Before diving in, you'll need two things:
- installation of Python 3.x - I'll be using 3.9
- either Build Tools for Visual Studio 2019 or Visual Studio 2022 (Community Edition) - this is required to automatically compile some of the python packages that come in source form
C:\nem\monitoring-win〉python3 -m pip install symbol-sdk-python --progress-bar off
Collecting symbol-sdk-python
Using cached symbol_sdk_python-3.1.0-py3-none-any.whl (77 kB)
Collecting pyzbar<0.2.0,>=0.1.9
Using cached pyzbar-0.1.9-py2.py3-none-win_amd64.whl (817 kB)
Collecting pillow<10.1.0,>=10.0.0
Using cached Pillow-10.0.0-cp39-cp39-win_amd64.whl (2.5 MB)
Collecting pynacl<1.6.0,>=1.5.0
Using cached PyNaCl-1.5.0-cp36-abi3-win_amd64.whl (212 kB)
Collecting qrcode<7.5.0,>=7.4.2
Using cached qrcode-7.4.2-py3-none-any.whl (46 kB)
Collecting pyyaml<6.1.0,>=6.0.1
Using cached PyYAML-6.0.1-cp39-cp39-win_amd64.whl (152 kB)
Collecting cryptography<41.1.0,>=41.0.3
Using cached cryptography-41.0.3-cp37-abi3-win_amd64.whl (2.6 MB)
Collecting safe-pysha3<1.1.0,>=1.0.4
Using cached safe_pysha3-1.0.4-cp39-cp39-win_amd64.whl
Collecting mnemonic<1.0,>=0.20
Using cached mnemonic-0.20-py3-none-any.whl (62 kB)
Collecting ripemd-hash<1.1.0,>=1.0.1
Using cached ripemd_hash-1.0.1-cp39-cp39-win_amd64.whl
Collecting cffi>=1.12
Using cached cffi-1.15.1-cp39-cp39-win_amd64.whl (179 kB)
Requirement already satisfied: pycparser in x:\users\gimre\appdata\local\programs\python\python39\lib\site-packages (from cffi>=1.12->cryptography<41.1.0,>=41.0.3->symbol-sdk-python) (2.21)
Requirement already satisfied: typing-extensions in x:\users\gimre\appdata\local\programs\python\python39\lib\site-packages (from qrcode<7.5.0,>=7.4.2->symbol-sdk-python) (4.7.1)
Requirement already satisfied: pypng in x:\users\gimre\appdata\local\programs\python\python39\lib\site-packages (from qrcode<7.5.0,>=7.4.2->symbol-sdk-python) (0.20220715.0)
Requirement already satisfied: colorama in x:\users\gimre\appdata\local\programs\python\python39\lib\site-packages (from qrcode<7.5.0,>=7.4.2->symbol-sdk-python) (0.4.6)
Installing collected packages: cffi, safe-pysha3, ripemd-hash, qrcode, pyzbar, pyyaml, pynacl, pillow, mnemonic, cryptography, symbol-sdk-python
Successfully installed cffi-1.15.1 cryptography-41.0.3 mnemonic-0.20 pillow-10.0.0 pynacl-1.5.0 pyyaml-6.0.1 pyzbar-0.1.9 qrcode-7.4.2 ripemd-hash-1.0.1 safe-pysha3-1.0.4 symbol-sdk-python-3.1.0
C:\nem\monitoring-win〉python3 -m pip install symbol-lightapi
Collecting symbol-lightapi
Downloading symbol-lightapi-0.0.5.tar.gz (24 kB)
Installing build dependencies ... done
Getting requirements to build wheel ... done
Preparing wheel metadata ... done
Building wheels for collected packages: symbol-lightapi
Building wheel for symbol-lightapi (PEP 517) ... done
Created wheel for symbol-lightapi: filename=symbol_lightapi-0.0.5-cp39-abi3-win_amd64.whl size=47046 sha256=6cdad06e0ba635bf6dddf2dc1272aeb6556ad146265524fde790057c3cb57767
Stored in directory: x:\users\gimre\appdata\local\pip\cache\wheels\8b\56\d8\4576d5e9f7c6cd071182a6ed4aaf084a9e5aa07939869fcf9f
Successfully built symbol-lightapi
Installing collected packages: symbol-lightapi
Successfully installed symbol-lightapi-0.0.5It seems lightapi package did not install it automatically, so we'll also need few more packages:
C:\nem\monitoring-win〉python3 -m pip install asyncio aiohttp zenlog
Collecting asyncio
Collecting aiohttp
Collecting zenlog
Installing collected packages: zenlog, asyncio, aiohttp
Successfully installed aiohttp-3.8.5 asyncio-3.4.3 zenlog-1.1
Now, that went well.
First some code, that I'll be describe in details below
import asyncio
from symbollightapi.connector.SymbolConnector import SymbolConnector
from symbollightapi.model.Exceptions import NodeException
async def main():
symbol_nodes = [
'https://angel.vistiel-arch.jp:3001',
'https://yumeya1.com:3001',
'https://age01.kitsutsuki.tokyo:3001',
'http://xymharvesting.net:3000'
]
symbol_connectors = [SymbolConnector(name) for name in symbol_nodes]
symbol_heights = {}
async def get_height(connector):
try:
height = await connector.chain_height()
except NodeException:
print(f'exception occured, when talking with node {connector.endpoint}')
height = 0
symbol_heights[connector.endpoint] = height
symbol_promises = [get_height(connector) for connector in symbol_connectors]
await asyncio.gather(*symbol_promises)
for name, height in sorted(symbol_heights.items()):
print(f'{name:40} {height}')
if '__main__' == __name__:
asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
asyncio.run(main())First we have set of imports:
import asyncio
from symbollightapi.connector.SymbolConnector import SymbolConnector
from symbollightapi.model.Exceptions import NodeExceptionasyncio is needed because whole application will be asynchronous. SymbolConnector will be used to talk to the nodes. Connectors might raise NodeException.
Now let's take a look at the bottom, there's quite usual:
if '__main__' == __name__:
asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
asyncio.run(main())This fires main() function within asynchronous loop. Call to set_event_loop_policy is required on Windows.
It's time to examine main function:
symbol_nodes = [
'https://angel.vistiel-arch.jp:3001',
'https://yumeya1.com:3001',
'https://age01.kitsutsuki.tokyo:3001',
'http://xymharvesting.net:3000'
]
symbol_connectors = [SymbolConnector(name) for name in symbol_nodes]Just some random Symbol REST endpoint, that are wrapped into SymbolConnectors array, right below.
symbol_heights = {}
async def get_height(connector):
try:
height = await connector.chain_height()
except NodeException:
print(f'exception occured, when talking with node {connector.endpoint}')
height = 0
symbol_heights[connector.endpoint] = height
Next we have a helper method that will invoke async method connector.chain_height() SymbolConnector.chain_height and store results for each node in symbol_heights dictionary.
symbol_promises = [get_height(connector) for connector in symbol_connectors]
await asyncio.gather(*symbol_promises)That's an array with promises, asyncio.gather will wait for promises to finish (I'm simplifying here, consult the docs if you want to know what it does).
Finally last part, just displays the results
for name, height in sorted(symbol_heights.items()):
print(f'{name:40} {height}')Yes, the example above can easily be modified to talk to nem nodes:
- there's symbollightapi.connector.NemConnector
- nem endpoints look like:
http://nis1.dusan.gq:7890
This part is slightly more complicated, as there's certificate required to talk with nodes.
On linux/macOS shoestring could be used to generate certs, on win there are currently problems with this, so let me refer you to this part instead: Generating Symbol certificates using openssl.
There are only slight differences:
- there's
SymbolPeerConnector, but it takes (host, port) pair rather than endpoint - obviously it also requires mentioned certificate directory (to identify to a node)
import asyncio
from pathlib import Path
from symbollightapi.connector.SymbolPeerConnector import SymbolPeerConnector
from symbollightapi.model.Exceptions import NodeException
async def get_height(connector):
try:
height = await connector.chain_height()
except NodeException:
print(f'exception occured, when talking with node {connector.node_host}:{connector.node_port}')
height = 0
return height
async def store(map_name, connector, callback):
result = await callback(connector)
name = f'{connector.node_host}:{connector.node_port}'
map_name[name] = result
async def main():
symbol_nodes = [
'ahra-symbol.com',
'x.innermedia.net',
'harvest-01.symbol.farm',
'i.symbol-nember.tokyo'
]
symbol_connectors = [SymbolPeerConnector(node_host, 7900, Path('cert')) for node_host in symbol_nodes]
symbol_heights = {}
symbol_promises = [store(symbol_heights, connector, get_height) for connector in symbol_connectors]
await asyncio.gather(*symbol_promises)
for name, height in sorted(symbol_heights.items()):
print(f'{name:40} {height}')
if '__main__' == __name__:
asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
asyncio.run(main())And result at the time of writing this:
ahra-symbol.com:7900 2516481
harvest-01.symbol.farm:7900 2516481
i.symbol-nember.tokyo:7900 2516481
x.innermedia.net:7900 2516481