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A Carbon Application, abbreviated as a C-App, is a collection of artifacts deployable on a Carbon instance. These artifacts are usually java-based or xml XML configurations, designed differently for each product in the Carbon platform. In a single Carbon-based solution, there can be numerous artifacts used, such as Axis2 services, data services, synapse configurations, endpoints, proxy services, mediators, registry resources, BEPL workflows etc. Usually, these artifacts are created in a development environment and then moved one by one into staging/production environments. When moving a Carbon solution from one setup to the other, the user has to manually configure these artifacts to build up the entire solution. This is a time-consuming process. Alternatively, bundling configuration files and artifacts in a C-App makes it easy for users to port their Web service based solution from one environment to another.
When a user deploys a C-App in a Carbon product, all its resources cannot be deployed in that particular product instance. To specify which can and which cannot be deployed, the server-role property ServerRoles property is used. When a C-App is being deployed, it reads the ServerRoles property from the carbon.xml and deploys only the resources which that match the server-role values ServerRoles values in there. Here The following is an example list of C-App resources that map to default server roles.
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Server roles manager is a component to manage the server roles property for WSO2 Carbon based products. Due to the functionality of the server roles manager, users do not have to manually modify the carbon.xml to include the server-roles related to the product feature that they have added to a Carbon product instance. The server roles manager stores both carbon.xml file's default product roles as well as the user/tenant specific server roles in the configuration registry. So, when a C-App is deployed in Carbon, the C-App deployer checks for auto-mentioned server roles from the registry instead of the carbon.xml file.
In the server roles manager, the server-roles properties ServerRoles properties are of two types:
- Default - All the server roles picked from that particular product instance's
carbon.xml. - Custom - All other server roles added by the users.
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