There is a lot of discussion about microservice architecture. What I am missing - or maybe what I did not yet understand is, how to solve the issue of security and user authentication?
For example: I develop a microservice which provides a Rest Service interface to a workflow engine. The engine is based on JEE and runs on application servers like GlassFish or Wildfly. One of the core concepts of the workflow engine is, that each call is user centric. This means depending of the role and access level of the current user, the workflow engine produces individual results (e.g. a user-centric tasklist or processing an open task which depends on the users role in the process).
In my eyes, thus a service is not accessible from everywhere. For example if someone plans to implement a modern Ajax based JavaScript application which should use the workflow microservice there are two problems:
1) to avoid the cross-scripting problem from JavaScript/Ajax the JavaScript Web application needs to be deployed under the same domain as the microservice runs
2) if the microservice forces a user authentication (which is the case in my scenario) the application need to provide a transparent authentication mechanism.
The situation becomes more complex if the client need to access more than one user-centric microservices forcing user authentication. I always end up with an architecture where all services and the client application running on the same application server under the same domain.
How can these problems be solved? What is the best practice for such an architecture?
Short answer: check OAUTH, and manage caches of credentials in each microservice that needs to access other microservices. By "manage" I mean, be careful with security. Specially, mind who can access those credentials and let the network topology be your friend. Create a DMZ layer and other internal layers reflecting the dependency graph of your microservices.
Long answer, keep reading. Your question is a good one because there is no simple silver bullet to do what you need although your problem is quite recurrent.
As with everything related with microservices that I saw so far, nothing is really new. Whenever you need to have a distributed system doing things on behalf of a certain user, you need distributed credentials to enable such solution. This is true since mainframe times. There is no way to violate that.
Auto SSH is, in a sense, such a thing. Perhaps it may sound like a glorified way to describe something simple, but in the end, it enables processes in one machine to use services in another machine.
In the Grid world, the Globus Toolkit, for instance, bases its distributed security using the following:
- X.509 certificates;
- MyProxy - manages a repository of credentials and helps you define a chain of certificate authorities up to finding the root one, which should be trusted by default;
- An extension of OpenSSH, which is the de facto standard SSH implementation for Linux distributions.
OAUTH is perhaps what you need. It is a way provide authorization with extra restrictions. For instance, imagine that a certain user has read and write permission on a certain service. When you issue an OAUTH authorization you do not necessarily give full user powers to the third party. You may only give read access.
CORS, mentioned in another answer, is useful when the end client (typically a web browser) needs single-sign-on across web sites. But it seems that your problem is closer to a cluster in which you have many microservices that are managed by you. Nevertheless, you can take advantage of solutions developed by the Grid field to ensure security in a cluster distributed across sites (for high availability reasons, for instance).
Complete security is something unattainable. So all this is of no use if credentials are valid forever or if you do not take enough care to keep them secret to whatever received them. For such purpose, I would recommend partitioning your network using layers. Each layer with a different degree of secrecy and exposure to the outside world.
If you do not want the burden to have the required infrastructure to allow for OAUTH, you can either use basic HTTP or create your own tokens.
When using basic HTTP authentication, the client needs to send credentials on each request, therefore eliminating the need to keep session state on the server side for the purpose of authorization.
If you want to create your own mechanism, then change your login requests such that a token is returned as the response to a successful login. Subsequent requests having the same token will act as the basic HTTP authentication with the advantage that this takes place at the application level (in contrast with the framework or app server level in basic HTTP authentication).
Your question is about two independent issues.
Making your service accessible from another origin is easily solved by implementing CORS. For non-browser clients, cross-origin is not an issue at all.
The second problem about service authentication is typically solved using token based authentication.
Any caller of one of your microservices would get an access token from the authorization server or STS for that specific service.
Your client authenticates with the authorization server or STS either through an established session (cookies) or by sending a valid token along with the request.
来源：https://stackoverflow.com/questions/32574103/microservices-how-to-solve-security-and-user-authentication