logger/README.md

# Mobicoop V3 - Logger Service

Logging system for all services.

## Requirements

You need [Docker](https://docs.docker.com/engine/) and [Docker-compose](https://docs.docker.com/compose/).

A RabbitMQ instance is also required to receive messages from other services.

## Installation

Copy `.env.dist` to `.env` :

```bash
cp .env.dist .env
```

and modify it to suit your needs.

Then execute :

```bash
docker-compose up -d
```

The app runs automatically on the port defined in `SERVICE_PORT` of `.env` file (default : _5099_).

## Usage

The app subscribes to RabbitMQ queues in order to log messages. We use the routing key with the given format : <**service**>.<**action**>.<**level**>, with :

-   **service** : the name of the service that has emitted the message
-   **action** : the action that was at the origin of the message (one or more words separated by a dot)
-   **level** : the severity (_log level_) of the message, as described in [RFC5424 syslog](https://www.rfc-editor.org/rfc/rfc5424) :
    -   **emer** : Emergency: system is unusable
    -   **alert** : Alert: action must be taken immediately
    -   **crit** : Critical: critical conditions
    -   **error** : Error: error conditions
    -   **warning** : Warning: warning conditions
    -   **notice** : Notice: normal but significant condition
    -   **info** : Informational: informational messages
    -   **debug** : Debug: debug-level messages

Examples of valid routing keys :

-   user.create.info
-   user.create.crit
-   user.update.warning
-   auth.username.add.info

It is the responsibility of each service to set the routing key to the appropriate value.

To handle logs for a given service, a controller corresponding to the service must be set. In this controller, you must define a handler for each action and level. You must also define a unique RabbitMQ queue for this handler (this permits to use durable queues, allowing to keep logs in RabbitMQ even if the logger service is down).

## Test

```bash
# unit tests
docker exec v3-user sh -c "npm run test"

# test coverage
docker exec v3-user sh -c "npm run test:cov"
```

Note : you can run all npm commands directly _outside_ the container (see _scripts_ section of `package.json` for available commands), but you need NodeJS installed locally. We **strongly** advise to install [Node Version Manager](https://github.com/nvm-sh/nvm) and use the latest LTS version of Node.

## License

Mobicoop V3 - Logger Service is [AGPL licensed](LICENSE).