Class: RedisCopy::KeyEmitter::Keys

Inherits:
Object
  • Object
show all
Defined in:
lib/redis-copy/key-emitter/keys.rb

Overview

Keys uses the KEYS command, which has always been available in Redis, but comes with a rather staunch warning to never use it in production. This is the first-required implementation of KeyEmitter, and is thus the fallback for no other emitters are available. A Warning Prompt will appear if your dbsize is greater than 10,000 keys.

Instance Method Summary collapse

Instance Method Details

#keys ⇒ Object 



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# File 'lib/redis-copy/key-emitter/keys.rb', line 12

def keys
  dbsize = self.dbsize

  # HT: http://stackoverflow.com/a/11466770
  dbsize_str = dbsize.to_s.reverse.gsub(/(\d{3})(?=\d)/, '\\1,').reverse

  @ui.abort unless (dbsize < 10_000) || (@ui.confirm? <<-EOWARNING.strip_heredoc)
    WARNING: #{self} key emitter uses redis.keys('*') to
    get its list of keys, and you have #{dbsize_str} keys in
    your source DB.

    The redis keys command [reference](http://redis.io/commands/keys)
    says this:

    > Warning: consider KEYS as a command that should only be used
    > in production environments with extreme care. It may ruin
    > performance when it is executed against large databases.
    > This command is intended for debugging and special operations,
    > such as changing your keyspace layout. Don't use KEYS in your
    > regular application code. If you're looking for a way to find
    > keys in a subset of your keyspace, consider using sets.
  EOWARNING

  @ui.debug "REDIS: #{@redis.client.id} KEYS #{pattern}"
  @redis.keys(pattern).to_enum
end