Trading Info

Service for obtaining currency exchange rates.

Table of Contents

• Requirements
• Deployment
  • Local
  • Docker Compose
• CLI
• Environment Variables
• API
  • Basic Info
  • Methods List
    • HelloWorld
    • GetOne
    • GetCurrenciesRates
• Service configuration for docker-compose stack
  • App Replication
  • PostgreSQL Configuration
  • NGINX Configuration

Requirements

1. Node.js (>=16.0)
2. Redis (>=6.2.6)
3. PostgreSQL (>=14.1) with TimescaleDB (>= 2.5.1)

Deployment

Local

1. Install dependencies: npm install.
2. Run migrations: npm run migration:run with DATABASE_URL environment variable.
3. Run project: npm run start:dev with environment variables.

Docker Compose

docker-compose -f docker/application.yml up

More configurations see here.

CLI

• npm run prebuild - Clear dist folder.
• npm run build - Compile TypeScript source code to JavaScript at dist folder.
• npm run start - Run compiled application. Need environment variables.
• npm run start:dev - Build and start application. Need environment variables.
• npm run migration:create -- {name} - Create database migration file with {name}. Need DATABASE_URL environment variable.
• npm run migration:run - Start database migrations. Need DATABASE_URL environment variable.
• npm run migration:down - Revert last database migration. Need DATABASE_URL environment variable.

Environment Variables

Environment Variable	Description	Example
REDIS_URL	URL for connecting to Redis	redis://localhost:6379/
DATABASE_URL	URL for connecting to PostgeSQL	postgresql://user:password@localhost:5432/db
CURRENCIES_FROM	List of currencies to convert from	BTC,ETH,MNR
CURRENCIES_TO	List of currencies to convert to	USD,EUR,RUB
CURRENCIES_RATE_UPDATER_CRON	Crontab for worker, that save currencies rates to database	*/1 * * * *
CRYPTOCOMPARE_PRICEMULTI_URL	URL to CryptoCompare API for getting currencies rates	https://min-api.cryptocompare.com/data/pricemulti

API

Basic Info

This application use socket.io for WebSocket server. API use custom RPC inspired JSON-RPC under WebSocket.

The Request object has the following members:

• method - Name of method.
• args - Object for passing arguments.

The Response object has the following members:

• status - Result status of method execution. Ok or Error.
• data - Object for result data.
• message - Error message.

Methods List

1. HelloWorld

Returns string Hello, world!

Args: undefined

Data: string

Example Request:

{
  "method": "HelloWorld"
}

Example Response:

{
  "status": "Ok",
  "data": "Hello, world!"
}

2. GetOne

Returns number 1

Args: undefined

Data: number

Example Request:

{
  "method": "GetOne"
}

Example Response:

{
  "status": "Ok",
  "data": 1
}

3. GetCurrenciesRates

Returns currencies rates

Args:

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "type": "object",
  "properties": {
    "from": {
      "type": "array",
      "items": {
        "type": "string"
      }
    },
    "to": {
      "type": "array",
      "items": {
        "type": "string"
      }
    }
  },
  "required": [
    "from",
    "to"
  ]
}

Data:

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "type": "array",
  "items": {
    "type": "object",
    "properties": {
      "from": {
        "type": "string"
      },
      "to": {
        "type": "string"
      },
      "price": {
        "type": "number"
      },
      "date": {
        "type": "string"
      }
    },
    "required": [
      "from",
      "to",
      "price",
      "date"
    ]
  }
}

Additional Info:

Cache	1 minute

Example Request:

{
  "method": "GetCurrenciesRates",
  "args": {
    "from": ["BTC", "ETH"],
    "to": ["USD"]
  }
}

Example Response:

{
  "status": "Ok",
  "data": [
    {
      "from": "BTC",
      "to": "USD",
      "price": 43958.55,
      "date": "2022-01-13T00:11:45.065Z"
    },
    {
      "from": "ETH",
      "to": "USD",
      "price": 3376.76,
      "date": "2022-01-13T00:11:45.065Z"
    }
  ]
}

Service configuration for docker-compose stack

App Replication

You can change replicas count of application in docker/application.yml.

By default, there are 4 replicas for the application.

More options here.

PostgreSQL Configuration

You can change some options for PostgeSQL in docker/postgresql/postgresql.conf.

By default, it listens from all hosts and loads TimescaleDB plugin.

More information about PostgreSQL here.

More information about TimescaleDB here.

NGINX Configuration

You can change some options for NGINX in docker/nginx/nginx.conf.

By default, NGINX listens 3000 port and proxy pass it with upstream to application on 3000 port.

More information about NGINX here.