Async Basic Callchain

# -*- coding: utf-8 -*-

import asyncio
import os
import sys


import ccxt.async_support as ccxt  # noqa: E402


async def run_all_exchanges(exchange_ids):
   results = {}

   for exchange_id in exchange_ids:

       exchange = getattr(ccxt, exchange_id)({
           'options': {
               'useWebapiForFetchingFees': False,
           }
       })

       symbol = 'ETH/BTC'
       print('Exchange:', exchange_id)

       print(exchange_id, 'symbols:')
       markets = await load_markets(exchange, symbol)  # ←----------- STEP 1
       print(list(markets.keys()))

       print(symbol, 'ticker:')
       ticker = await fetch_ticker(exchange, symbol)  # ←------------ STEP 2
       print(ticker)

       print(symbol, 'orderbook:')
       orderbook = await fetch_orderbook(exchange, symbol)  # ←------ STEP 3
       print(orderbook)

       await exchange.close()  # ←----------- LAST STEP GOES AFTER ALL CALLS

       results[exchange_id] = ticker

   return results


async def load_markets(exchange, symbol):
   try:
       result = await exchange.load_markets()
       return result
   except ccxt.BaseError as e:
       print(type(e).__name__, str(e), str(e.args))
       raise e


async def fetch_ticker(exchange, symbol):
   try:
       result = await exchange.fetch_ticker(symbol)
       return result
   except ccxt.BaseError as e:
       print(type(e).__name__, str(e), str(e.args))
       raise e


async def fetch_orderbook(exchange, symbol):
   try:
       result = await exchange.fetch_order_book(symbol)
       return result
   except ccxt.BaseError as e:
       print(type(e).__name__, str(e), str(e.args))
       raise e


if __name__ == '__main__':
   exchange_ids = ['bitfinex', 'okex', 'exmo']
   exchanges = []
   results = asyncio.run(run_all_exchanges(exchange_ids))
   print([(exchange_id, ticker) for exchange_id, ticker in results.items()])