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|
package cache
import (
"context"
"errors"
"sync"
"sync/atomic"
"testing"
"time"
"github.com/stretchr/testify/assert"
)
type client struct {
started uint64
resolutions uint64
bootup chan uint64
domain chan string
failure error
status int
}
func (c *client) Resolve(ctx context.Context, _ string) Lookup {
var domain Domain
c.bootup <- atomic.AddUint64(&c.started, 1)
defer atomic.AddUint64(&c.resolutions, 1)
if c.status == 0 {
c.status = 200
}
if c.failure == nil {
domain = Domain{Name: <-c.domain}
}
return Lookup{Domain: domain, Status: c.status, Error: c.failure}
}
func withTestCache(config resolverConfig, block func(*Cache, *client)) {
var chanSize int
if config.buffered {
chanSize = 1
} else {
chanSize = 0
}
resolver := &client{
domain: make(chan string, chanSize),
bootup: make(chan uint64, 100),
failure: config.failure,
}
cache := NewCache(resolver)
block(cache, resolver)
}
func (cache *Cache) withTestEntry(config entryConfig, block func(*Entry)) {
domain := "my.gitlab.com"
if len(config.domain) > 0 {
domain = config.domain
}
entry := cache.store.LoadOrCreate(domain)
if config.retrieved {
entry.setResponse(Lookup{Domain: Domain{Name: domain}, Status: 200})
}
if config.expired {
entry.created = time.Now().Add(-time.Hour)
}
block(entry)
}
type resolverConfig struct {
buffered bool
failure error
}
type entryConfig struct {
domain string
expired bool
retrieved bool
}
func TestResolve(t *testing.T) {
t.Run("when item is not cached", func(t *testing.T) {
withTestCache(resolverConfig{buffered: true}, func(cache *Cache, resolver *client) {
resolver.domain <- "my.gitlab.com"
lookup := cache.Resolve(context.Background(), "my.gitlab.com")
assert.NoError(t, lookup.Error)
assert.Equal(t, 200, lookup.Status)
assert.Equal(t, "my.gitlab.com", lookup.Domain.Name)
assert.Equal(t, uint64(1), resolver.resolutions)
})
})
t.Run("when item is not cached and accessed multiple times", func(t *testing.T) {
withTestCache(resolverConfig{}, func(cache *Cache, resolver *client) {
wg := &sync.WaitGroup{}
ctx := context.Background()
receiver := func() {
defer wg.Done()
cache.Resolve(ctx, "my.gitlab.com")
}
wg.Add(3)
go receiver()
go receiver()
go receiver()
assert.Equal(t, uint64(0), resolver.resolutions)
resolver.domain <- "my.gitlab.com"
wg.Wait()
assert.Equal(t, uint64(1), resolver.resolutions)
})
})
t.Run("when item is in short cache", func(t *testing.T) {
withTestCache(resolverConfig{}, func(cache *Cache, resolver *client) {
cache.withTestEntry(entryConfig{expired: false, retrieved: true}, func(*Entry) {
lookup := cache.Resolve(context.Background(), "my.gitlab.com")
assert.Equal(t, "my.gitlab.com", lookup.Domain.Name)
assert.Equal(t, uint64(0), resolver.resolutions)
})
})
})
t.Run("when a non-retrieved new item is in short cache", func(t *testing.T) {
withTestCache(resolverConfig{}, func(cache *Cache, resolver *client) {
cache.withTestEntry(entryConfig{expired: false, retrieved: false}, func(*Entry) {
lookup := make(chan *Lookup, 1)
go func() {
lookup <- cache.Resolve(context.Background(), "my.gitlab.com")
}()
<-resolver.bootup
assert.Equal(t, uint64(1), resolver.started)
assert.Equal(t, uint64(0), resolver.resolutions)
resolver.domain <- "my.gitlab.com"
<-lookup
assert.Equal(t, uint64(1), resolver.started)
assert.Equal(t, uint64(1), resolver.resolutions)
})
})
})
t.Run("when item is in long cache only", func(t *testing.T) {
withTestCache(resolverConfig{}, func(cache *Cache, resolver *client) {
cache.withTestEntry(entryConfig{expired: true, retrieved: true}, func(*Entry) {
lookup := cache.Resolve(context.Background(), "my.gitlab.com")
assert.Equal(t, "my.gitlab.com", lookup.Domain.Name)
assert.Equal(t, uint64(0), resolver.resolutions)
resolver.domain <- "my.gitlab.com"
assert.Equal(t, uint64(1), resolver.resolutions)
})
})
})
t.Run("when item in long cache is requested multiple times", func(t *testing.T) {
withTestCache(resolverConfig{}, func(cache *Cache, resolver *client) {
cache.withTestEntry(entryConfig{expired: true, retrieved: true}, func(*Entry) {
cache.Resolve(context.Background(), "my.gitlab.com")
cache.Resolve(context.Background(), "my.gitlab.com")
cache.Resolve(context.Background(), "my.gitlab.com")
assert.Equal(t, uint64(0), resolver.resolutions)
resolver.domain <- "my.gitlab.com"
assert.Equal(t, uint64(1), resolver.resolutions)
})
})
})
t.Run("when retrieval failed with an error", func(t *testing.T) {
withTestCache(resolverConfig{failure: errors.New("500 err")}, func(cache *Cache, resolver *client) {
maxRetrievalInterval = 0
lookup := cache.Resolve(context.Background(), "my.gitlab.com")
assert.Equal(t, uint64(3), resolver.resolutions)
assert.EqualError(t, lookup.Error, "500 err")
})
})
t.Run("when retrieval failed because of an external context timeout", func(t *testing.T) {
ctx, cancel := context.WithDeadline(context.Background(), time.Now().Add(-time.Hour))
defer cancel()
withTestCache(resolverConfig{}, func(cache *Cache, resolver *client) {
lookup := cache.Resolve(ctx, "my.gitlab.com")
assert.Equal(t, uint64(0), resolver.resolutions)
assert.EqualError(t, lookup.Error, "context done")
})
})
t.Run("when retrieval failed because of an internal context timeout", func(t *testing.T) {
retrievalTimeout = 0
defer func() { retrievalTimeout = 5 * time.Second }()
withTestCache(resolverConfig{}, func(cache *Cache, resolver *client) {
lookup := cache.Resolve(context.Background(), "my.gitlab.com")
assert.Equal(t, uint64(0), resolver.resolutions)
assert.EqualError(t, lookup.Error, "context done")
})
})
t.Run("when retrieval failed because of resolution context being canceled", func(t *testing.T) {
withTestCache(resolverConfig{}, func(cache *Cache, resolver *client) {
cache.withTestEntry(entryConfig{expired: false, retrieved: false}, func(entry *Entry) {
ctx, cancel := context.WithCancel(context.Background())
response := make(chan *Lookup, 1)
go func() { response <- cache.Resolve(ctx, "my.gitlab.com") }()
cancel()
resolver.domain <- "my.gitlab.com"
lookup := <-response
assert.EqualError(t, lookup.Error, "context done")
})
})
})
}
|