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Merge pull request #2886 from ganmacs/syslog-works-with-time_format
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Syslog parser works with any time format
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@ganmacs
ganmacs committed Mar 24, 2020
2 parents 485ab93 + 8c6b8bd commit 39df11a
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Showing 2 changed files with 156 additions and 71 deletions.
146 changes: 113 additions & 33 deletions lib/fluent/plugin/parser_syslog.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@ module Plugin
class SyslogParser < Parser
Plugin.register_parser('syslog', self)

# TODO: Remove them since these regexps are no longer needed. but keep them for compatibility for now
# From existence TextParser pattern
REGEXP = /^(?<time>[^ ]*\s*[^ ]* [^ ]*) (?<host>[^ ]*) (?<ident>[^ :\[]*)(?:\[(?<pid>[0-9]+)\])?(?:[^\:]*\:)? *(?<message>.*)$/
# From in_syslog default pattern
Expand All @@ -36,8 +37,17 @@ class SyslogParser < Parser
REGEXP_RFC5424_WITH_PRI = Regexp.new(<<~'EOS'.chomp % REGEXP_RFC5424, Regexp::MULTILINE)
\A<(?<pri>[0-9]{1,3})\>[1-9]\d{0,2} %s\z
EOS

REGEXP_DETECT_RFC5424 = /^\<[0-9]{1,3}\>[1-9]\d{0,2}/

RFC3164_WITHOUT_TIME_AND_PRI_REGEXP = /(?<host>[^ ]*) (?<ident>[^ :\[]*)(?:\[(?<pid>[0-9]+)\])?(?:[^\:]*\:)? *(?<message>.*)$/
RFC3164_CAPTURES = RFC3164_WITHOUT_TIME_AND_PRI_REGEXP.names.freeze
RFC3164_PRI_REGEXP = /^<(?<pri>[0-9]{1,3})>/

RFC5424_WITHOUT_TIME_AND_PRI_REGEXP = /(?<host>[!-~]{1,255}) (?<ident>[!-~]{1,48}) (?<pid>[!-~]{1,128}) (?<msgid>[!-~]{1,32}) (?<extradata>(?:\-|(?:\[.*?(?<!\\)\])+))(?: (?<message>.+))?\z/m
RFC5424_CAPTURES = RFC5424_WITHOUT_TIME_AND_PRI_REGEXP.names.freeze
RFC5424_PRI_REGEXP = /^<(?<pri>\d{1,3})>\d\d{0,2}\s/

config_set_default :time_format, "%b %d %H:%M:%S"
desc 'If the incoming logs have priority prefix, e.g. <9>, set true'
config_param :with_priority, :bool, default: false
Expand All @@ -53,6 +63,8 @@ class SyslogParser < Parser
def initialize
super
@mutex = Mutex.new
@space_count = nil
@space_count_rfc5424 = nil
end

def configure(conf)
Expand All @@ -66,21 +78,21 @@ def configure(conf)
when :rfc3164
if @regexp_parser
class << self
alias_method :parse, :parse_plain
alias_method :parse, :parse_rfc3164_regex
end
else
class << self
alias_method :parse, :parse_rfc3164
end
end
@with_priority ? REGEXP_WITH_PRI : REGEXP
RFC3164_WITHOUT_TIME_AND_PRI_REGEXP
when :rfc5424
class << self
alias_method :parse, :parse_plain
alias_method :parse, :parse_rfc5424_regex
end
@time_format = @rfc5424_time_format unless conf.has_key?('time_format')
@support_rfc5424_without_subseconds = true
@with_priority ? REGEXP_RFC5424_WITH_PRI : REGEXP_RFC5424_NO_PRI
RFC5424_WITHOUT_TIME_AND_PRI_REGEXP
when :auto
class << self
alias_method :parse, :parse_auto
Expand All @@ -89,10 +101,14 @@ class << self
@time_parser_rfc5424 = time_parser_create(format: @rfc5424_time_format)
nil
end

@space_count = @time_format.squeeze(' ').count(' ') + 1
@space_count_rfc5424 = @rfc5424_time_format.squeeze(' ').count(' ') + 1
@time_parser = time_parser_create
@time_parser_rfc5424_without_subseconds = time_parser_create(format: "%Y-%m-%dT%H:%M:%S%z")
end

# this method is for tests
def patterns
{'format' => @regexp, 'time_format' => @time_format}
end
Expand All @@ -103,51 +119,115 @@ def parse(text)

def parse_auto(text, &block)
if REGEXP_DETECT_RFC5424.match(text)
@regexp = @with_priority ? REGEXP_RFC5424_WITH_PRI : REGEXP_RFC5424_NO_PRI
@regexp = RFC5424_WITHOUT_TIME_AND_PRI_REGEXP
@time_parser = @time_parser_rfc5424
@support_rfc5424_without_subseconds = true
parse_plain(text, &block)
parse_rfc5424_regex(text, &block)
else
@regexp = @with_priority ? REGEXP_WITH_PRI : REGEXP
@regexp = RFC3164_WITHOUT_TIME_AND_PRI_REGEXP
@time_parser = @time_parser_rfc3164
if @regexp_parser
parse_plain(text, &block)
parse_rfc3164_regex(text, &block)
else
parse_rfc3164(text, &block)
end
end
end

def parse_plain(text, &block)
m = @regexp.match(text)
unless m
yield nil, nil
return
def parse_rfc3164_regex(text, &block)
idx = 0
record = {}

if @with_priority
if RFC3164_PRI_REGEXP.match?(text)
v = text.index('>')
record['pri'] = text[1..v].to_i # trim `<` and ``>
idx = v + 1
else
yield(nil, nil)
return
end
end

time = nil
i = idx - 1
sq = false
@space_count.times do
while text[i + 1] == ' '.freeze
sq = true
i += 1
end

i = text.index(' '.freeze, i + 1)
end

time_str = sq ? text.slice(idx, i - idx).squeeze(' ') : text.slice(idx, i - idx)
time = @mutex.synchronize { @time_parser.parse(time_str) }
if @keep_time_key
record['time'] = time_str
end

parse_plain(time, text, i + 1, record, RFC3164_CAPTURES, &block)
end

def parse_rfc5424_regex(text, &block)
idx = 0
record = {}

m.names.each { |name|
if value = m[name]
if @with_priority
if (m = RFC5424_PRI_REGEXP.match(text))
record['pri'] = m['pri']
idx = m.end(0)
else
yield(nil, nil)
return
end
end

i = idx - 1
sq = false
@space_count_rfc5424.times {
while text[i + 1] == ' '.freeze
sq = true
i += 1
end

i = text.index(' '.freeze, i + 1)
}

time_str = sq ? text.slice(idx, i - idx).squeeze(' '.freeze) : text.slice(idx, i - idx)
time = @mutex.synchronize do
begin
@time_parser.parse(time_str)
rescue Fluent::TimeParser::TimeParseError => e
if @support_rfc5424_without_subseconds
log.trace(e)
@time_parser_rfc5424_without_subseconds.parse(time_str)
else
raise
end
end
end

if @keep_time_key
record['time'] = time_str
end
parse_plain(time, text, i + 1, record, RFC5424_CAPTURES, &block)
end

# @param time [EventTime]
# @param idx [Integer] note: this argument is needed to avoid string creation
# @param record [Hash]
# @param capture_list [Array] for performance
def parse_plain(time, text, idx, record, capture_list, &block)
m = @regexp.match(text, idx)
if m.nil?
yield nil, nil
return
end

capture_list.each { |name|
if value = (m[name] rescue nil)
case name
when "pri"
record['pri'] = value.to_i
when "time"
time = @mutex.synchronize do
time_str = value.squeeze(' ')
begin
@time_parser.parse(time_str)
rescue Fluent::TimeParser::TimeParseError => e
if @support_rfc5424_without_subseconds
log.trace(e)
@time_parser_rfc5424_without_subseconds.parse(time_str)
else
raise
end
end
end
record[name] = value if @keep_time_key
when "message"
value.chomp!
record[name] = value
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