Dependencies

The dependency tree is built when a gateway’s resources are imported into DAGM. There are three kinds of dependencies in DAGM (while there are only two in the gateway itself).

Regular Dependencies

Regular dependencies are the most basic form of a dependency. One resource requires another resource to be present to work correctly. This might be a service referencing a JDBC connection, a policy fragment or a certificate for example.

Dynamic Dependencies

Dynamic dependencies are resolved during runtime. Instead of referencing the dependency directly a cluster property is referenced that holds the name of the dependency. This way it is possible for library authors to write policies that can be configured in the customer’s environment.

It is possible to reference either cluster properties (${gateway.NAME}) or variables within the policy itself (${NAME}).

DAGM is currently not able to resolve variables that are defined within a policy.

Missing Dependencies

Missing dependencies are either regular or dynamic. The target of the dependency is not available at the gateway. While migrating a service or policy with a missing dependency might work, running it however will fail during runtime.