Logstash can not find plugin after i install it successfully

[LiangxiongZhu]

i would like to extend logstash-input-jdbc so i download it to my local directory. and then i do following things.

1. rename the directory from logstash-input-jdbc to logstash-input-ias_person

2. rename lib/logstash/inputs/jdbc.ruby to lib/logstash/inputs/ias_person.ruby

3. rename class name from Jdbc to Ias_Person

4. change config_name to "ias_person"

5. change logstash-input-jdbc.gemspec to logstash-input-ias_person.gemspec

6. gem build logstash-input-ias_person.gemspec then i get a logstash-input-ias_person-4.2.2.gem

7. install this new plugin (yes, i just rename it for the first step) by command logstash-plugin install logstash-input-ias_person-4.2.2.gem. it shows validating, and installing and then succeed.

8. run command logstash-plugin list, i can see my logstash-input-ias_person in output.

9. open logstash/Gemfile, i see this line: gem "logstash-input-ias_person", "4.2.2", :path => "vendor/local_gems/89ca0712/logstash-input-ias_person-4.2.2"

10. so far so good! BUT when i try to use it. (just by replace jdbc plugin to ias_person in a verified working logstash conf file). i get this error:
    [2017-08-18T15:26:16,713][ERROR][logstash.plugins.registry] Problems loading a plugin with {:type=>"input", :name=>"ias_person", :path=>"logstash/inputs/ias_person", :error_message=>"NameError", :error_class=>NameError, :error_backtrace=>["c:/ElastiscSearch/logstash/logstash-core/lib/logstash/plugins/registry.rb:226:in namespace_lookup'", "c:/ElastiscSearch/logstash/logstash-core/lib/logstash/plugins/registry.rb:162:inlegacy_lookup'", "c:/ElastiscSearch/logstash/logstash-core/lib/logstash/plugins/registry.rb:138:in lookup'", "c:/ElastiscSearch/logstash/logstash-core/lib/logstash/plugins/registry.rb:180:inlookup_pipeline_plugin'", "c:/ElastiscSearch/logstash/logstash-core/lib/logstash/plugin.rb:140:in lookup'", "c:/ElastiscSearch/logstash/logstash-core/lib/logstash/pipeline.rb:100:inplugin'", "(eval):8:in initialize'", "org/jruby/RubyKernel.java:1079:ineval'", "c:/ElastiscSearch/logstash/logstash-core/lib/logstash/pipeline.rb:72:in initialize'", "c:/ElastiscSearch/logstash/logstash-core/lib/logstash/pipeline.rb:156:ininitialize'", "c:/ElastiscSearch/logstash/logstash-core/lib/logstash/agent.rb:286:in create_pipeline'", "c:/ElastiscSearch/logstash/logstash-core/lib/logstash/agent.rb:95:inregister_pipeline'", "c:/ElastiscSearch/logstash/logstash-core/lib/logstash/runner.rb:314:in execute'", "c:/ElastiscSearch/logstash/vendor/bundle/jruby/1.9/gems/clamp-0.6.5/lib/clamp/command.rb:67:inrun'", "c:/ElastiscSearch/logstash/logstash-core/lib/logstash/runner.rb:209:in run'", "c:/ElastiscSearch/logstash/vendor/bundle/jruby/1.9/gems/clamp-0.6.5/lib/clamp/command.rb:132:inrun'", "c:\ElastiscSearch\logstash\lib\bootstrap\environment.rb:71:in `(root)'"]}
    [2017-08-18T15:26:16,729][ERROR][logstash.agent ] Cannot create pipeline {:reason=>"Couldn't find any input plugin named 'ias_person'. Are you sure this is correct? Trying to load the ias_person input plugin resulted in this error: Problems loading the requested plugin named ias_person of type input. Error: NameError NameError"}

I GUESS, it trys to load plugin from "logstash/inputs/ias_person"???
Doesn't logstash/Gemfile shows it is at "vendor/local_gems/89ca0712/logstash-input-ias_person-4.2.2"??

[LiangxiongZhu]

plus:
get error after i uninstall it and try to install it again...

c:\ElastiscSearch\logstash>bin\logstash-plugin install plugins\logstash-input-ias_person-4.2.2.gem
ERROR: Something went wrong when installing plugins\logstash-input-ias_person-4.2.2.gem, message: bad URI(is not URI?): https://artifacts.elastic.co/downloads/logstash-plugins/plugins\logstash-input-ias_person-4.2.2.gem/plugins\logstash-input-ias_person-4.2.2.gem-5.5.1.zip

[LiangxiongZhu]

for my first problem: it is my mistake. i made some changes and installed gem. then continue make other changes.and rebuild and reinstall the gem. but i didn't copy the new gem from source directory to my installation directory. so logstash still loads old gem which has something incosistent by itself.

for my second problem: i am still unsure what is happening. after tried about 7 or 8 times. i can install it now. i did nothing but just repeat executing bin\logstash-plugin install plugins\logstash-input-ias_person-4.2.2.gem. hopefully some experienced plugin developer could tell me what is happening in my computer.