Creating a Java connector

OCCIware Studio » Creating a Java connector

Creating a Java Connector

TODO move to its own page.

Here is how to create a Java connector that will be able to manage the Cloud of your choice and expose its capabilities as OCCI.

See also slides 71-73 in the One Cloud API to rule them all talk given at EclipseCon France 2016.

TODO put its screenshots here.

1. In Eclipse, create a connector project by choosing File > New > Other… then Cloud Designer > Java Connector Project, and filling its name and extension dependencies (usually with one you’ve created for your own needs). This notably generates …/connector/YourOCCIResourceConnector.java files in the src/ directory, with empty connector methods (occiRetrieve, occiUpdate… as well as defined OCCI actions).

2. Creating a connector with an existing Cloud (IaaS, PaaS…) implies adding all dependencies that are required to talk to said Cloud’s management APIs, such as a REST client if those are REST APIs, or a dedicated client library provided by said Cloud. To this end :

in Eclipse, create a …connector.dependencies project using an existing one as a template and define all these dependencies in its pom.xml file.
run mvn clean install in this project, which will make maven download all dependencies in the …connector/lib folder.
in Eclipse, complete the …connector project’s META-INF/MANIFEST.MF by adding library dependencies on all …connector/lib/*jar files (refresh the project if you can’t see them).

NB. …connector.dependencies projects are the only case in the Studio were dependencies are declared in the pom.xml file. Otherwise they must be declared in a project’s META-INF/MANIFEST.MF file, as for any regular Eclipse plugin, where Maven will be able to find them thanks to using Tycho’s eclipse-plugin packaging.

3. You can now fill those connector methods by writing code that takes the current state of your OCCI resource (at execution time, those generated connector objects will be automatically filled with it : all attributes and links) and applies it to the management of the Cloud that your are creating a connector for by using said dependency libraries.

4. You can then test it by running it from source within Eclipse : Run > Run configurations… then create a new Eclipse Application (if none yet) and run it.

Next step is to expose this connector as an OCCI HTTP API.