Coin Watch

Get notified when a crypto pair goes above your desired price.

Quick Start

docker compose up --build

Connect to the web socket server on ws://127.0.0.1:9090/ws

send payload

{
    "cmd": "watch",
    "symbol": "btcusdc",
    "price": 1.0
}

You will get a response on the web socket connection on the next trade to Take profit on btcusdc.

Payload

cmd No need to change, watch is currently the only command.

symbol must be a lowercase coin pair available on Binance.

price can be any floating point number but INF is sure to cause issues.

Contol Flow

• ingest subscribes to default symbols and starts streaming prices.
• ingest adds prices to an internal queue with the symbol, current_price and price_target.
• watch checks each added price to see if a there is a price watch.
• if watch finds the price of a symbol has gone over any requested threshold, it will publish a price_above_target event.
• watch listens to it's own price_above_target events to purge the price watch list of that price point. This has a race condition edge case in multi-user environments.
• api listens to price_above_target events. If there is an event, any users watching this symbol at this price will be notified to take profit.
• api waits for a user to connect to the websocket endpoint.
• when user sends a valid command to the api a watch command is published internally with the symbol, and price_target.
• ingest process the command queue for watch commands.
• ingest will subscribe to the symbol in the command.
• ingest publishes a watched event with the the symbol, and price_target.
• watch listens for watched messages and will add the symbol, and price_target to the watched list.

Further development

• Error checking is very light, and things are sure to blow up if the happy path is not adheared to.
• There is no way for a user to stop watching, or unsubscribe from a symbol.
• Once a symbol is subscribed to the system will always be subscribed to that symbol untill redis restart.
• The control flow is confusing.
• Better documentation.