From c222bde14b8492e4fe9c53d9ebf5138d03b349e0 Mon Sep 17 00:00:00 2001
From: Harshavardhana <harsha@minio.io>
Date: Fri, 15 Jan 2021 14:04:56 -0800
Subject: [PATCH] fix: use common logging implementation for DNSCache (#11284)

---
 cmd/common-main.go             | 2 +-
 cmd/http/dial_dnscache.go      | 7 ++++---
 cmd/http/dial_dnscache_test.go | 6 +++++-
 cmd/test-utils_test.go         | 2 +-
 4 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/cmd/common-main.go b/cmd/common-main.go
index c9626e45d..b495821c8 100644
--- a/cmd/common-main.go
+++ b/cmd/common-main.go
@@ -51,7 +51,7 @@ func init() {
 	logger.RegisterError(config.FmtError)
 
 	rand.Seed(time.Now().UTC().UnixNano())
-	globalDNSCache = xhttp.NewDNSCache(10*time.Second, 10*time.Second)
+	globalDNSCache = xhttp.NewDNSCache(10*time.Second, 10*time.Second, logger.LogOnceIf)
 
 	initGlobalContext()
 
diff --git a/cmd/http/dial_dnscache.go b/cmd/http/dial_dnscache.go
index 91785e35b..34612d12c 100644
--- a/cmd/http/dial_dnscache.go
+++ b/cmd/http/dial_dnscache.go
@@ -18,7 +18,6 @@ package http
 
 import (
 	"context"
-	"log"
 	"math/rand"
 	"net"
 	"sync"
@@ -96,6 +95,7 @@ type DNSCache struct {
 
 	lookupHostFn  func(ctx context.Context, host string) ([]string, error)
 	lookupTimeout time.Duration
+	loggerOnce    func(ctx context.Context, err error, id interface{}, errKind ...interface{})
 
 	cache    map[string][]string
 	doneOnce sync.Once
@@ -105,7 +105,7 @@ type DNSCache struct {
 // NewDNSCache initializes DNS cache resolver and starts auto refreshing
 // in a new goroutine. To stop auto refreshing, call `Stop()` function.
 // Once `Stop()` is called auto refreshing cannot be resumed.
-func NewDNSCache(freq time.Duration, lookupTimeout time.Duration) *DNSCache {
+func NewDNSCache(freq time.Duration, lookupTimeout time.Duration, loggerOnce func(ctx context.Context, err error, id interface{}, errKind ...interface{})) *DNSCache {
 	if freq <= 0 {
 		freq = defaultFreq
 	}
@@ -117,6 +117,7 @@ func NewDNSCache(freq time.Duration, lookupTimeout time.Duration) *DNSCache {
 	r := &DNSCache{
 		lookupHostFn:  net.DefaultResolver.LookupHost,
 		lookupTimeout: lookupTimeout,
+		loggerOnce:    loggerOnce,
 		cache:         make(map[string][]string, cacheSize),
 		doneCh:        make(chan struct{}),
 	}
@@ -179,7 +180,7 @@ func (r *DNSCache) Refresh() {
 	for _, host := range hosts {
 		ctx, cancelF := context.WithTimeout(context.Background(), r.lookupTimeout)
 		if _, err := r.LookupHost(ctx, host); err != nil {
-			log.Println("failed to refresh DNS cache, resolver is unavailable", err)
+			r.loggerOnce(ctx, err, host)
 		}
 		cancelF()
 	}
diff --git a/cmd/http/dial_dnscache_test.go b/cmd/http/dial_dnscache_test.go
index f2f2951d4..80e669b7f 100644
--- a/cmd/http/dial_dnscache_test.go
+++ b/cmd/http/dial_dnscache_test.go
@@ -31,9 +31,13 @@ var (
 	testDefaultLookupTimeout = 1 * time.Second
 )
 
+func logOnce(ctx context.Context, err error, id interface{}, errKind ...interface{}) {
+	// no-op
+}
+
 func testDNSCache(t *testing.T) *DNSCache {
 	t.Helper() // skip printing file and line information from this function
-	return NewDNSCache(testFreq, testDefaultLookupTimeout)
+	return NewDNSCache(testFreq, testDefaultLookupTimeout, logOnce)
 }
 
 func TestDialContextWithDNSCache(t *testing.T) {
diff --git a/cmd/test-utils_test.go b/cmd/test-utils_test.go
index 82e217c89..63722faf9 100644
--- a/cmd/test-utils_test.go
+++ b/cmd/test-utils_test.go
@@ -107,7 +107,7 @@ func TestMain(m *testing.M) {
 	// Initialize globalConsoleSys system
 	globalConsoleSys = NewConsoleLogger(context.Background())
 
-	globalDNSCache = xhttp.NewDNSCache(3*time.Second, 10*time.Second)
+	globalDNSCache = xhttp.NewDNSCache(3*time.Second, 10*time.Second, logger.LogOnceIf)
 
 	globalInternodeTransport = newInternodeHTTPTransport(nil, rest.DefaultTimeout)()