Fixes #4202, correctly parse VMs with empty tags (#4450)

Signed-off-by: Johannes M. Scheuermann <joh.scheuer@gmail.com>

discovery/azure/azure.go

@@ -425,6 +425,11 @@ func (client *azureClient) getScaleSetVMs(scaleSet compute.VirtualMachineScaleSe
 
 func mapFromVM(vm compute.VirtualMachine) virtualMachine {
 	osType := string(vm.Properties.StorageProfile.OsDisk.OsType)
+	tags := map[string]*string{}
+
+	if vm.Tags != nil {
+		tags = *(vm.Tags)
+	}
 
 	return virtualMachine{
 		ID:             *(vm.ID),
@@ -433,13 +438,18 @@ func mapFromVM(vm compute.VirtualMachine) virtualMachine {
 		Location:       *(vm.Location),
 		OsType:         osType,
 		ScaleSet:       "",
-		Tags:           *(vm.Tags),
+		Tags:           tags,
 		NetworkProfile: *(vm.Properties.NetworkProfile),
 	}
 }
 
 func mapFromVMScaleSetVM(vm compute.VirtualMachineScaleSetVM, scaleSetName string) virtualMachine {
 	osType := string(vm.Properties.StorageProfile.OsDisk.OsType)
+	tags := map[string]*string{}
+
+	if vm.Tags != nil {
+		tags = *(vm.Tags)
+	}
 
 	return virtualMachine{
 		ID:             *(vm.ID),
@@ -448,7 +458,7 @@ func mapFromVMScaleSetVM(vm compute.VirtualMachineScaleSetVM, scaleSetName strin
 		Location:       *(vm.Location),
 		OsType:         osType,
 		ScaleSet:       scaleSetName,
-		Tags:           *(vm.Tags),
+		Tags:           tags,
 		NetworkProfile: *(vm.Properties.NetworkProfile),
 	}
 }

discovery/azure/azure_test.go

@@ -0,0 +1,195 @@
+// Copyright 2015 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package azure
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/Azure/azure-sdk-for-go/arm/compute"
+)
+
+func TestMapFromVMWithEmptyTags(t *testing.T) {
+	id := "test"
+	name := "name"
+	vmType := "type"
+	location := "westeurope"
+	networkProfile := compute.NetworkProfile{}
+	properties := &compute.VirtualMachineProperties{
+		StorageProfile: &compute.StorageProfile{
+			OsDisk: &compute.OSDisk{
+				OsType: "Linux",
+			},
+		},
+		NetworkProfile: &networkProfile,
+	}
+
+	testVM := compute.VirtualMachine{
+		ID:         &id,
+		Name:       &name,
+		Type:       &vmType,
+		Location:   &location,
+		Tags:       nil,
+		Properties: properties,
+	}
+
+	expectedVM := virtualMachine{
+		ID:             id,
+		Name:           name,
+		Type:           vmType,
+		Location:       location,
+		OsType:         "Linux",
+		Tags:           map[string]*string{},
+		NetworkProfile: networkProfile,
+	}
+
+	actualVM := mapFromVM(testVM)
+
+	if !reflect.DeepEqual(expectedVM, actualVM) {
+		t.Errorf("Expected %v got %v", expectedVM, actualVM)
+	}
+}
+
+func TestMapFromVMWithTags(t *testing.T) {
+	id := "test"
+	name := "name"
+	vmType := "type"
+	location := "westeurope"
+	tags := map[string]*string{
+		"prometheus": new(string),
+	}
+	networkProfile := compute.NetworkProfile{}
+	properties := &compute.VirtualMachineProperties{
+		StorageProfile: &compute.StorageProfile{
+			OsDisk: &compute.OSDisk{
+				OsType: "Linux",
+			},
+		},
+		NetworkProfile: &networkProfile,
+	}
+
+	testVM := compute.VirtualMachine{
+		ID:         &id,
+		Name:       &name,
+		Type:       &vmType,
+		Location:   &location,
+		Tags:       &tags,
+		Properties: properties,
+	}
+
+	expectedVM := virtualMachine{
+		ID:             id,
+		Name:           name,
+		Type:           vmType,
+		Location:       location,
+		OsType:         "Linux",
+		Tags:           tags,
+		NetworkProfile: networkProfile,
+	}
+
+	actualVM := mapFromVM(testVM)
+
+	if !reflect.DeepEqual(expectedVM, actualVM) {
+		t.Errorf("Expected %v got %v", expectedVM, actualVM)
+	}
+}
+
+func TestMapFromVMScaleSetVMWithEmptyTags(t *testing.T) {
+	id := "test"
+	name := "name"
+	vmType := "type"
+	location := "westeurope"
+	networkProfile := compute.NetworkProfile{}
+	properties := &compute.VirtualMachineScaleSetVMProperties{
+		StorageProfile: &compute.StorageProfile{
+			OsDisk: &compute.OSDisk{
+				OsType: "Linux",
+			},
+		},
+		NetworkProfile: &networkProfile,
+	}
+
+	testVM := compute.VirtualMachineScaleSetVM{
+		ID:         &id,
+		Name:       &name,
+		Type:       &vmType,
+		Location:   &location,
+		Tags:       nil,
+		Properties: properties,
+	}
+
+	scaleSet := "testSet"
+	expectedVM := virtualMachine{
+		ID:             id,
+		Name:           name,
+		Type:           vmType,
+		Location:       location,
+		OsType:         "Linux",
+		Tags:           map[string]*string{},
+		NetworkProfile: networkProfile,
+		ScaleSet:       scaleSet,
+	}
+
+	actualVM := mapFromVMScaleSetVM(testVM, scaleSet)
+
+	if !reflect.DeepEqual(expectedVM, actualVM) {
+		t.Errorf("Expected %v got %v", expectedVM, actualVM)
+	}
+}
+
+func TestMapFromVMScaleSetVMWithTags(t *testing.T) {
+	id := "test"
+	name := "name"
+	vmType := "type"
+	location := "westeurope"
+	tags := map[string]*string{
+		"prometheus": new(string),
+	}
+	networkProfile := compute.NetworkProfile{}
+	properties := &compute.VirtualMachineScaleSetVMProperties{
+		StorageProfile: &compute.StorageProfile{
+			OsDisk: &compute.OSDisk{
+				OsType: "Linux",
+			},
+		},
+		NetworkProfile: &networkProfile,
+	}
+
+	testVM := compute.VirtualMachineScaleSetVM{
+		ID:         &id,
+		Name:       &name,
+		Type:       &vmType,
+		Location:   &location,
+		Tags:       &tags,
+		Properties: properties,
+	}
+
+	scaleSet := "testSet"
+	expectedVM := virtualMachine{
+		ID:             id,
+		Name:           name,
+		Type:           vmType,
+		Location:       location,
+		OsType:         "Linux",
+		Tags:           tags,
+		NetworkProfile: networkProfile,
+		ScaleSet:       scaleSet,
+	}
+
+	actualVM := mapFromVMScaleSetVM(testVM, scaleSet)
+
+	if !reflect.DeepEqual(expectedVM, actualVM) {
+		t.Errorf("Expected %v got %v", expectedVM, actualVM)
+	}
+}