module RedisCopy

The Classic strategy borrows heavily from the utils/redis-copy.rb found in Redis source, which is also the inspiration for this gem.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright
  notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
  notice, this list of conditions and the following disclaimer in
  the documentation and/or other materials provided with the
  distribution.
* Neither the name of Redis nor the names of its contributors may
  be used to endorse or promote products derived from this software
  without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Constants

VERSION

Public Class Methods

copy(source, destination, options = {}) click to toggle source

@param source [String] @param destination [String] @options options [Hash<Symbol,Object>]

# File lib/redis-copy.rb, line 18
    def copy(source, destination, options = {})
      ui = UI.new(options)

      source = redis_from(source)
      destination = redis_from(destination)

      ui.abort('source cannot equal destination!') if same_redis?(source, destination)

      key_emitter = KeyEmitter.new(source, ui, options)
      strategem = Strategy.new(source, destination, ui, options)

      dest_empty = !(destination.randomkey) # randomkey returns string unless db empty.

      return false unless ui.confirm? <<-EODESC.strip_heredoc
        Source:      #{source.client.id}
        Destination: #{destination.client.id} (#{dest_empty ? '' : 'NOT '}empty)
        Pattern:     #{options[:pattern]}
        Key Emitter: #{key_emitter}
        Strategy:    #{strategem}
      EODESC

      ui.abort('Destination not empty!') unless dest_empty or options[:allow_nonempty]

      key_emitter.keys.each_with_object(Hash.new {0}) do |key, stats|
        success = strategem.copy(key)
        stats[success ? :success : :failure] += 1
        stats[:attempt] += 1

        unless success
          ui.notify("FAIL: #{key.dump}")
          ui.abort if options[:fail_fast]
        end

        probably(options[:verify]) do
          if strategem.verify?(key)
            stats[:verified] += 1
          else
            stats[:borked] += 1
            ui.notify("BORK: #{key.dump}")
            ui.abort if options[:fail_fast]
          end
        end

        ui.notify("PROGRESS: #{stats.inspect}") if (stats[:attempt] % 1000).zero?
      end.tap do |stats|
        ui.notify("DONE: #{stats.inspect}")
      end
    rescue Implements::Implementation::NotFound => e
      ui.notify(e.to_s)
      ui.abort
    end

Private Class Methods

probably(probability) { || ... } click to toggle source

yields the block, probably. @param probability [Integer] 0-100 @return [void] used by ::copy in determining whether to verify.

# File lib/redis-copy.rb, line 76
def probably(probability)
  return if probability.zero?
  if probability >= 100 || (Random::rand(100) % 100) < probability
    yield
  end
end

redis_from(connection_string) click to toggle source

# File lib/redis-copy.rb, line 89
def redis_from(connection_string)
  require 'uri'
  connection_string = "redis://#{connection_string}" unless connection_string.start_with?("redis://")
  uri = URI(connection_string)
  ret = {uri: uri}

  # Require the URL to have at least a host
  raise ArgumentError, "invalid url: #{connection_string}" unless uri.host

  host = uri.host
  port = uri.port if uri.port
  db = uri.path ? uri.path[1..-1].to_i : 0
  password = uri.password

  # Connect & Ping to ensure access.
  Redis.new(host: host, port: port, db: db, password: password).tap(&:ping)
rescue Redis::CommandError => e
  fail(Redis::CommandError,
       "There was a problem connecting to #{uri.to_s}\n#{e.message}")
end

same_redis?(redis_a, redis_b) click to toggle source

# File lib/redis-copy.rb, line 83
def same_redis?(redis_a, redis_b)
  # Redis::Client#id returns the connection uri
  # e.g. 'redis://localhost:6379/0'
  redis_a.client.id == redis_b.client.id
end