Marketing Events & Messaging Pipeline (Test Assignment)

🇬🇧 English language

Problem Description

This service simulates a marketing event pipeline for a fintech application.

The system:

1. Accepts user behavioral events via HTTP.
2. Applies declarative messaging rules.
3. Prevents duplicate or excessive messages.
4. Produces outbound send requests (stubbed).
5. Exposes an audit/debug endpoint to explain decisions.

The goal is to demonstrate clean modeling, idempotency, deduplication, and auditability.

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Supported Event Types

• signup_completed
• link_bank_success
• payment_initiated
• payment_failed

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Implemented Messaging Rules

1. WELCOME_EMAIL Trigger: signup_completed Condition: marketing_opt_in == true Limit: once per user

2. BANK_LINK_NUDGE_SMS Trigger: link_bank_success Condition: within 24h after signup_completed

3. INSUFFICIENT_FUNDS_EMAIL Trigger: payment_failed Condition: failure_reason == INSUFFICIENT_FUNDS Limit: once per user per calendar day

4. HIGH_RISK_ALERT (internal) Trigger: payment_failed Condition: attempt_number >= 3 Output: logs only

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API

POST /events GET /audit/{user_id}

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MVP Constraints

• In-memory only
• Single process
• UTC everywhere
• No auth, queues, retries, metrics
• Rules defined in code
• Deduplication by user_id + template (+ day)
• HIGH_RISK_ALERT logged only

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🇷🇺 Русский язык

Описание самого кода и пакетов

❗️тут

Описание задачи

Сервис моделирует маркетинговый pipeline событий для финтех-приложения.

Система:

1. Принимает события по HTTP
2. Применяет правила
3. Делает дедупликацию
4. Формирует outbound-запросы
5. Даёт audit/debug API

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Поддерживаемые события

• signup_completed
• link_bank_success
• payment_initiated
• payment_failed

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Правила

• WELCOME_EMAIL — при signup_completed и marketing_opt_in
• BANK_LINK_NUDGE_SMS — link_bank_success в течение 24ч
• INSUFFICIENT_FUNDS_EMAIL — 1 раз в день
• HIGH_RISK_ALERT — attempt_number >= 3, только лог

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Ограничения MVP

• Всё в памяти
• Один процесс
• UTC
• Без auth и очередей
• Правила только в коде