config.json

Overview

The `config.json` file serves as the primary configuration source for a Blockbook Indexer Service instance tailored to the Dogecoin blockchain. This JSON configuration file contains all necessary parameters for connecting to the Dogecoin RPC node, managing indexer worker concurrency, setting caching policies, integrating fiat currency exchange rates, and specifying blockchain-specific parameters such as address format and extended public key magic bytes.

This file enables the indexer service to operate correctly by providing connection credentials, runtime options, and external service endpoints. It is critical in customizing the indexer's behavior to the targeted blockchain and its ecosystem.

Detailed Explanation of Configuration Fields

Usage and Examples

Loading Configuration in the Indexer

The indexer service loads `config.json` at startup to configure its runtime behavior. For example, in Node.js:

const fs = require('fs');

const config = JSON.parse(fs.readFileSync('config.json', 'utf8'));

console.log(`Connecting to RPC node at ${config.rpc_url} with user ${config.rpc_user}`);

Example: Configuring Fiat Rates Fetching

The indexer uses the `fiat_rates`, `fiat_rates_vs_currencies`, and `fiat_rates_params` to query CoinGecko every 900 seconds for Dogecoin price data:

"fiat_rates": "coingecko",
"fiat_rates_vs_currencies": "USD,EUR,BTC,ETH,...",
"fiat_rates_params": "{\"url\": \"https://api.coingecko.com/api/v3\", \"coin\": \"dogecoin\", \"periodSeconds\": 900}"

The indexer's fiat rate module parses `fiat_rates_params` into an object and schedules periodic HTTP GET requests to:

https://api.coingecko.com/api/v3/simple/price?ids=dogecoin&vs_currencies=USD,EUR,BTC,ETH,...

Important Implementation Details

• RPC Connection: The indexer authenticates with the Dogecoin RPC node using rpc_user and rpc_pass and makes JSON-RPC calls over HTTP. The rpc_timeout governs the maximum wait time per RPC request.

• Mempool Workers: The fields mempool_workers and mempool_sub_workers control the concurrency level for processing unconfirmed transactions. This parallelism helps maintain responsive mempool tracking under high load.

• Cache Management: block_addresses_to_keep defines how many recent blocks’ worth of address data are cached in memory. This parameter balances memory consumption against query performance.

• Extended Public Key (xpub) Magic: The xpub_magic value is critical for wallet derivation and validation, ensuring that HD wallets are compatible with Dogecoin-specific key versions per SLIP-44 standard.

• Fiat Rates Integration: The fiat rates configuration allows the indexer to enrich transaction and address data with fiat values, enabling clients and API servers to display current or historical price information alongside blockchain data.

• Message Queue Binding: The message_queue_binding field is used to connect the indexer to a message queue (e.g., ZeroMQ or TCP socket) for receiving real-time blockchain updates or synchronizing across distributed indexer instances.

Interaction with Other System Components

• Daemon Node: The indexer connects to the Dogecoin daemon node via RPC (rpc_url) to fetch blockchain data, such as blocks and transactions.

• Message Queue: Via message_queue_binding, the indexer subscribes to blockchain event streams, allowing near real-time processing of new blocks and mempool transactions.

• API Servers: The indexer exposes processed and cached blockchain data to API servers, which serve client applications requesting transaction histories, balances, and mempool status.

• Fiat Rate Provider: The indexer periodically queries the external fiat rate provider (CoinGecko) configured in fiat_rates_params to obtain up-to-date exchange rates for Dogecoin against a list of fiat and crypto currencies.

• Wallets/Clients: Wallet software or clients consuming API data rely on parameters like address_format, xpub_magic, and slip44 to interpret addresses and keys correctly for Dogecoin.

Visual Diagram: Configuration Structure Flowchart

flowchart TD
    Config[config.json]

    Config --> RPC[RPC Connection]
    Config --> Mempool[Mempool Workers]
    Config --> Cache[Cache Settings]
    Config --> FiatRates[Fiat Rates Integration]
    Config --> MsgQueue[Message Queue Binding]
    Config --> BlockchainParams[Blockchain Parameters]

    RPC -->|Uses| rpc_url
    RPC -->|Uses| rpc_user
    RPC -->|Uses| rpc_pass
    RPC -->|Uses| rpc_timeout

    Mempool -->|Controls| mempool_workers
    Mempool -->|Controls| mempool_sub_workers

    Cache -->|Defines| block_addresses_to_keep

    FiatRates -->|Provider| fiat_rates
    FiatRates -->|Currencies| fiat_rates_vs_currencies
    FiatRates -->|Params| fiat_rates_params

    MsgQueue -->|Binding URI| message_queue_binding

    BlockchainParams -->|Coin Info| coin_name
    BlockchainParams -->|Coin Symbol| coin_shortcut
    BlockchainParams -->|Coin Label| coin_label
    BlockchainParams -->|Address Format| address_format
    BlockchainParams -->|xpub Magic| xpub_magic
    BlockchainParams -->|SLIP44 Index| slip44

Summary

The `config.json` file is a foundational configuration artifact for the Dogecoin Blockbook Indexer, specifying how the indexer connects to blockchain nodes, processes mempool transactions, caches address data, and integrates external fiat currency rates. It also defines blockchain-specific parameters that ensure data is interpreted and served correctly downstream to API servers and clients.

The clarity and completeness of this configuration enable the indexer to efficiently and reliably index Dogecoin blockchain data, supporting fast queries, real-time event notifications, and enriched data views for end users.

End of Documentation for config.json