KHealth 2+ stores all ApplicationCall objects

[glebignatieff]

Hi!

There seems to be a bug since version 2.0.0, leading to KHealth storing all ApplicationCall objects and calling them on each /health or /ready. As I understand, interceptor should create a route handler for /health and /ready only once, therefore right now it behaves weirdly.

It happens because there's already a call argument in the top function, which shadows the one in get handler:

khealth/src/main/kotlin/KHealthPlugin.kt

Lines 36 to 46 in 6847a29

	fun interceptor(call: ApplicationCall) {
	val routing: Routing.() -> Unit = {
	val routing: Route.() -> Unit = {
	if (config.readyCheckEnabled) route(config.readyCheckPath) {
	get {
	val (status, responseBody) = processChecks(
	checkLinkedList = config.readyChecks,
	passingStatusCode = config.successfulCheckStatusCode,
	failingStatusCode = config.unsuccessfulCheckStatusCode
	)
	call.respondText(responseBody, ContentType.Application.Json, status)

Steps to reproduce

1. Generate Ktor project with Routing and CallLogging.
2. Add khealth package to build.gradle.kts.
3. Add install(KHealth) to embeddedServer builder in Application.kt.
4. Run the app.
5. Get a few / and then /health.

Expected behavior

2 / and one /health:

2022-07-26 11:20:15.307 [eventLoopGroupProxy-4-3] INFO  ktor.application - 200 OK: GET - /
2022-07-26 11:20:15.308 [eventLoopGroupProxy-4-3] INFO  ktor.application - 200 OK: GET - /
2022-07-26 11:20:15.309 [eventLoopGroupProxy-4-3] INFO  ktor.application - 200 OK: GET - /health

Actual behavior

Calling /health gives two more / logs and then /health.

2022-07-26 11:20:12.121 [eventLoopGroupProxy-4-2] INFO  ktor.application - 200 OK: GET - /
2022-07-26 11:20:12.121 [eventLoopGroupProxy-4-1] INFO  ktor.application - 200 OK: GET - /
2022-07-26 11:20:15.307 [eventLoopGroupProxy-4-3] INFO  ktor.application - 200 OK: GET - /
2022-07-26 11:20:15.308 [eventLoopGroupProxy-4-3] INFO  ktor.application - 200 OK: GET - /
2022-07-26 11:20:15.309 [eventLoopGroupProxy-4-3] INFO  ktor.application - 200 OK: GET - /health

As you can see, 2 previous / calls have been stored and with each /health get handler is called with all these calls.

[HaydenMeloche]

Hi @glebignatieff
thanks for the detailed bug report! I published a fix for this under 2.1.1 in commit 7c7b239