deps: futur implementation proposal

README.md

@@ -26,6 +26,59 @@ help for a particular command.
 *   Code as the single source of thruth
 *   Work entirely offline
 
+## Documentation
+
+Note, this is a proposal for future Masson evolution and doesnt reflect the
+current implementation.
+
+### Option `deps`
+
+* `Single`
+  Inject a single dependency instead of an array of dependencies.
+  Throw an error if more than one service is present
+  Equals to null if no service is present
+  Used conjointly with `local`, it will return the local service even if the
+  service is present on more than one node.
+* `local`
+  Load the service on the local node if the service is already activated.
+* `auto`
+  Activate the service.
+  Can be used conjointly with `local` to ensure a dependency is executed on 
+  every node before a given service.
+* `recommanded`
+  Mark the depencency as important, only for information purpose.
+* `required`
+  Ensure a dependency is activated.
+  Cannot be used conjointly with `auto`, if a service cannot be automatically
+  loaded, then it is pointless to mark it as required.
+* `min`
+  Ensure a dependency isn't activated on less then a minimum values
+* `max`
+  Ensure a dependency isn't activated on more then a maximum values
+
+### Usecases:
+
+Considering a service A is declared on a node tagged as "client". A service B is
+declared on a node tagged as "master" and define a dependency on service A to be 
+colocalized on the same node.
+
+* Use `local: true` to automatically declare service A on the same node as 
+  service B if and only if service A is already defined elsewhere. In the
+  service configuration, the dependency will be set as "null" if service A
+  was not activated elsewhere.
+* Use `local: true, required: true` to automatically declare service A on the
+  same node as service B and ensure service B is activated elsewhere.
+* Use `local: true, single: true` to automatically declare service A on the
+  same node as service B. In the service configuration, the dependency will
+  be set as the service  object relative to the current node instead of an array
+  of services for every nodes.
+* Use `auto: true` to automatically activate service A. The service will not
+  be declared on any node. In the service configuration, the dependency will
+  be set as an empty array if the dependency affinity doesnt match any affinity.
+  of services for every nodes.
+* Use `auto: true, local: true` to automatically activate service A and declare 
+  service A as a dependency of service B.
+
 ## Contributors
 
 *   David Worms: <https://github.com/wdavidw>