Added infinite loop to awsutils.Initmetadata to fetch new CIDRs every…

… 30s, and update rule for running pods

pkg/awsutils/awsutils.go

@@ -21,6 +21,7 @@ import (
 	"os"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/pkg/errors"
@@ -159,14 +160,14 @@ type APIs interface {
 // EC2InstanceMetadataCache caches instance metadata
 type EC2InstanceMetadataCache struct {
 	// metadata info
-	securityGroups   []*string
+	securityGroups   StringSet
 	subnetID         string
 	cidrBlock        string
 	localIPv4        string
 	instanceID       string
 	instanceType     string
 	vpcIPv4CIDR      string
-	vpcIPv4CIDRs     []*string
+	vpcIPv4CIDRs     StringSet
 	primaryENI       string
 	primaryENImac    string
 	availabilityZone string
@@ -220,8 +221,35 @@ func prometheusRegister() {
 	}
 }
 
+//StringSet is a set of strings
+type StringSet struct {
+	sync.RWMutex
+	data map[string]bool
+}
+
+func (ss *StringSet) add(value string) {
+	ss.Lock()
+	defer ss.Unlock()
+	if len(ss.data) == 0 {
+		ss.data = make(map[string]bool)
+	}
+	ss.data[value] = true
+}
+
+func (ss *StringSet) contains(value string) bool {
+	_, found := ss.data[value]
+	return found //true if it existed already
+}
+
+func (ss *StringSet) reset() {
+	ss.Lock()
+	defer ss.Unlock()
+	ss.data = make(map[string]bool)
+}
+
 // New creates an EC2InstanceMetadataCache
 func New() (*EC2InstanceMetadataCache, error) {
+	ctx, _ := context.WithCancel(context.Background())
 	// Initializes prometheus metrics
 	prometheusRegister()
 
@@ -246,7 +274,7 @@ func New() (*EC2InstanceMetadataCache, error) {
 
 	ec2SVC := ec2wrapper.New(sess)
 	cache.ec2SVC = ec2SVC
-	err = cache.initWithEC2Metadata()
+	err = cache.initWithEC2Metadata(ctx)
 	if err != nil {
 		return nil, err
 	}
@@ -258,7 +286,7 @@ func New() (*EC2InstanceMetadataCache, error) {
 }
 
 // InitWithEC2metadata initializes the EC2InstanceMetadataCache with the data retrieved from EC2 metadata service
-func (cache *EC2InstanceMetadataCache) initWithEC2Metadata() error {
+func (cache *EC2InstanceMetadataCache) initWithEC2Metadata(ctx context.Context) error {
 	// retrieve availability-zone
 	az, err := cache.ec2Metadata.GetMetadata(metadataAZ)
 	if err != nil {
@@ -311,20 +339,6 @@ func (cache *EC2InstanceMetadataCache) initWithEC2Metadata() error {
 		return errors.Wrap(err, "get instance metadata: failed to find primary ENI")
 	}
 
-	// retrieve security groups
-	metadataSGIDs, err := cache.ec2Metadata.GetMetadata(metadataMACPath + mac + metadataSGs)
-	if err != nil {
-		awsAPIErrInc("GetMetadata", err)
-		log.Errorf("Failed to retrieve security-group-ids data from instance metadata service, %v", err)
-		return errors.Wrap(err, "get instance metadata: failed to retrieve security-group-ids")
-	}
-	sgIDs := strings.Fields(metadataSGIDs)
-
-	for _, sgID := range sgIDs {
-		log.Debugf("Found security-group id: %s", sgID)
-		cache.securityGroups = append(cache.securityGroups, aws.String(sgID))
-	}
-
 	// retrieve sub-id
 	cache.subnetID, err = cache.ec2Metadata.GetMetadata(metadataMACPath + mac + metadataSubnetID)
 	if err != nil {
@@ -343,19 +357,61 @@ func (cache *EC2InstanceMetadataCache) initWithEC2Metadata() error {
 	}
 	log.Debugf("Found vpc-ipv4-cidr-block: %s ", cache.vpcIPv4CIDR)
 
-	// retrieve vpc-ipv4-cidr-blocks
+	// initSGIDs retrieves security groups
+	err = cache.initSGIDs(mac)
+	if err != nil {
+		return err
+	}
+
+	// initVPCIPv4CIDRs retrieves VPC IPv4 CIDR blocks
+	err = cache.initVPCIPv4CIDRs(mac)
+	if err != nil {
+		return err
+	}
+
+	// refresh security groups and VPC CIDR blocks in the background
+	go wait.Forever(func() { cache.initSGIDs(mac) }, 30*time.Second)
+	go wait.Forever(func() { cache.initVPCIPv4CIDRs(mac) }, 30*time.Second)
+
+	select {
+	case <-ctx.Done():
+		return nil
+	}
+}
+
+// initSGIDs retrieves security groups
+func (cache *EC2InstanceMetadataCache) initSGIDs(mac string) error {
+	metadataSGIDs, err := cache.ec2Metadata.GetMetadata(metadataMACPath + mac + metadataSGs)
+	if err != nil {
+		awsAPIErrInc("GetMetadata", err)
+		log.Errorf("Failed to retrieve security-group-ids data from instance metadata service")
+		return errors.Wrap(err, "get instance metadata: failed to retrieve security-group-ids")
+	}
+
+	sgIDs := strings.Fields(metadataSGIDs)
+	cache.securityGroups.reset()
+	for _, sgID := range sgIDs {
+		log.Debugf("Found security-group id: %s", sgID)
+		cache.securityGroups.add(sgID)
+	}
+	return nil
+}
+
+// initVPCIPv4CIDRs retrieves VPC IPv4 CIDR blocks
+func (cache *EC2InstanceMetadataCache) initVPCIPv4CIDRs(mac string) error {
 	metadataVPCIPv4CIDRs, err := cache.ec2Metadata.GetMetadata(metadataMACPath + mac + metadataVPCcidrs)
+
 	if err != nil {
 		awsAPIErrInc("GetMetadata", err)
 		log.Errorf("Failed to retrieve vpc-ipv4-cidr-blocks from instance metadata service")
-		return errors.Wrap(err, "get instance metadata: failed to retrieve vpc-ipv4-cidr-block data")
+		return errors.Wrap(err, "get instance metadata: failed to retrieve vpc-ipv4-cidr-blocks data")
 	}
 
 	vpcIPv4CIDRs := strings.Fields(metadataVPCIPv4CIDRs)
-
+	cache.vpcIPv4CIDRs.reset()
 	for _, vpcCIDR := range vpcIPv4CIDRs {
 		log.Debugf("Found VPC CIDR: %s", vpcCIDR)
-		cache.vpcIPv4CIDRs = append(cache.vpcIPv4CIDRs, aws.String(vpcCIDR))
+		cache.vpcIPv4CIDRs.add(vpcCIDR)
 	}
 	return nil
 }
@@ -657,9 +713,15 @@ func (cache *EC2InstanceMetadataCache) attachENI(eniID string) (string, error) {
 // return ENI id, error
 func (cache *EC2InstanceMetadataCache) createENI(useCustomCfg bool, sg []*string, subnet string) (string, error) {
 	eniDescription := eniDescriptionPrefix + cache.instanceID
+	var securityGroups []*string
+	for securityGroup := range cache.securityGroups.data {
+		//In go, the loop iterator variable is a single variable that takes different values in each loop iteration.
+		tmpVar := securityGroup
+		securityGroups = append(securityGroups, aws.String(tmpVar))
+	}
 	input := &ec2.CreateNetworkInterfaceInput{
 		Description: aws.String(eniDescription),
-		Groups:      cache.securityGroups,
+		Groups:      securityGroups,
 		SubnetId:    aws.String(cache.subnetID),
 	}
 
@@ -1225,7 +1287,15 @@ func (cache *EC2InstanceMetadataCache) GetVPCIPv4CIDR() string {
 
 // GetVPCIPv4CIDRs returns VPC CIDRs
 func (cache *EC2InstanceMetadataCache) GetVPCIPv4CIDRs() []*string {
-	return cache.vpcIPv4CIDRs
+	cache.vpcIPv4CIDRs.RLock()
+	defer cache.vpcIPv4CIDRs.RUnlock()
+	var vpcIPv4CIDRslice []*string
+	for vpcIPv4CIDR := range cache.vpcIPv4CIDRs.data{
+		//In go, the loop iterator variable is a single variable that takes different values in each loop iteration.
+		tmpVar := vpcIPv4CIDR
+		vpcIPv4CIDRslice = append(vpcIPv4CIDRslice, aws.String(tmpVar))
+	}
+	return vpcIPv4CIDRslice
 }
 
 // GetLocalIPv4 returns the primary IP address on the primary interface