# Kafka 4.3.x in KRaft mode.
#
# Single broker on purpose: this compose file exists to reproduce the platform's Stable profile
# locally, not to model a production cluster. The settings below are the ones the profile guard
# enforces, so a local run fails the same way a misconfigured deployment would.
services:
  kafka:
    image: apache/kafka:4.3.0
    container_name: messaging-kafka
    ports:
      - "9092:9092"
    environment:
      KAFKA_NODE_ID: 1
      KAFKA_PROCESS_ROLES: broker,controller
      KAFKA_LISTENERS: PLAINTEXT://:9092,CONTROLLER://:9093
      KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://localhost:9092
      KAFKA_CONTROLLER_LISTENER_NAMES: CONTROLLER
      KAFKA_CONTROLLER_QUORUM_VOTERS: 1@localhost:9093
      KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: CONTROLLER:PLAINTEXT,PLAINTEXT:PLAINTEXT
      # acks=all is only a durability guarantee when more than one replica must acknowledge.
      # With a single broker the platform still requires acks=all; min.insync.replicas is 1 here
      # and is expected to be 2 in any environment that claims replication evidence.
      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
      KAFKA_TRANSACTION_STATE_LOG_REPLICATION_FACTOR: 1
      KAFKA_TRANSACTION_STATE_LOG_MIN_ISR: 1
      KAFKA_MIN_INSYNC_REPLICAS: 1
      # Topology is created by infrastructure, never by the application.
      KAFKA_AUTO_CREATE_TOPICS_ENABLE: "false"
    healthcheck:
      test: ["CMD-SHELL", "/opt/kafka/bin/kafka-broker-api-versions.sh --bootstrap-server localhost:9092 >/dev/null 2>&1"]
      interval: 5s
      timeout: 10s
      retries: 20