pkg/core/dns/lookup/cache_test.go

package lookup_test

import (
	"net"
	"time"
)

import (
	. "github.com/onsi/ginkgo/v2"

	. "github.com/onsi/gomega"
)

import (
	"github.com/apache/dubbo-kubernetes/pkg/core"
	"github.com/apache/dubbo-kubernetes/pkg/core/dns/lookup"
)

var _ = Describe("DNS with cache", func() {
	var counter int
	var table map[string][]net.IP
	var lookupFunc lookup.LookupIPFunc = func(host string) ([]net.IP, error) {
		counter++
		return table[host], nil
	}
	var cachingLookupFunc lookup.LookupIPFunc

	BeforeEach(func() {
		cachingLookupFunc = lookup.CachedLookupIP(lookupFunc, 1*time.Second)
		table = map[string][]net.IP{}
		counter = 0
	})

	It("should use cache on the second call", func() {
		_, _ = cachingLookupFunc("example.com")
		_, _ = cachingLookupFunc("example.com")
		Expect(counter).To(Equal(1))
	})

	It("should avoid cache after TTL", func() {
		table["example.com"] = []net.IP{net.ParseIP("192.168.0.1")}

		ip, _ := cachingLookupFunc("example.com")
		Expect(ip[0]).To(Equal(net.ParseIP("192.168.0.1")))

		ip, _ = cachingLookupFunc("example.com")
		Expect(ip[0]).To(Equal(net.ParseIP("192.168.0.1")))

		table["example.com"] = []net.IP{net.ParseIP("10.20.0.1")}
		core.Now = func() time.Time {
			return time.Now().Add(2 * time.Second)
		}
		ip, _ = cachingLookupFunc("example.com")
		Expect(ip[0]).To(Equal(net.ParseIP("10.20.0.1")))
		Expect(counter).To(Equal(2))
	})
})