ffapi-update-nodes.py

#!/usr/bin/python3

# This script can be used to dynamically update your ffapi-json-file with 
# the number of currently running nodes.

# The number of running nodes is received by parsing the output of the olsr
# jsoninfo plugin.

# Quickly hacked together by soma (freifunk at somakoma dot de) and released
# into the public domain.

# Version: 0.1

import os
import json
from datetime import datetime, timezone
from urllib.request import urlopen
# Configuration - replace these variables with your settings

host = '127.0.0.1'
port = 9090
olsrServices = "/var/run/services_olsr"
apiFile = "/var/www/ffapi/ffapi.json"

# End of configuration

def getTopo():
    """ Get the topology information from jsoninfo and return a dictionary """
    response = ''
    try:
        url = f"http://{host}:{port}/topology"
        response = urlopen(url, None, 10)
    except BaseException as e:
        print('Error, could not connect to %(host)s:%(port)s' % {"host": host, "port": port})
        print('Make sure the host is reachable and jsoninfo is running there.')
        exit()

    topo = {}
    if response != '':
        topo = json.loads(response.read().decode('utf-8'))['topology']
    else:
        print('Could not get any info from jsoninfo on %(host)s:%(port)s' % {"host": host, "port": port})
        print('Does it accept connections from this host?')
        exit()
    return topo

def uniqueIPs(topo):
    """ Iterate over a topology dictionary and create an array of unique node ips """
    ips = []
    for t in topo:
        ip = t['destinationIP']
        if not ip in ips:
            ips.append(ip)
    return ips

def getServices():
    """ read services from olsrServices """
    if not olsrServices or olsrServices == '':
        return False

    servicesText = []
    if not os.access(olsrServices, os.R_OK):
        print('Error: Could not read %(file)s.' % { "file": olsrServices })
        print('Make sure the path is correct and your user has read and write permissions.')
        return False
    with open(olsrServices, 'r') as services:
        servicesText = services.read().splitlines()
        services.closed
    return servicesText


def loadApiFile():
    """ Load an api file into a dictionary """
    if not os.access(apiFile, os.R_OK):
        print('Error: Could not read %(file)s.' % { "file": apiFile })
        print('Make sure the path is correct and your user has read and write permissions.')
        exit()
    with open(apiFile, 'r') as ffapi:
        apidict = json.load(ffapi)
        ffapi.closed
    return apidict

def updateApiNodes(apiDict, countNodes):
    """ Updates an ffapi dictionary with number of nodes and timestamp """
    try:
        apiDict['state']['nodes'] = countNodes
    except KeyError:
        print('Could not update %(field)s in the ffapi dictionary.' % { "field": "['state']['nodes']" })

    try:
        apiDict['state']['lastchange'] = datetime.now(timezone.utc).isoformat()
    except KeyError:
        print('Could not update %(field)s in the ffapi dictionary.' % { "field": "['state']['lastchange']" })
    return apiDict

def updateApiServices(apiDict, services):
    """ Updates the services section """
    if not 'services' in apiDict:
        apiDict['services'] = []

    for element in reversed(apiDict['services']):
        if (element['serviceDescription'] == "auto generated by olsr nameservice plugin"): 
            apiDict['services'].remove(element)
    for line in services:
        if (line == '' or line[1] == '#' or line.split("|").__len__() < 2 ): continue
        servicesDict = dict()
        serviceList = line.split("|")
        servicesDict['serviceName'] = serviceList[2].split("\t")[0]
        servicesDict['serviceDescription'] = "auto generated by olsr nameservice plugin"
        servicesDict['internalUri'] = serviceList[0]
        apiDict['services'].append(servicesDict)
    return apiDict



def writeApiFile(content):
    """ writes the dictionary to the ffapi json file """
    if not os.access(apiFile, os.W_OK):
        print('Error: Could not write %(file)s.' % { "file": apiFile })
        print('Make sure the path is correct and your user has write permissions for it.')
        exit()

    with open(apiFile, 'w') as ffapi:
        ffapi.write(json.dumps(content, indent=4))
    return True


def main():
    countNodes = len(uniqueIPs(getTopo()))
    apiDict = loadApiFile()
    apiDictUpdated = updateApiNodes(apiDict, countNodes)
    services = getServices()
    if services:
        apiDictUpdated = updateApiServices(apiDictUpdated, services)
    

    if writeApiFile(apiDictUpdated):
        print(('Update of %s successful.' % apiFile))
        print(('We now have %d Nodes' % countNodes))
        if services:
            print(('and %d services' % len(apiDictUpdated['services'])))

if __name__ == "__main__":
    main()