[keycloak-user] spring sec/boot:: SPA -> Bearer_1 -> Bearer_2

What's the best practice on this scenario: -- SPA (has the token from keycloak.js) -->Rest call--> Bearer_1 -->Rest call --> Bearer_2 Bearer_1 and Bearer_2 are spring sec/boot enabled. Rest calls between Bearer_1 and Bearer_2 using resttemplates and injecting into "Authorization" header the "Bearer token_long_string" Bearer_1 has the KeycloakAuthenticationToken object. Bearer_2 needs to be feed in with a valid non-expired token somehow - but how? Not sure if one can get this out from KeycloakAuthenticationToken and pass it in onto the header calls to bearer_2. Is this the right approach for in-flight rest calls between 2 bearers? What's the best practice on this scenario? Anyone has done this for real? - thx.