route-services.html.md.erb

---
title: Route Services
owner: Core Services
---

<strong><%= modified_date %></strong>

This documentation is intended for service authors who are interested in 
offering a service to a Cloud Foundry (CF) services marketplace. Developers 
interested in consuming these services can read the [Manage Application Requests with Route Services](../devguide/services/route-binding.html) topic.

<%= vars.route_services %>

## <a id='introduction'></a>Introduction ##

Cloud Foundry application developers may wish to apply transformation or 
processing to requests before they reach an application. Common examples of use 
cases include authentication, rate limiting, and caching services. Route 
Services are a kind of Marketplace Service that developers can use to apply 
various transformations to application requests by binding an application's 
route to a service instance. Through integrations with service brokers and,  
optionally, with the Cloud Foundry routing tier, providers can offer these 
services to developers with a familiar, automated, self-service, and on-demand 
user experience.

<%= vars.route_services_appsman1 %>

## <a id='architecture'></a>Architecture ##

Cloud Foundry supports the following three models for Route Services: 

* [Fully-brokered services](#fully-brokered)
* [Static, brokered services](#static-brokered)
* [User-provided services](#user-provided)

In each model, you configure a route service to process traffic addressed to an 
app.

### <a id="fully-brokered"></a>Fully-Brokered Service ###

In the fully-Brokered Service model, the CF router receives all traffic to apps 
in the deployment before any processing by the route service. Developers can 
bind a route service to any app, and if an app is bound to a route service, the 
CF router sends its traffic to the service. After the route service processes 
requests, it sends them back to the load balancer in front of the CF router. 
The second time through, the CF router recognizes that the route service has 
already handled them, and forwards them directly to app instances.

![Fully brokered](images/route-services-fully-brokered.png)

The route service can run inside or outside of CF, so long as it fulfills the 
[Service Instance Responsibilities](#service-instance-responsibilities) to 
integrate it with the CF router. A service broker publishes the route service 
to the CF marketplace, making it available to developers. Developers can then 
create an instance of the service and bind it to their apps with the following 
commands:

`cf create-service BROKER-SERVICE-PLAN SERVICE-INSTANCE`
`cf bind-route-service YOUR-APP-DOMAIN SERVICE-INSTANCE [--hostname HOSTNAME] [--path PATH]`

Developers configure the service either through the service provider's web 
interface or by passing [arbitrary parameters](../devguide/services/managing-services.html#arbitrary-params-create)
 to their `cf create-service` call through the `-c` flag.

**Advantages:**

- Developers can use a Service Broker to dynamically configure how the route service processes traffic to specific applications.
- Adding route services requires no manual infrastructure configuration.
- Traffic to apps that do not use the service makes fewer network hops because requests for those apps do not pass through the route service.

**Disadvantages:**

- Traffic to apps that use the route service makes additional network hops, as compared to the static model.

### <a id="static-brokered"></a>Static, Brokered Service ###

In the static, brokered service model, an operator installs a static routing 
service, which might be a piece of hardware, in front of the load balancer. The 
routing service runs outside of Cloud Foundry and receives traffic to all apps 
running in the CF deployment. The service provider creates a service broker to 
publish the service to the CF marketplace. As with a [fully-brokered service](#fully-brokered), a developer can use the service by instantiating it 
with `cf create-service` and binding it to an app with `cf bind-route-service`.

![Static, brokered](images/route-services-static-brokered.png)

In this model, you configure route services on an app-by-app basis. When you 
bind a service to an app, the service broker directs the routing service to 
process that app's traffic rather than pass the requests through unchanged.

**Advantages:**

- Developers can use a Service Broker to dynamically configure how the route service processes traffic to specific applications.
- Traffic to apps that use the route service takes fewer network hops.

**Disadvantages:**

- Adding route services requires manual infrastructure configuration.
- Traffic to apps that do not use the route service make unnecessary network hops. Requests for all apps hosted by the deployment pass through the route service component.

### <a id="user-provided"></a>User-Provided Service ###

If a route service is not listed in the CF marketplace by a broker, a developer 
can still bind it to their app as a user-provided service. The service can run 
anywhere, either inside or outside of CF, but it must fulfill the integration 
requirements described in [Service Instance Responsibilities](#service-instance-responsibilities). The service also needs 
to be reachable by an outbound connection from the CF router.

![User-provided](images/route-services-user-provided.png)

This model is identical to the [fully-brokered service](#fully-brokered) model, 
except without the broker. Developers configure the service manually, outside 
of Cloud Foundry. They can then create a user-provided service instance and bind it to their application with the following commands, supplying the URL of their route service:

`cf create-user-provided-service SERVICE-INSTANCE -r ROUTE-SERVICE-URL`
`cf bind-route-service DOMAIN SERVICE-INSTANCE [--hostname HOSTNAME]`

**Advantages:**

- Adding route services requires no manual infrastructure configuration.
- Traffic to apps that do not use the service makes fewer network hops because requests for those apps do not pass through the route service.

**Disadvantages:**

- Developers must manually provision and configure route services out of the context of Cloud Foundry because no service broker automates these operations.
- Traffic to apps that use the route service makes additional network hops, as compared to the static model.

### <a id="architecture-comparison"></a>Architecture Comparison ###

The models above require the [broker](#broker-responsibilities) and [service instance](#service-instance-responsibilities) responsibilities summarized in the following table:

<table id='architecture-comparison' border="1" class="nice" >
  <tr>
    <th>Route Services Architecture</th>
    <th>Fulfills CF <a href="#service-instance-responsibilities">Service Instance Responsibilities</a></th>
    <th>Fulfills CF <a href="#broker-responsibilities">Broker Responsibilities</a></th>
  </tr><tr>
    <td>Fully-Brokered</td>
    <td>Yes</td>
    <td>Yes</td>
  </tr><tr>
    <td>Static Brokered</td>
    <td>No</td>
    <td>Yes</td>
  </tr><tr>
    <td>User-Provided</td>
    <td>Yes</td>
    <td>No</td>
  </tr>
</table>

<%= vars.route_services_config %>

## <a id='service-instance-responsibilities'></a>Service Instance Responsibilities ##

The following applies only when a broker returns `route_service_url` in the bind response.

#### <a id='how-it-works'></a>How It Works ####

Binding a service instance to a route associates the `route_service_url` with the route in the CF router. All requests for the route are proxied to the URL specified by `route_service_url`.

Once a route service completes its function it may choose to forward the request to the originally requested URL or to another location, or it may choose to reject the request; rejected requests will be returned to the originating requestor. The CF router includes a header that provides the originally requested URL, as well as two headers that are used by the router itself to validate the request sent by the route service. These headers are described below in [Headers](#headers).

#### <a id='headers'></a>Headers ####

The following HTTP headers are added by the Gorouter to requests forwarded to route services.

##### X-CF-Forwarded-Url #####

The `X-CF-Forwarded-Url` header contains the originally requested URL. The route service may choose to forward the request to this URL or to another.

##### X-CF-Proxy-Signature #####

The `X-CF-Proxy-Signature` header contains an encypted value which only the Gorouter can decrypt. 

The header contains the originally requested URL and a timestamp. When this header is present, the Gorouter will reject the request if the requested URL does not match that in the header, or if a timeout has expired.

`X-CF-Proxy-Signature` also signals to the Gorouter that a request has transited a route service. If this header is present, the Gorouter will not forward the request to a route service, preventing recursive loops. For this reason, route services should not strip off the `X-CF-Proxy-Signature` and `X-CF-Proxy-Metadata` headers. 

If the route service forwards the request to a URL different from the originally requested one, and the URL resolves to a route for an application on Cloud Foundry, the route must not have a bound route service or the request will be rejected, as the requested URL will not match the one in the `X-CF-Proxy-Signature` header.

##### X-CF-Proxy-Metadata #####

The `X-CF-Proxy-Metadata` header aids in the encryption and description of `X-CF-Proxy-Signature`. 

#### <a id='ssl-certs'></a>SSL Certificates ####

When Cloud Foundry is deployed in a development environment, certificates hosted by the load balancer are self-signed, and not signed by a trusted certificate authority. When the route service finishes processing an inbound request and makes a call to the value of `X-CF-Forwarded-Url`, be prepared to accept the self-signed certificate when integrating with a non-production deployment of Cloud Foundry.

#### <a id='timeouts'></a>Timeouts ####

<% if vars.product_name == "CF" %>
Route services must forward the request to the application route within the number of seconds configured by the `router.route_service_timeout` property. The `router.route_service_timeout` property defaults to 60 seconds.

In addition, all requests must respond in the number of seconds configured by the `request_timeout_in_seconds` property. The `request_timeout_in_seconds` property default to 900 seconds.

Timeouts are configurable for the router using the cf-release BOSH deployment manifest. For more information, see the [spec](https://github.com/cloudfoundry-incubator/routing-release/blob/master/jobs/gorouter/spec).
<% else %>
Route services must forward the request to the application route within 60 seconds.

In addition, all requests must respond in 900 seconds.

<% end %>

## <a id='broker-responsibilities'></a>Broker Responsibilities ##

#### <a id='catalog'></a>Catalog Endpoint ####

Brokers must include `requires: ["route_forwarding"]` for a service in the catalog endpoint. If this is not present, Cloud Foundry will not permit users to bind an instance of the service to a route.

#### <a id='binding'></a>Binding Endpoint ####

When users bind a route to a service instance, Cloud Foundry sends a [bind request](./api.html#binding) to the broker, including the route address with `bind_resource.route`. A route is an address used by clients to reach apps mapped to the route. The broker may return `route_service_url`, containing a URL where Cloud Foundry should proxy requests for the route. This URL must have an `https` scheme, otherwise the Cloud Controller rejects the binding. `route_service_url` is optional, and not returning this field enables a broker to dynamically configure a network component already in the request path for the route, requiring no change in the CF router.

## <a id='examples'></a>Example Route Services ##
- [Logging Route Service](https://github.com/cloudfoundry-samples/logging-route-service): This route service can be pushed as an app to Cloud Foundry. It fulfills the service instance responsibilities above and logs requests received and sent. It can be used to see the route service integration in action by tailing its logs.
- [Rate Limiting Route Service](https://github.com/cloudfoundry-samples/ratelimit-service): This example route service is a simple Cloud Foundry app that provides rate limiting to control the rate of traffic to an application.
- [Spring Boot Example](https://github.com/nebhale/route-service-example): Logs requests received and sent; written in Spring Boot

## <a id='tutorial'></a>Tutorial ##

The following instructions show how to use the [Logging Route Service](https://github.com/cloudfoundry-samples/logging-route-service) described in <a href="#examples">Example Route Services</a> to verify that when a route service is bound to a route, requests for that route are proxied to the route service.

A video of this tutorial is available on [Youtube](https://youtu.be/VaaZJE2E4jI).

These commands requires the Cloud Foundry Command Line Interface (cf CLI) version 6.16 or later.

1. Push the [Logging Route Service](https://github.com/cloudfoundry-samples/logging-route-service) as an app.

    <pre class="terminal">
    $ cf push logger
    </pre>

1. Create a user-provided service instance, and include the route of the [Logging Route Service](https://github.com/cloudfoundry-samples/logging-route-service) you pushed as `route_service_url`. Be sure to use `https` for the scheme.

    <pre class="terminal">
    $ cf create-user-provided-service mylogger -r https://logger.cf.example.com
    </pre>

1. Push a sample app like [Spring Music](https://github.com/cloudfoundry-samples/spring-music). By default this creates a route `spring-music.cf.example.com`.

    <pre class="terminal">
    $ cf push spring-music
    </pre>

1. Bind the user-provided service instance to the route of your sample app. The `bind-route-service` command takes a route and a service instance; the route is specified in the following example by domain `cf.example.com` and hostname `spring-music`.

    <pre class="terminal">
    $ cf bind-route-service cf.example.com mylogger --hostname spring-music
    </pre>

1. Tail the logs for your route service.

    <pre class="terminal">
    $ cf logs logger
    </pre>

1. Send a request to the sample app and view in the route service logs that the request is forwarded to it.

    <pre class="terminal">
    $ curl spring-music.cf.example.com
    </pre>