3. Installation and Configuration

Installation

Pyro distributions contain a "distutils" setup.py script that will install Pyro for you; just enter the following command from a shell prompt: "python setup.py install" and off you go. The script will ask if you want to install the Pyro script tools, and where to put them. If you want to do an automated (unattended) install, edit the setup.cfg file, following the directions in that file. It will not install the documentation and the examples, only the core Pyro library and the scripts.

But I will explain what exactly is in the Pyro distribution. It has a few subdirectories:

Pyro/

This is the actual Pyro package. If you do not use the supplied setup.py install script (see above) you have to install it by hand. Install this directory somewhere in your Python search path. On most systems (also Windows), the lib/site-packages directory is a nice place. The exact location might vary according to your specific Python installation.

Alternatively, keep it where it is and manually add the Pyro root directory to your Python search path (e.g. in the environment variable PYTHONPATH).

bin/

This directory contains the command-line utilities. Move the contents of this directory somewhere in your shell search path.

Alternatively, keep it where it is and manually add it to your shell search path.

docs/   and   examples/

Put those wherever you like. In docs you can find the Pyro manual, and in examples there are some Pyro examples.

Configuration

The default settings will do nicely in most cases. But sooner or later you will have to change some parameters of Pyro. Pyro's configuration is accessed through Pyro.config. This object has several configuration items:

Configuration item	Type	Description	Default value
PYRO_CONFIG_FILE	string	The Pyro configuration file that is used. See below.	Special, see below
PYRO_STORAGE	string	Location where Pyro stores data like log files. Read the notice at the end!	Current directory
PYRO_LOGFILE	string	Name of the logfile. If it's not an absolute path, it's relative to $PYRO_STORAGE.	Pyro_log
PYRO_USER_LOGFILE	string	Name of the user logfile. If it's not an absolute path, it's relative to $PYRO_STORAGE.	Pyro_userlog
PYRO_TRACELEVEL	number	The tracing level of Pyro, 0-3. 0=nothing, 1=only errors, 2=warnings too, 3=full: errors, warnings and notes.	0
PYRO_USER_TRACELEVEL	number	The user tracing level, 0-3. 0=nothing, 1=only errors, 2=warnings too, 3=full: errors, warnings and notes.	0
PYRO_BINARY_PICKLE	boolean	Wether the default marshaling is done in binary format (faster and less memory usage) or in human-readable ASCII.	1
PYRO_XML_PICKLE	boolean order of a magnitude slower, and requires more bandwith. You need to have installed Gnosis_Utils (at least version 1.0.2).	0
PYRO_COMPRESSION	boolean	Wether the protocol should compress the data to save bandwidth (at the cost of CPU time). The zlib module is used for compression. If you don't have zlib, Pyro still works, but without compression.	0
PYRO_CHECKSUM	boolean	Wether the protocol should perform a checksum over the message data. This costs a little bit extra CPU time, but you will be quite sure that your communication is without errors. The zlib.adler32 function is used for checksumming. If you don't have zlib, Pyro still works, but without checksumming. The overhead of checksumming is very small, with regular messages less than 0.1%, but increasing with big messages (15% for 5 Mb or so). Note: the checksum is by no means secure. If you want secure transmissions, you'll have to use SSL or build your own encryption/secure hashing functions on top of Pyro.	0
PYRO_MAXCONNECTIONS	number	The maximum number of simultaneous connections to one Pyro server. Note that a custom connection validator may or may not take this in account. The default validator does check for this limit.	200
PYRO_MULTITHREADED	boolean	Wether Pyro servers should be multithreaded or not.	1 (if supported)
PYRO_MOBILE_CODE	boolean	Wether Pyro should automatically download Python code from clients if it isn't available on the server.	0
PYRO_DNS_URI	boolean	Wether symbolic DNS host names should be used in URIs instead of fixed IP addresses.	0
PYRO_BC_RETRIES	number	How often a broadcast will be retried if no answer has been received. Currently only used by the Name Server locator.	2
PYRO_BC_TIMEOUT	number	How long Pyro will wait (in seconds) for an answer to a broadcast request. Currently only used by the Name Server locator.	2
PYRO_PORT	number	The base socket number of the range of socket numbers that the Pyro daemon can use to listen for incoming requests (Pyro method calls).	7766
PYRO_PORT_RANGE	number	The size of the socket port range. Pyro will try connections in the range PYRO_PORT to PYRO_PORT+PYRO_PORT_RANGE.	100
PYRO_NS_DEFAULTGROUP	string	The default group name in which names are located. This must be an absolute name (starting with the root character).	:Default
PYRO_NS_URIFILE	string	The file where the Name Server will write its URI. If it's not an absolute path, it's relative to $PYRO_STORAGE.	Pyro_NS_URI
PYRO_NS_BC_PORT	number	The socket number on which the Name Server will listen for broadcast requests (usually to find the location).	9091
PYRO_NS_PORT	number	The socket number on which the Name Server will listen for incoming requests (Pyro method calls, in fact).	9090
PYRO_NS_HOSTNAME	string	The hostname that is tried to find the NameServer on, when the broadcast lookup mechanism fails.	empty
PYROSSL_CERTDIR	string	The directory where openssl certificates are stored.	'certs' in the PYRO_STORAGE location.
PYROSSL_CA_CERT	string	Certificate of the Certificate Authority. Used to check if client and server certificates are valid (that they are signed by the given CA)	ca.pem
PYROSSL_SERVER_CERT	string	Certificate for server side	server.pem
PYROSSL_CLIENT_CERT	string	Certificate for client side	client.pem

There are several ways to change the default settings:

1. Change the settings in your code, at runtime. You can change all settings before starting Pyro, and most settings can be changed dynamically during execution too. Note that you cannot use this to change Pyro.config.PYRO_STORAGE! See below!
   ... Pyro.config.PYRO_PORT = 7000
   ... Pyro.config.PYRO_TRACELEVEL = 3
2. Define environment variables that override the default settings.
   Every configuration item has an equivalent environment variable. If you define this, you can override the default setting for that item. For instance, it might be convenient to have your Pyro programs generate log files and put them in a designated log directory:
   ...$ export PYRO_LOGFILE=/var/log/PYRO/logfile
   ...$ export PYRO_TRACELEVEL=3
   (This is for bash - syntax is different for other shells or Windows.)
3. Configuration files
   You can use a configuration file that can contain some small configuration changes or a fully new configuration for all items. Pyro checks if the environment variable PYRO_CONFIG_FILE is set. If it isn't set, or set to an empty string, Pyro checks for a Pyro.conf file in the current directory. If it exists, Pyro uses it as a configuration file. If it doesn't exist, Pyro uses the default built-in configuration.
   If the environment variable is set, Pyro uses the value as the name for the configuration file. If the configuration file can't be read, a PyroError exception occurs.

   The format of the configuration file is very simple. It is a text file, and each line can be empty, a comment, or a configuration item setting. A comment starts with '#'. A config item setting is of the format 'ITEM=VALUE'. If Pyro finds an unknown config item, a KeyError exception occurs.

   Note that PYRO_CONFIG_FILE is useless inside a configuration file. After initialization, it is set to the absolute path of the configuration file that was used (or the empty string, if no configuration file was used). Note that setting PYRO_CONFIG_FILE from within your code is useless too because Pyro is already initialized at that point.

PYRO_STORAGE is used at initialization time, that is, as soon as a part of the Pyro package is imported in your program. You can only change PYRO_STORAGE beforehand by either setting the environment variable or making an entry in the configuration file. Changing Pyro.config.PYRO_STORAGE in your program leads to unexpected results, because the initilization has already been done using the old value. So don't do this, and use one of the two other ways.