X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/936ed3a6a7484917fc10636b3dc2c5fdd9578643..79036634292cc4ed13db98a834f33d617c85b1cd:/sdk/go/arvados/client.go

diff --git a/sdk/go/arvados/client.go b/sdk/go/arvados/client.go
index 735a44d24c..172763fe80 100644
--- a/sdk/go/arvados/client.go
+++ b/sdk/go/arvados/client.go
@@ -88,7 +88,10 @@ type Client struct {
 	// differs from an outgoing connection limit (a feature
 	// provided by http.Transport) when concurrent calls are
 	// multiplexed on a single http2 connection.
-	requestLimiter requestLimiter
+	//
+	// getRequestLimiter() should always be used, because this can
+	// be nil.
+	requestLimiter *requestLimiter
 
 	last503 atomic.Value
 }
@@ -150,7 +153,7 @@ func NewClientFromConfig(cluster *Cluster) (*Client, error) {
 		APIHost:        ctrlURL.Host,
 		Insecure:       cluster.TLS.Insecure,
 		Timeout:        5 * time.Minute,
-		requestLimiter: requestLimiter{maxlimit: int64(cluster.API.MaxConcurrentRequests / 4)},
+		requestLimiter: &requestLimiter{maxlimit: int64(cluster.API.MaxConcurrentRequests / 4)},
 	}, nil
 }
 
@@ -287,7 +290,7 @@ func (c *Client) Do(req *http.Request) (*http.Response, error) {
 		rclient.RetryMax = 0
 	}
 	rclient.CheckRetry = func(ctx context.Context, resp *http.Response, respErr error) (bool, error) {
-		if c.requestLimiter.Report(resp, respErr) {
+		if c.getRequestLimiter().Report(resp, respErr) {
 			c.last503.Store(time.Now())
 		}
 		if c.Timeout == 0 {
@@ -314,9 +317,10 @@ func (c *Client) Do(req *http.Request) (*http.Response, error) {
 	}
 	rclient.Logger = nil
 
-	c.requestLimiter.Acquire(ctx)
+	limiter := c.getRequestLimiter()
+	limiter.Acquire(ctx)
 	if ctx.Err() != nil {
-		c.requestLimiter.Release()
+		limiter.Release()
 		cancel()
 		return nil, ctx.Err()
 	}
@@ -328,7 +332,7 @@ func (c *Client) Do(req *http.Request) (*http.Response, error) {
 		}
 	}
 	if err != nil {
-		c.requestLimiter.Release()
+		limiter.Release()
 		cancel()
 		return nil, err
 	}
@@ -338,7 +342,7 @@ func (c *Client) Do(req *http.Request) (*http.Response, error) {
 	resp.Body = cancelOnClose{
 		ReadCloser: resp.Body,
 		cancel: func() {
-			c.requestLimiter.Release()
+			limiter.Release()
 			cancel()
 		},
 	}
@@ -352,6 +356,19 @@ func (c *Client) Last503() time.Time {
 	return t
 }
 
+// globalRequestLimiter doesn't have a maximum number of outgoing
+// connections, but is just used to backoff after 503 errors.
+var globalRequestLimiter requestLimiter
+
+// Get this client's requestLimiter, or the global requestLimiter
+// singleton if the client doesn't have its own.
+func (c *Client) getRequestLimiter() *requestLimiter {
+	if c.requestLimiter != nil {
+		return c.requestLimiter
+	}
+	return &globalRequestLimiter
+}
+
 // cancelOnClose calls a provided CancelFunc when its wrapped
 // ReadCloser's Close() method is called.
 type cancelOnClose struct {