Kredis
Kredis (Keyed Redis) encapsulates higher-level types and data structures around a single key, so you can interact with them as coherent objects rather than isolated procedural commands. These higher-level structures can be configured as attributes within Active Models and Active Records using a declarative DSL.
Kredis is configured using env-aware YAML files, using Rails.application.config_for
, so you can locate the data structures on separate Redis instances, if you’ve reached a scale where a single shared instance is no longer sufficient.
Kredis provides namespacing support for keys such that you can safely run parallel testing against the data structures without different tests trampling each others data.
Examples
Kredis provides typed scalars for strings, integers, decimals, floats, booleans, datetimes, and JSON hashes:
“by string = Kredis.string “mystring” string.value = “hello world!” # => SET mystring “hello world” “hello world!” == string.value # => GET mystring
integer = Kredis.integer “myinteger” integer.value = 5 # => SET myinteger “5” 5 == integer.value # => GET myinteger
json = Kredis.json “myjson” json.value = { “one” => 1, “two” => “2” } # => SET myjson “"one":1,"two":"2"” { “one” => 1, “two” => “2” } == json.value # => GET myjson
“
There are data structures for counters, enums, flags, lists, unique lists, sets, and slots:
“by list = Kredis.list “mylist” list « “hello world!” [hello world!] == list.elements
integer_list = Kredis.list “myintegerlist”, typed: :integer integer_list.append([1, 2, 3]) # => LPUSH myintegerlist “1” “2” “3” integer_list « 4 # => LPUSH myintegerlist “4” [1, 2, 3, 4] == integer_list.elements # LRANGE 0 -1
unique_list = Kredis.unique_list “myuniquelist” unique_list.append(%w[2 3 4]) unique_list.prepend(%w[1 2 3 4]) unique_list.append([]) unique_list « “5” unique_list.remove(3) [1, 2, 4, 5] == unique_list.elements
set = Kredis.set “myset”, typed: :datetime set.add(DateTime.tomorrow, DateTime.yesterday) # => SADD myset “2021-02-03 00:00:00 +0100” “2021-02-01 00:00:00 +0100” set « DateTime.tomorrow # => SADD myset “2021-02-03 00:00:00 +0100” 2 == set.size # => SCARD myset [DateTime.tomorrow, DateTime.yesterday] == set.elements # => SMEMBERS myset
head_count = Kredis.counter “headcount” 0 == head_count.value # => GET “headcount” head_count.increment head_count.increment head_count.decrement 1 == head_count.value # => GET “headcount”
counter = Kredis.counter “mycounter”, expires_in: 5.seconds counter.increment by: 2 # => SETEX “mycounter” 900 0 + INCR “mycounter” 2 2 == counter.value # => GET “mycounter” sleep 6.seconds 0 == counter.value # => GET “mycounter”
enum = Kredis.enum “myenum”, values: %w[one two three], default: “one” “one” == enum.value true == enum.one? enum.value = “two” “two” == enum.value enum.value = “four” “two” == enum.value enum.reset “one” == enum.value
slots = Kredis.slots “myslots”, available: 3 true == slots.available? slots.reserve true == slots.available? slots.reserve true == slots.available? slots.reserve true == slots.available? slots.reserve false == slots.available? slots.release true == slots.available? slots.reset
flag = Kredis.flag “myflag” false == flag.marked? flag.mark true == flag.marked? flag.remove false == flag.marked?
flag.mark(expires_in: 1.second) true == flag.marked? sleep 0.5.seconds true == flag.marked? sleep 0.6.seconds false == flag.marked?
“
And using structures on a different than the default shared
redis instance, relying on config/redis/secondary.yml
:
“by one_string = Kredis.string “mystring” two_string = Kredis.string “mystring”, config: :secondary
one_string.value = “just on shared” two_string.value != one_string.value
“
You can use all these structures in models:
“by class Person < ApplicationRecord kredis_list :names kredis_list :names_with_custom_key, key: ->(p) { “person:#pp.id:names_customized” } kredis_unique_list :skills, limit: 2 kredis_enum :morning, values: %w[bright blue black], default: “bright” end
person = Person.find(5) person.names.append “David”, “Heinemeier”, “Hansson” # => SADD person:5:names “David” “Heinemeier” “Hansson” true == person.morning.bright? person.morning.value = “blue” true == person.morning.blue?
“
Installation
- Add the
kredis
gem to your Gemfile:gem 'kredis'
- Run
./bin/bundle install
- Add a default configuration under
config/redis/shared.yml
A default configuration can look like this for config/redis/shared.yml
:
“ml production: &production host: <%= ENV.fetch(“REDIS_SHARED_HOST”, “127.0.0.1”) %> port: <%= ENV.fetch(“REDIS_SHARED_PORT”, “6379”) %> timeout: 1
development: &development host: <%= ENV.fetch(“REDIS_SHARED_HOST”, “127.0.0.1”) %> port: <%= ENV.fetch(“REDIS_SHARED_PORT”, “6379”) %> timeout: 1
test: «: development
“
Additional configurations can be added under config/redis/*.yml
and referenced when a type is created, e.g. Kredis.string("mystring", config: :strings)
would lookup config/redis/strings.yml
. Under the hood Kredis.configured_for
is called which’ll pass the configuration on to Redis.new
.
License
Kredis is released under the MIT License.