Logging

Use structured logging

• Such as slog in golang.

Exporting logs from docker to Loki

There are many options. One option is to use the fluent-bit plugin to export logs to Loki.

Fluent bit docker-compose.yaml

  fluent-bit:
    image: grafana/fluent-bit-plugin-loki:latest
    container_name: fluent-bit
    environment:
      - LOKI_URL=http://loki:3100/loki/api/v1/push
    volumes:
      - ./fluent-bit.conf:/fluent-bit/etc/fluent-bit.conf
    ports:
      - "24224:24224"
      - "24224:24224/udp"
    networks:
      - monitoring

fluent-bit.conf

[INPUT]
    Name        forward
    Listen      0.0.0.0
    Port        24224
[Output]
    Name grafana-loki
    Match *
    Url ${LOKI_URL}
    RemoveKeys source
    Labels {job="fluent-bit"}
    LabelKeys container_name
    BatchWait 1s
    BatchSize 1001024
    LineFormat json
    LogLevel info

In the docker-compose for your application, add:

    logging:
      driver: fluentd
      options:
        fluentd-address: ${FLUENT_BIT_ADDRESS}:24224