Add multiple API versions

What is API versioning?

API versioning is the practice of managing changes to an API and ensuring that these changes are made without disrupting clients. A good API versioning strategy clearly communicates the changes made and allows API consumers to decide when to upgrade to the latest version at their own pace.

Types of API versioning

URI Path

The most common way to version an API is in the URI path and is often done with the prefix “v”. This method employs URI routing to direct requests to a specific version of the API.

http://apisix.org/v1/hello
http://apisix.org/v2/hello

Query parameters

In this method, the version number is included in the URI, but as a query parameter instead of in the path.

http://apisix.org/hello?version=1
http://apisix.org/hello?version=2

Custom request Header

You can also set the version number using custom headers in requests and responses. This leaves the URI of your resources unchanged.

http://apisix.org/hello -H 'Version: 1'
http://apisix.org/hello -H 'Version: 2'

The primary goal of versioning is to provide users of an API with the most functionality possible while causing minimal inconvenience. Keeping this goal in mind, let’s have a look in this tutorial at how to publish and manage multiple versions of your API with Apache APISIX.

In this tutorial, you learn how to:

• Create a route and upstream for our sample API.
• Add a new version to the existing API.
• Use proxy-rewrite plugin to rewrite the path in a plugin configuration.
• Route API requests from the old version to the new one.

Prerequisites

For the demo case, we will leverage the sample repository Evolve APIs on GitHub built on the Spring boot that demonstrates our API. You can see the complete source code there.

To execute and customize the example project per your need shown in this tutorial, here are the minimum requirements you need to install in your system:

• Docker - you need Docker installed locally to complete this tutorial. It is available for Windows or macOS.

Also, complete the following steps to run the sample project with Docker.

Use git to clone the repository:

git clone 'https://github.com/nfrankel/evolve-apis'

Go to root directory of evolve-apis

cd evolve-apis

Now we can start our application by running docker compose up command from the root folder of the project:

docker compose up -d

Create a route and upstream for the API.

You first need to Route your HTTP requests from the gateway to an Upstream (your API). With APISIX, you can create a route by sending an HTTP request to the gateway.

curl http://apisix:9180/apisix/admin/routes/1 -H 'X-API-KEY: xyz' -X PUT -d '
{
  "name": "Direct Route to Old API",
  "methods": ["GET"],
  "uris": ["/hello", "/hello/", "/hello/*"],
  "upstream": {
    "type": "roundrobin",
    "nodes": {
      "oldapi:8081": 1
    }
  }
}'

At this stage, we do not have yet any version and you can query the gateway as below:

curl http://apisix.org/hello

output

Hello world

curl http://apisix.org/hello/Joe

output

Hello Joe

In the previous step, we created a route that wrapped an upstream inside its configuration. Also, APISIX allows us to create an upstream with a dedicated ID to reuse it across several routes.

Let’s create the shared upstream by running below curl cmd:

curl http://apisix:9180/apisix/admin/upstreams/1 -H 'X-API-KEY: xyz' -X PUT -d '
{
  "name": "Old API",
  "type": "roundrobin",
  "nodes": {
    "oldapi:8081": 1
  }
}'

Add a new version

In the scope of this tutorial, we will use URI path-based versioning because it’s the most widespread. We are going to add v1 version for our existing oldapi in this section.

Before introducing the new version, we also need to rewrite the query that comes to the API gateway before forwarding it to the upstream. Because both the old and new versions should point to the same upstream and the upstream exposes endpoint /hello, not /v1/hello. Let’s create a plugin configuration to rewrite the path:

curl http://apisix:9180/apisix/admin/plugin_configs/1 -H 'X-API-KEY: xyz' -X PUT -d '
{
  "plugins": {
    "proxy-rewrite": {
      "regex_uri": ["/v1/(.*)", "/$1"]
    }
  }
}'

We can now create the second versioned route that references the existing upstream and plugin config.

Note that we can create routes for different API versions.

curl http://apisix:9180/apisix/admin/routes/2 -H 'X-API-KEY: xyz' -X PUT -d '
{
  "name": "Versioned Route to Old API",
  "methods": ["GET"],
  "uris": ["/v1/hello", "/v1/hello/", "/v1/hello/*"],
  "upstream_id": 1,
  "plugin_config_id": 1
}'

At this stage, we have configured two routes, one versioned and the other non-versioned:

curl http://apisix.org/hello

output

Hello world

curl http://apisix.org/v1/hello

output

Hello world

Route API requests from the old version to the new one

We have versioned our API, but our API consumers probably still use the legacy non-versioned API. We want them to migrate, but we cannot just delete the legacy route as our users are unaware of it. Fortunately, the 301 HTTP status code is our friend: we can let users know that the resource has moved from http://apisix.org/hello to http://apisix.org/v1/hello. It requires configuring the redirect plugin on the initial route:

curl http://apisix:9180/apisix/admin/routes/1 -H 'X-API-KEY: xyz' -X PATCH -d '
{
  "plugins": {
    "redirect": {
      "uri": "/v1$uri",
      "ret_code": 301
    }
  }
}'

Now when we try to request the first non-versioned API endpoint, you will get an expected output:

curl http://apisix.org/hello
<html>
<head><title>301 Moved Permanently</title></head>
<body>
<center><h1>301 Moved Permanently</h1></center>
<hr><center>openresty</center>
</body>
</html>

Either API consumers will transparently use the new endpoint because they will follow, or their integration breaks and they will notice the 301 status and the new API location to use.

Next steps

As you followed throughout the tutorial, it is very easy to publish multiple versions of your API with Apache APISIX and it does not require setting up actual API endpoints for each version of your API in the backend. It also allows your clients to switch between two versions without any downtime and save assets if there’s ever an update.

Learn more about how to manage API consumers and protect your APIs.