You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: create_subnet_activity.go
    path of file: ./repos/pipeline/internal/cluster/distribution/eks/eksprovider/workflow
    
    the code of the file until where you have to start completion: // Copyright Â© 2019 Banzai Cloud
//
// 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 workflow

import (
	"context"

	"emperror.dev/errors"
	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/service/cloudformation"
	"go.uber.org/cadence/activity"

	"github.com/banzaicloud/pipeline/internal/cluster/infrastructure/aws/awsworkflow"
	sdkAmazon "github.com/banzaicloud/pipeline/pkg/sdk/providers/amazon"
)

const CreateSubnetActivityName = "eks-create-subnet"

// CreateSubnetActivity responsible for setting up a Subnet for an EKS cluster
type CreateSubnetActivity struct {
	awsSessionFactory *awsworkflow.AWSSessionFactory
	// body of the cloud formation template for setting up the Subnet
	cloudFormationTemplate string
}

// CreateSubnetActivityInput holds data needed for setting up
// a Subnet for EKS cluster
type CreateSubnetActivityInput struct {
	EKSActivityInput

	// the ID of the VPC to create the subnet into
	VpcID string

	// the ID of the Route Table to associate the Subnet with
	RouteTableID string

	// The AWS ID of the
    
func (a *CreateSubnetActivity) Execute(ctx context.Context, input CreateSubnetActivityInput) (*CreateSubnetActivityOutput, error) {
	logger := activity.GetLogger(ctx).Sugar().With(
		"organization", input.OrganizationID,
		"cluster", input.ClusterName,
		"vpcID", input.VpcID,
		"routeTableID", input.RouteTableID,
		"subnetID", input.SubnetID,
		"subnetCidr", input.Cidr,
		"availabilityZone", input.AvailabilityZone,
		"secret", input.SecretID,
	)

	session, err := a.awsSessionFactory.New(input.OrganizationID, input.SecretID, input.Region)
	if err = errors.WrapIf(err, "failed to create AWS session"); err != nil {
		return nil, err
	}

	if input.SubnetID == "" && input.Cidr != "" {
		logger.Debug("creating subnet")

		cloudformationClient := cloudformation.New(session)

		stackParams := []*cloudformation.Parameter{
			{
				ParameterKey:   aws.String("VpcId"),
				ParameterValue: aws.String(input.VpcID),
			},
			{
				ParameterKey:   aws.String("RouteTableId"),
				ParameterValue: aws.String(input.RouteTableID),
			},
			{
				ParameterKey:   aws.String("SubnetBlock"),
				ParameterValue: aws.String(input.Cidr),
			},
			{
				ParameterKey:   aws.String("AvailabilityZoneName"),
				ParameterValue: aws.String(input.AvailabilityZone),
			},
		}

		requestToken := aws.String(sdkAmazon.NewNormalizedClientRequestToken(activity.GetInfo(ctx).WorkflowExecution.ID))
		createStackInput := &cloudformation.CreateStackInput{
			ClientRequestToken: requestToken,
			DisableRollback:    aws.Bool(true),
			StackName:          aws.String(input.StackName),
			Parameters:         stackParams,
			Tags:               getSubnetStackTags(input.ClusterName, input.Tags),
			TemplateBody:       aws.String(a.cloudFormationTemplate),
			TimeoutInMinutes:   aws.Int64(10),
		}

		_, err := cloudformationClient.CreateStack(createStackInput)
		if err != nil {
			return nil, errors.WrapIf(err, "create stack failed")
		}

		describeStacksInput := &cloudformation.DescribeStacksInput{StackName: aws.String(input.StackName)}
		err = WaitUntilStackCreateCompleteWithContext(cloudformationClient, ctx, describeStacksInput)

		if err != nil {
			return nil, packageCFError(err, input.StackName, *requestToken, cloudformationClient, "failed to create subnet with cidr")
		}

		describeStacksOutput, err := cloudformationClient.DescribeStacks(describeStacksInput)
		if err != nil {
			return nil, errors.WrapIf(err, "failed to get subnet ID from stack output parameters")
		}

		var subnetId string
		for _, output := range describeStacksOutput.Stacks[0].Outputs {
			switch aws.StringValue(output.OutputKey) {
			case "SubnetId":
				subnetId = aws.StringValue(output.OutputValue)
			}
		}

		logger.Debug("subnet successfully created")

		return &CreateSubnetActivityOutput{
			SubnetID:         subnetId,
			Cidr:             input.Cidr,
			AvailabilityZone: input.AvailabilityZone,
		}, nil
	}

	return nil, nil
}