Recover onboarded parachain state from a relay chain node.

recover_para_info.py

# Usage python /parachain_info.py wss://relay-rpc.url [local_directory_name]
import sys

# install with `pip install substrate-interface
from substrateinterface import SubstrateInterface


def get_parachain_head(node_client, para_id):
    return str(node_client.query('Paras', 'Heads', params=[para_id]))

def get_parachain_code_hash(node_client, para_id):
    return str(node_client.query('Paras', 'CurrentCodeHash', params=[para_id]))

def get_parachain_wasm(node_client, code_hash):
    return str(node_client.query('Paras', 'CodeByHash', params=[code_hash]))

def paras_list(node_client):
    return node_client.query('Paras', 'Parachains', params=[])

def get_egress_channels(node_client, para_id):
    return str(node_client.query('Hrmp', 'HrmpEgressChannelsIndex', params=[para_id]))

def get_ingress_channels(node_client, para_id):
    return str(node_client.query('Hrmp', 'HrmpIngressChannelsIndex', params=[para_id]))

def get_dmp_queue_heads(node_client, para_id):
    return str(node_client.query('Dmp', 'DownwardMessageQueueHeads', params=[para_id]))

def get_dmp_head_storage_key(node_client, para_id):
    return str(node_client.generate_storage_hash(str('Dmp'), str('DownwardMessageQueueHeads'), [para_id], ['Twox64Concat']))

if len(sys.argv) > 1:
    url = sys.argv[1]
    file_path = sys.argv[2] if len(sys.argv) > 2 else '/tmp'
    node_client = SubstrateInterface(url=url)
    parachain_list = paras_list(node_client)

    for para_id in parachain_list:
        para_id = str(para_id)
        print(f'Parachain ID={para_id}')

        head = get_parachain_head(node_client, para_id)
        if head == 'None':
            continue

        with open(f'{file_path}/state-{para_id}', 'w') as file:
            file.write(head)
        print(f'Chain state writen to {file_path}state-{para_id}')
    
        code_hash = get_parachain_code_hash(node_client, para_id)
        if code_hash == 'None':
            continue

        wasm = get_parachain_wasm(node_client, code_hash)
        with open(f'{file_path}/wasm-{para_id}', 'w') as file:
            file.write(wasm)
        print(f'Chain wasm writen to {file_path}wasm-{para_id}')

        ingress_channels = get_ingress_channels(node_client, para_id)
        with open(f'{file_path}/ingress-channels', 'a') as file:
            file.write(f'{para_id }{ingress_channels}\n')

        egress_channels = get_egress_channels(node_client, para_id)
        with open(f'{file_path}/egress-channels', 'a') as file:
            file.write(f'{para_id }{egress_channels}\n')

        dmp_head = get_dmp_queue_heads(node_client, para_id)
        dmp_head_storage_key = get_dmp_head_storage_key(node_client, para_id)
        with open(f'{file_path}/dmp_heads', 'a') as file:
            file.write(f'{para_id }\nKey: {dmp_head_storage_key}\nValue: {dmp_head}\n')
else:
    print('No WS URL provided as arg')