ActiveAdmin Logs

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Inspired by Gitlab's Admin Logs (app/controllers/admin/logs_controller.rb)

Probably should put things in lib. Put in one file for breviety.

logs.rb

# begin - put this in lib/my_rails_app/* and load it in your application.rb 
module MyRailsApp
  class Logger < ::Logger
    def self.file_name
      file_name_noext + '.log'
    end

    def self.error(message)
      build.error(message)
    end

    def self.info(message)
      build.info(message)
    end

    def self.read_latest
      path = Rails.root.join("log", file_name)
      self.build unless File.exist?(path)
      tail_output, _ = Propertyprompt::Popen.popen(%W(tail -n 2000 #{path}))
      tail_output.split("\n")
    end

    def self.read_latest_for(filename)
      path = Rails.root.join("log", filename)
      tail_output, _ = Propertyprompt::Popen.popen(%W(tail -n 2000 #{path}))
      tail_output.split("\n")
    end

    def self.build
      new(Rails.root.join("log", file_name))
    end
  end
end

module MyRailsApp
  class AppLogger < MyRailsApp::Logger
    def self.file_name_noext
      'application'
    end

    def format_message(severity, timestamp, progname, msg)
      "#{timestamp.to_s(:long)}: #{msg}\n"
    end
  end
end

module Propertyprompt
  class ProductionLogger < MyRailsApp::Logger
    def self.file_name_noext
      'production'
    end
  end
end

module MyRailsApp
  class DevelopmentLogger < MyRailsApp::Logger
    def self.file_name_noext
      'development'
    end
  end
end

require 'fileutils'
require 'open3'

module MyRailsApp
  module Popen
    extend self

    def popen(cmd, path=nil)
      unless cmd.is_a?(Array)
        raise "System commands must be given as an array of strings"
      end

      path ||= Dir.pwd
      vars = { "PWD" => path }
      options = { chdir: path }

      unless File.directory?(path)
        FileUtils.mkdir_p(path)
      end

      @cmd_output = ""
      @cmd_status = 0
      Open3.popen3(vars, *cmd, options) do |stdin, stdout, stderr, wait_thr|
        # We are not using stdin so we should close it, in case the command we
        # are running waits for input.
        stdin.close
        @cmd_output << stdout.read
        @cmd_output << stderr.read
        @cmd_status = wait_thr.value.exitstatus
      end

      [@cmd_output, @cmd_status]
    end
  end
end
# end - put this in lib/my_rails_app/*

# app/admin/logs.rb 
ActiveAdmin.register_page "Logs" do

  content do
    render 'show'
  end

end

show.html.erb

<style>
/* sorry for the blatent rip */ 
    .file-holder {
        border: 1px solid #e5e5e5;
        margin-bottom: 1em;
    }
    .file-holder .file-title {
        position: relative;
        background: whitesmoke;
        border-bottom: 1px solid #e5e5e5;
        text-shadow: 0 1px 1px #fff;
        margin: 0;
        text-align: left;
        padding: 10px 15px;
    }
    .file-holder .file-content.logs {
        background: #eee;
        max-height: 700px;
        overflow-y: auto;
    }
    .file-holder .file-content.logs ol {
        margin-left: 40px;
        padding: 10px 0;
        border-left: 1px solid #e5e5e5;
        margin-bottom: 0;
        background: white;
    }
    .file-holder .file-content.logs ol li {
        color: #888;
    }
    .file-holder .file-content.logs ol li p {
        margin: 0;
        color: #333;
        line-height: 24px;
        padding-left: 10px;
    }
</style>

<% loggers = [MyRailsApp::AppLogger, MyRailsApp::ProductionLogger, MyRailsApp::DevelopmentLogger] %>
<% # development logger for dev purposes %>
<% klass = loggers.first
   if params[:log]
     loggers.each do |log|
       if log.file_name_noext == params[:log]
         klass = log
         break
         end
       end
     end
%>
<div class="table_tools">
  <ul class="scopes table_tools_segmented_control">
    <% loggers.each do |l| %>
    <li class="scope <%= 'selected' if klass == l %> ">
      <a href="/admin/logs?log=<%=l.file_name_noext%>" class="table_tools_button">
        <%=l.file_name_noext.capitalize%>
      </a>
    </li>
    <% end %>
  </ul>
</div>

<div class="file-holder">
  <div class="file-title">
    <i class="fa fa-file"></i>
    <%= klass::file_name %>
    <div style="float:right;"><a href="javascript:var objDiv = document.getElementById('log');objDiv.scrollTop = objDiv.scrollHeight;">Bottom</a></div>
  </div>
  <div class="file-content logs" id="log">
    <ol>
      <% klass.read_latest.each do |line| %>
          <li>
            <p>
              <%= line %>
            </p>
          </li>
      <% end %>
    </ol>
  </div>
</div>