gistfile1.txt

package main

import (
	"fmt"
	"log"

	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/elasticbeanstalk"
	"github.com/aws/aws-sdk-go/service/elbv2"
)

func main() {
	sess := session.Must(session.NewSessionWithOptions(session.Options{
		SharedConfigState: session.SharedConfigEnable,
	}))

	envName := "my-elasticbeanstalk-env"

	// Get Load Balancer Name
	lbName, err := GetLoadBalancerName(sess, envName)
	if err != nil {
		log.Fatalf("Error fetching load balancer name: %v", err)
	}

	// Get ALB Details
	ruleArn, targetGroupArn, err := GetALBDetails(sess, lbName)
	if err != nil {
		log.Fatalf("Error fetching ALB details: %v", err)
	}

	fmt.Printf("Rule ARN: %s\n", ruleArn)
	fmt.Printf("Target Group ARN: %s\n", targetGroupArn)
	
	

// Redirect traffic to ipchicken.com during maintenance
	redirectURL := "ipchicken.com"
	if err := RedirectTraffic(sess, ruleArn, redirectURL); err != nil {
		log.Fatalf("Error redirecting traffic: %v", err)
	}

	fmt.Println("Traffic is now redirected to:", redirectURL)
	// Include logic or monitoring to determine when to switch back
	// Restore original routing
	if err := RestoreOriginalTraffic(sess, ruleArn, targetGroupArn); err != nil {
		log.Fatalf("Error restoring original traffic: %v", err)
	}

	fmt.Println("Traffic is now restored to the original site")
	
}

// GetLoadBalancerName retrieves the name of the Load Balancer associated with a given Elastic Beanstalk environment.
func GetLoadBalancerName(sess *session.Session, envName string) (string, error) {
	ebSvc := elasticbeanstalk.New(sess)

	input := &elasticbeanstalk.DescribeEnvironmentResourcesInput{
		EnvironmentName: aws.String(envName),
	}

	resp, err := ebSvc.DescribeEnvironmentResources(input)
	if err != nil {
		return "", err
	}

	if len(resp.EnvironmentResources.LoadBalancers) == 0 {
		return "", fmt.Errorf("no load balancer found for environment %s", envName)
	}

	return *resp.EnvironmentResources.LoadBalancers[0].Name, nil
}

// GetALBDetails retrieves the rule ARN and target group ARN for the given load balancer name.
func GetALBDetails(sess *session.Session, lbName string) (string, string, error) {
	elbSvc := elbv2.New(sess)

	// Retrieve load balancer details using its name
	lbInput := &elbv2.DescribeLoadBalancersInput{
		Names: []*string{aws.String(lbName)},
	}
	lbOutput, err := elbSvc.DescribeLoadBalancers(lbInput)
	if err != nil {
		return "", "", err
	}

	if len(lbOutput.LoadBalancers) == 0 {
		return "", "", fmt.Errorf("load balancer %s not found", lbName)
	}

	lbArn := lbOutput.LoadBalancers[0].LoadBalancerArn

	// Retrieve the listener using the Load Balancer ARN
	listenerInput := &elbv2.DescribeListenersInput{
		LoadBalancerArn: lbArn,
	}
	listenerOutput, err := elbSvc.DescribeListeners(listenerInput)
	if err != nil {
		return "", "", err
	}

	if len(listenerOutput.Listeners) == 0 {
		return "", "", fmt.Errorf("no listeners found for load balancer %s", lbName)
	}

	// Assuming the first listener and the first rule
	// For more complex setups, you might need to iterate or filter based on specific conditions
	listenerArn := listenerOutput.Listeners[0].ListenerArn
	ruleInput := &elbv2.DescribeRulesInput{
		ListenerArn: listenerArn,
	}
	ruleOutput, err := elbSvc.DescribeRules(ruleInput)
	if err != nil {
		return "", "", err
	}

	if len(ruleOutput.Rules) == 0 {
		return "", "", fmt.Errorf("no rules found for listener %s", *listenerArn)
	}

	ruleArn := *ruleOutput.Rules[0].RuleArn
	var targetGroupArn string
	for _, action := range ruleOutput.Rules[0].Actions {
		if *action.Type == "forward" {
			targetGroupArn = *action.TargetGroupArn
			break
		}
	}

	if targetGroupArn == "" {
		return "", "", fmt.Errorf("no forwarding actions found in rules for listener %s", *listenerArn)
	}

	return ruleArn, targetGroupArn, nil
}

// RedirectTraffic sets up an ALB rule to redirect all traffic to a specified URL.
func RedirectTraffic(sess *session.Session, ruleArn string, redirectURL string) error {
	svc := elbv2.New(sess)

	modifyRuleInput := &elbv2.ModifyRuleInput{
		RuleArn: aws.String(ruleArn),
		Actions: []*elbv2.Action{
			{
				Type: aws.String("redirect"),
				RedirectConfig: &elbv2.RedirectActionConfig{
					Protocol:   aws.String("HTTPS"), // Ensure the protocol matches your requirements
					Host:       aws.String(redirectURL), // No need to specify the entire URL, just the host
					Port:       aws.String("443"), // Standard HTTPS port
					Path:       aws.String("/#{path}"),
					Query:      aws.String("#{query}"),
					StatusCode: aws.String("HTTP_302"),
				},
			},
		},
	}

	_, err := svc.ModifyRule(modifyRuleInput)
	return err
}


// RestoreOriginalTraffic restores the original rule to forward traffic to the primary target group.
func RestoreOriginalTraffic(sess *session.Session, ruleArn string, targetGroupArn string) error {
	svc := elbv2.New(sess)

	modifyRuleInput := &elbv2.ModifyRuleInput{
		RuleArn: aws.String(ruleArn),
		Actions: []*elbv2.Action{
			{
				Type:           aws.String("forward"),
				TargetGroupArn: aws.String(targetGroupArn),
			},
		},
	}

	_, err := svc.ModifyRule(modifyRuleInput)
	return err
}