remotes/docker/authorizer.go: refresh OAuth tokens when they expire

core/remotes/docker/auth/fetch.go

@@ -86,11 +86,11 @@ type TokenOptions struct {
 
 // OAuthTokenResponse is response from fetching token with a OAuth POST request
 type OAuthTokenResponse struct {
-	AccessToken  string    `json:"access_token"`
-	RefreshToken string    `json:"refresh_token"`
-	ExpiresIn    int       `json:"expires_in"`
-	IssuedAt     time.Time `json:"issued_at"`
-	Scope        string    `json:"scope"`
+	AccessToken      string    `json:"access_token"`
+	RefreshToken     string    `json:"refresh_token"`
+	ExpiresInSeconds int       `json:"expires_in"`
+	IssuedAt         time.Time `json:"issued_at"`
+	Scope            string    `json:"scope"`
 }
 
 // FetchTokenWithOAuth fetches a token using a POST request
@@ -152,11 +152,11 @@ func FetchTokenWithOAuth(ctx context.Context, client *http.Client, headers http.
 
 // FetchTokenResponse is response from fetching token with GET request
 type FetchTokenResponse struct {
-	Token        string    `json:"token"`
-	AccessToken  string    `json:"access_token"`
-	ExpiresIn    int       `json:"expires_in"`
-	IssuedAt     time.Time `json:"issued_at"`
-	RefreshToken string    `json:"refresh_token"`
+	Token            string    `json:"token"`
+	AccessToken      string    `json:"access_token"`
+	ExpiresInSeconds int       `json:"expires_in"`
+	IssuedAt         time.Time `json:"issued_at"`
+	RefreshToken     string    `json:"refresh_token"`
 }
 
 // FetchToken fetches a token using a GET request

core/remotes/docker/authorizer.go

@@ -24,6 +24,7 @@ import (
 	"net/http"
 	"strings"
 	"sync"
+	"time"
 
 	"github.com/containerd/containerd/v2/core/remotes/docker/auth"
 	remoteerrors "github.com/containerd/containerd/v2/core/remotes/errors"
@@ -205,9 +206,10 @@ func (a *dockerAuthorizer) AddResponses(ctx context.Context, responses []*http.R
 // authResult is used to control limit rate.
 type authResult struct {
 	sync.WaitGroup
-	token        string
-	refreshToken string
-	err          error
+	token          string
+	refreshToken   string
+	expirationTime *time.Time
+	err            error
 }
 
 // authHandler is used to handle auth request per registry server.
@@ -270,8 +272,12 @@ func (ah *authHandler) doBearerAuth(ctx context.Context) (token, refreshToken st
 	// Docs: https://docs.docker.com/registry/spec/auth/scope
 	scoped := strings.Join(to.Scopes, " ")
 
+	// Keep track of the expiration time of cached bearer tokens so they can be
+	// refreshed when they expire without a server roundtrip.
+	var expirationTime *time.Time
+
 	ah.Lock()
-	if r, exist := ah.scopedTokens[scoped]; exist {
+	if r, exist := ah.scopedTokens[scoped]; exist && (r.expirationTime == nil || r.expirationTime.After(time.Now())) {
 		ah.Unlock()
 		r.Wait()
 		return r.token, r.refreshToken, r.err
@@ -285,7 +291,7 @@ func (ah *authHandler) doBearerAuth(ctx context.Context) (token, refreshToken st
 
 	defer func() {
 		token = fmt.Sprintf("Bearer %s", token)
-		r.token, r.refreshToken, r.err = token, refreshToken, err
+		r.token, r.refreshToken, r.err, r.expirationTime = token, refreshToken, err, expirationTime
 		r.Done()
 	}()
 
@@ -311,6 +317,7 @@ func (ah *authHandler) doBearerAuth(ctx context.Context) (token, refreshToken st
 					if err != nil {
 						return "", "", err
 					}
+					expirationTime = getExpirationTime(resp.ExpiresInSeconds)
 					return resp.Token, resp.RefreshToken, nil
 				}
 				log.G(ctx).WithFields(log.Fields{
@@ -320,16 +327,26 @@ func (ah *authHandler) doBearerAuth(ctx context.Context) (token, refreshToken st
 			}
 			return "", "", err
 		}
+		expirationTime = getExpirationTime(resp.ExpiresInSeconds)
 		return resp.AccessToken, resp.RefreshToken, nil
 	}
 	// do request anonymously
 	resp, err := auth.FetchToken(ctx, ah.client, ah.header, to)
 	if err != nil {
 		return "", "", fmt.Errorf("failed to fetch anonymous token: %w", err)
 	}
+	expirationTime = getExpirationTime(resp.ExpiresInSeconds)
 	return resp.Token, resp.RefreshToken, nil
 }
 
+func getExpirationTime(expiresInSeconds int) *time.Time {
+	if expiresInSeconds <= 0 {
+		return nil
+	}
+	expirationTime := time.Now().Add(time.Duration(expiresInSeconds) * time.Second)
+	return &expirationTime
+}
+
 func invalidAuthorization(ctx context.Context, c auth.Challenge, responses []*http.Response) (retry bool, _ error) {
 	errStr := c.Parameters["error"]
 	if errStr == "" {