Fix support for me-central-1 & panic from private Gitpod network (#9)

* Fix panic on diagnose for private networks

* Introduce getPreferredInstanceType

The available types vary by region. T2 is the cheapest, but not always available. T3a is cheaper than T3 but uncommon. T3 more expensive, but available in most regions.

* Log the instance type selected

* Refactor

* Log input params

gitpod-network-check/cmd/checks.go

@@ -297,7 +297,14 @@ func launchInstances(ctx context.Context, ec2Client *ec2.Client, subnets []strin
 			return nil, fmt.Errorf("❌ failed to create security group for subnet '%v': %v", subnet, err)
 		}
 		SecurityGroups = append(SecurityGroups, secGroup)
-		instanceId, err := launchInstanceInSubnet(ctx, ec2Client, subnet, secGroup, profileArn)
+
+		instanceType, err := getPreferredInstanceType(ctx, ec2Client)
+		if err != nil {
+			return nil, fmt.Errorf("❌ failed to get preferred instance type: %v", err)
+		}
+		log.Infof("ℹ️  Instance type %s shall be used", instanceType)
+
+		instanceId, err := launchInstanceInSubnet(ctx, ec2Client, subnet, secGroup, profileArn, instanceType)
 		if err != nil {
 			return nil, fmt.Errorf("❌ Failed to launch instances in subnet %s: %v", subnet, err)
 		}
@@ -312,7 +319,7 @@ func launchInstances(ctx context.Context, ec2Client *ec2.Client, subnets []strin
 	return instanceIds, nil
 }
 
-func launchInstanceInSubnet(ctx context.Context, ec2Client *ec2.Client, subnetID, secGroupId string, instanceProfileName *string) (string, error) {
+func launchInstanceInSubnet(ctx context.Context, ec2Client *ec2.Client, subnetID, secGroupId string, instanceProfileName *string, instanceType types.InstanceType) (string, error) {
 	regionalAMI, err := findUbuntuAMI(ctx, ec2Client)
 	if err != nil {
 		return "", err
@@ -329,7 +336,7 @@ func launchInstanceInSubnet(ctx context.Context, ec2Client *ec2.Client, subnetID
 
 	input := &ec2.RunInstancesInput{
 		ImageId:          aws.String(regionalAMI), // Example AMI ID, replace with an actual one
-		InstanceType:     types.InstanceTypeT2Micro,
+		InstanceType:     instanceType,
 		MaxCount:         aws.Int32(1),
 		MinCount:         aws.Int32(1),
 		UserData:         &userDataEncoded,
@@ -588,3 +595,40 @@ func createInstanceProfileAndAttachRole(ctx context.Context, svc *iam.Client, ro
 
 	return instanceProfileOutput.InstanceProfile, nil
 }
+
+func getPreferredInstanceType(ctx context.Context, svc *ec2.Client) (types.InstanceType, error) {
+	instanceTypes := []types.InstanceType{
+		types.InstanceTypeT2Micro,
+		types.InstanceTypeT3aMicro,
+		types.InstanceTypeT3Micro,
+	}
+	for _, instanceType := range instanceTypes {
+		exists, err := instanceTypeExists(ctx, svc, instanceType)
+		if err != nil {
+			return "", err
+		}
+		if exists {
+			return instanceType, nil
+		}
+	}
+	return "", fmt.Errorf("No preferred instance type available in region: %s", networkConfig.AwsRegion)
+}
+
+func instanceTypeExists(ctx context.Context, svc *ec2.Client, instanceType types.InstanceType) (bool, error) {
+	input := &ec2.DescribeInstanceTypeOfferingsInput{
+		Filters: []types.Filter{
+			{
+				Name:  aws.String("instance-type"),
+				Values: []string{string(instanceType)},
+			},
+		},
+		LocationType: types.LocationTypeRegion,
+	}
+
+	resp, err := svc.DescribeInstanceTypeOfferings(ctx, input)
+	if err != nil {
+		return false, err
+	}
+
+	return len(resp.InstanceTypeOfferings) > 0, nil
+}

gitpod-network-check/cmd/common.go

@@ -51,14 +51,16 @@ func cleanup(ctx context.Context, svc *ec2.Client, iamsvc *iam.Client) {
 			},
 		})
 		if err != nil {
-			log.WithError(err).Warn("Failed to list instances, please cleanup manually")
+			log.WithError(err).Error("Failed to list instances, please cleanup instances manually")
 		} else if len(instances.Reservations) == 0 {
 			log.Info("No instances found.")
 		}
 
-		for _, r := range instances.Reservations {
-			for _, i := range r.Instances {
-				InstanceIds = append(InstanceIds, *i.InstanceId)
+		if instances != nil {
+			for _, r := range instances.Reservations {
+				for _, i := range r.Instances {
+					InstanceIds = append(InstanceIds, *i.InstanceId)
+				}
 			}
 		}
 	}
@@ -155,8 +157,10 @@ func cleanup(ctx context.Context, svc *ec2.Client, iamsvc *iam.Client) {
 			log.Info("No security groups found.")
 		}
 
-		for _, sg := range securityGroups.SecurityGroups {
-			SecurityGroups = append(SecurityGroups, *sg.GroupId)
+		if securityGroups != nil {
+			for _, sg := range securityGroups.SecurityGroups {
+				SecurityGroups = append(SecurityGroups, *sg.GroupId)
+			}
 		}
 	}
 

gitpod-network-check/cmd/root.go

@@ -89,6 +89,7 @@ func init() {
 	networkCheckCmd.PersistentFlags().StringSliceVar(&networkConfig.PodSubnets, "pod-subnets", []string{}, "List of pod subnets")
 	networkCheckCmd.PersistentFlags().StringSliceVar(&networkConfig.HttpsHosts, "https-hosts", []string{}, "Hosts to test for outbound HTTPS connectivity")
 	bindFlags(networkCheckCmd, v)
+	log.Infof("ℹ️  Running with region `%s`, main subnet `%v`, pod subnet `%v`, and hosts `%v`", networkConfig.AwsRegion, networkConfig.MainSubnets, networkConfig.PodSubnets, networkConfig.HttpsHosts)
 }
 
 func readConfigFile() *viper.Viper {