Cacheman

Cacheman is a Redis backed Rails.cache equivalent for Elixir applications.

The primary API for using Cacheman is Cacheman.fetch.

Install

Add Cacheman to your mix file

defp deps do
  [
    {:cacheman, github: "renderedtext/ex-cacheman"}
  ]
end

How to use

Add an instance of cache to your app's supervisor:

  cache_name = :app
  cache_opts = %{
    prefix: "example/",       # every key in the cache store will be prefixed with example/
    backend: %{
      type: :redis,           # redis for backend
      host: "localhost",      # redis instance is listening on localhost
      port: 6379,             # redis instance is listening on port 6379
      pool_size: 5            # 5 parallel connections are established to the cache server
    }
  }

  children = [
    {Cacheman, [cache_name, cache_opts]}
  ]

Fetch from the Cache, with a fallback function in case the entry is not found:

{:ok, dash} = Cacheman.fetch(:app, "users-#{user.id}-dashboard", fn ->
  {:ok, dashboard} = render_dashboard(user)
end)

The fallback function saves everything into the cache that has the {:ok, value} format.

Advanced usage (TTL, and low level get/put APIs)

TTL for entries:

{:ok, dash} = Cacheman.fetch(:app, "users-#{user.id}-dashboard", ttl: :timer.hours(6), fn -> render_dashboard(user) end)

Get a key:

{:ok, entry} = Cacheman.get(:app, "user-#{user.id}-dashboard")

Put values in cache:

{:ok, dashboard} = render_dashboard(user)

{:ok, _} = Cacheman.put(:app, "user-#{user.id}-dashboard", dashboard, ttl: :timer.hours(6))

Multiplexing caches

Every Cacheman instance must define a cache key prefix. This allows multiplexing of caches across multiple clients or areas of work.

Example, a dedicated namespace for user caches and project caches:

{:ok, _} = Cacheman.start_link(:user, %{
  prefix: "users/",
  backend: %{
    type: :redis,
    host: "redis",
    port: 6379,
    pool_size: 5
  }
})

{:ok, _} = Cacheman.start_link(:project, %{
  prefix: "projects/",
  backend: %{
    type: :redis,
    host: "redis",
    port: 6379,
    pool_size: 5
  }
})

License

Copyright 2020 Rendered Text

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.