What's the request "OPTIONS /cloudfoundryapplication" used for?

Products

• VMware Tanzu Application Service for VMs

Environment

Product Version: Other

Resolution

Checklist:

For apps running on the VMware Tanzu Application Service platform, you may see "OPTIONS /cloudfoundryapplication HTTP/1.1" requests in app logs. 

2020-03-26T16:00:24.14+0100 [RTR/0] OUT app.domain - [2020-03-26T15:00:24.131259308Z] "OPTIONS /cloudfoundryapplication HTTP/1.1" 404 0 42 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.149 Safari/537.36" "10.193.71.250:52090" "10.193.71.42:61030" x_forwarded_for:"10.255.212.232, 10.193.71.250" x_forwarded_proto:"https" vcap_request_id:"a8474a55-6936-4a0b-4c82-939777034cbd" response_time:0.015081 gorouter_time:0.000304 app_id:"791a1b86-1f79-4b77-b7e8-507fd6a3c38f" app_index:"1" x_b3_traceid:"1f59c7bcedab723b" x_b3_spanid:"1f59c7bcedab723b" x_b3_parentspanid:"-" b3:"1f59c7bcedab723b-1f59c7bcedab723b"

For Spring Boot apps, response code is usually 200, while for most apps in other languages, the response code is usually 404.

Apps Manager uses the /cloudfoundryapplication endpoint as the root for Spring Boot Actuator integrations. It calls this endpoint for an app when you view the app in the Apps Manager UI, regardless of whether you have configured Spring Boot Actuator endpoints for Apps Manager.

When a Spring Boot app is deployed on VMware Tanzu Application Service platform with `spring-boot-starter-actuator` dependency, the `/cloudfoundryapplication` endpoint is automatically mapped to Spring Boot actuator endpoint.

By reading the actuator endpoint, Apps Manager displays Spring icon as well as additional tabs like Trace and Threads. By using the actuator feature, you can capture thread dump, modify logs levels via Apps Manager web interface. 

In case that an apps doesn't support the actuator feature at /cloudfoundryapplication endpoint, you will see

"OPTIONS /cloudfoundryapplication HTTP/1.1" 404

In app logs, which is expected behavior without any impact, you can simply ignore the message.