monitor-image.py

#!/usr/bin/env python3

import subprocess
import time
import os
from datetime import datetime


# Check after every X minutes
delay = 60
upgrade_during_consensus = False

# Image name
image = 'quay.io/team-helium/validator:latest-validator-amd64'


def run(cmd, check=True):
    try:
        p = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, check=check)
    except subprocess.CalledProcessError:
        print(f'Error: could not execute `{" ".join(cmd)}`')
        return ''
    out = p.stdout.decode('utf-8')
    try:
        return out.split('\n')[0]
    except:
        return ''


def pull_image():
    run(['docker', 'pull', image])

def running_version():
    container = run(['docker', 'ps', '-q'])
    if not container:
        return ''
    else:
        return run(['docker', 'inspect', "--format='{{.Image}}'", container])


def downloaded_version():
    return run(['docker', 'inspect', "--format='{{index .Id}}'", image])


def in_consensus():
    try:
        status = bool(run(['docker', 'exec', 'validator', 'miner', 'info', 'in_consensus'], check=False))
    except:
        return False


def timestamp():
    return datetime.now().strftime('%Y-%m-%d %H:%M:%S')


while True:
    pull_image()

    dv = downloaded_version()
    rv = running_version()

    if not (rv == dv):
        if upgrade_during_consensus or (not in_consensus()):
            print(f'[{timestamp()}] Launching new Docker container {dv}')
            run(['docker', 'stop', 'validator'], check=False)
            run(['docker', 'rm', 'validator'], check=False)
            run(['docker', 'run', '-d',
                 '--restart', 'always',
                 '--publish', '2154:2154/tcp',
                 '--publish', '8080:8080/tcp',
                 '--name', 'validator',
                 '--mount',
                 os.path.expandvars('type=bind,source=$HOME/validator_data,target=/var/data'),
                 image])

            print(f'[{timestamp()}] Pruning old images')
            run(['docker', 'image', 'prune', '-f'], check=False)
        else:
            print(f'[{timestamp()}] Currently in consensus group; holding off on upgrade')

    print(f'[{timestamp()}] Waiting {delay} minutes')
    time.sleep(delay * 60)