# Kong

Kong is a powerful proxy built on nginx. By taking a request and passing it to an upstream server and then returning the result to the client Kong can perform his magic. To know which requests go to which service Kong looks for a `host` header to match against. There's a few other ways Kong can match requests to services but for now that's the most basic route. Pun intended.

# Kong Start

Assuming everything has been installed and setup, such as dependencies and config files which can be found in the docs, it's time to turn Kong on.

```
kong start
```

You'll see some Kong config values run the first migrations to a datastore. Hopefully it ended with an [OK], if not we're on gitter.

# Kong Add API

Now we can add our APIs and Microservices to Kong. To do that we'll use Kong's RESTful admin API. Let's say you have a service that returns countries and other meta data. It's a simple REST API and it's running on port 4444. You own the domain `restcountries.io` so let's use that as the `public_dns`.

```
curl -i -X POST \
 --url http://localhost:8001/apis/ \
 --data 'name=restcountries' \
 --data 'target_url=http://127.0.0.1:4444' \
 --data 'public_dns=restcountries.io'
```

# Kong Request

Now that it's added we can verify that Kong is serving it by making a request to Kong's proxy and suppyling the `Host` header which Kong will try to match any APIs with the same as the `public_dns` to know where to send the request upstream. Here's an example:

```
curl http://127.0.0.1:8000 -H "host:restcountries.io"
```

# DNS 

Now most likely you'll not want to add a host header manually with each request, so let's use our domain and have DNS take care of that for us. Set an A record for the domain pointing to your Kong installation. You can also modify `kong.yml` to use port 80 for the proxy and do a quick `kong restart` to have the effects take place. Now we can make a request directly to the domain and it will forward the correct `Host` header.

curl http://restcountries.io