Utility functions for performing operations on large Redis keyspaces

keys.rb

require 'redis'

REDIS = Redis.new( url: "..." )

def each_keys_chunk( pattern = nil, &block )
  opts = { count: 100 }
  opts[:match] = pattern if pattern
  cursor = 0
  loop do
    cursor, keys = REDIS.scan( cursor, opts )
    yield keys unless keys.size == 0
    break if cursor.to_i == 0
  end
end

def count_keys( pattern )
  count = 0
  each_keys_chunk( pattern ) { |keys| count += keys.size }
  count
end

def del_keys( pattern )
  count = 0
  each_keys_chunk( pattern ) do |keys|
    REDIS.pipelined do
      keys.each { |key| REDIS.del( key ) }
    end
    count += keys.size
    puts "Deleted #{count} keys"
  end
  puts "Done! Deleted #{count} keys"
end

def expire_keys( pattern, expiration )
  count = 0
  each_keys_chunk( pattern ) do |keys|
    REDIS.pipelined do
      keys.each { |key| REDIS.expire( key, expiration ) }
    end
    count += keys.size
    puts "Set TTL on #{count} keys"
  end
  puts "Done! Set TTL on #{count} keys"
end