Due to requirement changes we need to add a node server to our already existing system. We will be using sails.js for the realtime communication part of the app and redis store for session management. But the confusion now is what is the best way to authenticate the client app/user on both servers with one login form.
Any help will be much appreciated.
Unless you have specific limitations or widhes, this sounds like standard requirement for SSO (Single Sign-On) implementation. OAuth is wide-spread standard in this area.
Ruby have implementations for this, see this repository for example
OAuth2 A Ruby wrapper for the OAuth 2.0 specification.
As for reading materials, you can check this article:
Single Sign On (SSO) for Multiple Applications with Devise, OmniAuth and Custom OAuth2 Implementation in Rails
This tutorial may also help.
Then, you can implement OAuth in your node js server, and other services when needed.
Or detail your question and specific requirements or limits for other options. Meanwhile, you can check this SO question on other non-SSO options.
