Hard to debug and refactor fluent-plugin-grafana-loki

[takanabe]

Describe the bug

https://github.com/grafana/loki/tree/master/fluentd/fluent-plugin-grafana-loki is not well maintained and hard to debug because,

• the code creates many rubocop violations
• the spec does not work

To Reproduce
Steps to reproduce the behavior:

1. bin/setup
2. bundle exec rake spec creates the following violation messages and errors

bundle exec rake spec
Running RuboCop...
.rubocop.yml: Metrics/LineLength has the wrong namespace - should be Layout
Inspecting 7 files
....C..

Offenses:

lib/fluent/plugin/out_loki.rb:72:7: C: Metrics/CyclomaticComplexity: Cyclomatic complexity for configure is too high. [7/6]
      def configure(conf) ...
      ^^^^^^^^^^^^^^^^^^^
lib/fluent/plugin/out_loki.rb:76:21: C: Style/ClassCheck: Prefer Object#is_a? over Object#kind_of?.
        unless @uri.kind_of?(URI::HTTP) or @uri.kind_of?(URI::HTTPS)
                    ^^^^^^^^
lib/fluent/plugin/out_loki.rb:76:41: C: Style/AndOr: Use || instead of or.
        unless @uri.kind_of?(URI::HTTP) or @uri.kind_of?(URI::HTTPS)
                                        ^^
lib/fluent/plugin/out_loki.rb:76:49: C: Style/ClassCheck: Prefer Object#is_a? over Object#kind_of?.
        unless @uri.kind_of?(URI::HTTP) or @uri.kind_of?(URI::HTTPS)
                                                ^^^^^^^^
lib/fluent/plugin/out_loki.rb:77:38: C: Style/StringLiterals: Prefer single-quoted strings when you don't need string interpolation or special symbols.
          raise Fluent::ConfigError, "url parameter must be valid HTTP"
                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
lib/fluent/plugin/out_loki.rb:78:9: C: Layout/EmptyLineAfterGuardClause: Add empty line after guard clause.
        end
        ^^^

7 files inspected, 6 offenses detected

Even if we ignore the robocop by comment out Rakefile like

# frozen_string_literal: true

require 'bundler/gem_tasks'
require 'rspec/core/rake_task'
require 'rubocop/rake_task'

# comment out this line
#RuboCop::RakeTask.new(:spec)
RSpec::Core::RakeTask.new(:spec)

task default: :spec

bundle exec rake spec fails due to the following errors

bundle exec rake spec
/Users/takayuki-watanabe/.rbenv/versions/2.6.5/bin/ruby -I/Users/takayuki-watanabe/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/rspec-core-3.9.1/lib:/Users/takayuki-watanabe/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/rspec-support-3.9.2/lib /Users/takayuki-watanabe/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/rspec-core-3.9.1/exe/rspec --pattern spec/\*\*\{,/\*/\*\*\}/\*_spec.rb

An error occurred while loading spec_helper.
Failure/Error: require 'fluent/plugin/output'

NoMethodError:
  undefined method `windows?' for Fluent:Module
# ./lib/fluent/plugin/out_loki.rb:18:in `require'
# ./lib/fluent/plugin/out_loki.rb:18:in `<top (required)>'
# ./spec/spec_helper.rb:7:in `require'
# ./spec/spec_helper.rb:7:in `<top (required)>'
No examples found.
No examples found.


Finished in 0.00002 seconds (files took 0.80014 seconds to load)
0 examples, 0 failures, 1 error occurred outside of examples

Finished in 0.00002 seconds (files took 0.80014 seconds to load)
0 examples, 0 failures, 1 error occurred outside of examples


/Users/takayuki-watanabe/.rbenv/versions/2.6.5/bin/ruby -I/Users/takayuki-watanabe/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/rspec-core-3.9.1/lib:/Users/takayuki-watanabe/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/rspec-support-3.9.2/lib /Users/takayuki-watanabe/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/rspec-core-3.9.1/exe/rspec --pattern spec/\*\*\{,/\*/\*\*\}/\*_spec.rb failed

Expected behavior

• bundle exec rake spec succeeds without violations and errors

Environment:

• Infrastructure: MacOS Mojave(10.4.16)
• Ruby and bundler version:

$ ruby -v
ruby 2.6.5p114 (2019-10-01 revision 67812) [x86_64-darwin18]
$ bundle -v
Bundler version 2.1.4

Comment

Are we sure that the docs written in the development section are correct? (https://github.com/grafana/loki/tree/master/fluentd/fluent-plugin-grafana-loki#development). If not I want to refactor this directory.

According to the Slack comment, this directory isn't well maintained. I'm not sure who could run spec with the current master code.

In addition, there are no Gemfile.lock and .ruby-version(ruby version info). It's hard to develop this plugin without documentation and testable specs.

[cyriltovena]

Awesome please join #loki-dev on slack if you need help.

[takanabe]

@cyriltovena

This issue is ongoing 💨 could you reopen this issue so I can put all the information here? I'm planning to fix broken specs and introduce CI. Otherwise, this plugin won't be maintained.

[stale]

This issue has been automatically marked as stale because it has not had any activity in the past 30 days. It will be closed in 7 days if no further activity occurs. Thank you for your contributions.