Package org.epics.archiverappliance.utils.blackhole

Class BlackholeStoragePlugin

java.lang.Object
org.epics.archiverappliance.utils.blackhole.BlackholeStoragePlugin
All Implemented Interfaces:
ETLDest, Reader, StoragePlugin, Writer
public class BlackholeStoragePlugin extends Object implements StoragePlugin, ETLDest
A storage plugin that deletes all data that goes into it. Use this as an ETL dest for policies that eliminate data after a certain period.
Author:
mshankar

  • Field Details

  • Constructor Details

    • BlackholeStoragePlugin

      public BlackholeStoragePlugin()

  • Method Details

    • getDataForPV

      public List<Callable<EventStream>> getDataForPV(BasicContext context, String pvName, Instant startTime, Instant endTime, PostProcessor postProcessor) throws IOException
      Specified by:
      getDataForPV in interface Reader
      Throws:
      IOException

    • appendData

      public int appendData(BasicContext context, String pvName, EventStream stream)
      Specified by:
      appendData in interface Writer

    • getLastKnownEvent

      public Event getLastKnownEvent(BasicContext context, String pvName) throws IOException
      Description copied from interface: Writer
      Gets the last known event in this destination. Future events will be appended to this destination only if their timestamp is more recent than the timestamp of this event. If there is no last known event, then a null is returned.
      Specified by:
      getLastKnownEvent in interface Writer
      Parameters:
      context -  
      pvName - The PV name
      Returns:
      Event The last known event of pvName
      Throws:
      IOException -  

    • getFirstKnownEvent

      public Event getFirstKnownEvent(BasicContext context, String pvName) throws IOException
      Description copied from interface: Reader
      Get the first event for this PV. This call is used to optimize away calls to other readers that have older data.
      Specified by:
      getFirstKnownEvent in interface Reader
      Parameters:
      context -  
      pvName - The PV name
      Returns:
      Event The first event of pvName
      Throws:
      IOException -  

    • appendToETLAppendData

      public boolean appendToETLAppendData(String pvName, EventStream stream, ETLContext context)
      Description copied from interface: ETLDest
      This appends an EventStream to the ETL append data for a PV.
      Specified by:
      appendToETLAppendData in interface ETLDest
      Parameters:
      pvName - The name of PV.
      stream - The EventStream to append to the append data for a PV.
      context - ETLContext
      Returns:
      boolean True or False

    • commitETLAppendData

      public boolean commitETLAppendData(String pvName, ETLContext context) throws IOException
      Description copied from interface: ETLDest
      This concatenates the ETL append data for a PV with the PV's destination data.
      Specified by:
      commitETLAppendData in interface ETLDest
      Parameters:
      pvName - The name of PV.
      context - ETLContext
      Returns:
      boolean True or False
      Throws:
      IOException -  

    • runPostProcessors

      public boolean runPostProcessors(String pvName, ArchDBRTypes dbrtype, ETLContext context) throws IOException
      Description copied from interface: ETLDest
      Run the post processors associated with this plugin if any for this pv. The post processing is done after the commit and outside of the ETL transaction. This process is expected to catch up on previously missed/incomplete computation of cached post processing files. I can think of at least two usecases for this - one where we decide to go back and add a post processor for a pv and one where we change the algorithm for the post processor and want to recompute all the cached files again.
      Specified by:
      runPostProcessors in interface ETLDest
      Parameters:
      pvName - The name of PV.
      dbrtype - ArchDBRTypes
      context - ETLContext
      Returns:
      boolean True or False
      Throws:
      IOException -  

    • getPartitionGranularity

      public PartitionGranularity getPartitionGranularity()
      Specified by:
      getPartitionGranularity in interface ETLDest

    • getDescription

      public String getDescription()
      Description copied from interface: StoragePlugin
      Get a string description of this plugin; one that can potentially be used in log messages and provide context.
      Specified by:
      getDescription in interface ETLDest
      Specified by:
      getDescription in interface StoragePlugin
      Returns:
      description

    • getURLRepresentation

      public String getURLRepresentation()

    • initialize

      public void initialize(String configURL, ConfigService configService) throws IOException
      Description copied from interface: StoragePlugin
      Each storage plugin is registered to a URI scheme; for example, the PlainStoragePBPlugin uses pb:// as the scheme. Configuration for a storage plugin typically comes in as a URL like URI.
      1. The config service identifies the storage plugin using the scheme ("pb" maps to PlainStoragePBPlugin)
      2. Creates an instance using the default constructor.
      3. Calls initialize with the complete URL.
      The storage plugin is expected to use the parameters in the URL to initialize itself.
      Specified by:
      initialize in interface StoragePlugin
      Parameters:
      configURL - The complete URL
      configService -  
      Throws:
      IOException -  
      See Also:

    • pluginIdentifier

      public String pluginIdentifier()
      Description copied from interface: StoragePlugin
      Provide the prefix for storage plugin urls.
      Specified by:
      pluginIdentifier in interface StoragePlugin
      Returns:
      String of the Storage Plugin Identifier

    • getName

      public String getName()
      Description copied from interface: StoragePlugin
      Multiple PVs will probably use the same storage area and we identify the area using the name. This is principally used in capacity planning/load balancing to identify the storage area for the PV. We should make sure that storage's with similar lifetimes have the same name in all the appliances. The name is also used to identify the storage in the storage report. For example, the PlainStoragePlugin takes a name parameter and we should use something like STS as the identity for the short term store in all the appliances.
      Specified by:
      getName in interface ETLDest
      Specified by:
      getName in interface StoragePlugin
      Returns:
      name

    • renamePV

      public void renamePV(BasicContext context, String oldName, String newName) throws IOException
      Description copied from interface: StoragePlugin
      Change the name of a PV. This happens occasionally in the EPICS world when people change the names of PVs but want to retain the data. This method is used to change the name of the PV in any of the datasets for PV oldName. For example, in PB files, the name of the PV is encoded in the file names and is also stored in the header. In this case, we expect the plugin to move the data to new files names and change the PV name in the file header. To avoid getting into issues about data changing when renaming files, the PV can be assumed to be in a paused state.
      Specified by:
      renamePV in interface StoragePlugin
      Parameters:
      context -  
      oldName - The old PV name
      newName - The new PV name
      Throws:
      IOException -  

    • convert

      public void convert(BasicContext context, String pvName, ConversionFunction conversionFuntion) throws IOException
      Description copied from interface: StoragePlugin
      Sometimes, PVs change types, EGUs etc. In these cases, we are left with the problem of what to do with the already archived data. We can rename the PV to a new but related name - this keeps the existing data as is. Or, we can attempt to convert to the new type, EGU etc. This method can be used to convert the existing data using the supplied conversion function. Conversions should be all or nothing; that is, first convert all the streams into temporary chunks and then do a bulk rename once all the conversions have succeeded. Note that we'll also be using the same conversion mechanism for imports and other functions that change data. So, when/if implementing the conversion function, make sure we respect the typical expectations within the archiver - monotonically increasing timestamps and so on. To avoid getting into issues about data changing when converting, the PV can be assumed to be in a paused state.
      Specified by:
      convert in interface StoragePlugin
      Parameters:
      context -  
      pvName - The PV name
      conversionFuntion -  
      Throws:
      IOException -