title: How to handle auth in nifi-registry when calling from nifi in OIDC configuration?
body: <p>I've installed and configured nifi and nifi-registry. Both are configured to use OIDC authentication and I can successfully access both after authenticating in my OIDC provider (a Keycloak server FWIW).</p>
  <p>Problems arise when I want to start version control of a process group. I have configured the nifi-registry URL in nifi but I am unable to list the buckets available in nifi-registry.</p>
  <p>And indeed when I look at the nifi-registry logs, I see this:</p>
  <pre><code>2021-10-21 09:36:27,487 DEBUG [NiFi Registry Web Server-17] o.a.n.r.w.s.a.IdentityFilter Attempting to extract user credentials using X509IdentityProvider
  2021-10-21 09:36:27,488 DEBUG [NiFi Registry Web Server-17] o.a.n.r.w.s.a.x.X509CertificateExtractor No client certificate found in request.
  2021-10-21 09:36:27,488 DEBUG [NiFi Registry Web Server-17] o.a.n.r.w.s.a.IdentityFilter Attempting to extract user credentials using JwtIdentityProvider
  2021-10-21 09:36:27,488 DEBUG [NiFi Registry Web Server-17] o.a.n.r.s.a.BearerAuthIdentityProvider HTTP Bearer Auth credentials not present. Not attempting to extract credentials for authentication.
  2021-10-21 09:36:27,488 DEBUG [NiFi Registry Web Server-17] o.a.n.r.w.s.a.AnonymousIdentityFilter Set SecurityContextHolder to anonymous SecurityContext
  </code></pre>
  <p>So it is seen as an anonymous request which explains why I can't see any buckets from nifi-registry.</p>
  <p>I have not been able to find documentation explaining how security configuration should be done in this OIDC case. What am I missing here? How should user authentication be conveyed in this case?</p>