Prepare an application for deployment in Azure Spring Apps

Note

Azure Spring Apps is the new name for the Azure Spring Cloud service. Although the service has a new name, you'll see the old name in some places for a while as we work to update assets such as screenshots, videos, and diagrams.

This article applies to: ✔️ Basic/Standard tier ✔️ Enterprise tier

This article shows how to prepare an existing Steeltoe application for deployment to Azure Spring Apps. Azure Spring Apps provides robust services to host, monitor, scale, and update a Steeltoe app.

This article explains the dependencies, configuration, and code that are required to run a .NET Core Steeltoe app in Azure Spring Apps. For information about how to deploy an application to Azure Spring Apps, see Deploy your first Spring Boot app in Azure Spring Apps.

Note

Steeltoe support for Azure Spring Apps is currently offered as a public preview. Public preview offerings allow customers to experiment with new features prior to their official release. Public preview features and services are not meant for production use. For more information about support during previews, see the FAQ or file a Support request.

Supported versions

Azure Spring Apps supports:

  • .NET Core 3.1
  • Steeltoe 2.4 and 3.0

Dependencies

For Steeltoe 2.4, add the latest Microsoft.Azure.SpringCloud.Client 1.x.x package to the project file:

<ItemGroup>
  <PackageReference Include="Microsoft.Azure.SpringCloud.Client" Version="1.0.0-preview.1" />
  <PackageReference Include="Steeltoe.Discovery.ClientCore" Version="2.4.4" />
  <PackageReference Include="Steeltoe.Extensions.Configuration.ConfigServerCore" Version="2.4.4" />
  <PackageReference Include="Steeltoe.Management.TracingCore" Version="2.4.4" />
  <PackageReference Include="Steeltoe.Management.ExporterCore" Version="2.4.4" />
</ItemGroup>

For Steeltoe 3.0, add the latest Microsoft.Azure.SpringCloud.Client 2.x.x package to the project file:

<ItemGroup>
  <PackageReference Include="Microsoft.Azure.SpringCloud.Client" Version="2.0.0-preview.1" />
  <PackageReference Include="Steeltoe.Discovery.ClientCore" Version="3.0.0" />
  <PackageReference Include="Steeltoe.Extensions.Configuration.ConfigServerCore" Version="3.0.0" />
  <PackageReference Include="Steeltoe.Management.TracingCore" Version="3.0.0" />
</ItemGroup>

Update Program.cs

In the Program.Main method, call the UseAzureSpringCloudService method.

For Steeltoe 2.4.4, call UseAzureSpringCloudService after ConfigureWebHostDefaults and after AddConfigServer if it's called:

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseStartup<Startup>();
        })
        .AddConfigServer()
        .UseAzureSpringCloudService();

For Steeltoe 3.0.0, call UseAzureSpringCloudService before ConfigureWebHostDefaults and before any Steeltoe configuration code:

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .UseAzureSpringCloudService()
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseStartup<Startup>();
        })
        .AddConfigServer();

Enable Eureka Server service discovery

Note

Eureka is not applicable to enterprise tier. If you're using enterprise tier, see Use Service Registry.

In the configuration source that will be used when the app runs in Azure Spring Apps, set spring.application.name to the same name as the Azure Spring Apps app to which the project will be deployed.

For example, if you deploy a .NET project named EurekaDataProvider to an Azure Spring Apps app named planet-weather-provider the appSettings.json file should include the following JSON:

"spring": {
  "application": {
    "name": "planet-weather-provider"
  }
}

Use service discovery

To call a service by using the Eureka Server service discovery, make HTTP requests to http://<app_name> where app_name is the value of spring.application.name of the target app. For example, the following code calls the planet-weather-provider service:

using (var client = new HttpClient(discoveryHandler, false))
{
    var responses = await Task.WhenAll(
        client.GetAsync("http://planet-weather-provider/weatherforecast/mercury"),
        client.GetAsync("http://planet-weather-provider/weatherforecast/saturn"));
    var weathers = await Task.WhenAll(from res in responses select res.Content.ReadAsStringAsync());
    return new[]
    {
        new KeyValuePair<string, string>("Mercury", weathers[0]),
        new KeyValuePair<string, string>("Saturn", weathers[1]),
    };
}

This article shows how to prepare an existing Java Spring application for deployment to Azure Spring Apps. If configured properly, Azure Spring Apps provides robust services to monitor, scale, and update your Java Spring application.

Before running this example, you can try the basic quickstart.

Other examples explain how to deploy an application to Azure Spring Apps when the POM file is configured.

This article explains the required dependencies and how to add them to the POM file.

Java Runtime version

For details, see the Java runtime and OS versions section of the Azure Spring Apps FAQ.

Spring Boot and Spring Cloud versions

To prepare an existing Spring Boot application for deployment to Azure Spring Apps, include the Spring Boot and Spring Cloud dependencies in the application POM file as shown in the following sections.

Azure Spring Apps will support the latest Spring Boot or Spring Cloud major version starting from 30 days after its release. The latest minor version will be supported as soon as it's released. You can get supported Spring Boot versions from Spring Boot Releases and Spring Cloud versions from Spring Cloud Releases.

The following table lists the supported Spring Boot and Spring Cloud combinations:

Spring Boot version Spring Cloud version
3.0.0 2022.0.0-RC2
2.7.x 2021.0.3+ aka Jubilee
2.6.x 2021.0.0+ aka Jubilee

For more information, see the following pages:

Note

  • The support for Spring Boot 3.0 is still in preview, so you shouldn't use it in production.

Dependencies for Spring Boot version 2.4/2.5/2.6/2.7

For Spring Boot version 2.4/2.5, add the following dependencies to the application POM file.

<!-- Spring Boot dependencies -->
<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.4.8</version>
</parent>

<!-- Spring Cloud dependencies -->
<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>2020.0.2</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

For Spring Boot version 2.6/2.7, add the following dependencies to the application POM file.

<!-- Spring Boot dependencies -->
<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.7.2</version>
</parent>

<!-- Spring Cloud dependencies -->
<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>2021.0.3</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

Warning

Don't specify server.port in your configuration. Azure Spring Apps will override this setting to a fixed port number. You must also respect this setting and not specify a server port in your code.

To enable the built-in features of Azure Spring Apps from service registry to distributed tracing, you need to also include the following dependencies in your application. You can drop some of these dependencies if you don't need corresponding features for the specific apps.

Service Registry

To use the managed Azure Service Registry service, include the spring-cloud-starter-netflix-eureka-client dependency in the pom.xml file as shown here:

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>

The endpoint of the Service Registry server is automatically injected as environment variables with your app. Applications can register themselves with the Service Registry server and discover other dependent applications.

EnableDiscoveryClient annotation

Add the following annotation to the application source code.

@EnableDiscoveryClient

For example, see the piggymetrics application from earlier examples:

package com.piggymetrics.gateway;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;

@SpringBootApplication
@EnableDiscoveryClient
@EnableZuulProxy

public class GatewayApplication {
    public static void main(String[] args) {
        SpringApplication.run(GatewayApplication.class, args);
    }
}

Distributed configuration

To enable distributed configuration, include the following spring-cloud-config-client dependency in the dependencies section of your pom.xml file:

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-config-client</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-bootstrap</artifactId>
</dependency>

Warning

Don't specify spring.cloud.config.enabled=false in your bootstrap configuration. Otherwise, your application stops working with Config Server.

Metrics

Include the spring-boot-starter-actuator dependency in the dependencies section of your pom.xml file as shown here:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

Metrics are periodically pulled from the JMX endpoints. You can visualize the metrics by using the Azure portal.

Warning

You must specify spring.jmx.enabled=true in your configuration property. Otherwise, metrics can't be visualized in the Azure portal.

See also

Next steps

In this article, you learned how to configure your Java Spring application for deployment to Azure Spring Apps. To learn how to set up a Config Server instance, see Set up a Config Server instance.

More samples are available on GitHub: Azure Spring Apps Samples.