logger-service

This application subscribes to a [NATS] subject where the messages it receives are logs. The logs' destination is up to the user.

Sequence Diagram

sequenceDiagram
    participant Lumberjack
    participant Environment
    participant ElasticSearch
    participant Stdout
    participant NATS

    Lumberjack->>Environment: Read
    alt Startup
        alt STDOUT and ELASTIC unset or false
            Lumberjack->>Lumberjack: Throw fatal exception
        end

        opt
            activate ElasticSearch
            Note over Lumberjack,ElasticSearch: ELASTIC is set to true
            Lumberjack--> ElasticSearch: Configure pino-elasticsearch
        end

        opt
            activate Stdout          
            Note over Lumberjack,Stdout: STDOUT is set to true
            Lumberjack-->Stdout: Configure stdout
        end

        Lumberjack->>NATS: Subscribe to log subject
    end

    

    loop On each NATS message 
        NATS --) Lumberjack: Receive message
        par Send message to configured channels
            Lumberjack-> ElasticSearch: Send Log
        and 
            Lumberjack-> Stdout: Send Log
        end
    end
    deactivate Stdout
    deactivate ElasticSearch

Loading

Environment

Name	Example	Purpose
NATS_SERVER	nats://localhost:4222	Specifies the NATS server address.
NATS_SUBJECT	Lumberjack	Defines the NATS subject for message subscription.
ELASTIC_SEARCH_VERSION	8	The version of Elastic Search in your deployment
ELASTIC_HOST	http://localhost:9200	Specifies the Elasticsearch server address.
ELASTIC_USERNAME	elastic	Provides the username for Elasticsearch authentication.
ELASTIC_PASSWORD	password123	Provides the password for Elasticsearch authentication.
ELASTIC_INDEX	logs-tazama	Sets the Elasticsearch index to use for storing logs.
FLUSHBYTES	1024	Defines the number of bytes to flush before writing to the log.
STDOUT	true	Determines whether to output logs to standard output.
ELASTIC	true	Indicates whether to use Elasticsearch for logging.

Tip

A sample .env file has been provided. Adapt it to your use case.

Dependencies

• NATS: (Required)
• Elasticsearch: Required if ELASTIC=true. This includes:
  • ELASTIC_HOST
  • ELASTIC_USERNAME
  • ELASTIC_PASSWORD
  • ELASTIC_INDEX