Add stats formatting for riak-admin and http stats output

[bowrocker]

YZ stats are not currently displayed on the riak http stats endpoint, or by riak-admin status. Add YZ stats formatting appropriate for console output with 'riak-admin status' and the htts /stats endpoint. The stats namespace for Search is transformed to /search/[query | index]/... instead of 'yokozuna'.

This PR also depends on changes to riak_kv in order to publish the stats to the 2 interfaces:

basho/riak_kv#855

Example stats output:

search_query_fail_count : 0
search_query_fail_one : 0
search_index_throughput_count : 0
search_index_throughput_one : 0
search_index_fail_count : 0
search_index_fail_one : 0
search_query_throughput_count : 0
search_query_throughput_one : 0
search_query_latency_min : 0.0
search_query_latency_max : 0.0
search_query_latency_median : 0.0
search_query_latency_percentile_95 : 0.0
search_query_latency_percentile_99 : 0.0
search_index_latency_min : 0.0
search_index_latency_max : 0.0
search_index_latency_median : 0.0
search_index_latency_percentile_95 : 0.0
search_index_latency_percentile_99 : 0.0

[rzezeski]

• compile/unit
• dialyzer
• riak tests
• code review
• manual testing

# curl -s 'http://localhost:10018/stats' | json_pp | grep search
   "search_query_latency_max" : 0,
   "search_query_latency_min" : 0,
   "search_query_latency_95" : 0,
   "search_index_latency_median" : 0,
   "search_index_fail_count" : 0,
   "search_index_latency_99" : 0,
   "search_index_throughtput_one" : 0,
   "search_index_latency_999" : 0,
   "search_index_latency_min" : 0,
   "search_query_throughput_one" : 0,
   "search_index_latency_max" : 0,
   "search_query_latency_median" : 0,
   "search_query_latency_999" : 0,
   "search_query_throughput_count" : 0,
   "search_index_throughput_count" : 0,
   "riak_search_version" : "1.4.1-22-ga3893df",
   "search_query_latency_99" : 0,
   "search_index_latency_95" : 0,
   "search_index_fail_one" : 0,

#  ~/yz-verify/rt/riak_yz/dev/dev1/bin/riak-admin status | grep search
riak_search_version : <<"1.4.1-22-ga3893df">>
search_query_throughput_count : 0
search_query_throughput_one : 0
search_query_latency_min : 0
search_query_latency_max : 0
search_query_latency_median : 0
search_query_latency_95 : 0
search_query_latency_99 : 0
search_query_latency_999 : 0
search_index_throughput_count : 0
search_index_throughtput_one : 0
search_index_fail_count : 0
search_index_fail_one : 0
search_index_latency_min : 0
search_index_latency_max : 0
search_index_latency_median : 0
search_index_latency_95 : 0
search_index_latency_99 : 0
search_index_latency_999 : 0

Test Results:
yz_wm_extract_test-bitcask   : pass
yz_stat_test-bitcask         : pass
yz_solr_start_timeout-bitcask: pass
yz_siblings-bitcask          : pass
yz_security-bitcask          : pass
yz_schema_admin-bitcask      : pass
yz_rs_migration_test-bitcask : pass
yz_pb-bitcask                : pass
yz_monitor_solr-bitcask      : pass
yz_mapreduce-bitcask         : pass
yz_languages-bitcask         : pass
yz_index_admin-bitcask       : pass
yz_fallback-bitcask          : pass
yz_errors-bitcask            : pass
yz_dt_test-bitcask           : pass
yokozuna_essential-bitcask   : pass
aae_test-bitcask             : pass
---------------------------------------------
0 Tests Failed
17 Tests Passed
That's 100.0% for those keeping score

Everything works but we are missing the query failure stats. I say lets just get this PR in and make an issue for adding those stats.

+1 to merge.

[rzezeski]

# ~/yz-verify/rt/riak_yz/dev/dev2/bin/riak-admin status | grep search
riak_search_version : <<"1.4.1-22-ga3893df">>
search_query_throughput_count : 0
search_query_throughput_one : 0
search_query_fail_count : 0
search_query_fail_one : 0
search_query_latency_min : 0
search_query_latency_max : 0
search_query_latency_median : 0
search_query_latency_95 : 0
search_query_latency_99 : 0
search_query_latency_999 : 0
search_index_throughput_count : 0
search_index_throughtput_one : 0
search_index_fail_count : 0
search_index_fail_one : 0
search_index_latency_min : 0
search_index_latency_max : 0
search_index_latency_median : 0
search_index_latency_95 : 0
search_index_latency_99 : 0
search_index_latency_999 : 0

# curl -s 'http://localhost:10018/stats' | json_pp | grep search
   "riak_search_version" : "1.4.1-22-ga3893df",
   "search_index_fail_one" : 0,
   "search_query_fail_count" : 0,
   "search_query_throughput_one" : 0,
   "search_index_latency_max" : 0,
   "search_index_throughput_count" : 0,
   "search_query_fail_one" : 0,
   "search_query_latency_99" : 0,
   "search_query_latency_median" : 0,
   "search_index_throughtput_one" : 0,
   "search_query_latency_95" : 0,
   "search_index_latency_min" : 0,
   "search_index_latency_99" : 0,
   "search_query_latency_max" : 0,
   "search_query_latency_min" : 0,
   "search_query_latency_999" : 0,
   "search_index_latency_999" : 0,
   "search_index_latency_median" : 0,
   "search_query_throughput_count" : 0,
   "search_index_latency_95" : 0,
   "search_index_fail_count" : 0

Test Results:
yz_stat_test-bitcask: pass
---------------------------------------------
0 Tests Failed
1 Tests Passed
That's 100.0% for those keeping score

+1 to merge.