container_opts.go: add WithAdditionalContainerLabels

AkihiroSuda · AkihiroSuda · commit 041eb3ac31a1 · 2020-12-14T16:44:47.000+09:00
WithAdditionalContainerLabels() preserves the existing entries in c.Labels.
OTOH, WithContainerLabels() clears them.

Signed-off-by: Akihiro Suda &lt;akihiro.suda.cz@hco.ntt.co.jp&gt;
diff --git a/container_opts.go b/container_opts.go
@@ -85,14 +85,31 @@ func WithImageName(n string) NewContainerOpts {
 	}
 }
 
-// WithContainerLabels adds the provided labels to the container
+// WithContainerLabels sets the provided labels to the container.
+// The existing labels are cleared.
+// Use WithAdditionalContainerLabels to preserve the existing labels.
 func WithContainerLabels(labels map[string]string) NewContainerOpts {
 	return func(_ context.Context, _ *Client, c *containers.Container) error {
 		c.Labels = labels
 		return nil
 	}
 }
 
+// WithAdditionalContainerLabels adds the provided labels to the container
+// The existing labels are preserved as long as they do not conflict with the added labels.
+func WithAdditionalContainerLabels(labels map[string]string) NewContainerOpts {
+	return func(_ context.Context, _ *Client, c *containers.Container) error {
+		if c.Labels == nil {
+			c.Labels = labels
+			return nil
+		}
+		for k, v := range labels {
+			c.Labels[k] = v
+		}
+		return nil
+	}
+}
+
 // WithImageStopSignal sets a well-known containerd label (StopSignalLabel)
 // on the container for storing the stop signal specified in the OCI image
 // config
