moonstream/nodebalancer

Node Balancer application

Installation

• Prepare environment variables, according to sample.env.
• Build an application

go build -o nodebalancer .

CLI

IMPORTANT Do not use flag -debug in production.

Node balancer access manipulation requires an administration token to create and modify resources within the Bugout moonstream application.

add new access

Add new access for user:

./nodebalancer access add \
	--access-token "<bugout_access_token>"
	--name "Access name" \
	--description "Description of access"

delete access

Delete user access:

./nodebalancer access delete \
	--access-token "<bugout_access_token>"
	--access-id "<access_uuid>"

If access-id not specified, all user accesses will be deleted.

users

./nodebalancer access list --access-token "<bugout_access_token>" | jq .

This command will return a list of bugout resources of registered users to access node balancer.

[
	{
		"user_id": "<user_id_from_any_bugout_application>",
		"access_id": "<access_uuid_which_provided_with_query>",
		"name": "<short_description_of_purpose_of_this_crawler>",
		"description": "<long_description>",
		"blockchain_access": true,
		"extended_methods": false
	}
]

access_id - token which allows access to nodebalancer, could be specified in both ways:

• as a header x-moonstream-access-id with value access_id
• as query parameter access_id=access_id

blockchain_access - boolean which allows you or not to have access to blockchain node, otherwise you will be redirected to database

extended_methods - boolean which allows you to call not whitelisted method to blockchain node, by default for new user this is equal to false

server

./nodebalancer server --host 0.0.0.0 --port 8544 --healthcheck

Flag --healthcheck will execute background process to ping-pong available nodes to keep their status and current block number. Flag --debug will extend output of each request to server and healthchecks summary.

Work with node

Common request to fetch block number

curl --request POST 'http://127.0.0.1:8544/nb/ethereum/jsonrpc?access_id=<access_id>&data_source=<blockchain/database>' \
    --header 'Content-Type: application/json' \
    --data-raw '{
        "jsonrpc":"2.0",
        "method":"eth_getBlockByNumber",
        "params":["latest", false],
        "id":1
    }'

For Web3 providers access_id and data_source could be specified in headers

--header 'x-node-balancer-data-source: <blockchain/database>'
--header 'x-node-balancer-access-id: <access_id>'

Tests

Running all tests

/usr/local/go/bin/go test -run ^*$ github.com/bugout-dev/moonstream/nodes/node_balancer/cmd/nodebalancer -v -count=1

Running specified test

/usr/local/go/bin/go test -run ^TestCleanInactiveClientNodes$ github.com/bugout-dev/moonstream/nodes/node_balancer/cmd/nodebalancer -v -count=1

Migrations

To run migration:

python migrations/migrations.py run --key 20230522 \
    --token-current-owner "$NB_CONTROLLER_TOKEN" \
    --token-new-owner "$MOONSTREAM_ADMIN_OR_OTHER_CONTROLLER" \
    --new-application-id "$MOONSTREAM_APPLICATION_ID"

Balances Endpoint

The /balances endpoint allows you to retrieve token balances for a specified Ethereum address across multiple blockchains.

Request

GET /balances?address=<ethereumAddress>

Parameters:

• address (required): The Ethereum address to query balances for

Response

The endpoint returns a JSON object with the following structure:

{
  "1": {
    "chain_id": "1",
    "name": "ethereum",
    "image_url": "https://example.com/eth.png",
    "balances": {
      "0x0000000000000000000000000000000000000000": "1000000000000000000",
      "0xdac17f958d2ee523a2206206994597c13d831ec7": "2000000000000000000",
      "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48": "3000000000000000"
    }
  },
  "137": {
    "chain_id": "137", 
    "name": "polygon",
    "image_url": "https://example.com/matic.png",
    "balances": {
      "0x0000000000000000000000000000000000000000": "4000000000000000000",
      "0x2791bca1f2de4661ed88a30c99a7a9449aa84174": "5000000000000000",
      "0xc2132d05d31c914a87c6611c10748aeb04b58e8f": "6000000000000000000"
    }
  }
}

Where:

• The top-level keys are chain IDs (e.g. "1" for Ethereum, "137" for Polygon)
• Each chain object contains:
  • chain_id: The chain identifier as a string
  • name: The human-readable name of the chain
  • image_url: URL to the chain's logo/image
  • balances: Map of token addresses to their balances
    • Native token (ETH, MATIC etc) is represented by the zero address: 0x0000000000000000000000000000000000000000
    • All balances are returned as strings in the token's smallest unit (e.g., wei for ETH)

Features

1. Caching: Responses are cached for 10 seconds to minimize blockchain RPC calls
2. Multicall: Uses Multicall3 contract to batch balance queries for efficiency
3. Error Handling: Individual token or blockchain failures don't affect other

Example

curl "http://localhost:8080/balances?address=0x742d35Cc6634C0532925a3b844Bc454e4438f44e"

Contracts Config Structure

The contracts.json file should follow this structure:

{
  "ethereum": {
    "multicall3": "0xcA11bde05977b3631167028862bE2a173976CA11",
    "chain_id": "1",
    "name": "Ethereum",
    "image_url": "https://example.com/eth.png",
    "native_token": "ETH",
    "tokens": {
      "0xdac17f958d2ee523a2206206994597c13d831ec7": "USDT",
      "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48": "USDC"
    }
  },
  "polygon": {
    "multicall3": "0xcA11bde05977b3631167028862bE2a173976CA11",
    "chain_id": "137",
    "name": "Polygon",
    "image_url": "https://example.com/matic.png",
    "native_token": "MATIC",
    "tokens": {
      "0x2791bca1f2de4661ed88a30c99a7a9449aa84174": "USDC",
      "0xc2132d05d31c914a87c6611c10748aeb04b58e8f": "USDT"
    }
  }
}

Where:

• Top-level keys are blockchain identifiers used internally
• Each chain configuration contains:
  • multicall3: Address of the Multicall3 contract on that chain
  • chain_id: The chain identifier (e.g. "1" for Ethereum)
  • name: Human-readable name of the chain
  • image_url: URL to the chain's logo/image
  • native_token: Symbol for the chain's native token (ETH, MATIC etc)
  • tokens: Map of token addresses to their symbols