Cache node listings instead of random lookups (#131)

Author: okokes-akamai

cloud/linode/common.go

@@ -1,14 +1,9 @@
 package linode
 
 import (
-	"context"
 	"fmt"
 	"strconv"
 	"strings"
-
-	"github.com/linode/linodego"
-	"k8s.io/apimachinery/pkg/types"
-	cloudprovider "k8s.io/cloud-provider"
 )
 
 const providerIDPrefix = "linode://"
@@ -31,34 +26,3 @@ func parseProviderID(providerID string) (int, error) {
 	}
 	return id, nil
 }
-
-func linodeFilterListOptions(targetLabel string) *linodego.ListOptions {
-	jsonFilter := fmt.Sprintf(`{"label":%q}`, targetLabel)
-	return linodego.NewListOptions(0, jsonFilter)
-}
-
-func linodeByName(ctx context.Context, client Client, nodeName types.NodeName) (*linodego.Instance, error) {
-	linodes, err := client.ListInstances(ctx, linodeFilterListOptions(string(nodeName)))
-	if err != nil {
-		return nil, err
-	}
-
-	if len(linodes) == 0 {
-		return nil, cloudprovider.InstanceNotFound
-	} else if len(linodes) > 1 {
-		return nil, fmt.Errorf("Multiple instances found with name %v", nodeName)
-	}
-
-	return &linodes[0], nil
-}
-
-func linodeByID(ctx context.Context, client Client, id int) (*linodego.Instance, error) {
-	instance, err := client.GetInstance(ctx, id)
-	if err != nil {
-		return nil, err
-	}
-	if instance == nil {
-		return nil, fmt.Errorf("linode not found with id %v", id)
-	}
-	return instance, nil
-}

cloud/linode/instances.go

@@ -3,8 +3,10 @@ package linode
 import (
 	"context"
 	"fmt"
-	"net/http"
+	"os"
 	"strconv"
+	"sync"
+	"time"
 
 	"github.com/linode/linode-cloud-controller-manager/sentry"
 	"github.com/linode/linodego"
@@ -13,12 +15,56 @@ import (
 	cloudprovider "k8s.io/cloud-provider"
 )
 
+type nodeCache struct {
+	sync.RWMutex
+	nodes      map[int]*linodego.Instance
+	lastUpdate time.Time
+	ttl        time.Duration
+}
+
+// refreshInstances conditionally loads all instances from the Linode API and caches them.
+// It does not refresh if the last update happened less than `nodeCache.ttl` ago.
+func (nc *nodeCache) refreshInstances(ctx context.Context, client Client) error {
+	nc.Lock()
+	defer nc.Unlock()
+
+	if time.Since(nc.lastUpdate) < nc.ttl {
+		return nil
+	}
+
+	instances, err := client.ListInstances(ctx, nil)
+	if err != nil {
+		return err
+	}
+	nc.nodes = make(map[int]*linodego.Instance)
+	for _, instance := range instances {
+		instance := instance
+		nc.nodes[instance.ID] = &instance
+	}
+	nc.lastUpdate = time.Now()
+
+	return nil
+}
+
 type instances struct {
 	client Client
+
+	nodeCache *nodeCache
 }
 
 func newInstances(client Client) cloudprovider.InstancesV2 {
-	return &instances{client}
+	var timeout int
+	if raw, ok := os.LookupEnv("LINODE_INSTANCE_CACHE_TTL"); ok {
+		timeout, _ = strconv.Atoi(raw)
+	}
+	if timeout == 0 {
+		timeout = 15
+	}
+
+	return &instances{client, &nodeCache{
+		nodes: make(map[int]*linodego.Instance),
+		ttl:   time.Duration(timeout) * time.Second,
+	}}
 }
 
 type instanceNoIPAddressesError struct {
@@ -29,7 +75,33 @@ func (e instanceNoIPAddressesError) Error() string {
 	return fmt.Sprintf("instance %d has no IP addresses", e.id)
 }
 
+func (i *instances) linodeByName(nodeName types.NodeName) (*linodego.Instance, error) {
+	i.nodeCache.RLock()
+	defer i.nodeCache.RUnlock()
+	for _, node := range i.nodeCache.nodes {
+		if node.Label == string(nodeName) {
+			return node, nil
+		}
+	}
+
+	return nil, cloudprovider.InstanceNotFound
+}
+
+func (i *instances) linodeByID(id int) (*linodego.Instance, error) {
+	i.nodeCache.RLock()
+	defer i.nodeCache.RUnlock()
+	instance, ok := i.nodeCache.nodes[id]
+	if !ok {
+		return nil, cloudprovider.InstanceNotFound
+	}
+	return instance, nil
+}
+
 func (i *instances) lookupLinode(ctx context.Context, node *v1.Node) (*linodego.Instance, error) {
+	if err := i.nodeCache.refreshInstances(ctx, i.client); err != nil {
+		return nil, err
+	}
+
 	providerID := node.Spec.ProviderID
 	nodeName := types.NodeName(node.Name)
 
@@ -44,16 +116,16 @@ func (i *instances) lookupLinode(ctx context.Context, node *v1.Node) (*linodego.
 		}
 		sentry.SetTag(ctx, "linode_id", strconv.Itoa(id))
 
-		return linodeByID(ctx, i.client, id)
+		return i.linodeByID(id)
 	}
 
-	return linodeByName(ctx, i.client, nodeName)
+	return i.linodeByName(nodeName)
 }
 
 func (i *instances) InstanceExists(ctx context.Context, node *v1.Node) (bool, error) {
 	ctx = sentry.SetHubOnContext(ctx)
 	if _, err := i.lookupLinode(ctx, node); err != nil {
-		if apiError, ok := err.(*linodego.Error); ok && apiError.Code == http.StatusNotFound {
+		if err == cloudprovider.InstanceNotFound {
 			return false, nil
 		}
 		sentry.CaptureError(ctx, err)