Package org.apache.hadoop.net

Class ScriptBasedMapping.RawScriptBasedMapping

java.lang.Object
org.apache.hadoop.net.AbstractDNSToSwitchMapping
org.apache.hadoop.net.ScriptBasedMapping.RawScriptBasedMapping
All Implemented Interfaces:
Configurable, DNSToSwitchMapping
Enclosing class:
ScriptBasedMapping
protected static class ScriptBasedMapping.RawScriptBasedMapping extends AbstractDNSToSwitchMapping
This is the uncached script mapping that is fed into the cache managed by the superclass CachedDNSToSwitchMapping

  • Constructor Details

    • RawScriptBasedMapping

      public RawScriptBasedMapping()
      Constructor. The mapping is not ready to use until setConf(Configuration) has been called

  • Method Details

    • setConf

      public void setConf(Configuration conf)
      Set the configuration and extract the configuration parameters of interest
      Specified by:
      setConf in interface Configurable
      Overrides:
      setConf in class AbstractDNSToSwitchMapping
      Parameters:
      conf - the new configuration

    • resolve

      public List<String> resolve(List<String> names)
      Description copied from interface: DNSToSwitchMapping
      Resolves a list of DNS-names/IP-addresses and returns back a list of switch information (network paths). One-to-one correspondence must be maintained between the elements in the lists. Consider an element in the argument list - x.y.com. The switch information that is returned must be a network path of the form /foo/rack, where / is the root, and 'foo' is the switch where 'rack' is connected. Note the hostname/ip-address is not part of the returned path. The network topology of the cluster would determine the number of components in the network path.

      If a name cannot be resolved to a rack, the implementation should return NetworkTopology.DEFAULT_RACK. This is what the bundled implementations do, though it is not a formal requirement

      Parameters:
      names - the list of hosts to resolve (can be empty)
      Returns:
      list of resolved network paths. If names is empty, the returned list is also empty

    • runResolveCommand

      protected String runResolveCommand(List<String> args, String commandScriptName)
      Build and execute the resolution command. The command is executed in the directory specified by the system property "user.dir" if set; otherwise the current working directory is used.
      Parameters:
      args - a list of arguments
      commandScriptName - input commandScriptName.
      Returns:
      null if the number of arguments is out of range, or the output of the command.

    • isSingleSwitch

      public boolean isSingleSwitch()
      Declare that the mapper is single-switched if a script was not named in the configuration.
      Overrides:
      isSingleSwitch in class AbstractDNSToSwitchMapping
      Returns:
      true iff there is no script

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • reloadCachedMappings

      public void reloadCachedMappings()
      Description copied from interface: DNSToSwitchMapping
      Reload all of the cached mappings. If there is a cache, this method will clear it, so that future accesses will get a chance to see the new data.

    • reloadCachedMappings

      public void reloadCachedMappings(List<String> names)
      Description copied from interface: DNSToSwitchMapping
      Reload cached mappings on specific nodes. If there is a cache on these nodes, this method will clear it, so that future accesses will see updated data.
      Parameters:
      names - input names.