Replace Rails log with json format, then convert each json entries from the log file to csv.

log_json_to_csv.rb

require 'json'
require 'csv'

SAMPLE_DATA = {"key1": "value1", "key2": "value2", "key3": "value3"}

headers = JSON.parse(SAMPLE_DATA).keys
input_lines = File.readlines "path/to/log/file"
parsed_line = 0

csv_file = CSV.open "path/to/file.csv", "w"
csv_file << headers

input_lines.each do |line|
  begin
    record = JSON.parse line
    csv_file << headers.map {|h| record[h]}
    parsed_line += 1
  rescue
  end
end

puts "TOTAL LINES: #{input_lines.length}"
puts "PARSED LINES: #{parsed_line}"
puts "UNPARSED LINES: #{input_lines.length - parsed_line}"