context must be canceled to avoid memory leak

Author: clinta

docker/core/core.go

@@ -22,11 +22,6 @@ const (
 	dockerTimeout     = 5 * time.Second
 )
 
-func toCtx() context.Context {
-	c, _ := context.WithTimeout(context.Background(), dockerTimeout)
-	return c
-}
-
 // Core is a wrapper for docker client type things
 type Core struct {
 	dc       *client.Client
@@ -100,7 +95,9 @@ func (c *Core) getNrFromCache(s string) *types.NetworkResource {
 
 // GetContainers gets a list of docker containers
 func (c *Core) GetContainers() ([]types.Container, error) {
-	return c.dc.ContainerList(toCtx(), types.ContainerListOptions{})
+	ctx, cancel := context.WithTimeout(context.Background(), dockerTimeout)
+	defer cancel()
+	return c.dc.ContainerList(ctx, types.ContainerListOptions{})
 }
 
 // GetNetworkResourceByID gets a network resource by ID (checks cache first)
@@ -114,7 +111,9 @@ func (c *Core) GetNetworkResourceByID(id string) (*types.NetworkResource, error)
 	}
 
 	//netid wasn't in cache, fetch from docker inspect
-	nnr, err := c.dc.NetworkInspect(toCtx(), id)
+	ctx, cancel := context.WithTimeout(context.Background(), dockerTimeout)
+	defer cancel()
+	nnr, err := c.dc.NetworkInspect(ctx, id)
 	if err != nil {
 		log.WithError(err).Error("failed to inspect network")
 		return nil, err
@@ -138,7 +137,9 @@ func (c *Core) GetNetworkResourceByPool(pool string) (*types.NetworkResource, er
 
 	flts := filters.NewArgs()
 	flts.Add("driver", networkDriverName)
-	nl, err := c.dc.NetworkList(toCtx(), types.NetworkListOptions{Filters: flts})
+	ctx, cancel := context.WithTimeout(context.Background(), dockerTimeout)
+	defer cancel()
+	nl, err := c.dc.NetworkList(ctx, types.NetworkListOptions{Filters: flts})
 	if err != nil {
 		log.WithError(err).Error("failed to list networks")
 		return nil, err

docker/vxrnet/main.go

@@ -26,11 +26,6 @@ const (
 	shutdownTimeout = 10 * time.Second
 )
 
-func shutdownContext() context.Context {
-	c, _ := context.WithTimeout(context.Background(), shutdownTimeout)
-	return c
-}
-
 func main() {
 	app := cli.NewApp()
 	app.Name = "docker-" + network.DriverName
@@ -121,12 +116,16 @@ func Run(ctx *cli.Context) {
 	case <-c:
 	}
 
-	err = nh.Shutdown(shutdownContext())
+	nhCtx, nhCtxCancel := context.WithTimeout(context.Background(), shutdownTimeout)
+	defer nhCtxCancel()
+	err = nh.Shutdown(nhCtx)
 	if err != nil {
 		log.WithField("driver", network.DriverName).WithError(err).Error("error shutting down driver")
 	}
 
-	err = ih.Shutdown(shutdownContext())
+	ihCtx, ihCtxCancel := context.WithTimeout(context.Background(), shutdownTimeout)
+	defer ihCtxCancel()
+	err = ih.Shutdown(ihCtx)
 	if err != nil {
 		log.WithField("driver", ipam.DriverName).WithError(err).Error("error shutting down driver")
 	}