Hi Synapse-Devs,
While having a glance on the way Synapse creates its internal memory
representation of the Synapse configuration I think I stumbled across a design
flaw in the AbstractDBMediatorFactory and its sub classes.
Please correct me, if I’m wrong on the following assumptions:
- the process of building the in-memory object representation of the
Synapse configuration has to be separated from the initialisation of mediators
- it is not the responsibility of mediator factories to initialize
mediators, but to create the mediator (object representation) of the mediator
configuration as part of the Synapse configuration
- this allows one to create a configuration model from a synapse
configuration (e.g. stored in an XML file) without the need to have an
initialized environment running
- this separation is also manifested in different execution phases
within the startup process:
1) create Synapse configuration
2) create Synapse environment
3) initialize Synapse configuration with Synapse environment (calls init() on
all config elements supporting some kind of lifecycle)
Unfortunately I noticed that my assumptions are wrong, although I honestly
think they SHOULD be correct. It is currently not possible to create a Synapse
Configuration from a synapse.xml which makes use of mediators which are created
based on the AbstractDBMediatorFactory.
The reason is, mediator creation and initialization are mixed and the factories
take responsibility of both. During the creation defined datasources are build
(including datasource lookup which can only work, if the DataSourceHelper has
been initialized).
I think the creation of the synapse configuration model itself should not
depend on external dependencies. The initialization should rather be done in
the init-Method of the AbstractDBMediator, instead of the create-method of the
AbstractDBMediatorFactory.
What do others think?
Here is the current stacktrace, if someone tries to build a synapse
configuration with standalone code like this:
SynapseConfiguration synapseConfiguration =
scb.getConfiguration(synapseConfigFileName);
org.apache.synapse.commons.SynapseCommonsException: DataSourceHelper has not
been initialized, it requires to be initialized at
org.apache.synapse.commons.datasource.DataSourceHelper.assertInitialized(DataSourceHelper.java:108)
at
org.apache.synapse.commons.datasource.DataSourceHelper.getRepositoryBasedDataSourceFinder(DataSourceHelper.java:122)
at
org.apache.synapse.config.xml.AbstractDBMediatorFactory.lookupDataSource(AbstractDBMediatorFactory.java:145)
at
org.apache.synapse.config.xml.AbstractDBMediatorFactory.buildDataSource(AbstractDBMediatorFactory.java:121)
...
Regards,
Eric
