101 lines
4.1 KiB
Markdown
101 lines
4.1 KiB
Markdown
# Technical Assignment
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The candidate is asked to build a small project consisting of two Go processes:
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- The **API server** accepts trade submissions via POST `/trades` and writes them to a queue table.
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- The **worker process** continuously reads new trades, validates them, stores them, and instantly updates the account's profit.
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Your code must compile, pass `go vet` and `go test -race`, and run via `docker-compose up`.
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## Purpose of This Task
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We want to assess your ability to write clean HTTP code, work with SQL, and reason about concurrency.
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## What You Should Build
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### Components and Architecture
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```text
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┌──────────────┐ POST /trades ┌───────────────┐
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│ API Server │ ─────────────────► │ Queue Table │
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│ cmd/server │ └───────────────┘
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└──────────────┘ ▲
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│ SELECT … FOR UPDATE
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┌──────────────┐ UPDATE stats │
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│ Worker │ ◄───────────────────────┘
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│ cmd/worker │
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└──────────────┘
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```
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- **API (HTTP)** — exposes one POST endpoint and one GET endpoint.
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- **Queue** — an SQLite table `trades_q` used by the API to enqueue trades, and by the worker to mark them as processed.
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- **Worker** — a separate process that polls the queue every 100ms, calculates `profit`, and updates `account_stats`.
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### Trade Input Format
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| Field | Type | Validation Rule |
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| - | - | - |
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| `account` | string | must not be empty |
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| `symbol` | string | `^[A-Z]{6}$` (e.g. EURUSD) |
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| `volume` | float64 | must be > 0 |
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| `open` | float64 | must be > 0 |
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| `close` | float64 | must be > 0 |
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| `side` | string | either "buy" or "sell" |
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Profit calculation (performed by the worker):
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```go
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lot := 100000.0
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profit := (close - open) * volume * lot
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if side == "sell" { profit = -profit }
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```
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### HTTP Contracts
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| Method | URL | Request / Response | Expected Behavior |
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| - | - | - | - |
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| POST | `/trades` | JSON trade payload | Enqueue trade; respond with 200 OK or 400 on errors |
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| GET | `/stats/{acc}` | `{"account":"123","trades":37,"profit":1234.56}` | Return current statistics for the given account |
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| GET | `/healthz` | plain text OK | Health check endpoint (for Kubernetes liveness probe) |
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### How to Run
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```shell
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# Terminal 1
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go run ./cmd/server.go --db data.db --listen 8080
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# Terminal 2
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go run ./cmd/worker.go --db data.db --poll 100ms
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```
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Sample request:
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```
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curl -X POST http://localhost:8080/trades \
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-H 'Content-Type: application/json' \
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-d '{"account":"123","symbol":"EURUSD","volume":1.0,
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"open":1.1000,"close":1.1050,"side":"buy"}'
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curl http://localhost:8080/stats/123
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# {"account":"123","trades":1,"profit":500.0}
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```
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## What We Expect from Your Code
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| Requirement | Minimum / Bonus |
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| - | - |
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| Go 1.22+, only stdlib + light libs | sqlx / chi / validator OK |
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| `go vet` and `go test -race` pass | required |
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| Test coverage | ≥ 60% |
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| Dockerfile + docker-compose.yml | bonus (+1) |
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| README: how to run + curl examples | required |
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## How We Will Evaluate
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CI script (GitLab CI) will:
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- Run `go vet` and `go test -race -covermode=atomic`.
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- Launch both API and worker processes in the background.
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- Send one invalid and one valid POST request.
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- Fetch and validate the response from `/stats`.
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