Hi,
In our service, we provide a set of features which can be enabled/disabled
per tenant.
Our tenants implementation is based on the Sling Tenant API and we are
thinking to leverage the Sling Feature flags API to represent our features.
>From our application POV, we would need to implement this logical signature
status = enable(tenantId, featureName)
Looking at the Sling feature flags API, the signature we should implement
looks like [0]
status = feature(featureName).enable(request, resolver)
where the request and resolver are essentially the context provided by the
features manager implementation.
So, implementing our use case would be possible as we can derive a tenantId
from a resolver
status = feature(featureName).enable(tenantId(resolver))
With the current features manager implementation, this would be possible
only when features are checked upon a HTTP request as the features manager
would be able to provide a meaningful context.
However, with background services, the features manager would naturally not
be able to provide a meaningful context (currently the resolver and request
are null), thus our implementation would be useless for those use cases.
According to the javadoc in [2], it would also not be possible to
explicitly provide our own context implementation (that would embed the
tenantId, or a resource resolver that can be reduced to the tenantId) using
the API.
An option would be to implement our own features manager which would take
the tenantId in consideration, however I believe it would make more sense
to leverage the existing implementation and allow to pass custom contexts
to it (essentially removing the comment in [2]).
Another improvement may be to allow passing a map of properties via the
context. This way, a background service could pass directly the relevant
information to the Feature, instead of having to leverage a proxy
ResourceResolver or HttpServletRequest instance.
Anyway, are feature flags supposed to be accessible from background
services (as wished in [1]) ?
If yes, what is the recommended way to use contextual feature flags from
background services ?
Regards,
Timothee
[0]
https://github.com/apache/sling/blob/trunk/bundles/extensions/feature-flags/src/main/java/org/apache/sling/featureflags/Feature.java#L70
[1] http://markmail.org/message/rueoiuacmft5fdet
[2]
https://github.com/apache/sling/blob/trunk/bundles/extensions/feature-flags/src/main/java/org/apache/sling/featureflags/Feature.java#L60
