Expose your Services with Kong Gateway

Expose your Services with Kong Gateway

In this topic, you’ll learn how to expose your Services using Routes.

If you are following the Getting Started workflow, make sure you have completed Prepare to Administer Kong Gateway before moving on.

If you are not following the Getting Started workflow, make sure you have Kong Gateway installed and started.

What are Services and Routes?

Service and Route objects let you expose your services to clients with Kong Gateway. When configuring access to your API, you’ll start by specifying a Service. In Kong Gateway, a Service is an entity representing an external upstream API or microservice — for example, a data transformation microservice, a billing API, and so on.

The main attribute of a Service is its URL, where the service listens for requests. You can specify the URL with a single string, or by specifying its protocol, host, port, and path individually.

Before you can start making requests against the Service, you will need to add a Route to it. Routes determine how (and if) requests are sent to their Services after they reach Kong Gateway. A single Service can have many Routes.

After configuring the Service and the Route, you’ll be able to start making requests through Kong Gateway.

This diagram illustrates the flow of requests and responses being routed through the Service to the backend API.

Add a Service

For the purpose of this example, you’ll create a Service pointing to the Mockbin API. Mockbin is an “echo” type public website that returns requests back to the requester as responses. This visualization will be helpful for learning how Kong Gateway proxies API requests.

Kong Gateway exposes the RESTful Admin API on port 8001. The gateway’s configuration, including adding Services and Routes, is done through requests to the Admin API.

Using Kong Manager

Using the Admin API

Using decK (YAML)

On the Workspaces tab in Kong Manager, scroll to the Workspace section and click the default workspace.

This example uses the default workspace, but you can also create a new workspace, or use an existing workspace.
Scroll down to Services and click Add a Service.
In the Create Service dialog, enter the name example_service and the URL http://mockbin.org.
Click Create.

The service is created, and the page automatically redirects back to the example_service overview page.

cURL

HTTPie

curl -i -X POST http://<admin-hostname>:8001/services \
  --data name=example_service \
  --data url='http://mockbin.org'

http POST :8001/services \
  name=example_service \
  url='http://mockbin.org'

If the service is created successfully, you’ll get a 201 success message.

Verify the service’s endpoint:

cURL

HTTPie

curl -i http://<admin-hostname>:8001/services/example_service

http :8001/services/example_service

In the kong.yaml file you exported in Prepare to Administer Kong Gateway, define a Service with the name example_service and the URL http://mockbin.org:
```
 _format_version: "1.1"
 services:
 - host: mockbin.org
   name: example_service
   port: 80
   protocol: http
```
Save the file. From your terminal, sync the configuration to update your gateway instance:
```
 deck sync
```
The message should show that you’re creating a service:
```
 creating service example_service
 Summary:
 Created: 1
 Updated: 0
 Deleted: 0
```

Add a Route

For the Service to be accessible through the API gateway, you need to add a Route to it.

Using Kong Manager

Using the Admin API

Using decK (YAML)

From the example_service overview page, scroll down to the Routes section and click Add Route.

The Create Route dialog displays with the Service field auto-populated with the Service name and ID number. This field is required.

Note: If the Service field is not automatically populated, click Services in the left navigation pane. Find your Service, click the clipboard icon next to the id field, then go back to the Create Route page and paste it into the Service field.
Enter a name for the Route, and at least one of the following fields: Host, Methods, or Paths. For this example, use the following:
1. For Name, enter mocking.
2. For Path(s), click Add Path and enter /mock.
Click Create.

The Route is created and you are automatically redirected back to the example_service overview page. The new Route appears under the Routes section.

Define a Route (/mock) for the Service (example_service) with a specific path that clients need to request. Note at least one of the hosts, paths, or methods must be set for the Route to be matched to the service.

cURL

HTTPie

curl -i -X POST http://<admin-hostname>:8001/services/example_service/routes \
  --data 'paths[]=/mock' \
  --data name=mocking

http :8001/services/example_service/routes \
  paths:='["/mock"]' \
  name=mocking

A 201 message indicates the Route was created successfully.

Paste the following into the kong.yaml file, under the entry for example_service:

 routes:
 - name: mocking
   paths:
   - /mock
   strip_path: true

Your file should now look like this:

 _format_version: "1.1"
 services:
 - host: mockbin.org
   name: example_service
   port: 80
   protocol: http
   routes:
   - name: mocking
     paths:
     - /mock
     strip_path: true

Sync the configuration:
```
 deck sync
```
(Optional) You can update your local file with the new configuration:

Be careful! Any subsequent deck dump will overwrite the existing kong.yaml file. Create backups as needed.
```
 $ deck dump
```
Alternatively, you will also see this configuration in the diff that decK shows when you’re syncing a change to the configuration.

You’ll notice that both the Service and Route now have parameters that you did not explicitly set. These are default parameters that every Service and Route are created with:
```
 services:
 - connect_timeout: 60000
   host: mockbin.org
   name: example_service
   port: 80
   protocol: http
   read_timeout: 60000
   retries: 5
   write_timeout: 60000
   routes:
   - name: mocking
     paths:
     - /mock
     path_handling: v0
     preserve_host: false
     protocols:
     - http
     - https
     regex_priority: 0
     strip_path: true
     https_redirect_status_code: 426
```
You can do this after any deck sync to see Kong Gateway’s most recent configuration.

The rest of this guide continues using the simplified version of the configuration file without performing a deck dump for every step, to keep it easy to follow.

Verify the Route is forwarding requests to the Service

Using a Web Browser

Using the Admin API

By default, Kong Gateway handles proxy requests on port :8000.

From a web browser, enter http://<admin-hostname>:8000/mock.

Using the Admin API, issue the following:

cURL

HTTPie

curl -i -X GET http://<admin-hostname>:8000/mock/request

http :8000/mock/request

Summary and next steps

In this section, you:

Added a Service named example_service with a URL of http://mockbin.org.
Added a Route named /mock.
This means if an HTTP request is sent to the Kong Gateway node on port 8000(the proxy port) and it matches route /mock, then that request is sent to http://mockbin.org.
Abstracted a backend/upstream service and put a route of your choice on the front end, which you can now give to clients to make requests.

Next, go on to learn about enforcing rate limiting.