class Kredis::Migration

Constants

SCAN_BATCH_SIZE

Public Class Methods

new(config = :shared) click to toggle source
# File lib/kredis/migration.rb, line 6
def initialize(config = :shared)
  @redis = Kredis.configured_for config
  # TODO: Replace script loading with `copy` command once Redis 6.2+ is the minimum supported version.
  @copy_sha = @redis.script "load", "redis.call('SETNX', KEYS[2], redis.call('GET', KEYS[1])); return 1;"
end

Public Instance Methods

delete_all(key_pattern) click to toggle source
# File lib/kredis/migration.rb, line 33
def delete_all(key_pattern)
  each_key_batch_matching(key_pattern) do |keys|
    @redis.del *keys
  end
end
migrate(from:, to:) click to toggle source
# File lib/kredis/migration.rb, line 21
def migrate(from:, to:)
  namespaced_to = Kredis.namespaced_key(to)

  if to.present? && from != namespaced_to
    log_migration "Migrating key #{from} to #{namespaced_to}" do
      @redis.evalsha @copy_sha, keys: [ from, namespaced_to ]
    end
  else
    log_migration "Skipping blank/unaltered migration key #{from} → #{to}"
  end
end
migrate_all(key_pattern) { |key, *ids| ... } click to toggle source
# File lib/kredis/migration.rb, line 12
def migrate_all(key_pattern)
  each_key_batch_matching(key_pattern) do |keys|
    keys.each do |key|
      ids = key.scan(/\d+/).map(&:to_i)
      migrate from: key, to: yield(key, *ids)
    end
  end
end

Private Instance Methods

each_key_batch_matching(key_pattern) { |keys| ... } click to toggle source
# File lib/kredis/migration.rb, line 42
def each_key_batch_matching(key_pattern, &block)
  cursor = "0"
  begin
    cursor, keys = @redis.scan(cursor, match: key_pattern, count: SCAN_BATCH_SIZE)
    @redis.pipelined { yield keys }
  end until cursor == "0"
end
log_migration(message, &block) click to toggle source
# File lib/kredis/migration.rb, line 50
def log_migration(message, &block)
  Kredis.instrument :migration, message: message, &block
end