crux-hbase

This is a Crux key value store implementation with HBase. HBase KV Store is horizontally scalable. It is intended Crux deployment on environment like Kubernetes where Crux nodes can be provisioned dynamically on any nodes in the cluster without requiring local index store.

Usage

Maven

<dependency>
  <groupId>io.kosong.crux</groupId>
  <artifactId>crux-hbase</artifactId>
  <version>0.3.0-SNAPSHOT</version>
</dependency>

Leiningen

[io.kosong.crux.hbase/crux-hbase "0.3.0-SNAPSHOT"]

Module Configuration

Refer to Crux reference for details on how to configure Crux index store, document store and transaction log.

The first step is to specify the HBase client configuration with the io.kosong.crux.hbase/->hbase-config module.

This follows with the use of io.kosong.crux.hbase/->hbase-connection module to create the HBase connection.

And then we can use the io.kosong.crux.hbase/->kv-store module to configure the desired Crux components (index store, document store or transaction log) to use HBase KV Store.

Below is an example of configuring Crux to use HBase KV Stores for all three major components (index store, document store and transaction log).

The configuration allows multiple crux nodes to connect to the same distributed HBase KV index store with single curator coordinated cluster-wide tx-ingester executor to ingest the transactions into the shared distributed index store.

{
  ;; create a HBaseConfiguration
  :hbase-config
   {:crux/module 'io.kosong.crux.hbase/->hbase-config
    :properties  {"hbase.zookeeper.quorum" "127.0.0.1:2181"}}
 
  ;; create a shared HBase connection
  :hbase-connection
    {:crux/module  'io.kosong.crux.hbase/->hbase-connection
     :hbase-config :hbase-config}

  ;; create a curator client to coordinate singleton tx-ingester
  :curator
    {:crux/module      'io.kosong.crux.hbase/->curator
     :zookeeper-quorum "127.0.0.1:2181"}
 
  ;; cluster-wide singleton tx-ingest-executor with curator
  ;; to ensure that there is only one active tx-ingester
  ;; updating the remote hbase index-store at any one time
  :tx-ingest-executor
   {:crux/module       'io.kosong.crux.hbase/->tx-ingest-executor
    :curator           :curator}
 
  :crux/index-store
    {:kv-store {:crux/module       'io.kosong.crux.hbase/->kv-store
                :hbase-connection  :hbase-connection
                :table             "index-store"}}

  :crux/document-store
    {:kv-store {:crux/module       'io.kosong.crux.hbase/->kv-store
                :hbase-connection  :hbase-connection
                :table             "document-store"}}

   ;; HBase KV tx-log in ingest only mode as tx-ingester is managed
   ;; by tx-ingest-executor
  :crux/tx-log
    {:crux/module 'crux.kv.tx-log/->ingest-only-tx-log
     :kv-store    {:crux/module       'io.kosong.crux.hbase/->kv-store
                   :hbase-connection  :hbase-connection
                   :table             "tx-log"}}
}

Module io.kosong.crux.hbase/->hbase-config

Parameters

• properties - string map to set up HBaseConfiguration

Return

• An instance of org.apache.hbase.HBaseConfiguration

Module io.kosong.crux.hbase/->hbase-connection

Parameters

• hbase-config - An instance of HBaseConfiguration

Return

• An instance of org.apache.hbase.client.Connection

Module io.kosong.crux.hbase/->kv-store

Parameters

• hbase-connection - An instance of org.apache.hbase.client.Connection
• table - HBase table name of the KV Store.
• namespace - HBase namespace, default to crux.
• family - HBase column family name, default to cf.
• qualifier - HBase qualifier, default to val.
• create-table? - Create the HBase table if it doesn't exist, default to true.

Return

• An instance of crux.kv.KvStore with HBase table data store.

Module io.kosong.crux.hbase/->curator

Parameters

• zookeeper-quorum - Zookeeper connection string
• session-timeout - Zookeeper session timeout in milliseconds, default to 60000.
• connection-timeout - Zookeeper connection timeout in milliseconds, default to 60000.
• retry-base-sleep - Exponential backoff retry base sleep in milliseconds, default to 2000.
• retry-max-count - Exponential backoff retry max count, default to 10.

Return

• An instance of CuratorFrameworkl

Module io.kosong.crux.hbase/->tx-ingest-executor

Parameters

• curator - An instance of CuratorFramework.
• tx-ingester - Default to :crux/tx-ingester.
• tx-log - Default to :crux/tx-log.
• index-store - Default to :crux/index-store.
• mutex-path - Zookeeper leader election mutex path, defaults to /crux/tx-ingest-executor

Return

• An instance of io.kosong.hbase.TxIngestExector.

Development

To build

lein modules install

To test

lein modules test

To run a Clojure REPL for development

lein modules install
lein repl

When in Clojure REPL user namespace

; Switch to dev namespace
(dev)

; If required, start embedded Zookeeper, HBase cluster
; for local development
(start-embedded-cluster)

; Start Crux
(go)

(crux/status (crux-node))

; Stop Crux
(halt)

; Stop embeded Zookeeper, HBase cluster
(stop-embedded-cluster)