How to make an authenticated REST microservice calls using NiFi Processors

[#1]

Can NiFi handle authenticated calls to REST microservices? For example before calling a REST service, the client needs to call an authentication service to obtain a token or session id. The session token is then passed into a REST call to post the data.

Is there any mechanism for maintaining the token and renewing it periodically?

[#2 · Accepted solution]

If the token can be retrieved from an external resource via static credentials, you can use a separate InvokeHTTP processor to perform the authentication and load the token into flowfile content, which is then fed to the follow-on InvokeHTTP processor to perform the actual request.

@Pierre Villard has a good example of using OAuth 1.0 to generate credential material and then use that in a follow-on request.