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Spring Cloud Azure secret management

  • Article

This article applies to: ✔️ Version 4.19.0 ✔️ Version 5.18.0

Spring Cloud Azure construct PropertySource which holds secrets stored in Azure Key Vault Secrets.

Dependency setup

<dependency>
    <groupId>com.azure.spring</groupId>
    <artifactId>spring-cloud-azure-starter-keyvault-secrets</artifactId>
</dependency>

Tip

We also provide spring-cloud-azure-starter-keyvault to support all the features of Key Vault. If you choose to use it, spring.cloud.azure.keyvault.enable is the property to configure and the default value is true. You can then use spring.cloud.azure.keyvault.<keyvault-service>.enable to disable unneeded services.

Basic usage

If you want to authenticate by client-id and client-secret, the following properties are required:

Configuration Properties

spring:
  cloud:
    azure:
      keyvault:
        secret:
          property-sources:
            - name: key-vault-property-source-1
              endpoint: ${ENDPOINT_1}
            - name: key-vault-property-source-2
              endpoint: ${ENDPOINT_2}

Java code

@SpringBootApplication
public class SampleApplication implements CommandLineRunner {

    @Value("${sampleProperty1}")
    private String sampleProperty1;
    @Value("${sampleProperty2}")
    private String sampleProperty2;
    @Value("${samplePropertyInMultipleKeyVault}")
    private String samplePropertyInMultipleKeyVault;

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

    public void run(String[] args) {
        System.out.println("sampleProperty1: " + sampleProperty1);
        System.out.println("sampleProperty2: " + sampleProperty2);
        System.out.println("samplePropertyInMultipleKeyVault: " + samplePropertyInMultipleKeyVault);
    }
}

Advanced usage

Special characters in property name

Key Vault secret names support only characters in [0-9a-zA-Z-]. For more information, see theVault-name and Object-name section of Azure Key Vault keys, secrets and certificates overview. If your property name contains other characters, you can use the workarounds described in the following sections.

Use - instead of . in secret names

. isn't supported in secret names. If your application has a property name that contains ., such as spring.datasource.url, replace . with - when saving the secret in Azure Key Vault. For example, save spring-datasource-url in Azure Key Vault. In your application, you can still use spring.datasource.url to retrieve the property value.

Note

This method cannot satisfy a requirement like spring.datasource-url. When you save spring-datasource-url in Key Vault, only spring.datasource.url and spring-datasource-url is supported to retrieve the property value, but spring.datasource-url isn't supported. To handle this case, see the Use property placeholders section.

Use property placeholders

For example, suppose you're setting this property in your application.properties file:

property.with.special.character__=${propertyWithoutSpecialCharacter}

The application will get a propertyWithoutSpecialCharacter key name and assign its value to property.with.special.character__.

Case-sensitive

To enable case-sensitive mode, you can set the following property:

spring.cloud.azure.keyvault.secret.property-sources[].case-sensitive=true

Not retrieve all secrets in Key Vault

If you stored 1000 secrets in the Key Vault, and you just want to use 3 of them. You can list the 3 secret names by spring.cloud.azure.keyvault.secret.property-sources[].secret-keys.

Setting refresh interval

By default, the secrets in KeyVaultPropertySource will refresh every 30 minutes. You can configure the time by spring.cloud.azure.keyvault.secret.property-sources[].refresh-interval. For example: spring.cloud.azure.keyvault.secret.property-sources[].refresh-interval=60m means refresh every 60 minutes. Set to 0 to disable auto refresh.

PropertySource priority

If key exists in multiple PropertySources, which will take effect is decided by the priority.

  • If there is no SystemEnvironmentPropertySource in the PropertySource list, then KeyVaultPropertySource will take the highest priority.
  • If there is SystemEnvironmentPropertySource in the PropertySource list, then SystemEnvironmentPropertySource have higher priority than KeyVaultPropertySource, which means you can use an environment variable to override the Key Vault secret value in your application.
  • If there are multiple key vault property sources in the PropertySource list, then the definition order is the priority order. Taking the above sample as an example, key-vault-property-source-1 has a higher priority than key-vault-property-source-2.

Configure token credential for Key Vault property source

If you need to use a specified token credential for Key Vault PropertySource, you can register the TokenCredential bean in the ConfigurableBootstrapContext for KeyVaultEnvironmentPostProcessor, this feature is supported from Spring Cloud Azure 5.18.0. Here is an example to use AzureCliCredential:

public static void main(String[] args) {
    SpringApplication application = new SpringApplication(PropertySourceApplication.class);
    application.addBootstrapRegistryInitializer(registry -> 
            registry.register(TokenCredential.class, context -> new AzureCliCredentialBuilder().build()));

    application.run(args);
}

All configurable properties

Property Default value Description
spring.cloud.azure.keyvault.secret.property-source-enabled true Whether to enable the Key Vault property source.
spring.cloud.azure.keyvault.secret.property-sources[].name Name of this property source.
spring.cloud.azure.keyvault.secret.property-sources[].endpoint Azure Key Vault endpoint.
spring.cloud.azure.keyvault.secret.property-sources[].case-sensitive false Whether the secret keys are case-sensitive.
spring.cloud.azure.keyvault.secret.property-sources[].secret-keys The secret keys supported for this property source. All keys be retrieved if this property is missing.
spring.cloud.azure.keyvault.secret.property-sources[].refresh-interval 30m Time interval to refresh all Key Vault secrets.
spring.cloud.azure.keyvault.secret.property-sources[].service-version Secret service version used when making API requests.
spring.cloud.azure.keyvault.secret.property-sources[].client Client related properties.
spring.cloud.azure.keyvault.secret.property-sources[].credential Credential related properties.
spring.cloud.azure.keyvault.secret.property-sources[].profile Profile related properties.
spring.cloud.azure.keyvault.secret.property-sources[].proxy Proxy related properties.
spring.cloud.azure.keyvault.secret.property-sources[].retry Retry related properties.

Samples

See the spring-cloud-azure-starter-keyvault-secrets samples on GitHub.