Dynamically switching between properties files based on request header parameter in spring boot application

Question

I am developing an multi-tenant REST spring boot application. I am able to dynamically switch between different data-sources based on a header value in every request. But my problem is on the application.properties file. The different tenants have different values for the same properties in their properties files.

How can I separate the properties files per tenant and also dynamically determine which properties files to use based on a value in the request header

Answer 1

You can't switch profiles at runtime. Your options are limited to either creating a new ApplicationContext which comes with its own drawbacks or you can load the tenant property files at startup and implement a tenant-specific getProperty method to call when needed.

This ought-to handle the latter case:

@Component
public class TenantProperties {

  private Map<String, ConfigurableEnvironment> customEnvs;

  @Inject
  public TenantProperties(@Autowired ConfigurableEnvironment defaultEnv,
      @Value("${my.tenant.names}") List<String> tenantNames) {

    this.customEnvs = tenantNames
        .stream()
        .collect(Collectors.toMap(
            Function.identity(),
            tenantId -> {
              ConfigurableEnvironment customEnv = new StandardEnvironment();
              customEnv.merge(defaultEnv);
              Resource resource = new ClassPathResource(tenantId + ".properties");

              try {
                Properties props = PropertiesLoaderUtils.loadProperties(resource);
                customEnv.getPropertySources()
                    .addLast(new PropertiesPropertySource(tenantId, props));
                return customEnv;
              } catch (IOException ex) {
                throw new RuntimeException(ex);
              }
            }));
  }

  public String getProperty(String tenantId, String propertyName) {

    ConfigurableEnvironment ce = this.customEnvs.get(tenantId);
    if (ce == null) {
      throw new IllegalArgumentException("Invalid tenant");
    }

    return ce.getProperty(propertyName);
  }
}

You need to add a my.tenant.names property to your main application properties that contains a comma separated list of tenant names (name1, name2, etc.). tenant-specific properties are loaded from name1.properties, ... from the classpath. You get the idea.