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Stakeholder Proposals / b solution for hot standby(From BitSuperLab)
« on: July 30, 2014, 05:53:35 am »
here is another solution for hot standby, detected with a heartbeat signal.
master and slave exchange some data in real time, include: blockchain_head_block_num, network_num_connections.
they'll change block production flag automatic, depend on a rule to select which one should active.
we use a pusher service from PubNub to exchange data, this can avoid open a public service, and can still run behind a tor net.
so you need to register a free account in PubNub if you decide to use this. the demo account maybe not stable.
here is the command
here is the config file: config.json
master and slave exchange some data in real time, include: blockchain_head_block_num, network_num_connections.
they'll change block production flag automatic, depend on a rule to select which one should active.
we use a pusher service from PubNub to exchange data, this can avoid open a public service, and can still run behind a tor net.
so you need to register a free account in PubNub if you decide to use this. the demo account maybe not stable.
here is the command
Code: [Select]
./heartbeat.py master # run on master side
./heartbeat.py slave # run on slave side
here is the source code heartbeat.py, you need to install pubnub firstCode: [Select]
## www.pubnub.com - PubNub Real-time push service in the cloud.
# coding=utf8
## PubNub Real-time Push APIs and Notifications Framework
## Copyright (c) 2010 Stephen Blum
## http://www.pubnub.com/
#### required:
#### aptitude install python-pip
#### pip install pubnub==3.5.2
import requests
import json
import os
from pprint import pprint
import sys
from Pubnub import Pubnub
import datetime, threading, time
node_type = len(sys.argv) > 1 and sys.argv[1] or 'master'
if node_type == 'master':
node_type_other = 'slave'
else:
node_type = 'slave'
node_type_other = 'master'
print "node typ is " + node_type
config_data = open('config.json')
config = json.load(config_data)
config_data.close()
node_state = {'master':{'connect_num':100,'block_num':100000000}, 'slave':{'connect_num':0,'block_num':0}}
#pprint(config)
## -----------------------------------------------------------------------
## function about bts rpc
## -----------------------------------------------------------------------
auth = (config["bts_rpc"]["username"], config["bts_rpc"]["password"])
url = config["bts_rpc"]["url"]
def get_state():
global node_state
headers = {'content-type': 'application/json'}
info = {
"method": "get_info",
"params": [],
"jsonrpc": "2.0",
"id": 1
}
info_res = requests.post(url, data=json.dumps(info), headers=headers, auth=auth)
info_json = json.loads(vars(info_res)["_content"])
node_state[node_type]["block_num"] = info_json["result"]["blockchain_head_block_num"]
node_state[node_type]["connect_num"] = info_json["result"]["network_num_connections"]
node_state[node_type]["wallet_next_block_production_timestamp"] = info_json["result"]["wallet_next_block_production_timestamp"]
def is_active():
global node_state
return node_state[node_type]["wallet_next_block_production_timestamp"] != None
# unlock the delegate first in nodes
def set_delegate_production(enable):
if is_active() == enable:
return
headers = {'content-type': 'application/json'}
set_delegate = {
"method": "wallet_delegate_set_block_production",
"params": ["ALL", enable],
"jsonrpc": "2.0",
"id": 1
}
set_res = requests.post(url, data=json.dumps(set_delegate), headers=headers, auth=auth)
set_json = json.loads(vars(set_res)["_content"])
print 'set_delegate_production', enable, 'result:',set_json
def switch_active(type):
#print "switch active to", type
if node_type == type:
set_delegate_production(True)
else:
set_delegate_production(False)
def select_active():
# TODO check the next bock production timestamp of antoher node, require enough time (at least 2 min) for switch
if node_state["master"]["connect_num"] < 20 and node_state["slave"]["connect_num"] > 22:
switch_active("slave")
elif node_state["master"]["block_num"] + 2 < node_state["slave"]["block_num"]:
switch_active("slave")
else:
switch_active("master")
## -----------------------------------------------------------------------
## function about pubnub
## -----------------------------------------------------------------------
# Asynchronous usage
def callback(message, channel):
global node_state
node_state[node_type_other] = message
print datetime.datetime.now(), 'receive', node_state[node_type_other]
def error(message):
print("ERROR : " + str(message))
def state_publish():
global node_state
global next_call
get_state()
print datetime.datetime.now(), 'publish', node_state[node_type]
pubnub.publish(node_type, node_state[node_type])
select_active()
next_call = next_call + 10
threading.Timer( next_call - time.time(), state_publish).start()
## -----------------------------------------------------------------------
## Initiate Pubnub State
## -----------------------------------------------------------------------
publish_key = config["pubnub_auth"]["publish_key"]
subscribe_key = config["pubnub_auth"]["subscribe_key"]
secret_key = config["pubnub_auth"]["secret_key"]
cipher_key = config["pubnub_auth"]["cipher_key"]
ssl_on = False
pubnub = Pubnub(publish_key=publish_key, subscribe_key=subscribe_key,
secret_key=secret_key, cipher_key=cipher_key, ssl_on=ssl_on)
pubnub.subscribe(node_type_other, callback=callback, error=error)
next_call = (int (time.time() / 10)) * 10 + 5
state_publish()
here is the config file: config.json
Code: [Select]
{
"pubnub_auth": {
"_comment": "demo is for test, you should register from https://admin.pubnub.com, and set this key to yourself",
"publish_key" : "demo",
"subscribe_key" : "demo",
"secret_key" : "demo",
"cipher_key" : ""
},
"bts_rpc": {
"url": "http://localhost:9989/rpc",
"username": "user",
"password": "pass"
}
}
