Package org.opends.server.backends

Class ProxyBackend

java.lang.Object
org.opends.server.api.Backend<ProxyBackendCfg>
org.opends.server.backends.ProxyBackend
All Implemented Interfaces:
ConfigurationChangeListener<ProxyBackendCfg>, HealthStatusProvider
public final class ProxyBackend extends Backend<ProxyBackendCfg> implements ConfigurationChangeListener<ProxyBackendCfg>
Implements the proxy backend, i.e. an LDAP endpoint able to forward LDAP requests to remote LDAP servers.

The proxy backend forwards requests to remote servers using load balancers.

Implementation detail: the proxy backend uses a hierarchy of load balancers / LDAP clients that are setup this way: if the proxy backend is configured for distribution (with more than one partition): 

 Load Balancers - reference counted (one for bind operations + another one for other operations)
    |
    +--- newFixedSizeDistributionLoadBalancer (for n partitions)
      |
      +--- n newFailoverLoadBalancer (each fails over primary and secondary servers)
        |
        +--- 2 newAffinityRequestLoadBalancer (one for primary servers, one for secondary
          |    servers)
          |
          +--- newCachedConnectionPool - reference counted
            |
            +--- LdapClient
Otherwise, the proxy backend is configured for direct proxying (with only one partition): 
 Load Balancers - reference counted (one for bind operations + another one for other operations)
    |
    +--- newFailoverLoadBalancer (over primary and secondary servers)
      |
      +--- 2 newAffinityRequestLoadBalancer (one for primary servers, one for secondary servers)
        |
        +--- newCachedConnectionPool - reference counted
          |
          +--- LdapClient
Note: Some load balancers/LDAP clients are reference counted, in order to ease managing their lifecycle and to avoid disturbing clients. When a change affects the load balancers/LDAP clients, the proxy backend needs to rebuild a whole new load balancer hierarchy in order to make use of them. However, LDAP is a connected protocol, thus closing connections should be avoided when there is no need to. As a consequence some LDAP clients/load balancers are reference counted to ensure they are closed only when they are no longer referenced.

  • Constructor Details

    • ProxyBackend

      public ProxyBackend()

  • Method Details

    • handleRequest

      public void handleRequest(RequestContext context, Request request, Consumer<ResponseStream> out) throws LdapException
      Description copied from class: Backend
      Processes a request, publishing the response(s) to the provided consumer. Implementations may publish response in multiple steps if needed. If the request fails for any reason then the failure must be thrown as an LdapException.
      Specified by:
      handleRequest in class Backend<ProxyBackendCfg>
      Parameters:
      context - The request context.
      request - The request.
      out - A consumer responsible for sending responses to the client.
      Throws:
      LdapException - If an error occurred when processing the request.

    • configureBackend

      public void configureBackend(ProxyBackendCfg cfg, ServerContext serverContext) throws ConfigException
      Description copied from class: Backend
      Configure this backend based on the information in the provided configuration. When the method returns, the backend will have been configured (ready to be opened) but still unable to process operations.
      Specified by:
      configureBackend in class Backend<ProxyBackendCfg>
      Parameters:
      cfg - The configuration of this backend.
      serverContext - The server context for this instance
      Throws:
      ConfigException - If there is an error in the configuration.

    • openBackend

      public void openBackend() throws ConfigException
      Description copied from class: Backend
      Opens this backend based on the information provided when the backend was configured. It also should open any underlying storage and register all suffixes with the server.
      Specified by:
      openBackend in class Backend<ProxyBackendCfg>
      Throws:
      ConfigException - If an unrecoverable problem arises while opening the backend.
      See Also:

    • getBaseDNs

      public Set<Dn> getBaseDNs()
      Description copied from class: Backend
      Retrieves the set of base-level DNs that may be used within this backend.
      Specified by:
      getBaseDNs in class Backend<ProxyBackendCfg>
      Returns:
      The set of base-level DNs that may be used within this backend.

    • getSupportedControls

      public Set<String> getSupportedControls()
      Description copied from class: Backend
      Retrieves the OIDs of the controls that may be supported by this backend.
      Overrides:
      getSupportedControls in class Backend<ProxyBackendCfg>
      Returns:
      The OIDs of the controls that may be supported by this backend.

    • getSupportedFeatures

      public Set<String> getSupportedFeatures()
      Description copied from class: Backend
      Retrieves the OIDs of the features that may be supported by this backend.
      Overrides:
      getSupportedFeatures in class Backend<ProxyBackendCfg>
      Returns:
      The OIDs of the features that may be supported by this backend.

    • finalizeBackend

      public void finalizeBackend()
      Description copied from class: Backend
      Performs any necessary work to finalize this backend. The backend must be an opened backend, so do not use this method on backends where only configureBackend() has been called. This may be called during the Directory Server shutdown process or if a backend is disabled with the server online. It must not return until the backend is closed.

      This method may not throw any exceptions. If any problems are encountered, then they may be logged but the closure should progress as completely as possible.

      Specified by:
      finalizeBackend in class Backend<ProxyBackendCfg>

    • isPublicBackend

      public boolean isPublicBackend()
      Description copied from class: Backend
      Indicates whether the base DNs of this backend should be considered public or private.

      This method also controls the visibility of the associated naming contexts. i.e. if any base DN of this backend is a naming context, then it will be public or private, based on the value returned by this method.

      Reminder: Public naming contexts are returned when querying the root DSE entry.

      Specified by:
      isPublicBackend in class Backend<ProxyBackendCfg>
      Returns:
      true if this backend's baseDNs could be exposed as a public naming context, false if they must remain private naming contexts.

    • isConfigurationAcceptable

      public boolean isConfigurationAcceptable(ProxyBackendCfg config, List<LocalizableMessage> unacceptableReasons, ServerContext serverContext)
      Description copied from class: Backend
      Indicates whether the provided configuration is acceptable for this backend. It should be possible to call this method on an uninitialized backend instance in order to determine whether the backend would be able to use the provided configuration.
      Overrides:
      isConfigurationAcceptable in class Backend<ProxyBackendCfg>
      Parameters:
      config - The backend configuration for which to make the determination.
      unacceptableReasons - A list that may be used to hold the reasons that the provided configuration is not acceptable.
      serverContext - this Directory Server instance's server context
      Returns:
      true if the provided configuration is acceptable for this backend, or false if not.

    • isConfigurationChangeAcceptable

      public boolean isConfigurationChangeAcceptable(ProxyBackendCfg config, List<LocalizableMessage> unacceptableReasons)
      Description copied from interface: ConfigurationChangeListener
      Indicates whether the proposed change to the configuration is acceptable to this change listener.
      Specified by:
      isConfigurationChangeAcceptable in interface ConfigurationChangeListener<ProxyBackendCfg>
      Parameters:
      config - The new configuration containing the changes.
      unacceptableReasons - A list that can be used to hold messages about why the provided configuration is not acceptable.
      Returns:
      Returns true if the proposed change is acceptable, or false if it is not.

    • applyConfigurationChange

      public ConfigChangeResult applyConfigurationChange(ProxyBackendCfg newConfig)
      Description copied from interface: ConfigurationChangeListener
      Applies the configuration changes to this change listener.
      Specified by:
      applyConfigurationChange in interface ConfigurationChangeListener<ProxyBackendCfg>
      Parameters:
      newConfig - The new configuration containing the changes.
      Returns:
      Returns information about the result of changing the configuration.

    • registerBackendMonitor

      public void registerBackendMonitor()
      Description copied from class: Backend
      Registers a backend monitor for this backend.
      Overrides:
      registerBackendMonitor in class Backend<ProxyBackendCfg>

    • deregisterBackendMonitor

      public void deregisterBackendMonitor()
      Description copied from class: Backend
      Deregisters the backend monitor of this backend.
      Overrides:
      deregisterBackendMonitor in class Backend<ProxyBackendCfg>