Feature: Global Config helper (#844) (#845)

* Added a global config helper to easily access installation/global configs
  * this will fetch the keys from cache with fallback to DB on cache miss
  * ability to query multiple keys simultaneously
  * interface to delete the existing global config cache
* Added tests for this new helper module
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Sony Mathew 2020-05-11 19:00:33 +05:30 committed by GitHub
parent 6e0f02a38b
commit 8859880e55
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@ -30,6 +30,7 @@ Style/GlobalVars:
Exclude:
- 'config/initializers/redis.rb'
- 'lib/redis/alfred.rb'
- 'lib/global_config.rb'
Metrics/BlockLength:
Exclude:
- spec/**/*

44
lib/global_config.rb Normal file
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@ -0,0 +1,44 @@
class GlobalConfig
VERSION = 'V1'.freeze
KEY_PREFIX = 'GLOBAL_CONFIG'.freeze
DEFAULT_EXPIRY = 1.day
class << self
def get(*args)
config_keys = *args
config = {}
config_keys.each do |config_key|
config[config_key] = load_from_cache(config_key)
end
config.with_indifferent_access
end
def clear_cache
cached_keys = $alfred.keys("#{VERSION}:#{KEY_PREFIX}:*")
(cached_keys || []).each do |cached_key|
$alfred.expire(cached_key, 0)
end
end
private
def load_from_cache(config_key)
cache_key = "#{VERSION}:#{KEY_PREFIX}:#{config_key}"
cached_value = $alfred.get(cache_key)
if cached_value.blank?
value_from_db = db_fallback(config_key)
cached_value = { value: value_from_db }.to_json
$alfred.set(cache_key, cached_value, { expiry: DEFAULT_EXPIRY })
end
JSON.parse(cached_value)['value']
end
def db_fallback(config_key)
InstallationConfig.find_by(name: config_key)&.value
end
end
end

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@ -0,0 +1,39 @@
require 'rails_helper'
describe GlobalConfig do
subject(:trigger) { described_class }
describe 'execute' do
context 'when called with default options' do
before do
described_class.clear_cache
end
it 'hit DB for the first call' do
expect(InstallationConfig).to receive(:find_by)
described_class.get('test')
end
it 'get from cache for subsequent calls' do
# this loads from DB
described_class.get('test')
# subsequent calls should not hit DB
expect(InstallationConfig).not_to receive(:find_by)
described_class.get('test')
end
it 'clears cache and fetch from DB next time, when clear_cache is called' do
# this loads from DB and is cached
described_class.get('test')
# clears the cache
described_class.clear_cache
# should be loaded from DB
expect(InstallationConfig).to receive(:find_by).with({ name: 'test' }).and_return(nil)
described_class.get('test')
end
end
end
end