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