Syntrade Backend

📈 Syntrade Backend is a GraphQL API server built on top of Express.

Project Architecture

Backend uses server sent event to get real-time price from 4 in-house synthetic models:

Boom 100
Crash 100
Volatility 10
Volatility 25

Pricing Data Flow

Every 1 second, pricing server sends pricing data to both backend and frontend.

Backend stores the pricing data inside redis. Why? For historical data purposes. Whenever user performs a trade, the price for specified model at a specified time will be taken from redis.
Whenever the trade page is load for the first time or the synthetic model type is changed, frontend uses new data that it gets from pricing server sent events to keep on drawing the chart as time progresses.

Entity Relationship Diagram

Technologies Used

Docker
Express
Flask
GraphQL
Nginx
NodeJS
PostgreSQL
Redis
Server Sent Events

Prerequisites

All installation instructions are geared for Ubuntu

Make sure that your node version is v14.20.0. If your node version is different, install the specific node version.

node -v

# v14.20.0

Make sure that your npm version 8.19.3. If your npm version is different, install the specific npm version.

npm -v

# 8.19.3

Run It Locally

Clone repository

git clone git@github.com:ariessa-deriv/syntrade-backend.git

Create .env file and insert values

BACKEND_PORT="4000"
POSTGRES_HOST="syntrade-database"
POSTGRES_PORT="5432"
POSTGRES_DATABASE="syntrade"
POSTGRES_USER="" // Replace this with your own value
POSTGRES_PASSWORD="" // Replace this with your own value
REDIS_PASSWORD="" // Replace this with your own value
REDIS_PORT="6379"
REDIS_USER="default"
JWT_SECRET="" // Replace this with your own value
FLASK_HOST="syntrade-pricing"
FLASK_PORT="5000"
FLASK_SECRET_KEY="" // Replace this with your own value
FRONTEND_DEV_URL="http://localhost:3000"
FRONTEND_URL="" // Replace this with your own value
GMAIL_USER="" // Replace this with your own value
GMAIL_PASSWORD="" // Replace this with your own value

Build and start all Docker containers

sh start.sh

Troubleshooting

You might not need to rebuild all containers again so use the following commands as you see fit.

Error
docker: Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Post http://%2Fvar%2Frun%2Fdocker.sock/v1.35/containers/create: dial unix /var/run/docker.sock: connect: permission denied. See 'docker run --help'.

Solution
```
sudo chmod 666 /var/run/docker.sock
```
Error
ERROR: for postgres Cannot start service postgres: driver failed programming external connectivity on endpoint syntrade-database (1a20e2684584f681b8c8c84226cdf25b25b6b32c195ecd255261f43e20123cde): Error starting userland proxy: listen tcp4 0.0.0.0:5432: bind: address already in use
ERROR: Encountered errors while bringing up the project.

Solution

Check which process is running on port 5432 and kill the process by PID
```
sudo kill -9 $(sudo lsof -i :5432 | awk 'NR==2{print $2}')
```
Error
Containers with name of syntrade-backend or syntrade-pricing fails to be build or start up.

Solution
Clean your repository by running the clean.sh script. This script will remove all Docker containers and images.
```
sh clean.sh
```
Build and start all Docker containers
```
sh start.sh
```
Error
npm ERR! Failed at the syntrade-backend@1.0.0 dev script. npm ERR! This is probably not a problem with npm. There is likely additional logging output above. npm WARN Local package.json exists, but node_modules missing, did you mean to install?

Solution

Navigate to app folder and install packages using npm
```
cd app && npm install
```

Rest API endpoints

Example of sending GET request using cURL

curl --location --request POST 'http://localhost:4000/login' \
--header 'Content-Type: application/json' \
--data-raw '{
    "email": "test@gmail.com",
    "password": "Abc1234!"
}'

login
logout

GraphQL API endpoints

Example of sending GET request using cURL

curl --location --request GET 'http://localhost:4000' \
--header 'Content-Type: application/json' \
--data-raw '{"query":" {\n    tradesByUserId (userId: \"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VySWQiOiIwY2Q1MTA2Mi01Y2UxLTQ5ZTAtYjllMy04YWYzZGQ5ODNiNGEiLCJpYXQiOjE2NzAzMTU0ODYsImV4cCI6MTY3MDM0NDI4Nn0.bfBHy-sOXphI0RZPyoiiX-xkI33Wd560O9Fq-wtU0n0\"){\n      trade_id\n      synthetic_type\n      currency\n      transaction_time\n      transaction_type\n      transaction_amount\n      current_wallet_balance\n    }\n  }","variables":{}}' | json_pp

Query

trade

# Get trades by user id
{
  tradesByUserId {
    trade_id
    synthetic_type
    currency
    transaction_time
    transaction_type
    transaction_amount
    current_wallet_balance
  }
}

prices

# Get call and put prices of a synthetic model
query {
  prices(wagerType: "stake", syntheticModel: "boom_100", tradeType: "rise_fall", wagerAmount: 20, ticks: 5)
}

currentBalance

# Get current wallet balance by user id
{
  currentBalance
}

Mutation

signup

# Sign up
mutation {
  signup(email: "randomemail@gmail.com", password: "Abc4123!") {
    email,
    password
  }
}

createTrade

# Create new buy trade and execute sell trade when end time is reached
mutation {
  createTrade(user_id: "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VySWQiOiIwY2Q1MTA2Mi01Y2UxLTQ5ZTAtYjllMy04YWYzZGQ5ODNiNGEiLCJpYXQiOjE2NzAzMTU0ODYsImV4cCI6MTY3MDM0NDI4Nn0.bfBHy-sOXphI0RZPyoiiX-xkI33Wd560O9Fq-wtU0n0", synthetic_type: "volatility_10_rise", wager_amount: 198, option_type: "put", ticks: 4)
}

# Special case: Create buy and sell trades for matches differs trade type
mutation {
  createTrade(user_id: "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VySWQiOiIwY2Q1MTA2Mi01Y2UxLTQ5ZTAtYjllMy04YWYzZGQ5ODNiNGEiLCJpYXQiOjE2NzAzMTU0ODYsImV4cCI6MTY3MDM0NDI4Nn0.bfBHy-sOXphI0RZPyoiiX-xkI33Wd560O9Fq-wtU0n0", synthetic_type: "volatility_25_matches", wager_amount: 198, option_type: "call", ticks: 7, last_digit_prediction: 2)
}

resetBalance

# Reset wallet balance by user id
mutation {
  resetBalance(user_id: "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VySWQiOiIwY2Q1MTA2Mi01Y2UxLTQ5ZTAtYjllMy04YWYzZGQ5ODNiNGEiLCJpYXQiOjE2NzAzMTU0ODYsImV4cCI6MTY3MDM0NDI4Nn0.bfBHy-sOXphI0RZPyoiiX-xkI33Wd560O9Fq-wtU0n0")
}

Deployment

Subdomain Configurations

This section assumes that you bought your domain name from Namecheap, using Cloudflare Content Delivery Network as Content Delivery Network, and using Digital Ocean Droplet as Virtual Private Server. This section guides you to setup two subdomains: api.syntrade.xyz and pricing.syntrade.xyz.

Inside your Namecheap domain configuration dashboard, set your nameservers to Cloudflare nameservers.

Example:

beth.ns.cloudflare.com
tony.ns.cloudflare.com

Inside your Digital Ocean droplet, set A records for both api.syntrade.xyz and pricing.syntrade.xyz to direct to your Digital Ocean droplet's IPv4 address.

Example:

Type    Hostname                  Value                           TTL               
A       api.syntrade.xyz          directs to 143.198.218.123      3600
A       pricing.syntrade.xyz      directs to 143.198.218.123      3600

Inside your Cloudflare domain management, set A records for both api.syntrade.xyz and pricing.syntrade.xyz to direct to your Digital Ocean droplet's IPv4 address.

Example:

Type    Name                      Content              Proxy status     TTL               
A       api.syntrade.xyz          143.198.218.123      DNS only         Auto
A       pricing.syntrade.xyz      143.198.218.123      DNS only         Auto

Virtual Private Server Configurations

Connect to your Digital Ocean droplet using SSH

Example:
ssh ariessa@${your-digital-ocean-droplet-ipv4-address}

Install Nginx

sudo apt-get install nginx

Clone repository

git clone git@github.com:ariessa-deriv/syntrade-backend.git

Create .env file and insert values

BACKEND_PORT="4000"
POSTGRES_HOST="syntrade-database"
POSTGRES_PORT="5432"
POSTGRES_DATABASE="syntrade"
POSTGRES_USER="" // Replace this with your own value
POSTGRES_PASSWORD="" // Replace this with your own value
REDIS_PASSWORD="" // Replace this with your own value
REDIS_PORT="6379"
REDIS_USER="default"
JWT_SECRET="" // Replace this with your own value
FLASK_HOST="syntrade-pricing"
FLASK_PORT="5000"
FLASK_SECRET_KEY="" // Replace this with your own value
FRONTEND_DEV_URL="http://localhost:3000"
FRONTEND_URL="" // Replace this with your own value
GMAIL_USER="" // Replace this with your own value
GMAIL_PASSWORD="" // Replace this with your own value

Build and start all Docker containers

sh start.sh

Create SSL certificates using manual DNS challenge for subdomains api.syntrade.xyz and pricing.syntrade.xyz

sudo certbot certonly --manual --preferred-challenge dns -d api.syntrade.xyz -d pricing.syntrade.xyz

Copy the result of manual DNS challenge for api.syntrade.xyz and create TXT record inside Cloudflare domain management

Example:

Type    Name                      Content                                           Proxy status     TTL               
TXT     _acme-challenge.api       nOi3zto26NB_XwO5zJSE2w4KHM3sdhujWGj6VuEEImo       DNS only         Auto

Copy the result of manual DNS challenge for pricing.syntrade.xyz and create TXT record inside Cloudflare domain management

Example:

Type    Name                      Content                                           Proxy status     TTL               
TXT     _acme-challenge.pricing   nv--fKnH2GEHfw7DF8Jcq7WZMqD7siTBrw_lcVA05mA       DNS only         Auto

Store the SSL certificates inside /etc/ssl/nginx folder

Setup Nginx config file named /etc/nginx/conf.d/local_domains.conf. This config file attaches:
- The Docker container named syntrade-backend to the subdomain api.syntrade.xyz.
- The Docker container named syntrade-pricing to the subdomain pricing.syntrade.xyz.

server {
    listen         80;
    listen         443 ssl;
    server_name    api.syntrade.xyz;
    ssl_certificate /etc/ssl/nginx/cert.pem;
    ssl_certificate_key /etc/ssl/nginx/privkey.pem;

    location / {
    set $target http://127.0.0.1:4000;
    proxy_pass $target;
  }
}

server {
    listen         80;
    listen         443 ssl;
    server_name    pricing.syntrade.xyz;
    ssl_certificate /etc/ssl/nginx/fullchain.pem;
    ssl_certificate_key /etc/ssl/nginx/privkey.pem;

    location / {
    set $target http://127.0.0.1:5000;
    proxy_set_header Connection '';
    proxy_http_version 1.1;
    chunked_transfer_encoding off;
    proxy_buffering off;
    proxy_cache off;
    proxy_pass $target;
  }
}

Allow HTTP connections on port 80

sudo ufw allow 80/tcp

Allow HTTPS connections on port 443

sudo ufw allow 443/tcp

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README.md

README.md

Syntrade Backend

Project Architecture

Pricing Data Flow

Entity Relationship Diagram

Technologies Used

Prerequisites

Run It Locally

Troubleshooting

Rest API endpoints

GraphQL API endpoints

Query

Mutation

Deployment

Subdomain Configurations

Virtual Private Server Configurations

Files

README.md

Latest commit

History

README.md

File metadata and controls

Syntrade Backend

Project Architecture

Pricing Data Flow

Entity Relationship Diagram

Technologies Used

Prerequisites

Run It Locally

Troubleshooting

Rest API endpoints

GraphQL API endpoints

Query

Mutation

Deployment

Subdomain Configurations

Virtual Private Server Configurations