Configuration Methods
QPID supports two methods of configuration:
- command line switches (e.g. passing a -p flag on startup to specify the port)
- configuration file
It is intended that the configuration file will be used for nearly all configuration but that some very common or useful options are exposed using command line switches.
CLI
QPID uses Commons CLI to parse command line arguments. It provides the following features:
- Ability to parse both short and long flags (e.g. -p and --port) and treat them as the same logical option
- Generation of well formatted usage messages
- Ability to specify configuration options in different ways, such as from files or from system properties, which can help when writing unit tests
The result of parsing options, however they are specified, is a CommandLine object which can then be queried to find out specific values. Currently this is done in org.apache.qpid.server.Main and the CommandLine object is not exposed elsewhere but if it does require to be more widely used it could be added to the ApplicationRegistry. However it is strongly recommended that the configuration approach in the follow section is used where possible.
Configuration File
QPID uses Commons Configuration to handle all configuration. It provides methods that allow parsing of options from a range of sources, including configuration files, system properties or simply hard coded classes of values (which is very useful in unit test cases).
Broker configuration is accessed through the class in the org.apache.qpid.server.configuration, primarily starting at ServerConfiguration and retrieving values or other Configuration classes from there.
Command Line Options
The following options are available:
Option |
Long Option |
Description |
---|---|---|
b |
bind |
Bind to the specified address overriding any value in the config file |
c |
config |
Use the given configuration file |
h |
help |
Prints list of options |
l |
logconfig |
Use the specified log4j.xml file rather than that in the etc directory |
m |
mport |
Specify port to listen on for the JMX Management. Overrides value in config file |
p |
port |
Specify port to listen on. Overrides value in config file |
s |
sslport |
Specify SSL to listen on. Overrides value in config file (since 0.13) |
v |
version |
Print version information and exit |
w |
logwatch |
Specify interval for checking for logging config changes. Zero means no checking |
Logging
Logging is handled slightly differently. The main reason for this is that logging is something we want configured before the main configuration file is processed.
The broker uses log4j as the logging implementation, and configuration must be done using the more expressive XML format. A couple of command line switches are used to configure logging:
- -l, --logconfig specifies the log configuration file to use. By default it looks for a file called log4j.xml located in the same directory as the config.xml file
- -w, --logwatch the interval in seconds to poll the log configuration file for changes. The default is 60 seconds and zero means do not poll for changes.
By using the logwatch option it is possible to make changes to the logging configuration at runtime without restarting the broker. (For example, enabling more logging on certain packages in order to diagnose a problem).