Stack

• Go 1.25+
• PostgreSQL 15
• Docker Compose
• pgx v5

Setup

docker compose up db -d

Create the table:

docker exec -it coinflow-db-1 psql -U admin -d coinflow

CREATE TABLE coin_prices (
    id          SERIAL PRIMARY KEY,
    coin_id     VARCHAR(50) NOT NULL,
    symbol      VARCHAR(10) NOT NULL,
    price_usd   DECIMAL(20,8) NOT NULL,
    change_24h  DECIMAL(10,4),
    sentiment   VARCHAR(10),
    fetched_at  TIMESTAMP DEFAULT NOW()
);

Set the environment variable:

export DB_URL="postgres://admin:admin@localhost:5434/coinflow?sslmode=disable"

Run:

go run main.go

Endpoints

POST /pipeline/run

Triggers the ETL pipeline. Fetches bitcoin and ethereum prices in parallel, calculates sentiment, and stores results in PostgreSQL.

Returns:

{ "processed": 2, "failed": 0 }

GET /coins

Returns all stored coin price records ordered by fetch time.

GET /coins/latest

Returns the latest price for each coin using DISTINCT ON.

Sentiment Logic

Change 24h	Sentiment
> 2%	bullish
< -2%	bearish
between	neutral