Class: LogStash::Filters::Hashtree

Inherits:
Base
  • Object
show all
Defined in:
lib/logstash/filters/hashtree.rb

Overview

Combine fingerprints of one field of consecutive messages.

Instance Method Summary collapse

Instance Method Details

#filter(event) ⇒ Object 



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# File 'lib/logstash/filters/hashtree.rb', line 33

def filter(event)
  fingerprint = fingerprint(event.get(@source))
  File.open(@file, File::RDWR|File::CREAT, 0644) {|f|
    f.flock(File::LOCK_EX)
    event.set(@previous, previous = f.read)
    event.set(@target, combined = fingerprint(fingerprint + previous))
    f.rewind
    f.write(combined)
  }
  filter_matched(event)
end

#fingerprint(data) ⇒ Object 



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# File 'lib/logstash/filters/hashtree.rb', line 45

def fingerprint(data)
  # since OpenSSL::Digest instances aren't thread safe, we must ensure that
  # each pipeline worker thread gets its own instance.
  # Also, since a logstash pipeline may contain multiple fingerprint filters
  # we must include the id in the thread local variable name, so that we can
  # store multiple digest instances
  digest_string = "digest-#{id}"
  Thread.current[digest_string] ||= select_digest(@method)
  digest = Thread.current[digest_string]
  # in JRuby 1.7.11 outputs as ASCII-8BIT
  digest.hexdigest(data.to_s).force_encoding(Encoding::UTF_8)
end

#register ⇒ Object 



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# File 'lib/logstash/filters/hashtree.rb', line 27

def register
  # convert to symbol for faster comparisons
  @method = @method.to_sym
end

#select_digest(method) ⇒ Object 



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# File 'lib/logstash/filters/hashtree.rb', line 58

def select_digest(method)
  case method
  when :SHA1
    OpenSSL::Digest::SHA1.new
  when :SHA256
    OpenSSL::Digest::SHA256.new
  when :SHA384
    OpenSSL::Digest::SHA384.new
  when :SHA512
    OpenSSL::Digest::SHA512.new
  when :MD5
    OpenSSL::Digest::MD5.new
  else
    # we really should never get here
    raise(LogStash::ConfigurationError, "Unknown digest for method=#{method.to_s}")
  end
end