Amdatu Configurator

Project Info

Introduction

This project provides a simple way of provisioning configuration files to your OSGi application, allowing you to use the same set of configuration files to run your OSGi application locally as you would need for deploying your application using Apache ACE or DeploymentAdmin.It provides the following features:

• provisions MetaType/AutoConf based configuration files;
• provisions property-file based configuration files;
• allow simple variable substitutions similar as to Apache ACE supports;
• a simple API to provision configuration files programmatically;
• a couple of simple Felix Gogo shell commands to list and update configurations.

What this project does not provide:

• a Apache FileInstall like functionality, where configuration files and bundles are automatically monitored and updated if necessary. The reason for this is that we do not want to mimic the behaviour of FileInstall (FileInstall does this already), and that in production systems this functionality is often not desired nor used. However, this functionality can be mimicked by using the programmatic API of Amdatu Configurator;
• A set of Gogo shell commands to alter configurations such as provided by this project.

Usage

Deploy the org.amdatu.configurator.autoconf and/or org.amdatu.configurator.properties bundle with your application. When this bundle is started by the OSGi framework, it will look for a directory named conf in the current working directory of your framework and regard all files ending in .xml as possible AutoConf resources. Files ending in .cnf, .cfg or .config are considered property file resources.

The API of Amdatu Configurator is relatively straight forward, you can use the org.amdatu.configurator.Configurator services to provision a single configuration resource, provision all configuration resources in a given directory, or list the already provisioned configurations. Distinction between various configurator services can be made by using the type and/or file.extensions service properties. For example, you can ask for a configurator that is capable of handling .cfg files by:

ServiceReference[] serviceRefs = bundleContext.getServiceReferences(Configurator.class.getName(), "(file.extensions=.cfg)");

Or, if you want a specific type of configurator (currently autoconf and property are the only supported types):

ServiceReference[] serviceRefs = bundleContext.getServiceReferences(Configurator.class.getName(), "(type=autoconf)");

The Amdatu Configurator bundle depends on the following bundles:

1. Apache Felix DependencyManager v3.1.0;
2. An OSGi ConfigurationAdmin service implementation, for example Apache Felix ConfigAdmin v1.8.0;
3. (Optionally) an OSGi LogService implementation, for example Apache Felix LogService v1.0.1.

Configuration

A couple of configuration options exist for the Amdatu Configurator project. These options can be set as framework option in the run configuration of your application. For the AutoConf bundle, the following options are recognized:

• org.amdatu.configurator.autoconf.dir, takes a string argument that is used as directory where your configuration files are stored. Defaults to ./conf;
• org.amdatu.configurator.autoconf.prefix, allows one to specify the common prefix used for all placeholders in your configuration files. By default, the same prefix is used as Apache ACE, which is context.;
• org.amdatu.configurator.autoconf.verbose, if set to true, increases the verbosity of logging to show more details on the whole provisioning process. By default, non-verbose/sparse logging is enabled (false).

For the Properties bundle, the following options are recognized:

• org.amdatu.configurator.properties.dir, takes a string argument that is used as directory where your configuration files are stored. Defaults to ./conf;
• org.amdatu.configurator.properties.prefix, allows one to specify the common prefix used for all placeholders in your configuration files. Defaults to context.;
• org.amdatu.configurator.properties.verbose, increases the verbosity of logging to show additional details on the provisioning process. Defaults to false.

In addition, the logging of the bundles be managed as well, by using the following option:

• org.amdatu.configurator.loglevel, takes a value of [0..4] denoting the log level to use in which a higher value means more verbosity of logging. So, a value of 0 means no logging, 1 to only show errors and so on to 4 which shows all messages. Currently, log messages are printed to the console (stdout).

Variable/placeholder substitution

Though not allowed by the AutoConf specification, the Amdatu Configurator allows AutoConf resources to be parameterized with variables (or placeholders) in order to make them a little more reusable for different deployment scenarios. Variables are considered all strings that start with "${" and end with "}". When an AutoConf resource is processed by Amdatu Configurator, it will try to replace all variables with values found as framework properties. So, for example, a variable ${context.serverUrl} will be replaced with the value of the framework property serverUrl (the context. prefix is stripped off, see configuration). If no framework property is found, no substitution will take place.

Example

Consider the following AutoConf resource, named "myConfig.xml", stored in a directory named "config":

<?xml version="1.0" encoding="UTF-8"?>
<metatype:MetaData xmlns:metatype="http://www.osgi.org/xmlns/metatype/v1.1.0">
	<OCD id="ocd" name="ocd">
		<AD id="server" type="String" />
	</OCD>

	<Designate pid="org.amdatu.conf" bundle="org.amdatu.sample.bundle">
		<Object ocdref="ocd">
			<Attribute adref="server" name="serverurl" content="${context.serverUrl}" />
		</Object>
	</Designate>
</metatype:MetaData>

If we would start our OSGi application, for example, using a Bnd Run Descriptor with the following content:

-runbundles: \
	osgi.cmpn;version="[4.2,5)",\
	org.apache.felix.configadmin;version="[1.8,1.9)",\
	org.apache.felix.dependencymanager;version="[3.1,3.2)",\
	org.apache.felix.log;version="[1.0.1,1.0.2)",\
    org.amdatu.configurator.autoconf;version=latest
# ...many more properties...
-runproperties: \
  serverUrl=http://my.server.host:8080/,\
  org.amdatu.configurator.autoconf.dir=/path/to/config

The Amdatu Configurator will provision a configuration with a single property of "serverUrl = http://my.server.host:8080/" to ConfigAdmin. The result will be that this property will be given to the ManagedService implementation registered with the "org.amdatu.conf" PID.

License

The Amdatu Configurator project is licensed under Apache License 2.0.