grid_listener.py

#!/usr/bin/env python2.7

import json
import time
from noisemap import perform_noise_calculation_and_get_result, boot_h2_database_in_subprocess
from city_scope.parse_city_scope_table import save_buildings_from_city_scope
import argparse
import cityio_socket

# checks for updates on the cityIO grid
# If the grid changes the city-scope parser is called to create a new buildings.json
# The noise calculation is triggered
if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='calculate noise levels from cityIO.')
    parser.add_argument('--endpoint', type=int, default=-1,help="endpoint url to choose from config.ini/input_urls")
    args = parser.parse_args()
    print("endpoint",args.endpoint)

    try:
        with open("token.txt") as f:
            token = f.readline()
        if token == "": token = None  # happens with empty file
    except IOError:
        token = None

    oldHash = ""

    while True:
        gridHash = cityio_socket.getCurrentState("meta/hashes/grid", int(args.endpoint), token)  
        if gridHash != {} and gridHash != oldHash:

            # get the data from cityIO, convert it to geojson and write it to config['SETTINGS']['INPUT_JSON_BUILDINGS']
            save_buildings_from_city_scope(args.endpoint, token)

            # boot a h2_database server and import psycopg2 to connect to it
            h2_subprocess, psycopg2 = boot_h2_database_in_subprocess()
            # start noise calculation
            resultdata = perform_noise_calculation_and_get_result(psycopg2)
            resultdata["grid_hash"] = gridHash # state of grid, the results are based on

            # Also post result to cityIO
            print("trying to post to cityIO")
            cityio_socket.sendToCityIO(resultdata, int(args.endpoint), token)
            oldHash = gridHash

            # close h2_subprocess as it permanently blocks 1gb of memory
            h2_subprocess.terminate()
            # kills the process zombie
            h2_subprocess.wait()
            print("h2 database terminated")
        # grid has not changed
        else:
            print("No changes in grid")
            time.sleep(5)