Composite Environment Repositories

In some scenarios, you may wish to pull configuration data from multiple environment repositories. To do so, you can enable the composite profile in your configuration server’s application properties or YAML file. If, for example, you want to pull configuration data from a Subversion repository as well as two Git repositories, you can set the following properties for your configuration server:

spring:
  profiles:
    active: composite
  cloud:
    config:
      server:
        composite:
        -
          type: svn
          uri: file:///path/to/svn/repo
        -
          type: git
          uri: file:///path/to/rex/git/repo
        -
          type: git
          uri: file:///path/to/walter/git/repo

Using this configuration, precedence is determined by the order in which repositories are listed under the composite key. In the above example, the Subversion repository is listed first, so a value found in the Subversion repository will override values found for the same property in one of the Git repositories. A value found in the rex Git repository will be used before a value found for the same property in the walter Git repository.

If you want to pull configuration data only from repositories that are each of distinct types, you can enable the corresponding profiles, rather than the composite profile, in your configuration server’s application properties or YAML file. If, for example, you want to pull configuration data from a single Git repository and a single HashiCorp Vault server, you can set the following properties for your configuration server:

spring:
  profiles:
    active: git, vault
  cloud:
    config:
      server:
        git:
          uri: file:///path/to/git/repo
          order: 2
        vault:
          host: 127.0.0.1
          port: 8200
          order: 1

Using this configuration, precedence can be determined by an order property. You can use the order property to specify the priority order for all your repositories. The lower the numerical value of the order property, the higher priority it has. The priority order of a repository helps resolve any potential conflicts between repositories that contain values for the same properties.

If your composite environment includes a Vault server as in the previous example, you must include a Vault token in every request made to the configuration server. See Vault Backend.

Any type of failure when retrieving values from an environment repository results in a failure for the entire composite environment. If you would like the composite to continue even when a repository fails you can set spring.cloud.config.server.failOnCompositeError to false.

When using a composite environment, it is important that all repositories contain the same labels. If you have an environment similar to those in the preceding examples and you request configuration data with the master label but the Subversion repository does not contain a branch called master, the entire request fails.

Custom Composite Environment Repositories

In addition to using one of the environment repositories from Spring Cloud, you can also provide your own EnvironmentRepository bean to be included as part of a composite environment. To do so, your bean must implement the EnvironmentRepository interface. If you want to control the priority of your custom EnvironmentRepository within the composite environment, you should also implement the Ordered interface and override the getOrdered method. If you do not implement the Ordered interface, your EnvironmentRepository is given the lowest priority.