feat: prevent call bursts on oidc provider refresh

internal/proxy/director/director.go

@@ -4,12 +4,11 @@ import (
 	"context"
 	"net/http"
 	"sort"
-	"sync"
 
 	"forge.cadoles.com/Cadoles/go-proxy"
 	"forge.cadoles.com/Cadoles/go-proxy/wildcard"
-	"forge.cadoles.com/cadoles/bouncer/internal/cache"
 	"forge.cadoles.com/cadoles/bouncer/internal/store"
+	"forge.cadoles.com/cadoles/bouncer/internal/syncx"
 	"github.com/getsentry/sentry-go"
 	"github.com/pkg/errors"
 	"github.com/prometheus/client_golang/prometheus"
@@ -21,19 +20,18 @@ type Director struct {
 	layerRepository store.LayerRepository
 	layerRegistry   *LayerRegistry
 
-	proxyCache cache.Cache[string, []*store.Proxy]
+	cachedProxies *syncx.CachedResource[string, []*store.Proxy]
-	layerCache cache.Cache[string, []*store.Layer]
+	cachedLayers  *syncx.CachedResource[string, []*store.Layer]
-
-	proxyCacheLock sync.RWMutex
-	layerCacheLock sync.RWMutex
 
 	handleError HandleErrorFunc
 }
 
+const proxiesCacheKey = "proxies"
+
 func (d *Director) rewriteRequest(r *http.Request) (*http.Request, error) {
 	ctx := r.Context()
 
-	proxies, err := d.getProxies(ctx)
+	proxies, _, err := d.cachedProxies.Get(ctx, proxiesCacheKey)
 	if err != nil {
 		return r, errors.WithStack(err)
 	}
@@ -58,7 +56,7 @@ func (d *Director) rewriteRequest(r *http.Request) (*http.Request, error) {
 
 			metricProxyRequestsTotal.With(prometheus.Labels{metricLabelProxy: string(p.Name)}).Add(1)
 
-			proxyLayers, err := d.getLayers(proxyCtx, p.Name)
+			proxyLayers, _, err := d.cachedLayers.Get(proxyCtx, string(p.Name))
 			if err != nil {
 				return r, errors.WithStack(err)
 			}
@@ -98,35 +96,7 @@ func (d *Director) rewriteRequest(r *http.Request) (*http.Request, error) {
 	return r, nil
 }
 
-const proxiesCacheKey = "proxies"
+func (d *Director) getProxies(ctx context.Context, key string) ([]*store.Proxy, error) {
-
-func (d *Director) getProxies(ctx context.Context) ([]*store.Proxy, error) {
-	proxies, exists := d.proxyCache.Get(proxiesCacheKey)
-	if exists {
-		logger.Debug(ctx, "using cached proxies")
-		return proxies, nil
-	}
-
-	locked := d.proxyCacheLock.TryLock()
-	if !locked {
-		d.proxyCacheLock.RLock()
-
-		proxies, exists := d.proxyCache.Get(proxiesCacheKey)
-		if exists {
-			d.proxyCacheLock.RUnlock()
-			logger.Debug(ctx, "using cached proxies")
-			return proxies, nil
-		}
-
-		d.proxyCacheLock.RUnlock()
-	}
-
-	if !locked {
-		d.proxyCacheLock.Lock()
-	}
-
-	defer d.proxyCacheLock.Unlock()
-
 	logger.Debug(ctx, "querying fresh proxies")
 
 	headers, err := d.proxyRepository.QueryProxy(ctx, store.WithProxyQueryEnabled(true))
@@ -136,7 +106,7 @@ func (d *Director) getProxies(ctx context.Context) ([]*store.Proxy, error) {
 
 	sort.Sort(store.ByProxyWeight(headers))
 
-	proxies = make([]*store.Proxy, 0, len(headers))
+	proxies := make([]*store.Proxy, 0, len(headers))
 
 	for _, h := range headers {
 		if !h.Enabled {
@@ -151,39 +121,11 @@ func (d *Director) getProxies(ctx context.Context) ([]*store.Proxy, error) {
 		proxies = append(proxies, proxy)
 	}
 
-	d.proxyCache.Set(proxiesCacheKey, proxies)
-
 	return proxies, nil
 }
 
-func (d *Director) getLayers(ctx context.Context, proxyName store.ProxyName) ([]*store.Layer, error) {
+func (d *Director) getLayers(ctx context.Context, rawProxyName string) ([]*store.Layer, error) {
-	cacheKey := "layers-" + string(proxyName)
+	proxyName := store.ProxyName(rawProxyName)
-
-	layers, exists := d.layerCache.Get(cacheKey)
-	if exists {
-		logger.Debug(ctx, "using cached layers")
-		return layers, nil
-	}
-
-	locked := d.layerCacheLock.TryLock()
-	if !locked {
-		d.layerCacheLock.RLock()
-
-		layers, exists := d.layerCache.Get(cacheKey)
-		if exists {
-			d.layerCacheLock.RUnlock()
-			logger.Debug(ctx, "using cached layers")
-			return layers, nil
-		}
-
-		d.layerCacheLock.RUnlock()
-	}
-
-	if !locked {
-		d.layerCacheLock.Lock()
-	}
-
-	defer d.layerCacheLock.Unlock()
 
 	logger.Debug(ctx, "querying fresh layers")
 
@@ -194,7 +136,7 @@ func (d *Director) getLayers(ctx context.Context, proxyName store.ProxyName) ([]
 
 	sort.Sort(store.ByLayerWeight(headers))
 
-	layers = make([]*store.Layer, 0, len(headers))
+	layers := make([]*store.Layer, 0, len(headers))
 
 	for _, h := range headers {
 		if !h.Enabled {
@@ -209,8 +151,6 @@ func (d *Director) getLayers(ctx context.Context, proxyName store.ProxyName) ([]
 		layers = append(layers, layer)
 	}
 
-	d.layerCache.Set(cacheKey, layers)
-
 	return layers, nil
 }
 
@@ -322,12 +262,15 @@ func New(proxyRepository store.ProxyRepository, layerRepository store.LayerRepos
 
 	registry := NewLayerRegistry(opts.Layers...)
 
-	return &Director{
+	director := &Director{
 		proxyRepository: proxyRepository,
 		layerRepository: layerRepository,
 		layerRegistry:   registry,
-		proxyCache:      opts.ProxyCache,
-		layerCache:      opts.LayerCache,
 		handleError:     opts.HandleError,
 	}
+
+	director.cachedProxies = syncx.NewCachedResource(opts.ProxyCache, director.getProxies)
+	director.cachedLayers = syncx.NewCachedResource(opts.LayerCache, director.getLayers)
+
+	return director
 }

internal/proxy/director/layer/authn/oidc/authenticator.go

@@ -13,10 +13,12 @@ import (
 	"time"
 
 	"forge.cadoles.com/Cadoles/go-proxy/wildcard"
-	"forge.cadoles.com/cadoles/bouncer/internal/cache"
+	"forge.cadoles.com/cadoles/bouncer/internal/cache/memory"
+	"forge.cadoles.com/cadoles/bouncer/internal/cache/ttl"
 	"forge.cadoles.com/cadoles/bouncer/internal/proxy/director"
 	"forge.cadoles.com/cadoles/bouncer/internal/proxy/director/layer/authn"
 	"forge.cadoles.com/cadoles/bouncer/internal/store"
+	"forge.cadoles.com/cadoles/bouncer/internal/syncx"
 	"github.com/coreos/go-oidc/v3/oidc"
 	"github.com/gorilla/sessions"
 	"github.com/pkg/errors"
@@ -25,10 +27,10 @@ import (
 )
 
 type Authenticator struct {
-	store             sessions.Store
+	store              sessions.Store
-	httpTransport     *http.Transport
+	httpTransport      *http.Transport
-	httpClientTimeout time.Duration
+	httpClientTimeout  time.Duration
-	oidcProviderCache cache.Cache[string, *oidc.Provider]
+	cachedOIDCProvider *syncx.CachedResource[string, *oidc.Provider]
 }
 
 func (a *Authenticator) PreAuthentication(w http.ResponseWriter, r *http.Request, layer *store.Layer) error {
@@ -54,7 +56,7 @@ func (a *Authenticator) PreAuthentication(w http.ResponseWriter, r *http.Request
 		return errors.WithStack(err)
 	}
 
-	client, err := a.getClient(options, loginCallbackURL.String())
+	client, err := a.getClient(ctx, options, loginCallbackURL.String())
 	if err != nil {
 		return errors.WithStack(err)
 	}
@@ -160,7 +162,7 @@ func (a *Authenticator) Authenticate(w http.ResponseWriter, r *http.Request, lay
 		return nil, errors.WithStack(err)
 	}
 
-	client, err := a.getClient(options, loginCallbackURL.String())
+	client, err := a.getClient(ctx, options, loginCallbackURL.String())
 	if err != nil {
 		return nil, errors.WithStack(err)
 	}
@@ -362,9 +364,7 @@ func (a *Authenticator) templatize(rawTemplate string, proxyName store.ProxyName
 	return raw.String(), nil
 }
 
-func (a *Authenticator) getClient(options *LayerOptions, redirectURL string) (*Client, error) {
+func (a *Authenticator) getClient(ctx context.Context, options *LayerOptions, redirectURL string) (*Client, error) {
-	ctx := context.Background()
-
 	transport := a.httpTransport.Clone()
 
 	if options.OIDC.TLSInsecureSkipVerify {
@@ -375,28 +375,24 @@ func (a *Authenticator) getClient(options *LayerOptions, redirectURL string) (*C
 		transport.TLSClientConfig.InsecureSkipVerify = true
 	}
 
+	if options.OIDC.SkipIssuerVerification {
+		ctx = oidc.InsecureIssuerURLContext(ctx, options.OIDC.IssuerURL)
+	}
+
 	httpClient := &http.Client{
 		Timeout:   a.httpClientTimeout,
 		Transport: transport,
 	}
 
-	provider, exists := a.oidcProviderCache.Get(options.OIDC.IssuerURL)
+	ctx = oidc.ClientContext(ctx, httpClient)
-	if !exists {
-		var err error
-		ctx = oidc.ClientContext(ctx, httpClient)
 
-		if options.OIDC.SkipIssuerVerification {
+	if options.OIDC.SkipIssuerVerification {
-			ctx = oidc.InsecureIssuerURLContext(ctx, options.OIDC.IssuerURL)
+		ctx = oidc.InsecureIssuerURLContext(ctx, options.OIDC.IssuerURL)
-		}
+	}
 
-		logger.Debug(ctx, "refreshing oidc provider", logger.F("issuerURL", options.OIDC.IssuerURL))
+	provider, _, err := a.cachedOIDCProvider.Get(ctx, options.OIDC.IssuerURL)
-
+	if err != nil {
-		provider, err = oidc.NewProvider(ctx, options.OIDC.IssuerURL)
+		return nil, errors.Wrap(err, "could not retrieve oidc provider")
-		if err != nil {
-			return nil, errors.Wrap(err, "could not create oidc provider")
-		}
-
-		a.oidcProviderCache.Set(options.OIDC.IssuerURL, provider)
 	}
 
 	client := NewClient(
@@ -411,6 +407,17 @@ func (a *Authenticator) getClient(options *LayerOptions, redirectURL string) (*C
 	return client, nil
 }
 
+func (a *Authenticator) getOIDCProvider(ctx context.Context, issuerURL string) (*oidc.Provider, error) {
+	logger.Debug(ctx, "refreshing oidc provider", logger.F("issuerURL", issuerURL))
+
+	provider, err := oidc.NewProvider(ctx, issuerURL)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not create oidc provider")
+	}
+
+	return provider, nil
+}
+
 const defaultCookieNamePrefix = "_bouncer_authn_oidc"
 
 func (a *Authenticator) getCookieName(cookieName string, proxyName store.ProxyName, layerName store.LayerName) string {
@@ -421,6 +428,25 @@ func (a *Authenticator) getCookieName(cookieName string, proxyName store.ProxyNa
 	return strings.ToLower(fmt.Sprintf("%s_%s_%s", defaultCookieNamePrefix, proxyName, layerName))
 }
 
+func NewAuthenticator(httpTransport *http.Transport, clientTimeout time.Duration, store sessions.Store, oidcProviderCacheTimeout time.Duration) *Authenticator {
+	authenticator := &Authenticator{
+		httpTransport:     httpTransport,
+		httpClientTimeout: clientTimeout,
+		store:             store,
+	}
+
+	authenticator.cachedOIDCProvider = syncx.NewCachedResource(
+		ttl.NewCache(
+			memory.NewCache[string, *oidc.Provider](),
+			memory.NewCache[string, time.Time](),
+			oidcProviderCacheTimeout,
+		),
+		authenticator.getOIDCProvider,
+	)
+
+	return authenticator
+}
+
 var (
 	_ authn.PreAuthentication = &Authenticator{}
 	_ authn.Authenticator     = &Authenticator{}

internal/proxy/director/layer/authn/oidc/layer.go

@@ -1,13 +1,8 @@
 package oidc
 
 import (
-	"time"
-
-	"forge.cadoles.com/cadoles/bouncer/internal/cache/memory"
-	"forge.cadoles.com/cadoles/bouncer/internal/cache/ttl"
 	"forge.cadoles.com/cadoles/bouncer/internal/proxy/director/layer/authn"
 	"forge.cadoles.com/cadoles/bouncer/internal/store"
-	"github.com/coreos/go-oidc/v3/oidc"
 	"github.com/gorilla/sessions"
 )
 
@@ -15,14 +10,11 @@ const LayerType store.LayerType = "authn-oidc"
 
 func NewLayer(store sessions.Store, funcs ...OptionFunc) *authn.Layer {
 	opts := NewOptions(funcs...)
-	return authn.NewLayer(LayerType, &Authenticator{
+	authenticator := NewAuthenticator(
-		httpTransport:     opts.HTTPTransport,
+		opts.HTTPTransport,
-		httpClientTimeout: opts.HTTPClientTimeout,
+		opts.HTTPClientTimeout,
-		store:             store,
+		store,
-		oidcProviderCache: ttl.NewCache(
+		opts.OIDCProviderCacheTimeout,
-			memory.NewCache[string, *oidc.Provider](),
+	)
-			memory.NewCache[string, time.Time](),
+	return authn.NewLayer(LayerType, authenticator, opts.AuthnOptions...)
-			opts.OIDCProviderCacheTimeout,
-		),
-	}, opts.AuthnOptions...)
 }

internal/syncx/cached_resource.go

@@ -0,0 +1,63 @@
+package syncx
+
+import (
+	"context"
+	"sync"
+
+	"forge.cadoles.com/cadoles/bouncer/internal/cache"
+	"github.com/pkg/errors"
+)
+
+type RefreshFunc[K comparable, V any] func(ctx context.Context, key K) (V, error)
+
+type CachedResource[K comparable, V any] struct {
+	cache   cache.Cache[K, V]
+	lock    sync.RWMutex
+	refresh RefreshFunc[K, V]
+}
+
+func (r *CachedResource[K, V]) Clear() {
+	r.cache.Clear()
+}
+
+func (r *CachedResource[K, V]) Get(ctx context.Context, key K) (V, bool, error) {
+	value, exists := r.cache.Get(key)
+	if exists {
+		return value, false, nil
+	}
+
+	locked := r.lock.TryLock()
+	if !locked {
+		r.lock.RLock()
+
+		value, exists := r.cache.Get(key)
+		if exists {
+			r.lock.RUnlock()
+			return value, false, nil
+		}
+
+		r.lock.RUnlock()
+	}
+
+	if !locked {
+		r.lock.Lock()
+	}
+
+	defer r.lock.Unlock()
+
+	value, err := r.refresh(ctx, key)
+	if err != nil {
+		return *new(V), false, errors.WithStack(err)
+	}
+
+	r.cache.Set(key, value)
+
+	return value, true, nil
+}
+
+func NewCachedResource[K comparable, V any](cache cache.Cache[K, V], refresh RefreshFunc[K, V]) *CachedResource[K, V] {
+	return &CachedResource[K, V]{
+		cache:   cache,
+		refresh: refresh,
+	}
+}

internal/syncx/cached_resource_test.go

@@ -0,0 +1,66 @@
+package syncx
+
+import (
+	"context"
+	"math"
+	"sync"
+	"testing"
+	"time"
+
+	"forge.cadoles.com/cadoles/bouncer/internal/cache/memory"
+	"forge.cadoles.com/cadoles/bouncer/internal/cache/ttl"
+	"github.com/pkg/errors"
+)
+
+func TestCachedResource(t *testing.T) {
+	refreshCalls := 0
+	cacheTTL := 1*time.Second + 500*time.Millisecond
+	duration := 2 * time.Second
+
+	expectedCalls := math.Ceil(float64(duration) / float64(cacheTTL))
+
+	resource := NewCachedResource(
+		ttl.NewCache(
+			memory.NewCache[string, string](),
+			memory.NewCache[string, time.Time](),
+			cacheTTL,
+		),
+		func(ctx context.Context, key string) (string, error) {
+			refreshCalls++
+			return "bar", nil
+		},
+	)
+
+	concurrents := 50
+	key := "foo"
+
+	var wg sync.WaitGroup
+
+	wg.Add(concurrents)
+
+	for i := range concurrents {
+		go func(i int) {
+			done := time.After(duration)
+
+			defer wg.Done()
+			for {
+				select {
+				case <-done:
+					return
+				default:
+					value, fresh, err := resource.Get(context.Background(), key)
+					if err != nil {
+						t.Errorf("%+v", errors.WithStack(err))
+					}
+					t.Logf("resource retrieved for goroutine #%d: (%s, %s, %v)", i, key, value, fresh)
+				}
+			}
+		}(i)
+	}
+
+	wg.Wait()
+
+	if e, g := int(expectedCalls), refreshCalls; e != g {
+		t.Errorf("refreshCalls: expected '%d', got '%d'", e, g)
+	}
+}