', 'no group', 'name not found' or 'name not absolute' errors but I'm sure the names are correct.	You probably have reconfigured the special name characters for the group separator and root character (`PYRO_NS_GROUPSEP, PYRO_NS_ROOTCHAR`) wrong, or the Name Server uses a different configuration as your current process.	Check the log to see the configuration that is used by Pyro. Make sure the special characters are indeed a valid character, different from each other, and the same in your current program and in the Name Server.
'name not absolute' errors after changing default namespace group.	The default group name for the `PYRO_NS_DEFAULTGROUP` config item must be an absolute name (starting with the root char).	Change it to an absolute name.
Pyro crashes.	Most likely a bug.	Contact me.