SpringBootHealthCheckEnricher : Add /actuator/startup as startup probe if enabled

[rohanKanojia]

Description

Related to #1322

Spring Boot actuator provides a startup endpoint which shows startup data. Here is a sample response

{
  "springBootVersion": "2.5.6",
  "timeline": {
    "startTime": "2022-04-22T10:47:05.426341763Z",
    "events": [
      {
        "endTime": "2022-04-22T10:47:05.520464398Z",
        "duration": "PT0.062466167S",
        "startupStep": {
          "name": "spring.boot.application.starting",

I think this endpoint can be used by SpringBootHealthCheckEnricher as a startup probe. SpringBootHealthCheckEnricher should check whether startup is enabled or not; If enabled, it should add this endpoint as a startup probe in controller's PodTemplateSpec.

[Prathamkrishna]

I think i could pick this up if no one else has plans

[manusa]

We need to check if this is also supported in SpringBoot 1.x

[Prathamkrishna]

yep, it is is supported in SpringBoot 1.x
-> https://www.baeldung.com/spring-boot-actuators
You could check this out as a ref

[rohanKanojia]

Hi guys, I revisited this and realized I had a misunderstanding regarding /actuator/startup endpoint. It's not related to Kubernetes probes.

In Spring Boot Kubernetes probes documentation, it's clearly stated there is no explicit startup endpoint supported:

If an application takes longer to start than the configured liveness period, Kubernetes mentions the "startupProbe" as a possible solution. The "startupProbe" is not necessarily needed here, as the "readinessProbe" fails until all startup tasks are done.

Really sorry for the noise.