IPv6-only capability and config initialization (#4659)

Author: amogh09

agent/app/agent_capability.go

@@ -84,6 +84,7 @@ const (
 	capabilityEBSTaskAttach                                = "storage.ebs-task-volume-attach"
 	capabilityContainerRestartPolicy                       = "container-restart-policy"
 	capabilityFaultInjection                               = "fault-injection"
+	capabilityIPv6Only                                     = "ipv6-only"
 
 	// network capabilities, going forward, please append "network." prefix to any new networking capability we introduce
 	networkCapabilityPrefix      = "network."
@@ -318,6 +319,9 @@ func (agent *ecsAgent) capabilities() ([]types.Attribute, error) {
 
 	capabilities = agent.appendFaultInjectionCapabilities(capabilities)
 
+	// IPv6-only cap
+	capabilities = appendIPv6OnlyCapability(capabilities)
+
 	return capabilities, nil
 }
 

agent/app/agent_capability_unix.go

@@ -306,3 +306,9 @@ func checkTCShowTooling() bool {
 	}
 	return true
 }
+
+// appendIPv6OnlyCapability appends ecs.capability.ipv6-only to passed capabilities and returns
+// the updated capabilities slice.
+func appendIPv6OnlyCapability(capabilities []types.Attribute) []types.Attribute {
+	return appendNameOnlyAttribute(capabilities, attributePrefix+capabilityIPv6Only)
+}

agent/app/agent_capability_unix_test.go

@@ -1153,3 +1153,18 @@ func convertToInterfaceList(strings []string) []interface{} {
 	}
 	return interfaces
 }
+
+func TestAppendIPv6OnlyCapability(t *testing.T) {
+	capabilities := []types.Attribute{
+		types.Attribute{Name: aws.String("cap1")},
+		types.Attribute{Name: aws.String("cap2")},
+	}
+	capabilities = appendIPv6OnlyCapability(capabilities)
+	assert.Equal(t,
+		[]types.Attribute{
+			types.Attribute{Name: aws.String("cap1")},
+			types.Attribute{Name: aws.String("cap2")},
+			types.Attribute{Name: aws.String("ecs.capability.ipv6-only")},
+		},
+		capabilities)
+}

agent/app/agent_capability_unspecified.go

@@ -154,3 +154,8 @@ var isFaultInjectionToolingAvailable = checkFaultInjectionTooling
 func checkFaultInjectionTooling(_ *config.Config) bool {
 	return false
 }
+
+// appendIPv6OnlyCapability is a no-op.
+func appendIPv6OnlyCapability(capabilities []types.Attribute) []types.Attribute {
+	return capabilities
+}

agent/app/agent_capability_windows.go

@@ -153,3 +153,8 @@ func checkFaultInjectionTooling(_ *config.Config) bool {
 	seelog.Warnf("Fault injection tooling is not supported on windows")
 	return false
 }
+
+// appendIPv6OnlyCapability is a no-op as IPv6-only capability is not supported on Windows.
+func appendIPv6OnlyCapability(capabilities []types.Attribute) []types.Attribute {
+	return capabilities
+}

agent/app/agent_capability_windows_test.go

@@ -345,3 +345,17 @@ func TestAppendExecCapabilities(t *testing.T) {
 		})
 	}
 }
+
+func TestAppendIPv6OnlyCapability(t *testing.T) {
+	capabilities := []types.Attribute{
+		types.Attribute{Name: aws.String("cap1")},
+		types.Attribute{Name: aws.String("cap2")},
+	}
+	capabilities = appendIPv6OnlyCapability(capabilities)
+	assert.Equal(t,
+		[]types.Attribute{
+			types.Attribute{Name: aws.String("cap1")},
+			types.Attribute{Name: aws.String("cap2")},
+		},
+		capabilities)
+}

agent/config/config.go

@@ -240,8 +240,7 @@ func NewConfig(ec2client ec2.EC2MetadataClient) (*Config, error) {
 		ec2client = ec2.NewBlackholeEC2MetadataClient()
 	}
 
-	// TODO feat:IPv6-only - Enable when launching IPv6-only support
-	// config.determineIPCompatibility(ec2client)
+	config.determineIPCompatibility(ec2client)
 
 	if config.complete() {
 		// No need to do file / network IO

agent/config/config_unix.go

@@ -175,10 +175,6 @@ func getConfigFileName() (string, error) {
 // determining the IP compatibility of the container instance.
 // This is a fallback to help with graceful adoption of Agent in IPv6-only environments
 // without disrupting existing environments.
-//
-// TODO feat:IPv6-only - Remove lint rule below
-//
-//lint:ignore U1000 Function will be used in the future
 func (c *Config) determineIPCompatibility(ec2client ec2.EC2MetadataClient) {
 	var err error
 	c.InstanceIPCompatibility, err = netutils.DetermineIPCompatibility(nlWrapper, "")

agent/config/config_unix_test.go

@@ -353,8 +353,6 @@ func TestDetermineIPCompatibility(t *testing.T) {
 // Tests that IPCompatibility defaults to IPv4-only when determining IP compatibility of
 // the container instance fails due to some error.
 func TestIPCompatibilityFallback(t *testing.T) {
-	// TODO feat:IPv6-only - Remove skip
-	t.Skip("Enable when launching IPv6-only support")
 	defer setTestRegion()()
 	ctrl := gomock.NewController(t)
 	mockEc2Metadata := mock_ec2.NewMockEC2MetadataClient(ctrl)