Spring Boot Admin and Google Cloud Run

Dan Putt
As I continued moving services away from Google App Engine and into Google Cloud Run I ran into an unexpected issue with my Spring Boot Admin service that cost more more time than expected to dive into.  Hopefully this saves someone else (or me when I forget it) time in the future
 
To those that may not be aware, Spring Boot Admin provides an admin interface for managing all your registered Spring Boot ® applications.  From the documentation:
codecentric’s Spring Boot Admin is a community project to manage and monitor your Spring Boot ® applications. The applications register with our Spring Boot Admin Client (via HTTP) or are discovered using Spring Cloud ® (e.g. Eureka, Consul). The UI is just a Vue.js application on top of the Spring Boot Actuator endpoints.
It's easy to set up and provides a nice UI for manage a collection of Spring boot applications.  
Spring Boot admin wallboard
Spring Boot admin wallboard
Base Metrics
Base Metrics
Logging Levels
You can change log levels on the fly
 In switching from running this on App Engine to Cloud run I was not getting errors on startup and everything loked good in the logs.  The problem was the Spring Boot Admin UI was blank.  Empty.  Null.  Nada. Blank.  Nill.  
 
So, what was the problem?  
 
After looking through the logs and finding a lot of things that were NOT the problem, I finally noticed THIS message:
 
Endpoints for instance cf629ab00194 queried from https://catalog-service-jib-tmsragfh3a-ue.a.run.app:443/actuator are falsely using http. Rewritten to https. Consider configuring this instance to use 'server.use-forward-headers=true'.
 
Well, that makes sense.  When I click on the URL provided in Cloud Run I do see a redirect message from Google.  (I have yet to figure this part out)  After a quick search I was able to figure out that you have to allow processing of forward headers within spring boot admin.  Adding the following to my Spring Config everything was working as expected
server:
  port: 8080
  use-forward-headers: true
So, to summarize one quick setting in your spring application-cloud.yaml  to allow forward headers will enable your Spring Boot admin pages to not be blank.  

You should also read:

Comments