Method refreshTokenWithRetry

coderd/externalauth/externalauth.go:395–441

refreshTokenWithRetry exchanges the refresh token for a new access token, retrying with exponential backoff on transient failures. Permanent failures (as classified by isFailedRefresh) and the no-op case where no refresh token is set bypass the retry loop so a doomed refresh is not repeatedly attemp

(ctx context.Context, existingToken *oauth2.Token)

// refresh token is set bypass the retry loop so a doomed refresh is not
// repeatedly attempted.
func (c *Config) refreshTokenWithRetry(ctx context.Context, existingToken *oauth2.Token) (*oauth2.Token, error) {
	// Without a refresh token the oauth2 library short-circuits with
	// "token expired and refresh token is not set". No retry can recover
	// from that, so make a single attempt and return.
	if existingToken.RefreshToken == "" {
		return c.TokenSource(ctx, existingToken).Token()
	}

	initial := c.RefreshRetryInitialBackoff
	if initial <= 0 {
		initial = defaultRefreshRetryInitialBackoff
	}
	maximum := c.RefreshRetryMaxBackoff
	if maximum <= 0 {
		maximum = defaultRefreshRetryMaxBackoff
	}
	total := c.RefreshRetryTimeout
	if total <= 0 {
		total = defaultRefreshRetryTimeout
	}

	retryCtx, retryCancel := context.WithTimeout(ctx, total)
	defer retryCancel()
	backoff := retry.New(initial, maximum)

	var (
		token *oauth2.Token
		err   error
	)
	for {
		token, err = c.TokenSource(ctx, existingToken).Token()
		if err == nil || isFailedRefresh(existingToken, err) {
			return token, err
		}
		// Bail out before waiting if the retry budget is already gone.
		// retry.Wait selects between time.After(delay) and ctx.Done(); when
		// delay is zero and the context is already canceled the two cases
		// race nondeterministically, which would cause an unwanted extra
		// refresh attempt with a near-zero budget (notably in tests).
		if retryCtx.Err() != nil {
			return token, err
		}
		if !backoff.Wait(retryCtx) {
			return token, err
		}
	}
}

// ValidateToken checks if the Git token provided is valid.
// The user is optionally returned if the provider supports it.