wowtoken.app-backend/wow-token-updater.py

import datetime
import time
import boto3
import json
import os
import requests


dynamo_client = boto3.client('dynamodb', region_name='us-east-1')
timestream_client = boto3.client('timestream-write', region_name='us-east-1')
current_table = os.environ['TABLE_NAME']
recent_table = os.environ['RECENT_TABLE_NAME']


# a lambda handler to handle eventbridge triggered vents
def lambda_handler(event, context):
    regions = ['us', 'eu', 'kr', 'tw']
    live_prices = get_combined_live_price()
    print(live_prices)
    current_time_epoch = int(datetime.datetime.utcnow().timestamp())
    for region in regions:
        print(f'Updating {region.upper()}...')
        update_token_price(region, current_time_epoch, live_prices[region])


def update_token_price(region: str, current_time_epoch: int, live_price: int):
    stored_price = get_stored_price(region)
    print(f'Current stored price {stored_price}')
    if stored_price != live_price:
        update_stored_token_price(region, live_price, current_time_epoch)
        update_recent_token_price(region, live_price, current_time_epoch)
        update_timestream_token_price(region, live_price, current_time_epoch)
    else:
        # price hasn't changed
        print(f'Price has not changed for {region.upper()}')


# update the current price records in DynamoDB
def update_stored_token_price(region: str, price: int, current_time_epoch: int) -> None:
    dynamo_client.update_item(
        TableName=current_table,
        Key={
            'region': {
                'S': region
            }
        },
        UpdateExpression='SET price = :p, current_time = :t',
        ExpressionAttributeValues={
            ':p': {
                'S': str(price)
            },
            ':t': {
                'S': str(current_time_epoch)
            }
        }
        # ReturnValues="UPDATED_NEW"
    )
    print(f'Updated {region.upper()} price to {price}')


# add a record to the recent token price table in DynamoDB
def update_recent_token_price(region: str, price: int, current_time_epoch: int) -> None:
    dynamo_client.put_item(
        TableName=recent_table,
        Item={
            'region': {
                'S': region
            },
            'price': {
                'S': str(price)
            },
            'timestamp': {
                'N': str(current_time_epoch)
            },
            'expire': {
                'N': str(current_time_epoch + (60 * 60 * 24 * 31 * 12))
            }
        }
        # ReturnValues="UPDATED_NEW"
    )
    print(f'Added {region.upper()} price {price} to {recent_table} table')


def update_timestream_token_price(region: str, price: int, current_time_epoch: int) -> None:
    record_inserted = False
    while not record_inserted:
        try:
            print('Attempting to write to Timestream')
            timestream_client.write_records(
                DatabaseName=os.environ['TIMESTREAM_DATABASE'],
                TableName=f'{region}-price-history',
                Records=[
                    build_timestream_record(region, price, current_time_epoch),
                ]
            )
            record_inserted = True
        except Exception as e:
            print(f'Error writing to Timestream: {e}')
            time.sleep(2)
    print(f'Updated {region.upper()} price to {price} in Timestream')


def build_timestream_record(region: str, price: int, current_time_epoch: int) -> dict:
    return {
        'Dimensions': [
            {
                'Name': 'region',
                'Value': region,
                'DimensionValueType': 'VARCHAR'
            }
        ],
        'MeasureName': 'price',
        'MeasureValue': str(price),
        'MeasureValueType': 'BIGINT',
        'Time': str(current_time_epoch),
        'TimeUnit': 'SECONDS',
    }


# get the current stored token price from dynamodb
def get_stored_price(region: str) -> int:
    response = dynamo_client.get_item(
        TableName=current_table,
        Key={
            'region': {
                'S': region
            }
        }
    )
    return int(response['Item']['price']['S'])


def get_combined_live_price() -> dict:
    return {
        'us': get_token_price_from_blizzard('us'),
        'eu': get_token_price_from_blizzard('eu'),
        'kr': get_token_price_from_blizzard('kr'),
        'tw': get_token_price_from_blizzard('tw')
    }


def get_token_price_from_blizzard(region: str):
    api_endpoint = f'https://{region}.api.blizzard.com/data/wow/token/index'
    params = {'namespace': f'{os.environ.get("BLIZZARD_NAMESPACE")}-{region}'}
    headers = {'Authorization': f'Bearer {get_oauth_token()}'}
    response = requests.get(api_endpoint, params=params, headers=headers)
    return int(response.json()['price'])


def get_oauth_token():
    url = 'https://us.battle.net/oauth/token'
    payload = {
        'grant_type': 'client_credentials',
        'client_id': os.environ.get('BLIZZARD_CLIENT_ID'),
        'client_secret': os.environ.get('BLIZZARD_CLIENT_SECRET')
    }
    response = requests.post(url, data=payload)
    return json.loads(response.text)['access_token']


if __name__ == '__main__':
    lambda_handler(None, None)