Reproducer can be found at mvitz/actuator-time-to-live.
If setting management.endpoint.health.cache.time-to-live to any value (e.g. 60s) if hitting the health-endpoint with a trailing slash (e.g. localhost:8080/actuator/health/ the cache is ignored and all health indicators are executed every time. To show that the reproducer contains a custom HealthIndicator that prints out a line every time it's invoked.
The Actuator documentation states within Configuring Endpoints:
Endpoints automatically cache responses to read operations that do not take any parameters.
I know that you could argue that calling /actuator/health/ is resulting in a call to a read operation with an empty parameter, but I was confused by this behaviour, and it did me take some time to figure out what's happening here and why my time to live was “ignored”. In most cases, I, and I suspect others do too, expect that a URL that works with and without a trailing slash behaves the same.
Comment From: wilkinsona
This is expected and aligns with Framework's behavior around matching of trailing slashes. See https://github.com/spring-projects/spring-boot/issues/31563 for further background.