HBASE-21567 Allow overriding configs starting up the shell

Adds support for -D as option to 'hbase shell'

bin/hirb.rb

@@ -56,19 +56,45 @@ Usage: shell [OPTIONS] [SCRIPTFILE [ARGUMENTS]]
 
  -d | --debug            Set DEBUG log levels.
  -h | --help             This help.
- -n | --noninteractive          Do not run within an IRB session
-                                and exit with non-zero status on
-                                first error.
+ -n | --noninteractive   Do not run within an IRB session and exit with non-zero
+                         status on first error.
+ -Dkey=value             Pass hbase-*.xml Configuration overrides. For example, to
+                         use an alternate zookeeper ensemble, pass:
+                           -Dhbase.zookeeper.quorum=zookeeper.example.org
+                         For faster fail, pass the below and vary the values:
+                           -Dhbase.client.retries.number=7
+                           -Dhbase.ipc.client.connect.max.retries=3
 HERE
+
+# Takes configuration and an arg that is expected to be key=value format.
+# If c is empty, creates one and returns it
+def add_to_configuration(c, arg)
+  kv = arg.split('=')
+  kv.length == 2 || (raise "Expected parameter #{kv} in key=value format")
+  c = org.apache.hadoop.hbase.HBaseConfiguration.create if c.nil?
+  c.set(kv[0], kv[1])
+  c
+end
+
 found = []
 script2run = nil
 log_level = org.apache.log4j.Level::ERROR
 @shell_debug = false
 interactive = true
-for arg in ARGV
+_configuration = nil
+D_ARG = '-D'
+while (arg = ARGV.shift)
   if arg == '-h' || arg == '--help'
     puts cmdline_help
     exit
+  elsif arg == D_ARG
+    argValue = ARGV.shift || (raise "#{D_ARG} takes a 'key=value' parameter")
+    _configuration = add_to_configuration(_configuration, argValue)
+    found.push(arg)
+    found.push(argValue)
+  elsif arg.start_with? D_ARG
+    _configuration = add_to_configuration(_configuration, arg[2..-1])
+    found.push(arg)
   elsif arg == '-d' || arg == '--debug'
     log_level = org.apache.log4j.Level::DEBUG
     $fullBackTrace = true
@@ -111,7 +137,7 @@ require 'shell'
 require 'shell/formatter'
 
 # Setup the HBase module.  Create a configuration.
-@hbase = Hbase::Hbase.new
+@hbase = _configuration.nil? ? Hbase::Hbase.new : Hbase::Hbase.new(_configuration)
 
 # Setup console
 @shell = Shell::Shell.new(@hbase, interactive)

src/main/asciidoc/_chapters/shell.adoc

@@ -58,6 +58,7 @@ To run one of these files, do as follows:
 $ ./bin/hbase org.jruby.Main PATH_TO_SCRIPT
 ----
 
+
 == Running the Shell in Non-Interactive Mode
 
 A new non-interactive mode has been added to the HBase Shell (link:https://issues.apache.org/jira/browse/HBASE-11658[HBASE-11658)].
@@ -213,6 +214,21 @@ $ HBASE_SHELL_OPTS="-verbose:gc -XX:+PrintGCApplicationStoppedTime -XX:+PrintGCD
   -XX:+PrintGCDetails -Xloggc:$HBASE_HOME/logs/gc-hbase.log" ./bin/hbase shell
 ----
 
+== Overriding configuration starting the HBase Shell
+
+As of hbase-2.0.5/hbase-2.1.3/hbase-2.2.0/hbase-1.4.10/hbase-1.5.0, you can
+pass or override hbase configuration as specified in `hbase-*.xml` by passing
+your key/values prefixed with `-D` on the command-line as follows:
+[source,bash]
+----
+$ ./bin/hbase shell -Dhbase.zookeeper.quorum=ZK0.remote.cluster.example.org,ZK1.remote.cluster.example.org,ZK2.remote.cluster.example.org -Draining=false
+...
+hbase(main):001:0> @shell.hbase.configuration.get("hbase.zookeeper.quorum")
+=> "ZK0.remote.cluster.example.org,ZK1.remote.cluster.example.org,ZK2.remote.cluster.example.org"
+hbase(main):002:0> @shell.hbase.configuration.get("raining")
+=> "false"
+----
+
 == Shell Tricks
 
 === Table variables