AWS List EC2

by Mark Nielsen
Copyright Nov 2021


I wanted to make a scripts to view all the EC2 instances I had. You cane also use the CLI, but I made a python2 script years ago. This is a good example to start with to program with the API.

Requirements

  1. Boto3 installed in python2 libraries
  2. Python2 installed in linux. This should be upgraded to python2.
  3. AWS credential files need to be installed.
  4. The pem file needs to be installed.

List EC2

#!/usr/bin/python2

import re, sys, os, time
import argparse
import boto3


"""
./list_ec2.py -c  

./list_ec2.py
# With no options, lists out ec2 with status an info

Command : start stop reboot 
Instance Name: The name you give to the ec2 server. 

You need to setup the aws files in ~/.aws with the key file for ssh, the
default.pem file in ~/aws. 

"""

pem_directory = "~/aws"
pem_file = "default.pem"

#-----------------------------------------------------------------
  # Parse command libne arguments.
  # Must have 0 or 2 arguments.
parser = argparse.ArgumentParser(description='Process args.')
parser.add_argument('Command', nargs='?', default='')
parser.add_argument('Name', nargs='?', default='')
args = parser.parse_args()

  # Get all the instances and record info. 
ec2 = boto3.resource('ec2')

re_ = re.compile('^_')

all_info = {}
info = {}
instances = []
all_instances = {}
for inst in ec2.instances.all():
  instances.append(inst) 
  # For each instance, start, stop, restart, or nothing. 
  # Save the values fpr printing later.
  # If an action is taking, reget into for it.

  
for inst in instances:
  vars = [i for i in dir(inst) if not re_.search(str(i)) and hasattr(inst,i) ]

  name = None
  for tag in getattr(inst ,'tags'):
    if tag.has_key(u'Key') and tag.has_key(u'Value') and tag[u'Key'] == 'Name':
      name = tag[u'Value']
#  print "My name is:", name    
  all_instances[name] = inst

  state = "" 
  temp = getattr(inst ,'state')
  if temp.has_key(u'Name') and temp.has_key(u'Code'):
    state = temp[u'Name'] + " " + str(temp[u'Code']) 

  ip =  getattr(inst ,'public_ip_address')   
  instance = getattr(inst ,'instance_id')
  image =  getattr(inst ,'image_id')

  instance_type = getattr(inst ,'instance_type')
  dns = getattr(inst ,'public_dns_name') 
  
  v = [name, state, instance, instance_type, image,dns,ip ]
  info[name]= v
  all_info[name] = {}
  for v in vars:
    g = getattr(inst ,v) 
    all_info[name][v]=g
  
# Check if command and instance is valid.
i_names = info.keys()
if args.Command is None or args.Command == '': pass
elif args.Command not in ['start', 'stop','reboot', 'update', 'upgrade']:
  print "Command ignored, ", args.Command, ",should be one of ",  ['start', 'stop','reboot', 'update', 'upgrade']
elif args.Name not in i_names:
  print "Instance, " , args.Name, " not in ", i_names
else:
  # Do one of the commands.
  # You should have configured ssh with the right pem located at default directory and
  # and set the right username in ssh config. 

  host =  all_info[args.Name]['public_dns_name'] 
  ssh_command = "ssh -i " + pem_directory + "/" + pem_file + " " + host
 
  if args.Command in ["stop", "start", "reboot"] and args.Name in i_names:
    try: 
      if args.Command == "start": all_instances[args.Name].start(); print "Starting:", args.Name
      if args.Command == "stop": all_instances[args.Name].stop(); print "Stopping:", args.Name
      if args.Command == "reboot": all_instances[args.Name].reboot(); print "Rebooting:", args.Name
    except Exception,e:
      print "ERROR: command failed:", sys.exc_info()[0]
      print "  ", e
      
    print "Check in 15 seconds and get the status again."

    not_needed = """ 
    # Reset this instance. 
    instance_id = all_info[args.Name]['instance_id']
    inst = ec2.Instance(instance_id)

    all_info[args.Name][1] = getattr(inst ,'state')
    all_info[args.Name] = {}
    vars = [i for i in dir(inst) if not re_.search(str(i)) and hasattr(inst,i) ]
    for v in vars:
      g = getattr(inst ,v)
      all_info[args.Name][v]=g
    all_instances[args.Name] = inst
    """

i_keys = info.keys()
i_keys.sort()
for i in i_keys:
  print i, info[i]