Overview (Azure SDK for Java Reference Documentation)

Posted by Erma Hippe on Sunday, June 23, 2024
Current version is 3.1.0, click here for the index

Azure Spring Data Cosmos provides Spring Data support for Azure Cosmos DB using the SQL API, based on Spring Data framework. Azure Cosmos DB is a globally-distributed database service which allows developers to work with data using a variety of standard APIs, such as SQL, MongoDB, Cassandra, Graph, and Table.

Spring data version support

This project supports both spring-data-commons 2.2.x and spring-data-commons 2.3.x versions. Maven users can inherit from the spring-boot-starter-parent project to obtain a dependency management section to let Spring manage the versions for dependencies.

<!-- Inherit defaults from Spring Boot --> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>${spring.boot.version}</version> </parent>

With that setup, you can also override individual dependencies by overriding a property in your own project. For instance, to upgrade to another Spring Data release train you’d add the following to your pom.xml.

<properties> <spring-data-releasetrain.version>${spring.data.version}</spring-data-releasetrain.version> </properties>

If you don’t want to use the spring-boot-starter-parent, you can still keep the benefit of the dependency management by using a scope=import dependency:

<dependencyManagement> <dependencies> <dependency> <!-- Import dependency management from Spring Boot --> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-dependencies</artifactId> <version>${spring.boot.version}</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement>

That setup does not allow you to override individual dependencies using a property as explained above. To achieve the same result, you’d need to add an entry in the dependencyManagement of your project before the spring-boot-dependencies entry. For instance, to upgrade to another Spring Data release train you’d add the following to your pom.xml.

<dependencyManagement> <dependencies> <!-- Override Spring Data release train provided by Spring Boot --> <dependency> <groupId>org.springframework.data</groupId> <artifactId>spring-data-releasetrain</artifactId> <version>${spring.data.version}</version> <scope>import</scope> <type>pom</type> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-dependencies</artifactId> <version>${spring.boot.version}</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement>

Note: Replace the ${spring.boot.version} and ${spring.data.version} with the versions of Spring Boot and Spring Data you want to use in your project.

Getting started

Include the package

If you are using Maven, add the following dependency.

<dependency> <groupId>com.azure</groupId> <artifactId>azure-spring-data-cosmos</artifactId> <version>3.1.0</version> </dependency>

Prerequisites

  • Java Development Kit 8
  • An active Azure account. If you don't have one, you can sign up for a free account. Alternatively, you can use the Azure Cosmos DB Emulator for development and testing. As emulator https certificate is self signed, you need to import its certificate to java trusted cert store, explained here
  • (Optional) SLF4J is a logging facade.
  • (Optional) SLF4J binding is used to associate a specific logging framework with SLF4J.
  • (Optional) Maven

SLF4J is only needed if you plan to use logging, please also download an SLF4J binding which will link the SLF4J API with the logging implementation of your choice. See the SLF4J user manual for more information.

Setup Configuration Class

  • In order to set up configuration class, you'll need to extend AbstractCosmosConfiguration

  • Azure-spring-data-cosmos also supports Response Diagnostics String and Query Metrics. Set queryMetricsEnabled flag to true in application.properties to enable query metrics. In addition to setting the flag, implement ResponseDiagnosticsProcessor to log diagnostics information.

 @Configuration @EnableCosmosRepositories public class AppConfiguration extends AbstractCosmosConfiguration { private static final Logger LOGGER = LoggerFactory.getLogger(AppConfiguration.class); @Value("${azure.cosmos.uri}") private String uri; @Value("${azure.cosmos.key}") private String key; @Value("${azure.cosmos.secondaryKey}") private String secondaryKey; @Value("${azure.cosmos.database}") private String dbName; @Value("${azure.cosmos.queryMetricsEnabled}") private boolean queryMetricsEnabled; private AzureKeyCredential azureKeyCredential; @Bean public CosmosClientBuilder getCosmosClientBuilder() { this.azureKeyCredential = new AzureKeyCredential(key); DirectConnectionConfig directConnectionConfig = new DirectConnectionConfig(); GatewayConnectionConfig gatewayConnectionConfig = new GatewayConnectionConfig(); return new CosmosClientBuilder() .endpoint(uri) .credential(azureKeyCredential) .directMode(directConnectionConfig, gatewayConnectionConfig); } @Override public CosmosConfig cosmosConfig() { return CosmosConfig.builder() .enableQueryMetrics(queryMetricsEnabled) .responseDiagnosticsProcessor(new ResponseDiagnosticsProcessorImplementation()) .build(); } public void switchToSecondaryKey() { this.azureKeyCredential.update(secondaryKey); } @Override protected String getDatabaseName() { return "testdb"; } private static class ResponseDiagnosticsProcessorImplementation implements ResponseDiagnosticsProcessor { @Override public void processResponseDiagnostics( @Nullable ResponseDiagnostics responseDiagnostics) { LOGGER.info("Response Diagnostics {}", responseDiagnostics); } } }

Customizing Configuration

You can customize DirectConnectionConfig or GatewayConnectionConfig or both and provide them to CosmosClientBuilder bean to customize CosmosAsyncClient

 @Bean public CosmosClientBuilder getCosmosClientBuilder() { DirectConnectionConfig directConnectionConfig = new DirectConnectionConfig(); GatewayConnectionConfig gatewayConnectionConfig = new GatewayConnectionConfig(); return new CosmosClientBuilder() .endpoint(uri) .directMode(directConnectionConfig, gatewayConnectionConfig); } @Override public CosmosConfig cosmosConfig() { return CosmosConfig.builder() .enableQueryMetrics(queryMetricsEnabled) .responseDiagnosticsProcessor(new ResponseDiagnosticsProcessorImplementation()) .build(); }

By default, @EnableCosmosRepositories will scan the current package for any interfaces that extend one of Spring Data's repository interfaces. Use it to annotate your Configuration class to scan a different root package by @EnableCosmosRepositories(basePackageClass=UserRepository.class) if your project layout has multiple projects.

Define an entity

  • Define a simple entity as item in Azure Cosmos DB.

  • You can define entities by adding the @Container annotation and specifying properties related to the container, such as the container name, request units (RUs), time to live, and auto-create container.

  • Containers will be created automatically unless you don't want them to. Set autoCreateContainer to false in @Container annotation to disable auto creation of containers.

  • Note: By default request units assigned to newly created containers is 400. Specify different ru value to customize request units for the container created by the SDK (minimum RU value is 400).

 @Container(containerName = "myContainer", ru = "400") public class User { private String id; private String firstName; @PartitionKey private String lastName; public User() { // If you do not want to create a default constructor, // use annotation @JsonCreator and @JsonProperty in the full args constructor } public User(String id, String firstName, String lastName) { this.id = id; this.firstName = firstName; this.lastName = lastName; } @Override public String toString() { return String.format("User: %s %s, %s", firstName, lastName, id); } public String getId() { return id; } public void setId(String id) { this.id = id; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } }

  • id field will be used as Item id in Azure Cosmos DB. If you want use another field like firstName as item id, just annotate that field with @Id annotation.

  • Annotation @Container(containerName="myContainer") specifies container name in Azure Cosmos DB.

  • Annotation @PartitionKey on lastName field specifies this field as partition key in Azure Cosmos DB.
 @Container(containerName = "myContainer") public class UserSample { @Id private String emailAddress; }

Nested Partition Key support

  • Spring Data Cosmos SDK supports nested partition key. To add nested partition key, use partitionKeyPath field in @Container annotation.
  • partitionKeyPath should only be used to support nested partition key path. For general partition key support, use the @PartitionKey annotation.
  • By default @PartitionKey annotation will take precedence, unless not specified.
  • Below example shows how to properly use Nested Partition key feature.
 @Container(containerName = "nested-partition-key", partitionKeyPath = "/nestedEntitySample/nestedPartitionKey") public class NestedPartitionKeyEntitySample { private NestedEntitySample nestedEntitySample; } 
public class NestedEntitySample { private String nestedPartitionKey; }

Create repositories

Extends CosmosRepository interface, which provides Spring Data repository support.

 @Repository public interface UserRepository extends CosmosRepository<User, String> { Iterable<User> findByFirstName(String firstName); User findOne(String id, String lastName); }
  • findByFirstName method is custom query method, it will find items per firstName.

QueryAnnotation : Using annotated queries in repositories

Azure spring data cosmos supports specifying annotated queries in the repositories using @Query. - Examples for annotated queries in synchronous CosmosRepository:

public interface AnnotatedQueriesUserRepositoryCodeSnippet extends CosmosRepository<User, String> { @Query(value = "select * from c where c.firstName = @firstName and c.lastName = @lastName") List<User> getUsersByTitleAndValue( @Param("firstName") int firstName, @Param("lastName") String lastName); @Query(value = "select * from c offset @offset limit @limit") List<User> getUsersWithOffsetLimit( @Param("offset") int offset, @Param("limit") int limit); }
  • Examples for annotated queries in ReactiveCosmosRepository.
public interface AnnotatedQueriesUserReactiveRepositoryCodeSnippet extends ReactiveCosmosRepository<User, String> { @Query(value = "select * from c where c.firstName = @firstName and c.lastName = @lastName") Flux<User> getUsersByTitleAndValue( @Param("firstName") int firstName, @Param("lastName") String lastName); @Query(value = "select * from c offset @offset limit @limit") Flux<User> getUsersWithOffsetLimit( @Param("offset") int offset, @Param("limit") int limit); @Query(value = "select count(c.id) as num_ids, c.lastName from c group by c.lastName") Flux<ObjectNode> getCoursesGroupByDepartment(); }

The queries that are specified in the annotation are same as the cosmos queries. Please refer to the following articles for more information on sql queries in cosmos - sql-query-getting-started - tutorial-query-sql-api

Create an Application class

Here create an application class with all the components

 @SpringBootApplication public class SampleApplication implements CommandLineRunner { @Autowired private UserRepository repository; @Autowired private ApplicationContext applicationContext; public static void main(String[] args) { SpringApplication.run(SampleApplication.class, args); } public void run(String... var1) { final User testUser = new User("testId", "testFirstName", "testLastName"); repository.deleteAll(); repository.save(testUser); // to find by Id, please specify partition key value if collection is partitioned final User result = repository.findOne(testUser.getId(), testUser.getLastName()); // Switch to secondary key UserRepositoryConfiguration bean = applicationContext.getBean(UserRepositoryConfiguration.class); bean.switchToSecondaryKey(); // Now repository will use secondary key repository.save(testUser); } }
  • Autowire UserRepository interface, to perform operations like save, delete, find, etc.
  • Spring Data Azure Cosmos DB uses the CosmosTemplate and ReactiveCosmosTemplate to execute the queries behind find, save methods. You can use the template yourself for more complex queries.

Key concepts

CrudRepository and ReactiveCrudRepository

  • Azure Spring Data Cosmos supports ReactiveCrudRepository and CrudRepository which provides basic CRUD functionality
    • save
    • findAll
    • findOne by Id
    • deleteAll
    • delete by Id
    • delete entity

Spring Data Annotations

  • Spring Data @Id annotation. There are 2 ways to map a field in domain class to id field of Azure Cosmos DB Item.
    • annotate a field in domain class with @Id, this field will be mapped to Item id in Cosmos DB.
    • set name of this field to id, this field will be mapped to Item id in Azure Cosmos DB.

  • Supports auto generation of string type UUIDs using the @GeneratedValue annotation. The id field of an entity with a string type id can be annotated with @GeneratedValue to automatically generate a random UUID prior to insertion.

    public class GeneratedIdEntity { @Id @GeneratedValue private String id; }
  • Custom container Name. By default, container name will be class name of user domain class. To customize it, add the @Container(containerName="myCustomContainerName") annotation to the domain class. The container field also supports SpEL expressions (eg. container = "${dynamic.container.name}" or container = "#{@someBean.getContainerName()}") in order to provide container names programmatically/via configuration properties.
  • Custom IndexingPolicy By default, IndexingPolicy will be set by azure service. To customize it add annotation @CosmosIndexingPolicy to domain class. This annotation has 4 attributes to customize, see following:
// Indicate if indexing policy use automatic or not // Default value is true boolean automatic() default Constants.DEFAULT_INDEXING_POLICY_AUTOMATIC; // Indexing policy mode, option Consistent. IndexingMode mode() default IndexingMode.CONSISTENT; // Included paths for indexing String[] includePaths() default {}; // Excluded paths for indexing String[] excludePaths() default {};

Azure Cosmos DB Partition

  • Azure-spring-data-cosmos supports Azure Cosmos DB partition.
  • To specify a field of domain class to be partition key field, just annotate it with @PartitionKey.
  • When you perform CRUD operation, specify your partition value.
  • For more sample on partition CRUD, please refer test here

Optimistic Locking

  • Azure-spring-data-cosmos supports Optimistic Locking for specific containers, which means upserts/deletes by item will fail with an exception in case the item is modified by another process in the meanwhile.
  • To enable Optimistic Locking for a container, just create a string _etag field and mark it with the @Version annotation. See the following:
 @Container(containerName = "myContainer") public class MyItem { String id; String data; @Version String _etag; }

Spring Data custom query, pageable and sorting

  • Azure-spring-data-cosmos supports spring data custom queries
  • Example, find operation, e.g., findByAFieldAndBField
  • Supports Spring Data pageable and sort.
    • Based on available RUs on the database account, cosmosDB can return items less than or equal to the requested size.
    • Due to this variable number of returned items in every iteration, user should not rely on the totalPageSize, and instead iterating over pageable should be done in this way.
private List<T> findAllWithPageSize(int pageSize) { final CosmosPageRequest pageRequest = new CosmosPageRequest(0, pageSize, null); Page<T> page = repository.findAll(pageRequest); List<T> pageContent = page.getContent(); while (page.hasNext()) { Pageable nextPageable = page.nextPageable(); page = repository.findAll(nextPageable); pageContent = page.getContent(); } return pageContent; }

Spring Boot Starter Data Rest

  • Azure-spring-data-cosmos supports spring-boot-starter-data-rest.
  • Supports List and nested type in domain class.
  • Configurable ObjectMapper bean with unique name cosmosObjectMapper, only configure customized ObjectMapper if you really need to. e.g.,
 @Bean(name = "cosmosObjectMapper") public ObjectMapper objectMapper() { return new ObjectMapper(); // Do configuration to the ObjectMapper if required }

Auditing

  • Azure-spring-data-cosmos supports auditing fields on database entities using standard spring-data annotations.
  • This feature can be enabled by adding @EnableCosmosAuditing annotation to your application configuration.
  • Entities can annotate fields using @CreatedBy, @CreatedDate, @LastModifiedBy and @LastModifiedDate. These fields will be updated automatically.
 @Container(containerName = "myContainer") public class AuditableUser { private String id; private String firstName; @CreatedBy private String createdBy; @CreatedDate private OffsetDateTime createdDate; @LastModifiedBy private String lastModifiedBy; @LastModifiedDate private OffsetDateTime lastModifiedByDate; }

Multi-database configuration

  • Azure-spring-data-cosmos supports multi-database configuration, including "multiple database accounts" and "single account, with multiple databases".

The example uses the application.properties file

# primary account cosmos config azure.cosmos.primary.uri=your-primary-cosmosDb-uri azure.cosmos.primary.key=your-primary-cosmosDb-key azure.cosmos.primary.secondaryKey=your-primary-cosmosDb-secondary-key azure.cosmos.primary.database=your-primary-cosmosDb-dbName azure.cosmos.primary.populateQueryMetrics=if-populate-query-metrics # secondary account cosmos config azure.cosmos.secondary.uri=your-secondary-cosmosDb-uri azure.cosmos.secondary.key=your-secondary-cosmosDb-key azure.cosmos.secondary.secondaryKey=your-secondary-cosmosDb-secondary-key azure.cosmos.secondary.database=your-secondary-cosmosDb-dbName azure.cosmos.secondary.populateQueryMetrics=if-populate-query-metrics

  • The Entity and Repository definition is similar as above. You can put different database entities into different packages.

  • The @EnableReactiveCosmosRepositories or @EnableCosmosRepositories support user-define the cosmos template, use reactiveCosmosTemplateRef or cosmosTemplateRef to config the name of the ReactiveCosmosTemplate or CosmosTemplate bean to be used with the repositories detected.

  • If you have multiple cosmos database accounts, you can define multiple CosmosAsyncClient. If the single cosmos account has multiple databases, you can use the same CosmosAsyncClient to initialize the cosmos template.
 @Configuration public class PrimaryDatasourceConfiguration { private static final String DATABASE1 = "primary_database1"; private static final String DATABASE2 = "primary_database2"; @Bean @ConfigurationProperties(prefix = "azure.cosmos.primary") public CosmosProperties primary() { return new CosmosProperties(); } @Bean public CosmosClientBuilder primaryClientBuilder( @Qualifier("primary") CosmosProperties primaryProperties) { return new CosmosClientBuilder() .key(primaryProperties.getKey()) .endpoint(primaryProperties.getUri()); } @EnableReactiveCosmosRepositories(basePackages = "com.azure.cosmos.multidatasource.primary.database1") public class DataBase1Configuration extends AbstractCosmosConfiguration { @Override protected String getDatabaseName() { return DATABASE1; } } @EnableReactiveCosmosRepositories(basePackages = "com.azure.cosmos.multidatasource.primary.database2", reactiveCosmosTemplateRef = "primaryDatabase2Template") public class Database2Configuration { @Bean public ReactiveCosmosTemplate primaryDatabase2Template(CosmosAsyncClient cosmosAsyncClient, CosmosConfig cosmosConfig, MappingCosmosConverter mappingCosmosConverter) { return new ReactiveCosmosTemplate(cosmosAsyncClient, DATABASE2, cosmosConfig, mappingCosmosConverter); } } } 
 @Configuration public class SecondaryDatasourceConfiguration { private static final Logger LOGGER = LoggerFactory.getLogger(SecondaryDatasourceConfiguration.class); public static final String DATABASE3 = "secondary_database3"; public static final String DATABASE4 = "secondary_database4"; @Bean @ConfigurationProperties(prefix = "azure.cosmos.secondary") public CosmosProperties secondary() { return new CosmosProperties(); } @Bean("secondaryCosmosClient") public CosmosAsyncClient getCosmosAsyncClient( @Qualifier("secondary") CosmosProperties secondaryProperties) { return CosmosFactory.createCosmosAsyncClient(new CosmosClientBuilder() .key(secondaryProperties.getKey()) .endpoint(secondaryProperties.getUri())); } @Bean("secondaryCosmosConfig") public CosmosConfig getCosmosConfig() { return CosmosConfig.builder() .enableQueryMetrics(true) .responseDiagnosticsProcessor(new ResponseDiagnosticsProcessorImplementation()) .build(); } @EnableCosmosRepositories(basePackages = "com.azure.cosmos.multidatasource.secondary.database3", cosmosTemplateRef = "secondaryDatabase3Template") public class Database3Configuration { @Bean public CosmosTemplate secondaryDatabase3Template( @Qualifier("secondaryCosmosClient") CosmosAsyncClient client, @Qualifier("secondaryCosmosConfig") CosmosConfig cosmosConfig, MappingCosmosConverter mappingCosmosConverter) { return new CosmosTemplate(client, DATABASE3, cosmosConfig, mappingCosmosConverter); } } @EnableCosmosRepositories(basePackages = "com.azure.cosmos.multidatasource.secondary.database4", cosmosTemplateRef = "secondaryDatabase4Template") public class Database4Configuration { @Bean public CosmosTemplate secondaryDatabase4Template( @Qualifier("secondaryCosmosClient") CosmosAsyncClient client, @Qualifier("secondaryCosmosConfig") CosmosConfig cosmosConfig, MappingCosmosConverter mappingCosmosConverter) { return new CosmosTemplate(client, DATABASE4, cosmosConfig, mappingCosmosConverter); } } private static class ResponseDiagnosticsProcessorImplementation implements ResponseDiagnosticsProcessor { @Override public void processResponseDiagnostics( @Nullable ResponseDiagnostics responseDiagnostics) { LOGGER.info("Response Diagnostics {}", responseDiagnostics); } } }
  • In the above example, we have two cosmos account, each account has two databases. For each account, we can use the same Cosmos Client. You can create the CosmosAsyncClient like this:
 @Bean("secondaryCosmosClient") public CosmosAsyncClient getCosmosAsyncClient( @Qualifier("secondary") CosmosProperties secondaryProperties) { return CosmosFactory.createCosmosAsyncClient(new CosmosClientBuilder() .key(secondaryProperties.getKey()) .endpoint(secondaryProperties.getUri())); }
  • Besides, if you want to define queryMetricsEnabled or ResponseDiagnosticsProcessor , you can create the CosmosConfig for your cosmos template.
 @Bean("secondaryCosmosConfig") public CosmosConfig getCosmosConfig() { return CosmosConfig.builder() .enableQueryMetrics(true) .responseDiagnosticsProcessor(new ResponseDiagnosticsProcessorImplementation()) .build(); }
  • Create an Application class
 @SpringBootApplication public class MultiDatasourceApplication implements CommandLineRunner { @Autowired private UserRepository userRepository; @Autowired private BookRepository bookRepository; private final User user = new User("1024", "1024 @geek.com", "1k", "Mars"); private final Book book = new Book("9780792745488", "Zen and the Art of Motorcycle Maintenance", "Robert M. Pirsig"); public static void main(String[] args) { SpringApplication.run(MultiDatasourceApplication.class, args); } @Override public void run(String... args) { final List<User> users = this.userRepository.findByEmailOrName(this.user.getEmail(), this.user.getName()).collectList().block(); users.forEach(System.out::println); final Book book = this.bookRepository.findById("9780792745488").block(); System.out.println(book); } @PostConstruct public void setup() { this.userRepository.save(user).block(); this.bookRepository.save(book).block(); } @PreDestroy public void cleanup() { this.userRepository.deleteAll().block(); this.bookRepository.deleteAll().block(); } }

Beta version package

Beta version built from master branch are available, you can refer to the instruction to use beta version packages.

Troubleshooting

General

If you encounter any bug, please file an issue here.

To suggest a new feature or changes that could be made, file an issue the same way you would for a bug.

Enable Client Logging

  • Azure-spring-data-cosmos uses SLF4j as the logging facade that supports logging into popular logging frameworks such as log4j and logback. For example, if you want to use spring logback as logging framework, add the following xml to resources folder.
<configuration> <include resource="/org/springframework/boot/logging/logback/base.xml"/> <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender"> <encoder> <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n </pattern> </encoder> </appender> <root level="info"> <appender-ref ref="STDOUT"/> </root> <logger name="com.azure.cosmos" level="error"/> <logger name="org.springframework" level="error"/> <logger name="io.netty" level="error"/> </configuration>

Examples

Next steps

Contributing

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution.

When you submit a pull request, a CLA-bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., label, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repos using our CLA.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.

Impressions

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