Application Communication :: Payara Cloud Documentation

Payara Cloud designates a distinct domain under payara.app for each namespace, like https://staging-118842.payara.app. In this namespace, apps are deployed at specific paths. For instance, an app named foo will be deployed at https://staging-118842.payara.app/foo.

Apps within the same namespace can interact using the URL format http://deployedAppName/contextRoot/someEndpoint.

Custom Domain Linking

You can link custom domains to a namespace. For example, myApp.foocompany.com can point to https://staging-118842.payara.app. Once linked, foo app becomes accessible at https://myApp.foocompany.com/foo.

Context Root Definition

By default, the app’s context root is either the application name or a path specified in glassfish-web.xml. Apps can also designate a sub-path for external exposure, like app-context-root/public, keeping other paths like app-context-root/api internal.

Setting up Communication Between Applications

Assume bar and bazz are deployed to the same namespace on Payara Cloud, with bar exposing a REST endpoint api/finance that bazz consumes. The following sections illustrate their communication setup.

Deploying `bar` and `bazz`

Deploy both apps to a namespace, say https://staging-118842.payara.app, making them accessible at https://staging-118842.payara.app/bar and https://staging-118842.payara.app/bazz.

If a custom domain foocompany.com is configured, the apps are available at https://foocompany.com/bar and https://foocompany.com/bazz respectively.

Accessing Endpoint in `bazz`

bazz can access bars /api/finance endpoint at the internal address http://bar/bar/api/finance. This address utilizes the app name and context root for in-namespace routing.

Below is a code snippet demonstrating a call from bar to `bazz’s api/finance endpoint:

public class FinanceApiClient {

    public  void doSomeFinance() {
        HttpClient client = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("http://bar/bar/api/finance"))
                .GET()
                .build();
            HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
            if (response.statusCode() == 200) {
               //Do custom work with the response
            }

    }
}

Use MicroProfile Config For Utmost Flexibility

Employ MicroProfile Config properties to specify the endpoints, allowing different server URLs during development and production. With this setup, app deployment configuration on Payara Cloud can override these properties.

Here’s how the above snippet can be adapted to use MicroProfile Config properties:

public class FinanceApiClient {

    @Inject
    @ConfigProperty(name="`bar`.finance.endpoint")
    String resourceUrl;

    public  void doSomeFinance() {
        HttpClient client = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(resourceUrl))
                .GET()
                .build();
            HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
            if (response.statusCode() == 200) {
               //Do custom work with the response
            }

    }
}

With this setup, different URLs can be passed dynamically without redeploying the app. Modify this property anytime on the Payara Cloud dashboard to suit your needs.

Payara Cloud

Application Communication