Contents

module Prick
  class Diff
    def initialize(db1, db2)
      @db1, @db2 = db1, db2
      @diffed = false
      @diff = nil
      @result = nil
    end

    def self.same?(db1, db2) Diff.new(db1, db2).same? end

    # Return true if the two databases are equal. Named #same? to avoid name
    # collision with the built in #equal?
    def same?
      do_diff if @result.nil?
      @result
    end

    # Return the diff between the two databases or nil if they're equal
    def read
      @diffed ? @diff : do_diff
    end

    # Write the diff between the databases to the given file. Return true if
    # the databases are equal
    def write(file)
      if @diffed
        IO.write(file, @diff)
      else
        do_diff(file)
      end
      @result
    end

  private
    def do_diff(file = nil)
      file_arg = file ? ">#{file}" : ""
      command = "migra --unsafe postgres:///#{@db1} postgres:///#{@db2} #{file_arg}"
      stdout = Command.command command, fail: false
      [0,2].include? Command.status or 
          raise Fail, "migra command failed with status #{Command.status}: #{command}"
      @result = Command.status == 0
      @diffed = !file
      @diff = @diffed && !@result ? stdout : nil
    end
  end
end

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
prick-0.4.0	lib/prick/diff.rb
prick-0.3.0	lib/prick/diff.rb