org.apache.storm.blobstore

## Class ClientBlobStore

- java.lang.Object
- - org.apache.storm.blobstore.ClientBlobStore

- All Implemented Interfaces:
    AutoCloseable, Shutdownable
  Direct Known Subclasses:
    HdfsClientBlobStore, LocalModeClientBlobStore, NimbusBlobStore

      public abstract class ClientBlobStore
      extends Object
      implements Shutdownable, AutoCloseable

  The ClientBlobStore has two concrete implementations 1. NimbusBlobStore 2. HdfsClientBlobStore.

  Create, update, read and delete are some of the basic operations defined by this interface. Each operation is validated for permissions against an user. We currently have NIMBUS_ADMINS and SUPERVISOR_ADMINS configuration. NIMBUS_ADMINS are given READ, WRITE and ADMIN access whereas the SUPERVISOR_ADMINS are given READ access in order to read and download the blobs form the nimbus.

  The ACLs for the blob store are validated against whether the subject is a NIMBUS_ADMIN, SUPERVISOR_ADMIN or USER who has read, write or admin privileges in order to perform respective operations on the blob.

  For more detailed implementation

  See Also:
    `NimbusBlobStore`

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static interface` | `ClientBlobStore.WithBlobstore`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `ClientBlobStore()`

  - ### Method Summary

    All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `abstract void` | `close()`
    `AtomicOutputStream` | `createBlob(String key, SettableBlobMeta meta)` Client facing API to create a blob.
    `protected abstract AtomicOutputStream` | `createBlobToExtend(String key, SettableBlobMeta meta)` Client facing API to create a blob.
    `abstract void` | `createStateInZookeeper(String key)` Creates state inside a zookeeper.
    `abstract void` | `deleteBlob(String key)` Client facing API to delete a blob.
    `abstract InputStreamWithMeta` | `getBlob(String key)` Client facing API to read a blob.
    `abstract ReadableBlobMeta` | `getBlobMeta(String key)` Client facing API to read the metadata information.
    `abstract int` | `getBlobReplication(String key)` Client facing API to read the replication of a blob.
    `abstract long` | `getRemoteBlobstoreUpdateTime()` Client facing API to get the last update time of existing blobs in a blobstore.
    `abstract boolean` | `isRemoteBlobExists(String blobKey)` Decide if the blob is deleted from cluster.
    `abstract Iterator<String>` | `listKeys()` List keys.
    `abstract void` | `prepare(Map<String,Object> conf)` Sets up the client API by parsing the configs.
    `void` | `setBlobMeta(String key, SettableBlobMeta meta)` Client facing API to set the metadata for a blob.
    `protected abstract void` | `setBlobMetaToExtend(String key, SettableBlobMeta meta)` Client facing API to set the metadata for a blob.
    `abstract boolean` | `setClient(Map<String,Object> conf, NimbusClient client)` Client facing API to set a nimbus client.
    `abstract AtomicOutputStream` | `updateBlob(String key)` Client facing API to update a blob.
    `abstract int` | `updateBlobReplication(String key, int replication)` Client facing API to update the replication of a blob.
    `static void` | `withConfiguredClient(ClientBlobStore.WithBlobstore withBlobstore)`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

    - ### Methods inherited from interface org.apache.storm.daemon.Shutdownable

      `shutdown`

- - ### Constructor Detail

    - #### ClientBlobStore

          public ClientBlobStore()

  - ### Method Detail

    - #### withConfiguredClient

          public static void withConfiguredClient(ClientBlobStore.WithBlobstore withBlobstore)
                                           throws Exception

      Throws:
        `Exception`

    - #### prepare

          public abstract void prepare(Map<String,Object> conf)

      Sets up the client API by parsing the configs.

      Parameters:
        `conf` - The storm conf containing the config details

    - #### createBlobToExtend

          protected abstract AtomicOutputStream createBlobToExtend(String key,
                                                                   SettableBlobMeta meta)
                                                            throws AuthorizationException,
                                                                   KeyAlreadyExistsException

      Client facing API to create a blob.

      Parameters:
        `key` - blob key name
        `meta` - contains ACL information
      Returns:
        AtomicOutputStream returns an output stream into which data can be written
      Throws:
        `AuthorizationException`
        `KeyAlreadyExistsException`

    - #### updateBlob

          public abstract AtomicOutputStream updateBlob(String key)
                                                 throws AuthorizationException,
                                                        KeyNotFoundException

      Client facing API to update a blob.

      Parameters:
        `key` - blob key name
      Returns:
        AtomicOutputStream returns an output stream into which data can be written
      Throws:
        `AuthorizationException`
        `KeyNotFoundException`

    - #### getBlobMeta

          public abstract ReadableBlobMeta getBlobMeta(String key)
                                                throws AuthorizationException,
                                                       KeyNotFoundException

      Client facing API to read the metadata information.

      Parameters:
        `key` - blob key name
      Returns:
        AtomicOutputStream returns an output stream into which data can be written
      Throws:
        `AuthorizationException`
        `KeyNotFoundException`

    - #### isRemoteBlobExists

          public abstract boolean isRemoteBlobExists(String blobKey)
                                              throws AuthorizationException

      Decide if the blob is deleted from cluster.

      Parameters:
        `blobKey` - blob key
      Throws:
        `AuthorizationException`

    - #### setBlobMetaToExtend

          protected abstract void setBlobMetaToExtend(String key,
                                                      SettableBlobMeta meta)
                                               throws AuthorizationException,
                                                      KeyNotFoundException

      Client facing API to set the metadata for a blob.

      Parameters:
        `key` - blob key name
        `meta` - contains ACL information
      Throws:
        `AuthorizationException`
        `KeyNotFoundException`

    - #### deleteBlob

          public abstract void deleteBlob(String key)
                                   throws AuthorizationException,
                                          KeyNotFoundException

      Client facing API to delete a blob.

      Parameters:
        `key` - blob key name
      Throws:
        `AuthorizationException`
        `KeyNotFoundException`

    - #### getBlob

          public abstract InputStreamWithMeta getBlob(String key)
                                               throws AuthorizationException,
                                                      KeyNotFoundException

      Client facing API to read a blob.

      Parameters:
        `key` - blob key name
      Returns:
        an InputStream to read the metadata for a blob
      Throws:
        `AuthorizationException`
        `KeyNotFoundException`

    - #### listKeys

          public abstract Iterator<String> listKeys()

      List keys.

      Returns:
        Iterator for a list of keys currently present in the blob store.

    - #### getBlobReplication

          public abstract int getBlobReplication(String key)
                                          throws AuthorizationException,
                                                 KeyNotFoundException

      Client facing API to read the replication of a blob.

      Parameters:
        `key` - blob key name
      Returns:
        int indicates the replication factor of a blob
      Throws:
        `AuthorizationException`
        `KeyNotFoundException`

    - #### updateBlobReplication

          public abstract int updateBlobReplication(String key,
                                                    int replication)
                                             throws AuthorizationException,
                                                    KeyNotFoundException

      Client facing API to update the replication of a blob.

      Parameters:
        `key` - blob key name
        `replication` - int indicates the replication factor a blob has to be set
      Returns:
        int indicates the replication factor of a blob
      Throws:
        `AuthorizationException`
        `KeyNotFoundException`

    - #### setClient

          public abstract boolean setClient(Map<String,Object> conf,
                                            NimbusClient client)

      Client facing API to set a nimbus client.

      Parameters:
        `conf` - storm conf
        `client` - NimbusClient
      Returns:
        indicates where the client connection has been setup.

    - #### createStateInZookeeper

          public abstract void createStateInZookeeper(String key)

      Creates state inside a zookeeper. Required for blobstore to write to zookeeper when Nimbus HA is turned on in order to maintain state consistency.

    - #### close

          public abstract void close()

      Specified by:
        `close` in interface `AutoCloseable`

    - #### createBlob

          public final AtomicOutputStream createBlob(String key,
                                                     SettableBlobMeta meta)
                                              throws AuthorizationException,
                                                     KeyAlreadyExistsException

      Client facing API to create a blob.

      Parameters:
        `key` - blob key name
        `meta` - contains ACL information
      Returns:
        AtomicOutputStream returns an output stream into which data can be written
      Throws:
        `AuthorizationException`
        `KeyAlreadyExistsException`

    - #### setBlobMeta

          public final void setBlobMeta(String key,
                                        SettableBlobMeta meta)
                                 throws AuthorizationException,
                                        KeyNotFoundException

      Client facing API to set the metadata for a blob.

      Parameters:
        `key` - blob key name
        `meta` - contains ACL information
      Throws:
        `AuthorizationException`
        `KeyNotFoundException`

    - #### getRemoteBlobstoreUpdateTime

          public abstract long getRemoteBlobstoreUpdateTime()
                                                     throws IOException

      Client facing API to get the last update time of existing blobs in a blobstore. This is only required for use on supervisors.

      Returns:
        the timestamp of when the blobstore was last updated. -1L if the blobstore does not support this.
      Throws:
        `IOException`

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