Python unknown number of commandline arguments in boto3 - python-3.x

Question

I am trying to add tags based on commandline arguments passed to python script something like below:
./snapshot-create.py --id abcd --key1 Env --value1 Test
The script is like below:
client = boto3.client('ec2')
response = client.create_tags(
Resources=[
ID,
],
Tags=[
{
'Key': 'key1',
'Value': 'value1'
},
]
)
I want to use --key1 and --values as Tags as above but the problem is that there could be more than one tags that need to be added like:
./snapshot-create.py --id abcd --key1 Env --value1 Test -key2 Loca --value2 US -key1 Size --value1 small ...
How would I use those key-values if their number of arguments is not fixed.
I don't mind using function or any other way than what I came up with.

Answer 1

One option would be loading a json string as a dictionary and iterating it when creating the tags.
For example, consider this invocation:
$ my_script.py --tags "{'tag1': 'value1', 'tag2': 'value2'}" --id i-1234567890 i-0987654321
and this code snippet:
import json
import boto3
import argparse
parser.add_argument('-t', '--tags', type=str)
parser.add_argument('-i', '--id', nargs='+')
args = parser.parse_args()
client = boto3.client('ec2')
def create_tags(key, value, resources, c):
c.create_tags(
Resources=
resources,
,
Tags=[
{
'Key': key,
'Value': value
},
]
)
my_tags = json.loads(args.tags) # {'tag1': 'value1', 'tag2': 'value2'}
resources = args.id # ['i-1234567890', 'i-0987654321']
for k, v in my_tags.items():
create_tags(k, v, resources, client)
This should cause instances i-1234567890 & i-0987654321 to be tagged with both tags tag1 and tag2 described in --tags above.
If you require a more dynamic interface for resources as well, consider adding it to the json as such:
{ 'instance_id': [{'tag_key': 'tag_value'} ... ] ... }
You can the take a single argument --tags which will contain a mapping of resources and tags, instead of the above example where resources is statically mapped to the tags.
Pretty sure there are better, more pythonic, solutions than this though - this is one viable solution.