gas_price.py

import os
import click
import logging
import pandas as pd
from time import sleep
from threading import Thread
from collections import deque
from statistics import mean
from itertools import chain
from web3 import Web3, HTTPProvider
from sanic import Sanic, response
from retry import retry


ETH_RPC_URL = os.environ.get('ETH_RPC_URL', 'http://localhost:8545')
QUANTILES = dict(slow=35, standard=60, fast=90, instant=100)
WINDOW = 200


w3 = Web3(HTTPProvider(ETH_RPC_URL))
app = Sanic()
log = logging.getLogger('sanic.error')
app.config.LOGO = ''
block_times = deque(maxlen=WINDOW)
blocks_gwei = deque(maxlen=WINDOW)
stats = {}


@retry(Exception, delay=1, logger=log)
def worker(skip_warmup):
    stats['health'] = False
    latest = w3.eth.filter('latest')

    if not skip_warmup and not block_times:
        warmup()

    while True:
        for n in latest.get_new_entries():
            process_block(n)
            log.info(str(stats))
        if not w3.eth.syncing:
            stats['health'] = True
        sleep(1)


def warmup():
    tip = w3.eth.blockNumber
    with click.progressbar(range(tip - WINDOW, tip), label='warming up') as bar:
        for n in bar:
            process_block(n)


def block_time():
    if len(block_times) < 2:
        return 0
    times = sorted(block_times)
    avg = mean(b - a for a, b in zip(times, times[1:]))
    stats['block_time'] = round(avg, 2)
    return avg


def process_block(n):
    block = w3.eth.getBlock(n, True)
    stats['block_number'] = block.number

    block_times.append(block.timestamp)
    if len(block_times) > 1:
        t = sorted(block_times)
        stats['block_time'] = round(mean(b - a for a, b in zip(t, t[1:])), 3)

    if block.transactions:
        blocks_gwei.append(min(tx.gasPrice for tx in block.transactions))
        data = pd.Series(blocks_gwei)
        for name, q in QUANTILES.items():
            price = data.quantile(q / 100)
            stats[name] = round(float(w3.fromWei(price, 'gwei')), 3)

    return block


@app.route('/')
async def api(request):
    return response.json(stats)


@app.route('/health')
async def health(request):
    return response.json({'health': stats['health']}, status=200 if stats['health'] else 503)


@click.command()
@click.option('--host', '-h', default='127.0.0.1')
@click.option('--port', '-p', default=8000)
@click.option('--skip-warmup', '-s', is_flag=True)
def main(host, port, skip_warmup):
    bg = Thread(target=worker, args=(skip_warmup,))
    bg.daemon = True
    bg.start()
    app.run(host=host, port=port, access_log=False)


if __name__ == '__main__':
    main()