Use boto3 to get current price for given EC2 instance type

Question

Now that AWS have a Pricing API, how could one use Boto3 to fetch the current hourly price for a given on-demand EC2 instance type (e.g. t2.micro), region (e.g. eu-west-1) and operating system (e.g. Linux)? I only want the price returned. Based on my understanding, having those four pieces of information should be enough to filter down to a singular result.

However, all the examples I've seen fetch huge lists of data from the API that would have to be post-processed in order to get what I want. I would like to filter the data on the API side, before it's being returned.

Answer 1

Here is the solution I ended up with. Using Boto3's own Pricing API with a filter for the instance type, region and operating system. The API still returns a lot of information, so I needed to do a bit of post-processing.

import boto3
import json
from pkg_resources import resource_filename

# Search product filter. This will reduce the amount of data returned by the
# get_products function of the Pricing API
FLT = '[{{"Field": "tenancy", "Value": "shared", "Type": "TERM_MATCH"}},'\
      '{{"Field": "operatingSystem", "Value": "{o}", "Type": "TERM_MATCH"}},'\
      '{{"Field": "preInstalledSw", "Value": "NA", "Type": "TERM_MATCH"}},'\
      '{{"Field": "instanceType", "Value": "{t}", "Type": "TERM_MATCH"}},'\
      '{{"Field": "location", "Value": "{r}", "Type": "TERM_MATCH"}},'\
      '{{"Field": "capacitystatus", "Value": "Used", "Type": "TERM_MATCH"}}]'


# Get current AWS price for an on-demand instance
def get_price(region, instance, os):
    f = FLT.format(r=region, t=instance, o=os)
    data = client.get_products(ServiceCode='AmazonEC2', Filters=json.loads(f))
    od = json.loads(data['PriceList'][0])['terms']['OnDemand']
    id1 = list(od)[0]
    id2 = list(od[id1]['priceDimensions'])[0]
    return od[id1]['priceDimensions'][id2]['pricePerUnit']['USD']

# Translate region code to region name. Even though the API data contains
# regionCode field, it will not return accurate data. However using the location
# field will, but then we need to translate the region code into a region name.
# You could skip this by using the region names in your code directly, but most
# other APIs are using the region code.
def get_region_name(region_code):
    default_region = 'US East (N. Virginia)'
    endpoint_file = resource_filename('botocore', 'data/endpoints.json')
    try:
        with open(endpoint_file, 'r') as f:
            data = json.load(f)
        # Botocore is using Europe while Pricing API using EU...sigh...
        return data['partitions'][0]['regions'][region_code]['description'].replace('Europe', 'EU')
    except IOError:
        return default_region


# Use AWS Pricing API through Boto3
# API only has us-east-1 and ap-south-1 as valid endpoints.
# It doesn't have any impact on your selected region for your instance.
client = boto3.client('pricing', region_name='us-east-1')

# Get current price for a given instance, region and os
price = get_price(get_region_name('eu-west-1'), 't3.micro', 'Linux')
print(price)

This example outputs 0.0114000000 (hourly price in USD) fairly quickly. (This number was verified to match the current value listed here at the date of this writing)