Services and Routes

Kong Gateway administrators work with an object model to define their desired traffic management policies. Two important objects in that model are services and routes. Services and routes are configured in a coordinated manner to define the routing path that requests and responses will take through the system.

The high level overview below shows requests arriving at routes and being forwarded to services, with responses taking the opposite pathway:

 
flowchart LR
  A(API client)
  B("`Route 
  (/mock)`")
  C("`Service
  (example_service)`")
  D(Upstream 
  application)
  
  A <--requests
  responses--> B
  subgraph id1 ["`
  **KONG GATEWAY**`"]
    B <--requests
    responses--> C
  end
  C <--requests
  responses--> D

  style id1 rx:10,ry:10

What is a service

In Kong Gateway, a service is an abstraction of an existing upstream application. Services can store collections of objects like plugin configurations, and policies, and they can be associated with routes.

When defining a service, the administrator provides a name and the upstream application connection information. The connection details can be provided in the url field as a single string, or by providing individual values for protocol, host, port, and path individually.

Services have a one-to-many relationship with upstream applications, which allows administrators to create sophisticated traffic management behaviors.

What is a route

A route is a path to a resource within an upstream application. Routes are added to services to allow access to the underlying application. In Kong Gateway, routes typically map to endpoints that are exposed through the Kong Gateway application. Routes can also define rules that match requests to associated services. Because of this, one route can reference multiple endpoints. A basic route should have a name, path or paths, and reference an existing service.

You can also configure routes with:

Protocols: The protocol used to communicate with the upstream application.
Hosts: Lists of domains that match a route
Methods: HTTP methods that match a route
Headers: Lists of values that are expected in the header of a request
Redirect status codes: HTTPS status codes
Tags: Optional set of strings to group routes with

See Routes for a description of how Kong Gateway routes requests.

Managing services and routes

The following tutorial walks through managing and testing services and routes using the Kong Gateway Admin API. Kong Gateway also offers other options for configuration management including Kong Konnect and decK.

In this section of the tutorial, you will complete the following steps:

Create a service pointing to the httpbin API, which provides testing facilities for HTTP requests and responses.
Define a route by providing a URL path that will be available to clients on the running Kong Gateway.
Use the new httpbin service to echo a test request, helping you understand how Kong Gateway proxies API requests.

Prerequisites

This chapter is part of the Get Started with Kong series. For the best experience, it is recommended that you follow the series from the beginning.

The introduction, Get Kong, includes tool prerequisites and instructions for running a local Kong Gateway.

If you haven’t completed the Get Kong step already, complete that before proceeding.

Managing services

Creating services

To add a new service, send a POST request to Kong Gateway’s Admin API /services route:
```
curl -i -s -X POST http://localhost:8001/services \
  --data name=example_service \
  --data url='https://httpbin.konghq.com'
```
This request instructs Kong Gateway to create a new service mapped to the upstream URL https://httpbin.konghq.com.

In our example, the request body contained two strings:
- name: The name of the service
- url : An argument that populates the host, port, and path attributes of the service
If your request was successful, you will see a 201 response header from Kong Gateway confirming that your service was created and the response body will be similar to:
```
{
  "host": "httpbin.konghq.com",
  "name": "example_service",
  "enabled": true,
  "connect_timeout": 60000,
  "read_timeout": 60000,
  "retries": 5,
  "protocol": "http",
  "path": null,
  "port": 80,
  "tags": null,
  "client_certificate": null,
  "tls_verify": null,
  "created_at": 1661346938,
  "updated_at": 1661346938,
  "tls_verify_depth": null,
  "id": "3b2be74e-335b-4f25-9f08-6c41b4720315",
  "write_timeout": 60000,
  "ca_certificates": null
}
```
Fields that are not explicitly provided in the create request are automatically given a default value based on the current Kong Gateway configuration.
Viewing service configuration

When you create a service, Kong Gateway assigns it a unique id as shown in the response above. The id field, or the name provided when creating the service, can be used to identify the service in subsequent requests. This is the service URL and takes the form of /services/{service name or id}.

To view the current state of a service, make a GET request to the service URL.
```
curl -X GET http://localhost:8001/services/example_service
```
A successful request will contain the current configuration of your service in the response body and will look something like the following snippet:
```
{
  "host": "httpbin.konghq.com",
  "name": "example_service",
  "enabled": true,
  ...
}
```
Updating services

Existing service configurations can be updated dynamically by sending a PATCH request to the service URL.

To dynamically set the service retries from 5 to 6, send this PATCH request:
```
curl --request PATCH \
  --url localhost:8001/services/example_service \
  --data retries=6
```
The response body contains the full service configuration including the updated value:
```
{
  "host": "httpbin.konghq.com",
  "name": "example_service",
  "enabled": true,
  "retries": 6,
  ...
}
```
Listing services

You can list all current services by sending a GET request to the base /services URL.
```
curl -X GET http://localhost:8001/services
```

The Admin API documentation provides the full service update specification.

You can also view the configuration for your services in the Kong Manager UI by navigating to the following URL in your browser:

Kong Manager OSS: http://localhost:8002/services
Kong Manager Enterprise: http://localhost:8002/default/services, where default is the workspace name.

Managing routes

Creating routes

Routes define how requests are proxied by Kong Gateway. You can create a route associated with a specific service by sending a POST request to the service URL.

Configure a new route on the /mock path to direct traffic to the example_service service created earlier:

curl -i -X POST http://localhost:8001/services/example_service/routes \
  --data 'paths[]=/mock' \
  --data name=example_route

If the route was successfully created, the API returns a 201 response code and a response body like this:

{
  "paths": [
    "/mock"
  ],
  "methods": null,
  "sources": null,
  "destinations": null,
  "name": "example_route",
  "headers": null,
  "hosts": null,
  "preserve_host": false,
  "regex_priority": 0,
  "snis": null,
  "https_redirect_status_code": 426,
  "tags": null,
  "protocols": [
    "http",
    "https"
  ],
  "path_handling": "v0",
  "id": "52d58293-ae25-4c69-acc8-6dd729718a61",
  "updated_at": 1661345592,
  "service": {
    "id": "c1e98b2b-6e77-476c-82ca-a5f1fb877e07"
  },
  "response_buffering": true,
  "strip_path": true,
  "request_buffering": true,
  "created_at": 1661345592
}

Viewing route configuration

Like services, when you create a route, Kong Gateway assigns it a unique id as shown in the response above. The id field, or the name provided when creating the route, can be used to identify the route in subsequent requests. The route URL can take either of the following forms:

/services/{service name or id}/routes/{route name or id}
/routes/{route name or id}

To view the current state of the example_route route, make a GET request to the route URL:

curl -X GET http://localhost:8001/services/example_service/routes/example_route

The response body contains the current configuration of your route:

{
  "paths": [
    "/mock"
  ],
  "methods": null,
  "sources": null,
  "destinations": null,
  "name": "example_route",
  "headers": null,
  "hosts": null,
  "preserve_host": false,
  "regex_priority": 0,
  "snis": null,
  "https_redirect_status_code": 426,
  "tags": null,
  "protocols": [
    "http",
    "https"
  ],
  "path_handling": "v0",
  "id": "189e0a57-205a-4f48-aec6-d57f2e8a9985",
  "updated_at": 1661347991,
  "service": {
    "id": "3b2be74e-335b-4f25-9f08-6c41b4720315"
  },
  "response_buffering": true,
  "strip_path": true,
  "request_buffering": true,
  "created_at": 1661347991
}

Updating routes

Like services, routes can be updated dynamically by sending a PATCH request to the route URL.

Tags are an optional set of strings that can be associated with the route for grouping and filtering. You can assign tags by sending a PATCH request to the services endpoint and specifying a route.

Update the route by assigning it a tag with the value tutorial:
```
curl --request PATCH \
  --url localhost:8001/services/example_service/routes/example_route \
  --data tags="tutorial"
```
The above example used the service and route name fields for the route URL.

If the tag was successfully applied, the response body will contain the following JSON value:
```
...
"tags":["tutorial"]
...
```

Listing routes

The Admin API also supports the listing of all routes currently configured:

curl http://localhost:8001/routes

This request returns an HTTP 200 status code and a JSON response body object array with all of the routes configured on this Kong Gateway instance. Your response should look like the following:

{
  "next": null,
  "data": [
    {
      "paths": [
        "/mock"
      ],
      "methods": null,
      "sources": null,
      "destinations": null,
      "name": "example_route",
      "headers": null,
      "hosts": null,
      "preserve_host": false,
      "regex_priority": 0,
      "snis": null,
      "https_redirect_status_code": 426,
      "tags": [
        "tutorial"
      ],
      "protocols": [
        "http",
        "https"
      ],
      "path_handling": "v0",
      "id": "52d58293-ae25-4c69-acc8-6dd729718a61",
      "updated_at": 1661346132,
      "service": {
        "id": "c1e98b2b-6e77-476c-82ca-a5f1fb877e07"
      },
      "response_buffering": true,
      "strip_path": true,
      "request_buffering": true,
      "created_at": 1661345592
    }
  ]
}

The Admin API documentation has the full specification for managing route objects.

You can also view the configuration for your routes in the Kong Manager UI by navigating to the following URL in your browser: http://localhost:8002/default/routes

Proxy a request

Kong is an API Gateway, it takes requests from clients and routes them to the appropriate upstream application based on a the current configuration. Using the service and route that was previously configured, you can now access https://httpbin.konghq.com/ using http://localhost:8000/mock.

By default, Kong Gateway’s Admin API listens for administrative requests on port 8001, this is sometimes referred to as the control plane. Clients use port 8000 to make data requests, and this is often referred to as the data plane.

Httpbin provides an /anything resource which will echo back to clients information about requests made to it. Proxy a request through Kong Gateway to the /anything resource:

curl -X GET http://localhost:8000/mock/anything

You should see a response similar to the following:

{
  "startedDateTime": "2022-08-24T13:44:28.449Z",
  "clientIPAddress": "172.19.0.1",
  "method": "GET",
  "url": "http://localhost/anything",
  "httpVersion": "HTTP/1.1",
  "cookies": {},
  "headers": {
    "host": "httpbin.konghq.com",
    "connection": "close",
    "accept-encoding": "gzip",
    "x-forwarded-for": "172.19.0.1,98.63.188.11, 162.158.63.41",
    "cf-ray": "73fc85d999f2e6b0-EWR",
    "x-forwarded-proto": "http",
    "cf-visitor": "{\"scheme\":\"http\"}",
    "x-forwarded-host": "localhost",
    "x-forwarded-port": "80",
    "x-forwarded-path": "/mock/anything",
    "x-forwarded-prefix": "/mock",
    "user-agent": "curl/7.79.1",
    "accept": "*/*",
    "cf-connecting-ip": "00.00.00.00",
    "cdn-loop": "cloudflare",
    "x-request-id": "1dae4762-5d7f-4d7b-af45-b05720762878",
    "via": "1.1 vegur",
    "connect-time": "0",
    "x-request-start": "1661348668447",
    "total-route-time": "0"
  },
  "queryString": {},
  "postData": {
    "mimeType": "application/octet-stream",
    "text": "",
    "params": []
  },
  "headersSize": 588,
  "bodySize": 0
}

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