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Introduction to the sample app

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Note

The first 50 vCPU hours and 100 GB hours of memory are free each month. For more information, see Price Reduction - Azure Spring Apps does more, costs less! on the Apps on Azure Blog.

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 ✔️ Enterprise

In this quickstart, we use the well-known sample app PetClinic to show you how to deploy apps to the Azure Spring Apps service. The Pet Clinic sample demonstrates the microservice architecture pattern and highlights the services breakdown. You see how to deploy services to Azure with Azure Spring Apps capabilities such as service discovery, config server, logs, metrics, distributed tracing, and developer-friendly tooling support.

To follow the Azure Spring Apps deployment examples, you only need the location of the source code, which is provided as needed.

The following diagram shows the architecture of the PetClinic application.

Diagram that shows the architecture of the PetClinic app.

Note

When the application is hosted in Azure Spring Apps Enterprise plan, the managed Application Configuration Service for VMware Tanzu assumes the role of Spring Cloud Config Server and the managed VMware Tanzu Service Registry assumes the role of Eureka Service Discovery without any code changes to the application. For more information, see the Infrastructure services hosted by Azure Spring Apps section later in this article.

Functional services to be deployed

PetClinic is decomposed into four core Spring apps. All of them are independently deployable applications organized by business domains.

  • Customers service: Contains general user input logic and validation including pets and owners information (Name, Address, City, Telephone).
  • Visits service: Stores and shows visits information for each pet's comments.
  • Vets service: Stores and shows Veterinarians' information, including names and specialties.
  • API Gateway: The API Gateway is a single entry point into the system, used to handle requests and route them to an appropriate service or to invoke multiple services, and aggregate the results. The three core services expose an external API to client. In real-world systems, the number of functions can grow quickly with system complexity. Hundreds of services might be involved in rendering one complex webpage.

Infrastructure services hosted by Azure Spring Apps

There are several common patterns in distributed systems that support core services. Azure Spring Apps provides tools that enhance Spring Boot applications to implement the following patterns:

  • Application Configuration Service for Tanzu: Application Configuration Service for Tanzu is one of the commercial VMware Tanzu components. It enables the management of Kubernetes-native ConfigMap resources that are populated from properties defined in one or more Git repositories.
  • Tanzu Service Registry: Tanzu Service Registry is one of the commercial VMware Tanzu components. It provides your apps with an implementation of the Service Discovery pattern, one of the key tenets of a Spring-based architecture. Your apps can use the Service Registry to dynamically discover and call registered services.

Database configuration

In its default configuration, Pet Clinic uses an in-memory database (HSQLDB) which is populated at startup with data. A similar setup is provided for MySQL if a persistent database configuration is needed. A dependency for Connector/J, the MySQL JDBC driver, is already included in the pom.xml files.

Sample usage of PetClinic

For full implementation details, see our fork of PetClinic. The samples reference the source code as needed.

Next steps