Spring graceful shutdown demo

To run: ./gradlew bootRun

Graceful shutdown was introduced in Spring Boot 2.3.

curl localhost:8080/ping -v

Java exit code

128 + exit_code_value

SIGKILL (9) - application exists without waiting with non-zero exit value 137

SIGINT (2) = Ctrl+C - application waits for requests to finish, but finishes with non-zero exit value 130

SIGTERM (15)- application waits for requests to finish, but finishes with non-zero exit value 143

calling curl localhost:8287/actuator/shutdown -X POST -v- application waits for requests to finish, ends with 0 return code

K8s apps must end with status code 0 otherwise it's taken as failed shutdown.

prestop hook not possible to use because Actuator shutdown is not blocking, so sigterm is called immediately. Block on calling some url is also not possible because Spring stops accepting all connections.

Spring Docker image

./gradlew bootBuildImage docker run docker.io/library/spring-graceful-shutdown-demo:0.0.1-SNAPSHOT

There is no fix in Spring build image.

Docker image

docker build -t matejuh/spring-graceful-shutdown-demo:0.1.1 .