A lambda function that will copy EC2 tags to all related Volumes and Network Interfaces. A full writeup can be found on my site https://empty.coffee/tagging-and-snapshotting-with-lambda/ - Thank you to the community for keeping this updated!

EC2-Tag-Assets-Lambda.py

from __future__ import print_function

import json
import boto3
import logging

#setup simple logging for INFO
logger = logging.getLogger()
logger.setLevel(logging.ERROR)

#define the connection region
ec2 = boto3.resource('ec2', region_name="us-west-2")

#Set this to True if you don't want the function to perform any actions
debugMode = False

def lambda_handler(event, context):
    #List all EC2 instances
    base = ec2.instances.all()

    #loop through by running instances
    for instance in base:
        
        #Tag the Volumes
        for vol in instance.volumes.all():
            #print(vol.attachments[0]['Device'])
            if debugMode == True:
                print("[DEBUG] " + str(vol))
                tag_cleanup(instance, vol.attachments[0]['Device'])
            else:
                tag = vol.create_tags(Tags=tag_cleanup(instance, vol.attachments[0]['Device']))
                print("[INFO]: " + str(tag))
        
        #Tag the Network Interfaces
        for eni in instance.network_interfaces:
            #print(eni.attachment['DeviceIndex'])
            if debugMode == True:
                print("[DEBUG] " + str(eni))
                tag_cleanup(instance, "eth"+str(eni.attachment['DeviceIndex']))
            else:
                tag = eni.create_tags(Tags=tag_cleanup(instance, "eth"+str(eni.attachment['DeviceIndex'])))
                print("[INFO]: " + str(tag))
    
#------------- Functions ------------------
#returns the type of configuration that was performed    
        
def tag_cleanup(instance, detail):
    tempTags=[]
    v={}
    
    for t in instance.tags:
        #pull the name tag
        if t['Key'] == 'Name':
            v['Value'] = t['Value'] + " - " + str(detail)
            v['Key'] = 'Name'
            tempTags.append(v)
        #Set the important tags that should be written here  
        elif t['Key'] == 'Application Owner':
            print("[INFO]: Application Owner Tag " + str(t))
            tempTags.append(t)    
        elif t['Key'] == 'Cost Center':
            print("[INFO]: Cost Center Tag " + str(t))
            tempTags.append(t)  
        elif t['Key'] == 'Date Created':
            print("[INFO]: Date Created Tag " + str(t))
            tempTags.append(t)  
        elif t['Key'] == 'Requestor':
            print("[INFO]: Requestor Tag " + str(t))
            tempTags.append(t)  
        elif t['Key'] == 'System Owner':
            print("[INFO]: System Owner Tag " + str(t))
            tempTags.append(t)
        else:
            print("[INFO]: Skip Tag - " + str(t))
    
    print("[INFO] " + str(tempTags))
    return(tempTags)

@jamesduffy i want to exclude some ec2 instances and volumes from tagging, how can i do that?

I don't know if negative filters work in boto3. I haven't tried it, but I would start there. I would try to add a tag to the instances/resources that tell the script not to copy the tags. For example my ideal setup I would create a copy-tags-ignore=true on anything I wanted to ignore. Then if I can't do a negative filter to replace boto3.resource('ec2').instances.all(). If I can't use a negative filter than if you can check for that tag in the for loop and check if it exists and continue if it is exists and set to true.

Not ideal instead of using a tag named something like copy-tags-ignore you could create a list of resource names you don't want the script to copy and in the loop do a check like if instance.tags['Name'] in do_not_copy continue instead of copying.