Merge pull request #3461 from hashicorp/b-node-race

Node access is done using locked Node copy

CHANGELOG.md

@@ -45,6 +45,8 @@ BUG FIXES:
    [GH_-3452]
  * client: Fix lock contention that could cause a node to miss a heartbeat and
    be marked as down [GH-3195]
+ * client: Fix data race that could lead to concurrent map read/writes during
+   hearbeating and fingerprinting [GH-3461]
  * driver/docker: Fix docker user specified syslogging [GH-3184]
  * driver/docker: Fix issue where CPU usage statistics were artificially high
    [GH-3229]

client/client.go

@@ -501,7 +501,7 @@ func (c *Client) CollectAllAllocs() error {
 func (c *Client) Node() *structs.Node {
 	c.configLock.RLock()
 	defer c.configLock.RUnlock()
-	return c.config.Node
+	return c.configCopy.Node
 }
 
 // StatsReporter exposes the various APIs related resource usage of a Nomad

client/client_test.go

@@ -222,7 +222,7 @@ func TestClient_HasNodeChanged(t *testing.T) {
 	c := testClient(t, nil)
 	defer c.Shutdown()
 
-	node := c.Node()
+	node := c.config.Node
 	attrHash, err := hashstructure.Hash(node.Attributes, nil)
 	if err != nil {
 		c.logger.Printf("[DEBUG] client: unable to calculate node attributes hash: %v", err)