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306 changes: 49 additions & 257 deletions README.md
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Expand Up @@ -6,9 +6,11 @@

# Cangaroo

Cangaroo helps developers integrating their apps with any service.
It is a Rails Engine that can be installed on any Rails application and is used
as a connection hub from one or multiple applications and external services.
Cangaroo is a Rails Engine that helps developers integrating their apps with
any service.
It's like a message broker, it receive messages from apps/services then based
on developer defined rules it can route the messages to other apps/services or
just execute jobs.

[TODO] add self-explanatory image here.

Expand All @@ -30,44 +32,6 @@ message and retry sending it until it's successfully delivered;
- use and contribute to a lot of integrations that has already be done by the
community.


#### Integrations

Cangaroo integrations are pieces of code that allow interacting with external
services via API.

An usual flow is:

1. Cangaroo receives some data from an application;
2. Data is sent to one or more integrations;
3. Integrations convert data to be compatible with an external service API;
4. Integrations send converted data to the external service.

Cangaroo is born with built-in Wombat extensions compatibility. All the
old Wombat exensions have been migrated to the [Cangaroo organization](https://github.com/cangaroo)
so that they can be maintained more easily.

## The whole story

Some time ago Spree decided to shut down Wombat and to release its closed
source code to customers only, so we had to decide how to go ahead, and the
alternative were:

1. hosting Wombat by ourselves for some of our clients
2. starting a new open source project with an API compliant with Wombat.

We believe in open source so we chose the latter.

The idea is a bit different from Wombat, the goal of this project is to
provide a backwards compatible API and give the developers the freedom to change
and customize it.

At least for the first release we won't have an admin interface, we believe
developers prefer code and using Rails console directly.

We hope this project can help to make the migration from Wombat easier and we
believe the Spree/Solidus community will help to make it better.

## Dependencies

- rails (>= 4.2.4)
Expand Down Expand Up @@ -105,7 +69,12 @@ Now mount the engine into your `routes.rb` file:

## Usage

First create a `connection`:
To authenticate incoming messages from an app/service we need to instruct
Cangaroo, this is done through [connections](https://github.com/nebulab/cangaroo/wiki/Connection).
A basic connection have a custom `name` the `url` of that connection and a `key`
and `password` for authentication; on the other side the `connection` will use
the [Push API](https://github.com/nebulab/cangaroo/wiki/Push-API) to send messages to Cangaroo.
Praticaly create a `connection` means add it to the database:

```ruby
Cangaroo::Connection.create(
Expand All @@ -116,35 +85,62 @@ First create a `connection`:
)
```

then create a `cangaroo job`:
Then Jobs are used to do stuff with incoming connection messages, they are
simple `ActiveJob::Base` with a little more features, Cangaroo provide three
different kind of jobs:

- Simple Job
- [Push Job](https://github.com/nebulab/cangaroo/wiki/Push-Job)
- Poll Job

in this example the simple job is used, suppose that an ecommerce sends a
message to Cangaroo with all new orders and the only feature is to log only the
`completed` orders.
For this feature is needed a `Job` that inherits from `Cangaroo::Job` class,
this job implement two method, the standard `perform` method that will log
the message and a `perform?` method, this is were rules that decide to run or
not run the job leaves.
The job could be something like this:

```ruby
module Cangaroo
class ShipmentJob < Cangaroo::Job
connection :mystore
path '/update_shipment'

class LogJob < Cangaroo::Job
def perform(:source_connection, :type, :payload)
super
Cangaroo.logger.info 'New order received', payload: payload
end

def perform?
type == 'shipments' &&
payload['status'] == 'shipped'
type == 'orders' &&
payload['status'] == 'completed'
end
end
end
```

and add this job to the `Rails.configuration.cangaroo.jobs`:
The first thing to notice is that `super` is called on the `perform` method,
this is because `Cangaroo::Job#perform` sets the `source_connection`, `type` and
the `payload` attributes so they can be used in `perform?` and `perform`
methods.
The `perform?` method check if the message type is an `orders` kind and if
the the order is completed looking into the payload. Every time Cangaroo receive
a message run the `perform?` method for each job, if it return `true`
it enqueue the job.
Then the `perform` method simple log the information.

The last thing to do is let Cangaroo know that the job exists, this is done by
add it to the `Rails.configuration.cangaroo.jobs`:

```ruby
# config/initializers/cangaroo.rb

Rails.configuration.cangaroo.jobs = [Cangaroo::ShipmentJob]
Rails.configuration.cangaroo.jobs = [Cangaroo::LogJob]
```

## How it works

Cangaroo provides a Push API where you can send your data. After data has
been received, Cangaroo sends data to integrations and webhooks based on your
business logic.
been received, Cangaroo run jobs based on your business logic.

This is the detailed flow:

Expand All @@ -159,210 +155,6 @@ This is the detailed flow:
what jobs must be enqueued by calling the `#perform?` method. Each job
returning `true` to `#perform?` will be enqueued.

## Push API

Cangaroo has just a single endpoint where you can push your data, based on
where `Cangaroo::Engine` is mounted, it will be reachable under the `/endpoint`
path. For example, if the `Cangaroo::Engine` is mounted under `/cangaroo` the
Push API path will be `/cangaroo/endpoint`.

When you push to the endpoint the HTTP Request must respect this conventions:

* It must be a `POST` request
* It must be an `application/json` request so you have to set the
`Content-Type` header to `application/json`
* The request must have the `X-Hub-Store` and `X-Hub-Access-Token` headers set
to a value that exists in the `Cangaroo::Connection` model (to learn more
refer to the `Connection` documentation below)
* The request body must be a well formatted json.

The json body contains data that will be processed by Cangaroo, the following is
an example of an order that will be processed on Cangaroo:

```json
{
"orders": [
{
"id": "O154085346",
"status": "complete",
"email": "[email protected]"
}
]
}
```

The root objects of the json body must contain an array with the objects that
Cangaroo needs to process. The only required field for the objects contained
in the arrays will be the `id` key.
Push API also supports multiple objects so a request with the following body:

```json
{
"orders":[
{
"id":"O154085346172",
"state":"cart"
},
{
"id":"O154085343224",
"state":"payed"
}
],
"shipments":[
{
"id":"S53454325",
"state":"shipped"
},
{
"id":"S53565543",
"state":"waiting"
}
]
}

```

will create 2 `orders` and 2 `shipments`.

When Cangaroo receives the request it responds with a 200(OK) HTTP status code
and the response body will contain numbers of the objects in the payload, for
example for the previous request the response will be:

```json
{
"orders": 2,
"shipments": 2
}
```

if something goes wrong Cangaroo responds with an HTTP error code with an error
message in the body, for example:

```json
{
"error": "The property '#/orders/0' did not contain a required property of 'id' in schema"
}
```

## Connection

Connection are services that can send and receive data from Cangaroo.
Each connection must have these fields:

* name - (required, String) A generic name for this connection
* url - (required, String) The url where Cangaroo pushes the data
* key - (required, String) It's used for authentication
(used to check the request's 'X-Hub-Store' header)
* token - (required, String) It's used for authentication
(used to check the request's 'X-Hub-Access-Token' header)
* basic_auth - (optional, Boolean) Defaults to false. If you would like to
use HTTP basic auth in your integration instead of Wombat's key + token.
Basic auth is handled [Stripe-style](https://www.quora.com/Why-does-Stripe-use-HTTP-Basic-Auth-with-a-token-instead-of-a-header),
without a username using `key` as your password.
* parameters - (optional, Hash) Used as parameters when Cangaroo makes a
request to this connection

For now we don't have a Web GUI so you have to create the connection on your
own by running the code somewhere on your server, for example from the Rails
console:

```ruby
Cangaroo::Connection.create(
name: 'mystore',
url: 'http://www.mystore.com',
key: 'puniethahquoe5aisefoh9ci0Shuaniemei6jahx',
token: 'ahsh8phuezu3xuhohs6kai5vaB1tae0wiy1shohp',
parameters: {
'channel': 'mysubstore'
}
)
```

## Cangaroo Jobs

Jobs are where the `payload` is pushed to the configured connection.

To allow a job to be executed add it to the `Rails.configuration.cangaroo.jobs`
configuration, for example in an initializer:

```ruby
# config/initializers/cangaroo.rb

Rails.configuration.cangaroo.jobs = [Cangaroo::AddOrderJob, Cangaroo::UpdateShipmentJob]
```

The `Cangaroo::Job` class inherits from `ActiveJob::Base`, so you can use
any 3rd-party queuing library supported by ActiveJob.
When the job is performed Cangaroo makes a `POST` request to the connection with
the configured path and build the json body with the result of the `#transform`
instance method merged with this attributes:

* `request_id` - is the `job_id` coming from `ActiveJob::Base`
* `parameters` - are the parameters configured by the `parameters` class method

You can use the following `Cangaroo::Job` class methods to configure the job's
behaivor:

* connection - is the connection name (see connection for more info)
* path - this path will be appended to your `connection.url`
* parameters - these parameters will be merged with `connection.parameters`,
they will be added to the json body.

it also has a `#perform?` instance method that must be implemented. This method
must return `true` or `false` as Cangaroo will use it to understand if the job
must be performed. Inside the `#perform?` method you'll be able to access the
`source_connection`, `type` and `payload` instance attributes.

The `#transform` instance method can be overridden to customize the json body
request, it will have the `source_connection`, `type` and `payload` variables
(like the `#perform?` method) and must return an `Hash`.

The following is an example of a `Cangaroo::Job`:

```ruby
module Cangaroo
class ShipmentJob < Cangaroo::Job
connection :mystore
path '/update_shipment'
parameters({ timestamp: Time.now })

def transform
payload = super
payload['shipment']['updated_at'] = Time.now
payload
end

def perform?
type == 'shipments' &&
payload['status'] == 'shipped'
end
end
end
```

Suppose that the `mystore` connection has a `url` set to "http://mystore.com"
an the `payload` is something like:

```ruby
{ "id": "S123", "status": "shipped" }
```

It will do a `POST` request to `http://mystore.com/update_shipment` with
this json body:

```json
{
"request_id": "088e29b0ab0079560dea5d3e5aeb2f7868af661e",
"parameters": {
"timestamp": "2015-11-04 14:14:30 +0100"
},
"shipment": {
"id": "S123",
"status": "shipped"
}
}
```

## Tests

Tests are written using rspec and Appraisals
Expand Down