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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`

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

`fluent-bit.conf`

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

In the docker-compose for your application, add:

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