Hey !
Happy to see the IPFS pinning issue discussed 
Here are a couple of remarks / questions.
EDIT. I didn’t see @Daniel post before I write that post. There is some redundancy but I leave my post here as it is as a +1 to Daniel’s comments
IPFS Cluster
I think the use of an IPFS Cluster is a must-go here. This is something we have already researched a little on our side - mostly for Pando - and we were on our way to deploy a IPFS Cluster node and propose A1 / Autark / AA to join forces We can coordinate on this!
Authentication
This is something which has already been discussed during the All Devs Call so I lay it out there publicly for discussion purposes. It would be great to have the ‘subscription’ to this service handle at the DAO level. This would allow DAOs to pay fees to have their files pinned. I’m not sure such is a system is that easy to design, though. It would require a standard DAO-membership system to check whether an Ethereum key is a member of a DAO …
Server API
My main concern in the current state of the proposal is the use of a custom API. I feel like the Aragon IPFS service should be 100% compatible with the IPFS API. This way switching the service on / off would be as simple as modifying the gateway URL in the Aragon Client.
Also: I don’t see the rationale of using MongoDB here. I feel like it introduces a very centralized additionnal layer … Moreover I remember there are plans in the Aragon roadmap to provide Graph Protocol as caching / querying layer. Thus, I think the query layer of the IPFS service could somehow rely on Graph Protocol to avoid relying on tons of different API.
Client API
For now, each Aragon app has to deal with its own IPFS settings. This leads to a lot of redundancy both in terms of local storage and of library import: it’s a non-necessary overhead to re-import the js-ipfs-api tens of times Maybe the IPFS API could be exposed directly at the wrapper / app level. This way, user would just have to configure their IPFS settings once - at the client level, as it is now - and all apps would be up-to-date.
