Better azure ip handling

README.md

@@ -32,8 +32,8 @@ Below you will find documentation on how to use nginx-asg-sync.
   - [Documentation](#documentation)
   - [Supported Operating Systems](#supported-operating-systems)
   - [Installation](#installation)
-  - [Configuration](#configuration)
     - [NGINX Plus Configuration](#nginx-plus-configuration)
+    - [Configuration for Cloud Providers](#configuration-for-cloud-providers)
   - [Usage](#usage)
   - [Troubleshooting](#troubleshooting)
   - [Building a Software Package](#building-a-software-package)
@@ -58,11 +58,6 @@ Support for other operating systems can be added.
     * For Amazon Linux or CentOS/RHEL, run: `$ sudo rpm -i <package-name>.rpm`
     * For Ubuntu, run: `$ sudo dpkg -i <package-name>.deb`
 
-## Configuration
-
-* For AWS, check [this example](./docs/aws.md).
-* For Azure, check [this example](./docs/azure.md).
-
 ### NGINX Plus Configuration
 
 As an example, we configure NGINX Plus to load balance two groups of instances -- backend-group-one and backend-group-two. NGINX Plus routes requests to the appropriate group based on the request URI:
@@ -141,6 +136,10 @@ Because cloud provider APIs return the instances IP addresses before the instanc
 
 Small timeouts ensure that a health check will fail fast if the backend instance is not healthy. Also, the mandatory parameter ensures NGINX Plus won't consider a newly added instance healthy until a health check passes.
 
+### Configuration for Cloud Providers
+
+See the example for your cloud provider: [AWS](examples/aws.md), [Azure](examples/azure.md).
+
 ## Usage
 
 nginx-asg-sync runs as a system service and supports the start/stop/restart commands.

cmd/sync/azure.go

@@ -65,7 +65,8 @@ func (client *AzureClient) GetPrivateIPsForScalingGroup(name string) ([]string,
 		for _, iFace := range iFaces.Values() {
 			if iFace.VirtualMachine != nil && iFace.VirtualMachine.ID != nil {
 				for _, n := range *iFace.IPConfigurations {
-					if n.Primary != nil && *n.Primary && n.InterfaceIPConfigurationPropertiesFormat.PrivateIPAddress != nil {
+					ip := getPrimaryIPFromInterfaceIPConfiguration(n)
+					if ip != "" {
 						ips = append(ips, *n.InterfaceIPConfigurationPropertiesFormat.PrivateIPAddress)
 						break
 					}
@@ -76,6 +77,30 @@ func (client *AzureClient) GetPrivateIPsForScalingGroup(name string) ([]string,
 	return ips, nil
 }
 
+func getPrimaryIPFromInterfaceIPConfiguration(ipConfig network.InterfaceIPConfiguration) string {
+	if ipConfig == (network.InterfaceIPConfiguration{}) {
+		return ""
+	}
+
+	if ipConfig.Primary == nil {
+		return ""
+	}
+
+	if !*ipConfig.Primary {
+		return ""
+	}
+
+	if ipConfig.InterfaceIPConfigurationPropertiesFormat == nil {
+		return ""
+	}
+
+	if ipConfig.InterfaceIPConfigurationPropertiesFormat.PrivateIPAddress == nil {
+		return ""
+	}
+
+	return *ipConfig.InterfaceIPConfigurationPropertiesFormat.PrivateIPAddress
+}
+
 // CheckIfScalingGroupExists checks if the Virtual Machine Scale Set exists
 func (client *AzureClient) CheckIfScalingGroupExists(name string) (bool, error) {
 	ctx := context.TODO()

cmd/sync/azure_test.go

@@ -1,6 +1,10 @@
 package main
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/Azure/azure-sdk-for-go/profiles/latest/network/mgmt/network"
+)
 
 type testInputAzure struct {
 	cfg *azureConfig
@@ -78,3 +82,61 @@ func TestValidateAzureConfigValid(t *testing.T) {
 		t.Errorf("validateAzureConfig() failed for the valid config: %v", err)
 	}
 }
+
+func TestGetPrimaryIPFromInterfaceIPConfiguration(t *testing.T) {
+	primary := true
+	address := "127.0.0.1"
+	ipConfig := network.InterfaceIPConfiguration{
+		InterfaceIPConfigurationPropertiesFormat: &network.InterfaceIPConfigurationPropertiesFormat{
+			Primary:          &primary,
+			PrivateIPAddress: &address,
+		},
+	}
+
+	if getPrimaryIPFromInterfaceIPConfiguration(ipConfig) == "" {
+		t.Errorf("getPrimaryIPFromInterfaceIPConfiguration() returned an empty ip, expected: %v", address)
+	}
+}
+
+func TestGetPrimaryIPFromInterfaceIPConfigurationFail(t *testing.T) {
+	primaryFalse := false
+	primaryTrue := true
+	var tests = []struct {
+		ipConfig network.InterfaceIPConfiguration
+		msg      string
+	}{
+		{
+			ipConfig: network.InterfaceIPConfiguration{},
+			msg:      "empty primary",
+		},
+		{
+			ipConfig: network.InterfaceIPConfiguration{
+				InterfaceIPConfigurationPropertiesFormat: &network.InterfaceIPConfigurationPropertiesFormat{
+					Primary: &primaryFalse,
+				},
+			},
+			msg: "not primary interface",
+		},
+		{
+			ipConfig: network.InterfaceIPConfiguration{
+				InterfaceIPConfigurationPropertiesFormat: nil,
+			},
+			msg: "no interface properties",
+		},
+		{
+			ipConfig: network.InterfaceIPConfiguration{
+				InterfaceIPConfigurationPropertiesFormat: &network.InterfaceIPConfigurationPropertiesFormat{
+					Primary:          &primaryTrue,
+					PrivateIPAddress: nil,
+				},
+			},
+			msg: "no private ip address",
+		},
+	}
+
+	for _, test := range tests {
+		if getPrimaryIPFromInterfaceIPConfiguration(test.ipConfig) != "" {
+			t.Errorf("getPrimaryIPFromInterfaceIPConfiguration() returned a non empty string for case: %v", test.msg)
+		}
+	}
+}