Crypto Client POC Application

This Crypto Client Proof of Concept (POC) application is designed to work in conjunction with the crypto-monitor-api-poc project. It fetches cryptocurrency data from Coingecko.com, processes it, and sends it to the crypto-monitor-api-poc service for storage and monitoring purposes.

Features

Fetch current cryptocurrency data from Coingecko API
Update historical data for multiple cryptocurrencies
Parse data into Coin format
Post processed data to crypto-monitor-api-poc service
Respect API rate limiting to prevent request throttling
Robust error handling and retry mechanism
Efficient data processing
Comprehensive logging for monitoring and debugging

Coin Object

The Coin object is a crucial component of this client application. It serves as the data model for cryptocurrency information and is used for communication with the crypto-monitor-api-poc service.

The Coin class is defined in the crypto-monitor-api-poc project and is included as a dependency in this client. The client application populates Coin objects with data fetched from Coingecko and sends these objects to the server, which expects this specific format.

Key fields of the Coin object include:

coinId: Unique identifier for the cryptocurrency
coinName: Name of the cryptocurrency
symbol: Symbol of the cryptocurrency
priceUsd, priceEur, priceBtc, priceEth: Current prices in various currencies
marketCapUsd, marketCapEur, marketCapBtc, marketCapEth: Market capitalization data
timestamp: Time of data retrieval

For a complete list of fields and methods, refer to the Coin.java file in the crypto-monitor-api-poc project.

Prerequisites

Before setting up and running the Crypto Client POC, ensure you have the following:

Java 11 or higher
Maven 3.6 or higher
crypto-monitor-api-poc project set up and built:
- Clone the crypto-monitor-api-poc repository
- Navigate to the crypto-monitor-api-poc directory
- Run mvn clean install to build the project and install its artifacts in your local Maven repository
  - This step is crucial as the Crypto Client POC depends on classes (such as the Coin object) from the crypto-monitor-api-poc project
The crypto-monitor-api-poc service should be running and accessible:
- Start the crypto-monitor-api-poc service (either in a Docker container or as a standalone Java application)
- Ensure the service is accessible at http://localhost:8080
  - This is the default URL the Crypto Client POC will use to communicate with the backend service
- If you need to use a different URL, update the backendUrl in the CryptoConfig class accordingly

Ensuring these prerequisites are met will allow for smooth compilation, execution, and proper functionality of the Crypto Client POC application.

Installation

Clone the repository:

git clone https://github.com/src-dbgr/crypto-client-poc.git

Navigate to the project directory:
```
cd crypto-client-poc
```
Build the project using Maven:
```
mvn clean install
```

Usage

The CryptoClient now offers the following main operations for both bulk and individual cryptocurrency data fetching:

updateCurrentData(): Updates all chosen and backend-enabled cryptos with current price and metadata information.
updateCurrentData(CryptoId cryptoId): Updates a single cryptocurrency with current price and metadata information.
updateHistoricalData(): Fetches and updates historical data for all cryptocurrencies based on the last valid date from the backend.
updateHistoricalData(CryptoId cryptoId): Fetches and updates historical data for a single cryptocurrency based on the last valid date from the backend.
fetchAllHistoricalData(int timeFrame): Updates historical data for all cryptocurrencies for the specified number of days, starting from today and going backwards.
fetchAllHistoricalData(CryptoId cryptoId, int timeFrame): Updates historical data for a single cryptocurrency for the specified number of days, starting from today and going backwards.

To use the CryptoClient:

Ensure the crypto-monitor-api-poc is up and running.
The CryptoId enum in the crypto.config package now defines all supported cryptocurrencies. Use these enum values when working with individual cryptocurrencies.
In the main method of CryptoClient, uncomment, or remove comment, or modify the operations you want to execute.
The major methods are now:
- client.updateCurrentData()
- client.updateCurrentData({CryptoId})
- client.updateHistoricalData()
- client.updateHistoricalData({CryptoId})
- client.fetchAllHistoricalData({time-frame})
- client.fetchAllHistoricalData({CryptoId}, {time-frame})
Run the CryptoClient as a Java application.

Example usage in main method:

public static void main(String[] args) {
    // ... initialization code ...

    CryptoClient client = new CryptoClient(config, dataSource, backendService);

    try {
        LOG.info("Updating current crypto data for all cryptocurrencies...");
        client.updateCurrentData();
        LOG.info("Current crypto data update completed for all cryptocurrencies.");

        // ...

    } catch (Exception e) {
        LOG.error("An error occurred", e);
    }
}

Configuration

The application configuration is managed through the CryptoConfig class. This class contains several important settings:

backendUrl: The URL of your crypto-monitor-api-poc service
coingeckoApiUrl: The base URL for the Coingecko API
maxRetries: Maximum number of retries for failed requests
rateLimitDelay: Delay between requests to respect rate limiting

Cryptocurrency IDs

The supported cryptocurrency IDs are now defined in the CryptoId enum in the crypto.config package. This enum provides a type-safe way to work with cryptocurrency IDs. For example:

public enum CryptoId {
    BITCOIN("bitcoin"),
    ETHEREUM("ethereum"),
    CARDANO("cardano"),
    POLKADOT("polkadot"),
    CHAINLINK("chainlink"),
    // ... other cryptocurrencies ...
}

To add or remove cryptocurrencies from tracking, modify this enum in the CryptoId.java file. The string value in each enum constant should match exactly with the identifiers used by the Coingecko API.

When using methods that operate on individual cryptocurrencies, use the enum constants. For example:

client.updateCurrentData(CryptoId.BITCOIN);
client.updateHistoricalData(CryptoId.ETHEREUM);
client.fetchAllHistoricalData(CryptoId.CARDANO, 30);

API Limitations and Rate Limiting

Please note that Coingecko has recently imposed significant restrictions on their public API. These limitations may result in rate limiting issues when fetching data. To mitigate this, the application implements a RateLimiter class that enforces delays between API requests:

public class RateLimiter {
    private final long delayMs;
    // ... implementation ...
}

The delay between requests is configurable via the rateLimitDelay parameter in CryptoConfig. Adjust this value if you encounter rate limiting issues:

private final long rateLimitDelay = 5000; // 5 seconds delay

A retry mechanism with growing delays is in place. Despite these precautions, you may still experience limitations when using the Coingecko public API extensively. Consider using their pro services for more reliable and extensive data fetching capabilities in a production environment.

Configuration

The application uses several configuration constants that can be modified in the CryptoConfig class:

backendUrl: The URL of your crypto-monitor-api-poc service
coingeckoApiUrl: The base URL for the Coingecko API
maxRetries: Maximum number of retries for failed requests
rateLimitDelay: Delay between requests to respect rate limiting
cryptoIds: List of cryptocurrency IDs to fetch data for

Contact

devsam.io

Project Link: https://github.com/src-dbgr/crypto-client-poc

Related Project

This client application is tightly coupled with the crypto-monitor-api-poc project, which stores the data in a PostgreSQL database and serves as the data source for Grafana Monitoring Dashboards.