Class: HQ::LogMonitorClient::Script

Inherits:
Object
  • Object
show all
Defined in:
lib/hq/log-monitor-client/script.rb

Defined Under Namespace

Classes: ContextReader

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#args ⇒ Object

Returns the value of attribute args.



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# File 'lib/hq/log-monitor-client/script.rb', line 11

def args
  @args
end

#status ⇒ Object

Returns the value of attribute status.



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# File 'lib/hq/log-monitor-client/script.rb', line 12

def status
  @status
end

#stderr ⇒ Object

Returns the value of attribute stderr.



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# File 'lib/hq/log-monitor-client/script.rb', line 15

def stderr
  @stderr
end

#stdout ⇒ Object

Returns the value of attribute stdout.



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# File 'lib/hq/log-monitor-client/script.rb', line 14

def stdout
  @stdout
end

Instance Method Details

#debug(message) ⇒ Object 



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# File 'lib/hq/log-monitor-client/script.rb', line 461

def debug message
  return unless @debug
  $stderr.puts message
end

#main ⇒ Object 



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# File 'lib/hq/log-monitor-client/script.rb', line 17

def main

  process_args
  read_config
  read_cache
  perform_checks
  write_cache

  @status = 0

end

#perform_checks ⇒ Object 



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# File 'lib/hq/log-monitor-client/script.rb', line 108

def perform_checks

  @service_elems.each do
    |service_elem|

    debug "==== service #{service_elem["name"]}"

    fileset_elems = service_elem.find("fileset").to_a

    fileset_elems.each do
      |fileset_elem|

      scan_elems = fileset_elem.find("scan").to_a
      match_elems = fileset_elem.find("match").to_a

      max_before =
        match_elems.map {
          |match_elem|
          (match_elem["before"] || 0).to_i
        }.max

      max_after =
        match_elems.map {
          |match_elem|
          (match_elem["after"] || 0).to_i
        }.max

      # find files

      file_names =
        scan_elems.map {
          |scan_elem|
          Dir[scan_elem["glob"]]
        }.flatten

      # scan files

      file_names.each do
        |file_name|

        debug "-- file #{file_name}"

        file_mtime = File.mtime file_name
        file_size = File.size file_name

        # fast check for modified files

        cache_file = @cache[:files][file_name]

        if cache_file &&
          file_mtime == cache_file[:mtime] &&
          file_size == cache_file[:size]

          debug "mtime %s and size %s match, skip" % [
            file_mtime,
            file_size,
          ]

          next

        end

        # scan the file for matching lines

        mode = cache_file ? :scan : :report

        File.open file_name, "r" do
          |file_io|

          file_reader =
            ContextReader.new \
              file_io,
              max_before + max_after + 1

          file_digest = Digest::MD5.new

          # check if the file has changed

          if cache_file

            if file_size < cache_file[:size]

              debug \
                "size %s is less than cache size %s" % [
                  file_size,
                  cache_file[:size],
                ]

              changed = true

            else

              debug "scanning start of file"

              changed = false

              cache_file[:lines].times do
                |line_num|

                line = file_reader.gets

                unless line

                  debug \
                    "only read %s lines, previously " \
                    "read %s" % [
                      line_num,
                      cache_file[:lines],
                    ]

                  changed = true
                  break

                end

                file_digest.update line

              end

              file_hash = file_digest.to_s

              if file_hash != cache_file[:hash]

                debug \
                  "hash %s does not match previous " \
                  "value %s" % [
                    file_hash,
                    cache_file[:hash]
                  ]

                changed = true

              end

            end

            # go back to start if it changed

            if changed
              debug "seeking to start"
              file_io.seek 0
              file_reader.reset
              file_digest = Digest::MD5.new
            else
              debug "start of file not changed"
            end

          end

          # scan the new part of the file

          debug "searching for events"

          while line = file_reader.gets

            file_digest.update line

            # check for a match

            match_elem =
              match_elems.find {
                |match_elem|
                line =~ /#{match_elem["regex"]}/
              }

            # report the match

            if match_elem

              # get context

              lines_before =
                file_reader.lines_before \
                  (match_elem["before"] || 0).to_i + 1

              lines_before.pop

              lines_after =
                file_reader.lines_after \
                  (match_elem["after"] || 0).to_i

              # send event

              submit_event({
                type: match_elem["type"],
                source: {
                  class: @client_elem["class"],
                  host: @client_elem["host"],
                  service: service_elem["name"],
                },
                location: {
                  file: file_name,
                  line: file_reader.last_line_number,
                },
                lines: {
                  before: lines_before,
                  matching: line,
                  after: lines_after,
                },
              })

            end

          end

          # save the file's current info in the cache

          file_hash = file_digest.to_s

          file_lines = file_reader.next_line_number

          debug \
            "updating cache mtime %s, size %s, lines %s, " \
            "hash %s" % [
              file_mtime,
              file_size,
              file_lines,
              file_hash,
            ]

          @cache[:files][file_name] = {
            mtime: file_mtime,
            size: file_size,
            lines: file_reader.next_line_number,
            hash: file_hash,
          }

        end

      end

    end

  end

end

#process_args ⇒ Object 



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# File 'lib/hq/log-monitor-client/script.rb', line 29

def process_args

  @opts, @args =
    Tools::Getopt.process @args, [

    { :name => :config,
      :required => true },

    { :name => :debug,
      :boolean => true,
      :required => false },

  ]

  @args.empty? \
    or raise "Extra args on command line"

  @debug = @opts[:debug]

end

#read_cache ⇒ Object 



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# File 'lib/hq/log-monitor-client/script.rb', line 72

def read_cache

  cache_path = @cache_elem["path"]

  if File.exist? cache_path

    @cache =
      YAML.load File.read cache_path

  else

    @cache = {
      files: {},
    }

  end

end

#read_config ⇒ Object 



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# File 'lib/hq/log-monitor-client/script.rb', line 50

def read_config

  config_doc =
    XML::Document.file @opts[:config]

  @config_elem =
    config_doc.root

  @cache_elem =
    @config_elem.find_first("cache")

  @client_elem =
    @config_elem.find_first("client")

  @server_elem =
    @config_elem.find_first("server")

  @service_elems =
    @config_elem.find("service").to_a

end

#submit_event(event) ⇒ Object 



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# File 'lib/hq/log-monitor-client/script.rb', line 345

def submit_event event

  url =
    URI.parse @server_elem["url"]

  http =
    Net::HTTP.new url.host, url.port

  request =
    Net::HTTP::Post.new url.path

  request.body =
    MultiJson.dump event

  response =
    http.request request

end

#write_cache ⇒ Object 



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# File 'lib/hq/log-monitor-client/script.rb', line 91

def write_cache

  cache_path = @cache_elem["path"]
  cache_temp_path = "#{cache_path}.new"

  File.open cache_temp_path, "w" do
    |cache_temp_io|

    cache_temp_io.write YAML.dump @cache
    cache_temp_io.fsync

  end

  File.rename cache_temp_path, cache_path

end