Fix Insufficient Logging & Monitoring in Ktor

fun Application.module() {
    routing {
        post("/api/v1/auth/login") {
            val params = call.receiveParameters()
            val username = params["username"]
            // VULNERABILITY: No logging of failed attempts, no request correlation,
            // and no visibility into source IP or user-agent. 
            // If this endpoint is hit 10k times, the logs remain silent.
            call.respond(HttpStatusCode.OK, "Success")
        }
    }
}

fun Application.module() {
    install(CallLogging) {
        level = Level.INFO
        filter { call -> call.request.path().startsWith("/api") }
        // Correlation ID for log aggregation/tracing
        mdc("request_id") { call -> call.request.headers["X-Request-ID"] ?: UUID.randomUUID().toString() }
        format { call ->
            val status = call.response.status()
            val httpMethod = call.request.httpMethod.value
            val userAgent = call.request.headers["User-Agent"]
            val remoteHost = call.request.origin.remoteHost
            "Remote: $remoteHost | Method: $httpMethod | Status: $status | UA: $userAgent"
        }
    }
routing {
    post("/api/v1/auth/login") {
        val username = call.receiveParameters()["username"]
        // LOGGING SECURITY EVENTS
        application.log.info("Login attempt for user: $username")
        // ... auth logic ...
        call.respond(HttpStatusCode.OK)
    }
}
}