capsul-flask/capsulflask/http_client.py

import sys
import json

import aiohttp
import asyncio
from flask import current_app
from capsulflask.db import  my_exec_info_message
from capsulflask.db_model import OnlineHost
from typing import List

class HTTPResult:
  def __init__(self, status_code, body=None):
    self.status_code = status_code
    self.body = body

class MyHTTPClient:
  def __init__(self, timeout_seconds = 5):
    self.client_session = aiohttp.ClientSession(timeout=aiohttp.ClientTimeout(total=timeout_seconds))
    self.event_loop = asyncio.get_event_loop()

  def make_requests_sync(self, online_hosts: List[OnlineHost], body: str) -> List(HTTPResult):
    self.event_loop.run_until_complete(self.make_requests(online_hosts=online_hosts, body=body))

  def post_json_sync(self, url: str,  body: str, method="POST", authorization_header=None) -> HTTPResult:
      self.event_loop.run_until_complete(self.post_json_sync(method=method, url=url, body=body))

  async def post_json(self, url: str,  body: str, method="POST", authorization_header=None) -> HTTPResult:
    response = None
    try:
      headers = {}
      if authorization_header != None:
        headers['Authorization'] = authorization_header
      response = await self.client_session.request(
        method=method, 
        url=url, 
        json=body, 
        headers=headers,
        auth=aiohttp.BasicAuth("hub", current_app.config['HUB_TOKEN']), 
        verify_ssl=True,
      )
    except:
      error_message = my_exec_info_message(sys.exc_info())
      response_body = json.dumps({"error_message": f"error contacting spoke: {error_message}"})
      current_app.logger.error(f"""
        error contacting spoke: post_json (HTTP {method} {url}) failed with: {error_message}"""
      )
      return HTTPResult(-1, response_body)

    response_body = None
    try:
      response_body = await response.text()
    except:
      error_message = my_exec_info_message(sys.exc_info())
      response_body = json.dumps({"error_message": f"error reading response from spoke: {error_message}"})
      current_app.logger.error(f"""
        error reading response from spoke: HTTP {method} {url} (status {response.status}) failed with: {error_message}"""
      )
      
    return HTTPResult(response.status, response_body)

  async def make_requests(self, online_hosts: List[OnlineHost], body: str) -> List(HTTPResult):
    tasks = []
    # append to tasks in the same order as online_hosts
    for host in online_hosts:
        tasks.append(
            self.post_json(url=host.url, body=body)
        )
    # gather is like Promise.all from javascript, it returns a future which resolves to an array of results 
    # in the same order as the tasks that we passed in -- which were in the same order as online_hosts
    results = await asyncio.gather(*tasks)

    return results