Repository Guidelines

This repo is a small Docker Compose environment for learning Apache NiFi with NiFi Registry, Postgres, Kafka, and Kafka UI.

Project Structure & Module Organization

docker-compose.yml: single entrypoint defining all services and ports.
drivers/: JDBC drivers mounted into the NiFi container (e.g. drivers/postgresql-42.7.4.jar).
nifi-templates/: NiFi templates/flows and helper SQL (*.json, *.xml, *.sql) mounted into Postgres at /nifi-templates.
README.md: usage notes, URLs, and connection strings.
(local) shared-folder/: host folder mounted to /opt/nifi/nifi-current/ls-target for file-based demos.

docker compose up: start the full stack.
docker compose stop: stop containers without removing volumes.
docker compose start: start previously stopped containers (preserves all state).
docker compose down: remove containers and networks.
docker compose down -v: remove containers, networks, and all named volumes (destructive clean reset).
docker compose logs -f nifi: follow NiFi logs while debugging processors.
docker compose exec postgres bash -c "export PGPASSWORD=postgres; psql -U postgres -d app": open psql in the Postgres container.

Notes on state persistence:

postgres, nifi, and registry persist state via named volumes in docker-compose.yml (survive docker compose down, wiped by docker compose down -v).
Kafka message/topic persistence is disabled by default (see the commented kafka-data volume in docker-compose.yml).

YAML: 2-space indentation; keep service names stable (nifi, registry, postgres, kafka, kafka-ui) to avoid breaking docs.
Templates: name files by purpose and target, e.g. SampleKafka2Postgres.json and matching SampleKafka2Postgres.sql.
Docs: keep README.md examples runnable and aligned with docker-compose.yml ports/URLs.

No automated tests are currently included. Validate changes by:

running docker compose up and checking UIs load (NiFi http://localhost:18443/nifi/, Registry http://localhost:18080/nifi-registry, Kafka UI http://localhost:8082/);
importing/updating a template from nifi-templates/ and performing a small end-to-end smoke run. If you need a clean slate for validation, use docker compose down -v (this wipes Postgres/NiFi/Registry state).

Commit messages in history are short, descriptive, and written in Russian (e.g. “Доработки документации”, “Добавлены Postgres, Kafka…”). Follow the same style.
PRs: include a short description, the motivation (issue link if applicable), and note any port/credential changes. Add screenshots for UI-facing doc updates when helpful.

This is for local learning, not production. Defaults include: