diff --git a/docs/plugins/call-existing-api.md b/docs/plugins/call-existing-api.md index f6c9990b90..9658176224 100644 --- a/docs/plugins/call-existing-api.md +++ b/docs/plugins/call-existing-api.md @@ -71,11 +71,7 @@ Example: ```yaml # In app-config.yaml proxy: - '/frobs': - target: 'http://api.frobsco.com/v1' - changeOrigin: true - pathRewrite: - '^/proxy/frobs/': '/' + '/frobs': http://api.frobsco.com/v1 ``` ```ts @@ -86,9 +82,8 @@ fetch(`${backendUrl}/proxy/frobs/list`) .then(payload => setFrobs(payload as Frob[])); ``` -The proxy is powered by the `http-proxy-middleware` package, and supports all of -its -[configuration options](https://github.com/chimurai/http-proxy-middleware#options). +The proxy is powered by the `http-proxy-middleware` package. See +[Proxying](proxying.md) for a full description of its configuration options. Internally at Spotify, the proxy option has been the overwhelmingly most popular choice for plugin makers. Since we have DNS based service discovery in place and diff --git a/docs/plugins/proxying.md b/docs/plugins/proxying.md index 4cf5b4c025..658df3dda1 100644 --- a/docs/plugins/proxying.md +++ b/docs/plugins/proxying.md @@ -3,4 +3,73 @@ id: proxying title: Proxying --- -## TODO +## Overview + +The Backstage backend comes packaged with a basic HTTP proxy, that can aid in +reaching backend service APIs from frontend plugin code. See +[Call Existing API](call-existing-api.md) for a description of when the proxy +can be the best choice for communicating with an API. + +## Getting Started + +The plugin is already added to a default Backstage project. + +In `packages/backend/src/index.ts`: + +```ts +const proxyEnv = useHotMemoize(module, () => createEnv('proxy')); + +const service = createServiceBuilder(module) + .loadConfig(configReader) + /** ... other routers ... */ + .addRouter('/proxy', await proxy(proxyEnv, '/proxy')); +``` + +## Configuration + +Configuration for the proxy plugin lives under a `proxy` root key of your +`app-config.yaml` file. + +Example: + +```yaml +# in app-config.yaml +proxy: + '/simple-example': http://simple.example.com:8080 + '/larger-example/v1': + target: http://larger.example.com:8080/svc.v1 + headers: + Authorization: + $secret: + env: EXAMPLE_AUTH_HEADER +``` + +Each key under the proxy configuration entry is a route to match, below the +prefix that the proxy plugin is mounted on. It must start with a slash. For +example, if the backend mounts the proxy plugin as `/proxy`, the above +configuration will lead to the proxy acting on backend requests to +`/proxy/simple-example/...` and `/proxy/larger-example/v1/...`. + +The value inside each route is either a simple URL string, or an object on the +format accepted by +[http-proxy-middleware](https://www.npmjs.com/package/http-proxy-middleware). + +If the value is a string, it is assumed to correspond to: + +```yaml +target: +changeOrigin: true +pathRewrite: + '^/': '/' +``` + +When the target is an object, it is given verbatim to `http-proxy-middleware` +except with the following caveats for convenience: + +- If `changeOrigin` is not specified, it is set to `true`. This is the most + commonly useful value. +- If `pathRewrite` is not specified, it is set to a single rewrite that removes + the entire prefix and route. In the above example, a rewrite of + `'^/proxy/larger-example/v1/': '/'` is added. That means that a request to + `/proxy/larger-example/v1/some/path` will be translated to a request to + `http://larger.example.com:8080/svc.v1/some/path`. diff --git a/plugins/proxy-backend/README.md b/plugins/proxy-backend/README.md index baa2709820..f67449dda3 100644 --- a/plugins/proxy-backend/README.md +++ b/plugins/proxy-backend/README.md @@ -1,6 +1,7 @@ # Proxy backend plugin -This is the backend plugin that enables proxy definitions to be declared in and read from app-config.yaml. +This is the backend plugin that enables proxy definitions to be declared in, +and read from, `app-config.yaml`. Relies on the `http-proxy-middleware` package. @@ -10,69 +11,22 @@ This backend plugin can be started in a standalone mode from directly in this pa with `yarn start`. However, it will have limited functionality and that process is most convenient when developing the plugin itself. -To run it within the backend do: - -1. Register the router in `packages/backend/src/index.ts`: - -```ts -const proxyEnv = useHotMemoize(module, () => createEnv('proxy')); - -const service = createServiceBuilder(module) - .loadConfig(configReader) - /** ... other routers ... */ - .addRouter('/proxy', await proxy(proxyEnv, '/proxy')); -``` - -2. Start the backend +The proxy is already installed in the Backstage backend per default, so you can also +start up the full example backend to experiment with the proxy. ```bash yarn workspace example-backend start ``` -This will launch the full example backend. - ## Configuration -Example: - -```yaml -# in app-config.yaml -proxy: - '/simple-example': http://simple.example.com:8080 - '/larger-example/v1': - target: http://larger.example.com:8080/svc.v1 - headers: - Authorization: - $secret: - env: EXAMPLE_AUTH_HEADER -``` - -Each key under the proxy configuration entry is a route to match, below the prefix that the proxy -plugin is mounted on. For example, if the backend mounts the proxy plugin as `/proxy`, -the above configuration will lead to the proxy acting on backend requests to -`/proxy/simple-example/...` and `/proxy/larger-example/v1/...`. - -The value inside each route is either a simple URL string, or an object on the format accepted by -[http-proxy-middleware](https://www.npmjs.com/package/http-proxy-middleware). - -If the value is a string, it is assumed to correspond to: - -```yaml -target: -changeOrigin: true -pathRewrite: - '^/': '/' -``` - -When the target is an object, it is given verbatim to `http-proxy-middleware` except with the -following caveats for convenience: - -- If `changeOrigin` is not specified, it is set to `true`. This is the most commonly useful value. -- If `pathRewrite` is not specified, it is set to a single rewrite that removes the entire route. In the - above example, a rewrite of `'^/proxy/larger-example/v1/': '/'` is added. That means that a request to - `/proxy/larger-example/v1/some/path` will be translated to a request to - `http://larger.example.com:8080/svc.v1/some/path`. +See [the proxy docs](https://backstage.io/docs/plugins/proxying). ## Links +- [Call Existing API](https://backstage.io/docs/plugins/call-existing-api) helps the + decision process of what method of communication to use from a frontend plugin to + your API +- [The proxy plugin documentation](https://backstage.io/docs/plugins/proxying) describes + configuration options and more - [http-proxy-middleware](https://www.npmjs.com/package/http-proxy-middleware)