hbase/hbase-examples/README.txt

Example code.

* org.apache.hadoop.hbase.mapreduce.SampleUploader
    Demonstrates uploading data from text files (presumably stored in HDFS) to HBase.

* org.apache.hadoop.hbase.mapreduce.IndexBuilder
    Demonstrates map/reduce with a table as the source and other tables as the sink.
    You can generate sample data for this MR job via hbase-examples/src/main/ruby/index-builder-setup.rb.


* Thrift examples
    Sample clients of the HBase ThriftServer. They perform the same actions, implemented in
    C++, Java, Ruby, PHP, Perl, and Python. Pre-generated Thrift code for HBase is included
    to be able to compile/run the examples without Thrift installed.
    If desired, the code can be re-generated as follows:
    thrift --gen cpp --gen java --gen rb --gen py --gen php --gen perl \
        ${HBASE_ROOT}/hbase-thrift/src/main/resources/org/apache/hadoop/hbase/thrift/Hbase.thrift
    and re-placed at the corresponding paths. You should not have to do this generally.

    Before you run any Thrift examples, find a running HBase Thrift server (and a running
    hbase cluster for this server to talk to -- at a minimum start a standalone instance
    by doing ./bin/start-hbase.sh). If you start one locally (bin/hbase thrift start),
    the default port is 9090 (a webserver with basic stats defaults showing on port 9095).

    * Java: org.apache.hadoop.hbase.thrift.DemoClient (jar under lib/).
      1. Make sure your client has all required jars on the CLASSPATH when it starts. If lazy,
      just add all jars as follows: {HBASE_EXAMPLE_CLASSPATH=`./bin/hbase classpath`}
      2. If HBase server is not secure, or authentication is not enabled for the Thrift server, execute:
      {java -cp hbase-examples-[VERSION].jar:${HBASE_EXAMPLE_CLASSPATH} org.apache.hadoop.hbase.thrift.DemoClient <host> <port>}
      3. If HBase server is secure, and authentication is enabled for the Thrift server, run kinit at first, then execute:
      {java -cp hbase-examples-[VERSION].jar:${HBASE_EXAMPLE_CLASSPATH} org.apache.hadoop.hbase.thrift.DemoClient <host> <port> true}
      4. Here is a lazy example that just pulls in all hbase dependency jars and that goes against default location on localhost.
      It should work with a standalone hbase instance started by doing ./bin/start-hbase.sh:
      {java -cp ./hbase-examples/target/hbase-examples-2.0.0-SNAPSHOT.jar:`./bin/hbase classpath` org.apache.hadoop.hbase.thrift.DemoClient localhost 9090}

    * Ruby: hbase-examples/src/main/ruby/DemoClient.rb
      1. Modify the import path in the file to point to {$THRIFT_HOME}/lib/rb/lib.
      2. Execute {ruby DemoClient.rb} (or {ruby DemoClient.rb <host> <port>}).

    * Python: hbase-examples/src/main/python/DemoClient.py
      1. Modify the added system path in the file to point to {$THRIFT_HOME}/lib/py/build/lib.[YOUR SYSTEM]
      2. Execute {python DemoClient.py <host> <port>}.

    * PHP: hbase-examples/src/main/php/DemoClient.php
      1. Modify the THRIFT_HOME path in the file to point to actual {$THRIFT_HOME}.
      2. Execute {php DemoClient.php}.
      3. Starting from Thrift 0.9.0, if Thrift.php complains about some files it cannot include, go to thrift root,
        and copy the contents of php/lib/Thrift under lib/php/src. Thrift.php appears to include, from under the same root,
        both TStringUtils.php, only present in src/, and other files only present under lib/; this will bring them under
        the same root (src/).
        If you know better about PHP and Thrift, please feel free to fix this.

    * Perl: hbase-examples/src/main/perl/DemoClient.pl
      1. Modify the "use lib" path in the file to point to {$THRIFT_HOME}/lib/perl/lib.
      2. Use CPAN to get Bit::Vector and Class::Accessor modules if not present (see thrift perl README if more modules are missing).
      3. Execute {perl DemoClient.pl}.

    * CPP: hbase-examples/src/main/cpp/DemoClient.cpp
      1. Make sure you have boost and Thrift C++ libraries; modify Makefile if necessary.
        The recent (0.9.0 as of this writing) version of Thrift can be downloaded from http://thrift.apache.org/download/.
        Boost can be found at http://www.boost.org/users/download/.
      2. Execute {make}.
      3. Execute {./DemoClient}.

ON PROTOBUFS
This maven module has  protobuf definition files ('.protos') used by hbase
Coprocessor Endpoints examples including tests. Coprocessor
Endpoints are meant to be standalone, independent code not reliant on hbase
internals. They define their Service using protobuf. The protobuf version
they use can be distinct from that used by HBase internally since HBase started
shading its protobuf references. Endpoints have no access to the shaded protobuf
hbase uses. They do have access to the content of hbase-protocol -- the
.protos found in here -- but avoid using as much of this as you can as it is
liable to change.

Generation of java files from protobuf .proto files included here is done apart
from the build. Run the generation whenever you make changes to the .orotos files
and then check in the produced java (The reasoning is that change is infrequent
so why pay the price of generating files anew on each build.

To generate java files from protos run:

 $ mvn compile -Dcompile-protobuf
or
 $ mvn compile -Pcompile-protobuf

After you've done the above, check it and then check in changes (or post a patch
on a JIRA with your definition file changes and the generated files). Be careful
to notice new files and files removed and do appropriate git rm/adds.