Module: Taps::Utils

Extended by:
Utils
Included in:
Utils
Defined in:
lib/taps/utils.rb

Instance Method Summary collapse

Instance Method Details

#blobs_to_string(row, columns) ⇒ Object 



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# File 'lib/taps/utils.rb', line 58

def blobs_to_string(row, columns)
	return row if columns.size == 0
	columns.each do |c|
		row[c] = row[c].to_s if row[c].kind_of?(Sequel::SQL::Blob)
	end
	row
end

#calculate_chunksize(old_chunksize) ⇒ Object 



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# File 'lib/taps/utils.rb', line 66

def calculate_chunksize(old_chunksize)
	chunksize = old_chunksize

	retries = 0
	begin
		t1 = Time.now
		yield chunksize
	rescue Errno::EPIPE
		retries += 1
		raise if retries > 1
		# we got disconnected, the chunksize could be too large
		# so we're resetting to a very small value
		chunksize = 100
		retry
	end

	t2 = Time.now

	diff = t2 - t1
	new_chunksize = if diff > 3.0
		(chunksize / 3).ceil
	elsif diff > 1.1
		chunksize - 100
	elsif diff < 0.8
		chunksize * 2
	else
		chunksize + 100
	end
	new_chunksize = 100 if new_chunksize < 100
	new_chunksize
end

#checksum(data) ⇒ Object 



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# File 'lib/taps/utils.rb', line 10

def checksum(data)
	Zlib.crc32(data)
end

#format_data(data, string_columns) ⇒ Object 



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# File 'lib/taps/utils.rb', line 34

def format_data(data, string_columns)
	return {} if data.size == 0
	header = data[0].keys
	only_data = data.collect do |row|
		row = blobs_to_string(row, string_columns)
		header.collect { |h| row[h] }
	end
	{ :header => header, :data => only_data }
end

#gunzip(gzip_data) ⇒ Object 



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# File 'lib/taps/utils.rb', line 26

def gunzip(gzip_data)
	io = StringIO.new(gzip_data)
	gz = Zlib::GzipReader.new(io)
	data = gz.read
	gz.close
	data
end

#gzip(data) ⇒ Object 



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# File 'lib/taps/utils.rb', line 18

def gzip(data)
	io = StringIO.new
	gz = Zlib::GzipWriter.new(io)
	gz.write data
	gz.close
	io.string
end

#incorrect_blobs(db, table) ⇒ Object

mysql text and blobs fields are handled the same way internally this is not true for other databases so we must check if the field is actually text and manually convert it back to a string



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# File 'lib/taps/utils.rb', line 47

def incorrect_blobs(db, table)
	return [] unless db.class.to_s == "Sequel::MySQL::Database"

	columns = []
	db.schema(table).each do |data|
		column, cdata = data
		columns << column if cdata[:db_type] =~ /text/
	end
	columns
end

#order_by(db, table) ⇒ Object 



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# File 'lib/taps/utils.rb', line 106

def order_by(db, table)
	pkey = primary_key(db, table)
	if pkey
		[pkey.to_sym]
	else
		db[table].columns
	end
end

#primary_key(db, table) ⇒ Object 



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# File 'lib/taps/utils.rb', line 98

def primary_key(db, table)
	if db.respond_to?(:primary_key)
		db.primary_key(table)
	else
		db.schema(table).select { |c| c[1][:primary_key] }.map { |c| c.first }.shift
	end
end

#valid_data?(data, crc32) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/taps/utils.rb', line 14

def valid_data?(data, crc32)
	Zlib.crc32(data) == crc32.to_i
end