Managing AWS EC2 Instances with Python and Boto3: A Step-by-Step Guide

import boto3

class EC2Manager:
    def __init__(self, region):
        # Constructor to initialize the EC2Manager with a specified region
        self.region = region
        # Create an EC2 resource object for the specified region
        self.ec2 = boto3.resource('ec2', region_name=region)
        # Get a dictionary of all EC2 instances in the region
        self.instances = self.get_instances()

    def get_instances(self):
        # Retrieve all EC2 instances and store them in a dictionary with instance ID as the key
        instances = self.ec2.instances.all()
        return {instance.id: instance for instance in instances}

    def list_instances(self):
        # Print a list of EC2 instances with their IDs, names, and states
        print("List of EC2 instances:")
        for instance_id, instance in self.instances.items():
            instance_name = self.get_instance_name(instance)
            instance_state = instance.state['Name']
            print(f"ID: {instance_id}, Name: {instance_name}, State: {instance_state}")

    def get_instance_name(self, instance):
        # Retrieve the name of an EC2 instance using its tags
        for tag in instance.tags or []:
            if tag['Key'] == 'Name':
                return tag['Value']
        return 'N/A'

    def stop_instance(self, instance_id):
        # Stop the specified EC2 instance and print its current state
        try:
            instance = self.instances.get(instance_id)
            if instance:
                response = instance.stop()
                print(f"Instance {instance_id} is in the process of stopping. Current state: {response['StoppingInstances'][0]['CurrentState']['Name']}")
            else:
                print(f"Instance with ID {instance_id} not found.")
        except Exception as e:
            print(f"Error stopping the instance: {str(e)}")

    def start_instance(self, instance_id):
        # Start the specified EC2 instance and print its current state
        try:
            instance = self.instances.get(instance_id)
            if instance:
                response = instance.start()
                print(f"Instance {instance_id} is in the process of starting. Current state: {response['StartingInstances'][0]['CurrentState']['Name']}")
            else:
                print(f"Instance with ID {instance_id} not found.")
        except Exception as e:
            print(f"Error starting the instance: {str(e)}")

if __name__ == "__main__":
    # Replace 'your_region' with the region of your instance
    # Create an EC2Manager object for the specified region
    manager = EC2Manager(region='us-east-1')

    while True:
        print("\n===== Menu =====")
        print("1. List instances")
        print("2. Stop instance")
        print("3. Start instance")
        print("4. Exit")

        choice = input("Choose an option (1/2/3/4): ")

        if choice == '1':
            manager.list_instances()
        elif choice == '2':
            manager.list_instances()
            instance_id = input("Enter the ID of the instance you want to stop: ")
            manager.stop_instance(instance_id)
        elif choice == '3':
            manager.list_instances()
            instance_id = input("Enter the ID of the instance you want to start: ")
            manager.start_instance(instance_id)
        elif choice == '4':
            print("Exiting the program. Goodbye!")
            break
        else:
            print("Invalid option. Please try again.")

pip install boto3

def __init__(self, region):

Constructor to initialize the EC2Manager with a specified AWS region.
Creates an EC2 resource object for the region and retrieves a dictionary of all EC2 instances.

Parameters:
– region (str): AWS region where EC2 instances are managed.

def get_instances(self):

Retrieves all EC2 instances in the specified region and returns a dictionary with instance ID as the key.

Returns:
– dict: Dictionary of EC2 instances with instance ID as the key.

def list_instances(self):

Prints a list of EC2 instances with their IDs, names, and states.

def get_instance_name(self, instance):

Retrieves the name of an EC2 instance using its tags.

Parameters:
– instance (boto3.resources.factory.ec2.Instance): EC2 instance object.

Returns:
– str: Name of the EC2 instance.

def start_instance(self, instance_id):

Starts the specified EC2 instance and prints its current state.

Parameters:
– instance_id (str): ID of the EC2 instance to be started.