# Configuring Pyro

Pyro can be configured using several configuration items. The current configuration is accessible from the `Pyro4.config` object, it contains all config items as attributes. You can read them and update them to change Pyro’s configuration. (usually you need to do this at the start of your program). For instance, to enable message compression and change the server type, you add something like this to the start of your code:

    Pyro4.config.COMPRESSION = True
    Pyro4.config.SERVERTYPE = "multiplex"

You can also set them outside of your program, using environment variables from the shell. To avoid conflicts, the environment variables have a ``PYRO_`` prefix. This means that if you want to change the same two settings as above, but by using environment variables, you would do something like:

    $ export PYRO_COMPRESSION=true
    $ export PYRO_SERVERTYPE=multiplex

    (or on windows:)
    C:\> set PYRO_COMPRESSION=true
    C:\> set PYRO_SERVERTYPE=multiplex

This environment defined configuration is simply used as initial values for Pyro’s configuration object. Your code can still overwrite them by setting the items to other values, or by resetting the config as a whole.

## Resetting the config to default values

`Pyro4.config.``reset`([useenvironment=True])

  Resets the configuration items to their builtin default values. If useenvironment is True, it will overwrite builtin config items with any values set by environment variables. If you don’t trust your environment, it may be a good idea to reset the config items to just the builtin defaults (ignoring any environment variables) by calling this method with useenvironment set to False. Do this before using any other part of the Pyro library.

## Inspecting current config

To inspect the current configuration you have several options:

1. Access individual config items: `print(Pyro4.config.COMPRESSION)`

2. Dump the config in a console window: python -m Pyro4.configuration (or simply pyro4-check-config) This will print something like:

       Pyro version: 4.6
       Loaded from: E:\Projects\Pyro4\src\Pyro4
       Active configuration settings:
       AUTOPROXY = True
       COMMTIMEOUT = 0.0
       COMPRESSION = False
       ...

3. Access the config as a dictionary: `Pyro4.config.asDict()`

4. Access the config string dump (used in #2): `Pyro4.config.dump()`

## Overview of Config Items

config item | type | default | meaning
--- | --- | --- | ---
AUTOPROXY | bool | True | Enable to make Pyro automatically replace Pyro objects by proxies in the method arguments and return values of remote method calls. Doesn’t work with marshal serializer.
COMMTIMEOUT | float | 0.0 | network communication timeout in seconds. 0.0=no timeout (infinite wait)
COMPRESSION | bool | False | Enable to make Pyro compress the data that travels over the network
DETAILED_TRACEBACK | bool | False | Enable to get detailed exception tracebacks (including the value of local variables per stack frame)
HOST | str | localhost | Hostname where Pyro daemons will bind on
MAX_MESSAGE_SIZE | int | 0 | Maximum size in bytes of the messages sent or received on the wire. If a message exceeds this size, a ProtocolError is raised.
NS_HOST | str | equal to HOST | Hostname for the name server. Used for locating in clients only (use the normal HOST config item in the name server itself)
NS_PORT | int | 9090 | TCP port of the name server. Used by the server and for locating in clients.
NS_BCPORT | int | 9091 | UDP port of the broadcast responder from the name server. Used by the server and for locating in clients.
NS_BCHOST | str | None | Hostname for the broadcast responder of the name server. Used by the server only.
NS_AUTOCLEAN | float | 0.0 | Specify a recurring period in seconds where the Name server checks its registrations and removes the ones that are not available anymore. (0=disabled, otherwise should be >=3)
NATHOST | str | None | External hostname in case of NAT (used by the server)
NATPORT | int | None | External port in case of NAT (used by the server)
BROADCAST_ADDRS | str | <broadcast>, 0.0.0.0 | List of comma separated addresses that Pyro should send broadcasts to (for NS locating in clients)
ONEWAY_THREADED | bool | True | Enable to make oneway calls be processed in their own separate thread
POLLTIMEOUT | float | 2.0 | For the multiplexing server only: the timeout of the select or poll calls
SERVERTYPE | str | thread | Select the Pyro server type. thread=thread pool based, multiplex=select/poll/kqueue based
SOCK_REUSE | bool | False | Should SO_REUSEADDR be used on sockets that Pyro creates.
PREFER_IP_VERSION | int | 4 | The IP address type that is preferred (4=ipv4, 6=ipv6, 0=let OS decide).
THREADPOOL_SIZE | int | 40 | For the thread pool server: maximum number of threads running
THREADPOOL_SIZE_MIN | int | 4 | For the thread pool server: minimum number of threads running
FLAME_ENABLED | bool | False | Should Pyro Flame be enabled on the server
SERIALIZER | str | serpent | The wire protocol serializer to use for clients/proxies (one of: serpent, json, marshal, msgpack, pickle, cloudpickle, dill)
SERIALIZERS_ACCEPTED | set | json,marshal,serpent | The wire protocol serializers accepted in the server/daemon. In your code it should be a set of strings, use a comma separated string instead when setting the shell environment variable.
PICKLE_PROTOCOL_VERSION | int | highest possible | The pickle protocol version to use, if pickle is selected as serializer. Defaults to pickle.HIGHEST_PROTOCOL
DILL_PROTOCOL_VERSION | int | highest possible | The dill protocol version to use, if dill is selected as serializer. Defaults to dill.HIGHEST_PROTOCOL (-1 if dill is not installed)
JSON_MODULE | str | json | The json module to use for the json serializer. (json is included in the stdlib, simplejson is a possible 3rd party alternative).
LOGWIRE | bool | False | If wire-level message data should be written to the logfile (you may want to disable COMPRESSION)
METADATA | bool | True | Client: Get remote object metadata from server automatically on proxy connect (methods, attributes, oneways, etc) and use local checks in the proxy against it (set to False to use compatible behavior with Pyro 4.26 and earlier)
REQUIRE_EXPOSE | bool | True | Server: Is @expose required to make members remotely accessible. If False, everything is accessible (use this only for backwards compatibility).
USE_MSG_WAITALL | bool | True (False if on Windows) | Some systems have broken socket MSG_WAITALL support. Set this item to False if your system is one of these. Pyro will then use another (but slower) piece of code to receive network data.
MAX_RETRIES | int | 0 | Automatically retry network operations for some exceptions (timeout / connection closed), be careful to use when remote functions have a side effect (e.g.: calling twice results in error)
ITER_STREAMING | bool | True | Should iterator item streaming support be enabled in the server (default=True)
ITER_STREAM_LIFETIME | float | 0.0 | Maximum lifetime in seconds for item streams (default=0, no limit - iterator only stops when exhausted or client disconnects)
ITER_STREAM_LINGER | float | 30.0 | Linger time in seconds to keep an item stream alive after proxy disconnects (allows to reconnect to stream)
SSL | bool | False | Should SSL/TSL communication security be used
SSL_SERVERCERT | str | empty str | Location of the server’s certificate file
SSL_SERVERKEY | str | empty str | Location of the server’s private key file
SSL_SERVERKEYPASSWD | str | empty str | Password for the server’s private key
SSL_REQUIRECLIENTCERT | bool | False | Should the server require clients to connect with their own certificate (2-way-ssl)
SSL_CLIENTCERT | str | empty str | Location of the client’s certificate file
SSL_CLIENTKEY | str | empty str | Location of the client’s private key file
SSL_CLIENTKEYPASSWD | str | empty str | Password for the client’s private key

There are two special config items that control Pyro’s logging, and that are only available as environment variable settings. This is because they are used at the moment the Pyro4 package is being imported (which means that modifying them as regular config items after importing Pyro4 is too late and won’t work).

It is up to you to set the environment variable you want to the desired value. You can do this from your OS or shell, or perhaps by modifying `os.environ` in your Python code before importing Pyro4.

environment variable | type | default | meaning
--- | --- | --- | ---
PYRO_LOGLEVEL | string | not set | The log level to use for Pyro’s logger (DEBUG, WARN, …) See Python’s standard `logging` module for the allowed values (https://docs.python.org/2/library/logging.html#levels). If it is not set, no logging is being configured.
PYRO_LOGFILE | string | pyro.log | The name of the log file. Use {stderr} to make the log go to the standard error output.