From 55e00be36e62b6fe798db1954abc2eea329f4b1b Mon Sep 17 00:00:00 2001
From: Kevin McConnell <kevin.mcconnell@gmail.com>
Date: Tue, 8 Aug 2023 15:40:05 +0100
Subject: [PATCH] Allow short healthcheck interval with long timeout

---
 docs/content/routing/services/index.md |  1 -
 pkg/healthcheck/healthcheck.go         |  5 ---
 pkg/healthcheck/healthcheck_test.go    | 51 ++++++++++++++++++++++++++
 3 files changed, 51 insertions(+), 6 deletions(-)

diff --git a/docs/content/routing/services/index.md b/docs/content/routing/services/index.md
index c809392f4..fb6af7563 100644
--- a/docs/content/routing/services/index.md
+++ b/docs/content/routing/services/index.md
@@ -338,7 +338,6 @@ Below are the available options for the health check mechanism:
 !!! info "Interval & Timeout Format"
 
     Interval and timeout are to be given in a format understood by [time.ParseDuration](https://golang.org/pkg/time/#ParseDuration).
-    The interval must be greater than the timeout. If configuration doesn't reflect this, the interval will be set to timeout + 1 second.
 
 !!! info "Recovering Servers"
 
diff --git a/pkg/healthcheck/healthcheck.go b/pkg/healthcheck/healthcheck.go
index 1452bfa66..747999889 100644
--- a/pkg/healthcheck/healthcheck.go
+++ b/pkg/healthcheck/healthcheck.go
@@ -69,11 +69,6 @@ func NewServiceHealthChecker(ctx context.Context, metrics metricsHealthCheck, co
 		timeout = time.Duration(dynamic.DefaultHealthCheckTimeout)
 	}
 
-	if timeout >= interval {
-		logger.Warn().Msgf("Health check timeout should be lower than the health check interval. Interval set to timeout + 1 second (%s).", interval)
-		interval = timeout + time.Second
-	}
-
 	client := &http.Client{
 		Transport: transport,
 	}
diff --git a/pkg/healthcheck/healthcheck_test.go b/pkg/healthcheck/healthcheck_test.go
index c7813fae0..52b70448c 100644
--- a/pkg/healthcheck/healthcheck_test.go
+++ b/pkg/healthcheck/healthcheck_test.go
@@ -18,6 +18,57 @@ import (
 	healthpb "google.golang.org/grpc/health/grpc_health_v1"
 )
 
+func TestNewServiceHealthChecker_durations(t *testing.T) {
+	testCases := []struct {
+		desc        string
+		config      *dynamic.ServerHealthCheck
+		expInterval time.Duration
+		expTimeout  time.Duration
+	}{
+		{
+			desc:        "default values",
+			config:      &dynamic.ServerHealthCheck{},
+			expInterval: time.Duration(dynamic.DefaultHealthCheckInterval),
+			expTimeout:  time.Duration(dynamic.DefaultHealthCheckTimeout),
+		},
+		{
+			desc: "out of range values",
+			config: &dynamic.ServerHealthCheck{
+				Interval: ptypes.Duration(-time.Second),
+				Timeout:  ptypes.Duration(-time.Second),
+			},
+			expInterval: time.Duration(dynamic.DefaultHealthCheckInterval),
+			expTimeout:  time.Duration(dynamic.DefaultHealthCheckTimeout),
+		},
+		{
+			desc: "custom durations",
+			config: &dynamic.ServerHealthCheck{
+				Interval: ptypes.Duration(time.Second * 10),
+				Timeout:  ptypes.Duration(time.Second * 5),
+			},
+			expInterval: time.Second * 10,
+			expTimeout:  time.Second * 5,
+		},
+		{
+			desc: "interval shorter than timeout",
+			config: &dynamic.ServerHealthCheck{
+				Interval: ptypes.Duration(time.Second),
+				Timeout:  ptypes.Duration(time.Second * 5),
+			},
+			expInterval: time.Second,
+			expTimeout:  time.Second * 5,
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.desc, func(t *testing.T) {
+			healthChecker := NewServiceHealthChecker(context.Background(), nil, test.config, nil, nil, http.DefaultTransport, nil)
+			assert.Equal(t, test.expInterval, healthChecker.interval)
+			assert.Equal(t, test.expTimeout, healthChecker.timeout)
+		})
+	}
+}
+
 func TestServiceHealthChecker_newRequest(t *testing.T) {
 	testCases := []struct {
 		desc        string