With new rails and ruby minimum versions

gem 'github-ds'

$ bundle

$ gem install github-ds

rails generate github:ds:active_record
rails db:migrate

GitHub::KV.configure do |config|
  config.table_name = "new_key_values_table"
end

require "pp"

# Create new instance using ActiveRecord's default connection.
kv = GitHub::KV.new { ActiveRecord::Base.connection }

# Get a key.
pp kv.get("foo")
#<GitHub::Result:0x3fd88cd3ea9c value: nil>

# Set a key.
kv.set("foo", "bar")
# nil

# Get the key again.
pp kv.get("foo")
#<GitHub::Result:0x3fe810d06e4c value: "bar">

# Get multiple keys at once.
pp kv.mget(["foo", "bar"])
#<GitHub::Result:0x3fccccd1b57c value: ["bar", nil]>

# Check for existence of a key.
pp kv.exists("foo")
#<GitHub::Result:0x3fd4ae55ce8c value: true>

# Check for existence of key that does not exist.
pp kv.exists("bar")
#<GitHub::Result:0x3fd4ae55c554 value: false>

# Check for existence of multiple keys at once.
pp kv.mexists(["foo", "bar"])
#<GitHub::Result:0x3ff1e98e18e8 value: [true, false]>

# Set a key's value if the key does not already exist.
pp kv.setnx("foo", "bar")
# false

# Delete a key.
pp kv.del("bar")
# nil

# Delete multiple keys at once.
pp kv.mdel(["foo", "bar"])
# nil

# Select, insert, update, delete or whatever you need...
GitHub::SQL.results <<-SQL
  SELECT * FROM example_key_values
SQL

GitHub::SQL.run <<-SQL, key: "foo", value: "bar"
  INSERT INTO example_key_values (`key`, `value`)
  VALUES (:key, :value)
SQL

GitHub::SQL.value <<-SQL, key: "foo"
  SELECT value FROM example_key_values WHERE `key` = :key
SQL

# Or slowly build up a query based on conditionals...
sql = GitHub::SQL.new <<-SQL
  SELECT `value` FROM example_key_values
SQL

key = ENV["KEY"]
unless key.nil?
  sql.add <<-SQL, key: key
    WHERE `key` = :key
  SQL
end

limit = ENV["LIMIT"]
unless limit.nil?
  sql.add <<-SQL, limit: limit.to_i
    ORDER BY `key` ASC
    LIMIT :limit
  SQL
end

p sql.results

def do_something
  1
end

def do_something_that_errors
  raise "noooooppppeeeee"
end

result = GitHub::Result.new { do_something }
p result.ok? # => true
p result.value! # =>1

result = GitHub::Result.new { do_something_that_errors }
p result.ok? # => false
p result.value { "default when error happens" } # => "default when error happens"
begin
  result.value! # raises exception because error happened
rescue => error
  p result.error
  p error
end

# Outputs Step 1, 2, 3
result = GitHub::Result.new {
  GitHub::Result.new { puts "Step 1: success!" }
}.then { |value|
  GitHub::Result.new { puts "Step 2: success!" }
}.then { |value|
  GitHub::Result.new { puts "Step 3: success!" }
}
p result.ok? # => true

# Outputs Step 1, 2 and stops.
result = GitHub::Result.new {
  GitHub::Result.new { puts "Step 1: success!" }
}.then { |value|
  GitHub::Result.new {
    puts "Step 2: failed!"
    raise
  }
}.then { |value|
  GitHub::Result.new {
    puts "Step 3: should not get here because previous step failed!"
  }
}
p result.ok? # => false