# Moleculer
![Moleculer logo](https://github.com/moleculerjs/moleculer/raw/master/docs/assets/logo.png)

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Moleculer is a fast, modern and powerful microservices framework for originally written for [Node.js](). It helps you to 
build efficient, reliable & scalable services. Moleculer provides many features for building and managing your 
microservices.


## Getting Started
### Install the Gem

```ruby
gem install "moleculer-ruby"
```

or add to your Gemfile:

```ruby
gem "moleculer-ruby", "~>0.3"
```

### Create a  Simple Service

```ruby
class SimpleService < Moleculer::Service::Base
  action :get_user, :get_user
  
  
  def get_user
    # .. usery getting stuff
  end
end


Moleculer.config do |c|
  c.services << SimpleService
end

Moleculer.start

```


## Configuration

Moleculer is configured through the Moleculer::config method. Example:

```ruby
Moleculer.configure do |c|
  c.log_level = :debug
end
```

Some Moleculer configuration values can also be set through environment variables.

### Configuration Options

#### rescue_from
Sets an error handler that ties into the infrastructure of Moleculer instructing it how to handle errors of the specified
class. This allows things like Airbrake to easily tie in to exception handling. By default Moleculer rescues from 
`StandardError` and simply logs it out.

#### log_file (default: STDOUT)
Sets the moleculer log_file. This value can also be set by setting the `MOLECULER_LOG_FILE` environment variable.

#### logger
Sets the moleculer logger. The logger must be an instance of `Moleculer::Support::LogProxy`. The log proxy supports any
ruby logger that supports the ruby `Logger` interface.

Example: 
```
c.logger = Moleculer::Support::Logger.new(Rails.logger)
```

In the case that the logger is set to something other than the default, the log level set for moleculer is ignored, and the
level of the passed logger is used.

#### log_level (default: debug)
Sets the log level of the node. defaults to `:debug`. Can be one of `:trace`, `:debug`, `:info`, `:warn`, `:error`, 
`:fatal`. This value can also be set by setting the `MOLECULER_LOG_LEVEL` environment variable.

#### heartbeat_interval (default: 5)
The interval in which to send heartbeats. This value can also be set by setting the `MOLECULER_HEARTBEAT` environment variable.

#### node_id (default: \<hostname\>-\<pid\>)
The node id. Node IDs are required to be unique. In Moleculer-ruby all node ids are suffixed with the PID of the 
running process, allowing multiple copies of the same node to be run on the same machine. When using a containerized
environment (i.e. Docker), it is suggested that the node_id also include a random set of characters as there is a chance
that does running in separate containers can have the same PID.

#### serializer (default: :json)
Which serializer to use. For more information serializers see [Serialization](https://moleculer.services/docs/0.13/networking.html#Serialization)

#### service_prefix (default: nil)
The service prefix. This will be prefixed to all services. For example if `service_prefix` were to be `foo` then a
service whose `service_name` is set to `users` would get the full `service_name` of `foo.users`.

#### timeout (default: 5)
The Moleculer system timeout. This is used to determine how long a moleculer `call` will wait for a response until it
times out and throws an error. This value can also be set by setting the `MOLECULER_TIMEOUT` environment variable.

#### transporter (default: redis://localhost)
The transporter Moleculer should use. For more information on transporters see [Transporters](https://moleculer.services/docs/0.13/networking.html#Transporters)
This value can also be set by setting the `MOLECULER_TRANSPORTER` environment variable.


## Roadmap

### 0.1 (COMPLETE)
Initial release

* Redis transporter
* Round robin load balancing
* Service registry & dynamic service discovery
* JSON serializer

### 0.2 (COMPLETE)
* Fake transporter (for testing)
* Error handling, (ability to use Airbrake, etc.)

### 0.3 (COMPLETE)
* Service versioning
* Environment variable based configuration

### 0.4 (IN PROGRESS)
* Protobuf serializer
* Add MessagePack serializer
* Circuit Breaker support
* Retry support

### 0.5 (PLANNED)
* Bulkhead support
* Fallback support
* Nested call support