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minio/cmd/http/dial_dnscache_test.go

205 lines
4.9 KiB

/*
* MinIO Cloud Storage, (C) 2020 MinIO, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package http
import (
"context"
"errors"
"fmt"
"math/rand"
"net"
"testing"
"time"
)
var (
testFreq = 1 * time.Second
testDefaultLookupTimeout = 1 * time.Second
)
func testDNSCache(t *testing.T) *DNSCache {
t.Helper() // skip printing file and line information from this function
return NewDNSCache(testFreq, testDefaultLookupTimeout)
}
func TestDialContextWithDNSCache(t *testing.T) {
resolver := &DNSCache{
cache: map[string][]string{
"play.min.io": {
"127.0.0.1",
"127.0.0.2",
"127.0.0.3",
},
},
}
cases := []struct {
permF func(n int) []int
dialF DialContext
}{
{
permF: func(n int) []int {
return []int{0}
},
dialF: func(ctx context.Context, network, addr string) (net.Conn, error) {
if got, want := addr, net.JoinHostPort("127.0.0.1", "443"); got != want {
t.Fatalf("got addr %q, want %q", got, want)
}
return nil, nil
},
},
{
permF: func(n int) []int {
return []int{1}
},
dialF: func(ctx context.Context, network, addr string) (net.Conn, error) {
if got, want := addr, net.JoinHostPort("127.0.0.2", "443"); got != want {
t.Fatalf("got addr %q, want %q", got, want)
}
return nil, nil
},
},
{
permF: func(n int) []int {
return []int{2}
},
dialF: func(ctx context.Context, network, addr string) (net.Conn, error) {
if got, want := addr, net.JoinHostPort("127.0.0.3", "443"); got != want {
t.Fatalf("got addr %q, want %q", got, want)
}
return nil, nil
},
},
}
origFunc := randPerm
defer func() {
randPerm = origFunc
}()
for _, tc := range cases {
t.Run("", func(t *testing.T) {
randPerm = tc.permF
if _, err := DialContextWithDNSCache(resolver, tc.dialF)(context.Background(), "tcp", "play.min.io:443"); err != nil {
t.Fatalf("err: %s", err)
}
})
}
}
func TestDialContextWithDNSCacheRand(t *testing.T) {
rand.Seed(time.Now().UTC().UnixNano())
defer func() {
rand.Seed(1)
}()
resolver := &DNSCache{
cache: map[string][]string{
"play.min.io": {
"127.0.0.1",
"127.0.0.2",
"127.0.0.3",
},
},
}
count := make(map[string]int)
dialF := func(ctx context.Context, network, addr string) (net.Conn, error) {
count[addr]++
return nil, nil
}
for i := 0; i < 100; i++ {
if _, err := DialContextWithDNSCache(resolver, dialF)(context.Background(), "tcp", "play.min.io:443"); err != nil {
t.Fatalf("err: %s", err)
}
}
for _, c := range count {
got := float32(c) / float32(100)
if got < float32(0.1) {
t.Fatalf("expected 0.1 rate got %f", got)
}
}
}
// Verify without port Dial fails, Go stdlib net.Dial expects port
func TestDialContextWithDNSCacheScenario1(t *testing.T) {
resolver := testDNSCache(t)
if _, err := DialContextWithDNSCache(resolver, nil)(context.Background(), "tcp", "play.min.io"); err == nil {
t.Fatalf("expect to fail") // expected port
}
}
// Verify if the host lookup function failed to return addresses
func TestDialContextWithDNSCacheScenario2(t *testing.T) {
res := testDNSCache(t)
originalFunc := res.lookupHostFn
defer func() {
res.lookupHostFn = originalFunc
}()
res.lookupHostFn = func(ctx context.Context, host string) ([]string, error) {
return nil, fmt.Errorf("err")
}
if _, err := DialContextWithDNSCache(res, nil)(context.Background(), "tcp", "min.io:443"); err == nil {
t.Fatalf("exect to fail")
}
}
// Verify we always return the first error from net.Dial failure
func TestDialContextWithDNSCacheScenario3(t *testing.T) {
resolver := &DNSCache{
cache: map[string][]string{
"min.io": {
"1.1.1.1",
"2.2.2.2",
"3.3.3.3",
},
},
}
origFunc := randPerm
randPerm = func(n int) []int {
return []int{0, 1, 2}
}
defer func() {
randPerm = origFunc
}()
want := errors.New("error1")
dialF := func(ctx context.Context, network, addr string) (net.Conn, error) {
if addr == net.JoinHostPort("1.1.1.1", "443") {
return nil, want // first error should be returned
}
if addr == net.JoinHostPort("2.2.2.2", "443") {
return nil, fmt.Errorf("error2")
}
if addr == net.JoinHostPort("3.3.3.3", "443") {
return nil, fmt.Errorf("error3")
}
return nil, nil
}
_, got := DialContextWithDNSCache(resolver, dialF)(context.Background(), "tcp", "min.io:443")
if got != want {
t.Fatalf("got error %v, want %v", got, want)
}
}