Class LocallyCachedBlob

Direct Known Subclasses:
LocalizedResource, LocallyCachedTopologyBlob

public abstract class LocallyCachedBlob extends Object
Represents a blob that is cached locally on disk by the supervisor.
  • Field Details


      public static final long NOT_DOWNLOADED_VERSION
      See Also:
    • localUpdateTime

      protected long localUpdateTime
  • Constructor Details

    • LocallyCachedBlob

      protected LocallyCachedBlob(String blobDescription, String blobKey, StormMetricsRegistry metricsRegistry)
      Create a new LocallyCachedBlob.
      blobDescription - a description of the blob this represents. Typically it should at least be the blob key, but ideally also include if it is an archive or not, what user or topology it is for, or if it is a storm.jar etc.
  • Method Details

    • fetch

      protected org.apache.storm.localizer.LocallyCachedBlob.DownloadMeta fetch(ClientBlobStore store, String key, IOFunction<Long,Path> pathSupplier, IOFunction<File,OutputStream> outStreamSupplier) throws KeyNotFoundException, AuthorizationException, IOException
      Helper function to download blob from blob store.
      store - Blob store to fetch blobs from
      key - Key to retrieve blobs
      pathSupplier - A function that supplies the download destination of a blob. It guarantees the validity of path or throws IOException
      outStreamSupplier - A function that supplies the OutputStream object
      The metadata of the download session, including blob's version and download destination
      KeyNotFoundException - Thrown if key to retrieve blob is invalid
      AuthorizationException - Thrown if the retrieval is not under security authorization
      IOException - Thrown if any IO error occurs
    • getLocalVersion

      public abstract long getLocalVersion()
      Get the version of the blob cached locally. If the version is unknown or it has not been downloaded NOT_DOWNLOADED_VERSION should be returned. PRECONDITION: this can only be called with a lock on this instance held.
    • getRemoteVersion

      public abstract long getRemoteVersion(ClientBlobStore store) throws KeyNotFoundException, AuthorizationException
      Get the version of the blob in the blob store. PRECONDITION: this can only be called with a lock on this instance held.
    • fetchUnzipToTemp

      public abstract long fetchUnzipToTemp(ClientBlobStore store) throws IOException, KeyNotFoundException, AuthorizationException
      Download the latest version to a temp location. This may also include unzipping some or all of the data to a temp location. PRECONDITION: this can only be called with a lock on this instance held.
      store - the store to us to download the data.
      the version that was downloaded.
    • commitNewVersion

      protected abstract void commitNewVersion(long version) throws IOException
      Commit the new version and make it available for the end user. PRECONDITION: uncompressToTempLocationIfNeeded will have been called. PRECONDITION: this can only be called with a lock on this instance held.
      version - the version of the blob to commit.
    • cleanupOrphanedData

      public abstract void cleanupOrphanedData() throws IOException
      Clean up any temporary files. This will be called after updating a blob, either successfully or if an error has occured. The goal is to find any files that may be left over and remove them so space is not leaked. PRECONDITION: this can only be called with a lock on this instance held.
    • completelyRemove

      public abstract void completelyRemove() throws IOException
      Completely remove anything that is cached locally for this blob and all tracking files also stored for it. This will be called after the blob was determined to no longer be needed in the cache. PRECONDITION: this can only be called with a lock on this instance held.
    • getSizeOnDisk

      public abstract long getSizeOnDisk()
      Get the amount of disk space that is used by this blob. If the blob is uncompressed it should be the sum of the space used by all of the uncompressed files. In general this will not be called with any locks held so it is a good idea to cache it and updated it when committing a new version.
    • getSizeOnDisk

      protected static long getSizeOnDisk(Path p) throws IOException
      Get the size of p in bytes.
      p - the path to read.
      the size of p in bytes.
    • touch

      protected void touch()
      Updates the last updated time. This should be called when references are added or removed.
    • getLastUsed

      public long getLastUsed()
      Get the last time that this used for LRU calculations.
    • isUsed

      public boolean isUsed()
      Return true if this blob is actively being used, else false (meaning it can be deleted, but might not be).
    • addReference

      public void addReference(PortAndAssignment pna, BlobChangingCallback cb)
      Mark that a given port and assignment are using this.
      pna - the slot and assignment that are using this blob.
      cb - an optional callback indicating that they want to know/synchronize when a blob is updated.
    • removeReference

      public boolean removeReference(PortAndAssignment pna)
      Removes a reservation for this blob from a given slot and assignemnt.
      pna - the slot + assignment that no longer needs this blob.
      false if a reference was failed to be removed
    • informReferencesAndCommitNewVersion

      public void informReferencesAndCommitNewVersion(long newVersion) throws IOException
      Inform all of the callbacks that a change is going to happen and then wait for them to all get back that it is OK to make that change. Commit the new version once all callbacks are ready. Finally inform all callbacks that the commit is complete.
    • getKey

      public String getKey()
      Get the key for this blob.
    • getDependencies

      public Collection<PortAndAssignment> getDependencies()
    • isFullyDownloaded

      public abstract boolean isFullyDownloaded()
    • update

      public void update(ClientBlobStore blobStore, long remoteBlobstoreUpdateTime) throws KeyNotFoundException, AuthorizationException, IOException
      Checks and downloads a blob locally as necessary.
      blobStore - the client blobstore
      remoteBlobstoreUpdateTime - last update time of remote blobstore
      KeyNotFoundException - if the remote blob is missing
      AuthorizationException - if authorization is failed
      IOException - on errors