[aerogear-dev] Sync Day 2: All our cars are frozen in ice

[Summers Pittman]

I'm going to take some time to roll up yesterday's Sync Thread so we can 
stop chasing down individual ideas.

Also I am going to propose a potential milestone conga line.  I think 
one of the things that keeps happening in these discussions is everyone 
has an idea of what sync is but we don't really know what order things 
should be done or released in.

If everyone likes this I'll slice things into JIRA epics.

# M1 - Basic revision Control, Data Model, Change Management, Server <-> 
Client Contract

  * We seem to be in agreement on a basic set of metadata to be kept for 
each object.  [objectId, revision, object].
  * We should have a basic server definition which supports CRUD and 
keeps our revision numbers in check.  This may not be a server product 
but just a spec that can be implemented by anything at this point.
  * We should have basic client code which keeps up with revisions, can 
check the server for new revisions, and alert the user if there is a 
sync conflict.


M2 - Sync Listener w/ Polling based sync listener, conflict management, 
Serve user management
  * We define on the client how callbacks will work for alerts when 
remote data changes
  * We implement a listener which polls a data source and delivers 
changes to the user.
  * We define how conflicts are managed
  * The server should have a basic authentication and authorization plan 
for controlling how data is synced

M3 - Push based Sync Listener, Network Management, Serverside session 
management
  * We will build on our previous Listener work from M2 to include a 
Push listener that the server can speak to.
  * We will define in the client how network state and sync state 
interact.  IE how to handle errors in fetching new data when the 
Listener is alerted. (Exponential back off, retry, etc)
  * The server will need to have some mechanism for managing user 
"sessions".  This is what users are actively being synced.

M4 - "Real Time" Sync Listener.  Bidirectional automatic sync
  * Instead of using push, Realtime Sync uses something like web 
sockects. to automatically sync local and remote data.
  * Previous Sync listeners may have to be upgraded to include "upload" 
abilities.
  * The server will need to support this as well.

M5 - Conflict resolution, Error detection and support
  * Provide a more comprehensive strategy for managing conflicts.
  * Provide some automated conflict resolvers
  * The server could get a larger set of conflict and errors messages

M6 - Sync connection Upgrading
  * The client and server will negotiate when it is appropriate to 
switch between polling, push, and realtime sync strategies.

M7 - Party
  * We have a sync party.