Fuse ESB - Deploying into the OSGi Container - Blueprint Configuration

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Blueprint Configuration

Location of blueprint files in a JAR file

Relative to the root of the bundle JAR file, the standard location for blueprint configuration files is the following directory:

OSGI-INF/blueprint

Any files with the suffix, .xml, under this directory are interpreted as blueprint configuration files; in other words, any files that match the pattern, OSGI-INF/blueprint/*.xml.

Location of blueprint files in a Maven project

In the context of a Maven project, ProjectDir, the standard location for blueprint configuration files is the following directory:

ProjectDir/src/main/resources/OSGI-INF/blueprint

Blueprint namespace and root element

Blueprint configuration elements are associated with the following XML namespace:

http://www.osgi.org/xmlns/blueprint/v1.0.0

The root element for blueprint configuration is blueprint, so a blueprint XML configuration file normally has the following outline form:

<?xml version="1.0" encoding="UTF-8"?>
<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0">
  ...
</blueprint>

	Note
	In the `blueprint` root element, there is no need to specify the location of the blueprint schema using an `xsi:schemaLocation` attribute, because the schema location is already known to the blueprint framework.

Blueprint Manifest configuration

There are a few aspects of blueprint configuration that are controlled by headers in the JAR's manifest file, META-INF/MANIFEST.MF, as follows:

Custom Blueprint file locations

If you need to place your blueprint configuration files in a non-standard location (that is, somewhere other than OSGI-INF/blueprint/*.xml), you can specify a comma-separated list of alternative locations in the Bundle-Blueprint header in the manifest file—for example:

Bundle-Blueprint: lib/account.xml, security.bp, cnf/*.xml

Mandatory dependencies

Dependencies on an OSGi service are mandatory by default (although this can be changed by setting the availability attribute to optional on a reference element or a reference-list element). Declaring a dependency to be mandatory means that the bundle cannot function properly without that dependency and the dependency must be available at all times.

Normally, while a blueprint container is initializing, it passes through a grace period, during which time it attempts to resolve all mandatory dependencies. If the mandatory dependencies cannot be resolved in this time (the default timeout is 5 minutes), container initialization is aborted and the bundle is not started. The following settings can be appended to the Bundle-SymbolicName manifest header to configure the grace period:

blueprint.graceperiod: If true (the default), the grace period is enabled and the blueprint container waits for mandatory dependencies to be resolved during initialization; if false, the grace period is skipped and the container does not check whether the mandatory dependencies are resolved.
blueprint.timeout: Specifies the grace period timeout in milliseconds. The default is 300000 (5 minutes).

For example, to enable a grace period of 10 seconds, you could define the following Bundle-SymbolicName header in the manifest file:

Bundle-SymbolicName: org.fusesource.example.osgi-client;
 blueprint.graceperiod:=true;
 blueprint.timeout:= 10000

The value of the Bundle-SymbolicName header is a semi-colon separated list, where the first item is the actual bundle symbolic name, the second item, blueprint.graceperiod:=true, enables the grace period and the third item, blueprint.timeout:= 10000, specifies a 10 second timeout.

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