Cache: Create the base of the caching subsystem

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Samantaz Fox 2022-10-23 14:15:16 +02:00
parent 1388d02b31
commit d3b0cb88ca
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9 changed files with 162 additions and 8 deletions

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@ -42,6 +42,24 @@ db:
#########################################
#
# Cache configuration
#
#########################################
cache:
##
## URL of the caching server. To not use a caching server,
## set to an empty string or leave empty.
##
## Note: The same "long" format as the 'db' parameter is
## also supported.
##
url: ""
#########################################
#
# Server config

29
src/invidious/cache.cr Normal file
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@ -0,0 +1,29 @@
require "./cache/*"
module Invidious::Cache
extend self
INSTANCE = self.init(CONFIG.cache)
def init(cfg : Config::CacheConfig) : ItemStore
# Environment variable takes precedence over local config
url = ENV.fetch("INVIDIOUS_CACHE_URL", nil).try { |u| URI.parse(u) }
url ||= cfg.url
url ||= URI.new
# Determine cache type from URL scheme
type = StoreType.parse?(url.scheme || "none") || StoreType::None
case type
when .none?
return NullItemStore.new
when .redis?
if url.nil?
raise InvalidConfigException.new "Redis cache requires an URL."
end
return RedisItemStore.new(url)
else
raise InvalidConfigException.new "Invalid cache url. Only redis:// URL are currently supported."
end
end
end

9
src/invidious/cache/cacheable_item.cr vendored Normal file
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@ -0,0 +1,9 @@
require "json"
module Invidious::Cache
# Including this module allows the includer object to be cached.
# The object will automatically inherit from JSON::Serializable.
module CacheableItem
include JSON::Serializable
end
end

22
src/invidious/cache/item_store.cr vendored Normal file
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@ -0,0 +1,22 @@
require "./cacheable_item"
module Invidious::Cache
# Abstract class from which any cached element should inherit
# Note: class is used here, instead of a module, in order to benefit
# from various compiler checks (e.g methods must be implemented)
abstract class ItemStore
# Retrieves an item from the store
# Returns nil if item wasn't found or is expired
abstract def fetch(key : String, *, as : T.class)
# Stores a given item into cache
abstract def store(key : String, value : CacheableItem, expires : Time::Span)
# Prematurely deletes item(s) from the cache
abstract def delete(key : String)
abstract def delete(keys : Array(String))
# Removes all the items stored in the cache
abstract def clear
end
end

24
src/invidious/cache/null_item_store.cr vendored Normal file
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@ -0,0 +1,24 @@
require "./item_store"
module Invidious::Cache
class NullItemStore < ItemStore
def initialize
end
def fetch(key : String, *, as : T.class) : T? forall T
return nil
end
def store(key : String, value : CacheableItem, expires : Time::Span)
end
def delete(key : String)
end
def delete(keys : Array(String))
end
def clear
end
end
end

36
src/invidious/cache/redis_item_store.cr vendored Normal file
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@ -0,0 +1,36 @@
require "./item_store"
require "json"
require "redis"
module Invidious::Cache
class RedisItemStore < ItemStore
@redis : Redis::PooledClient
@node_name : String
def initialize(url : URI, @node_name = "")
@redis = Redis::PooledClient.new url
end
def fetch(key : String, *, as : T.class) : (T | Nil) forall T
value = @redis.get(key)
return nil if value.nil?
return T.from_json(JSON::PullParser.new(value))
end
def store(key : String, value : CacheableItem, expires : Time::Span)
@redis.set(key, value, ex: expires.to_i)
end
def delete(key : String)
@redis.del(key)
end
def delete(keys : Array(String))
@redis.del(keys)
end
def clear
@redis.flushdb
end
end
end

6
src/invidious/cache/store_type.cr vendored Normal file
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@ -0,0 +1,6 @@
module Invidious::Cache
enum StoreType
None
Redis
end
end

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@ -74,6 +74,8 @@ class Config
# Jobs config structure. See jobs.cr and jobs/base_job.cr
property jobs = Invidious::Jobs::JobsConfig.new
# Cache configuration. See cache/cache.cr
property cache = Invidious::Config::CacheConfig.new
# Used to tell Invidious it is behind a proxy, so links to resources should be https://
property https_only : Bool?
@ -208,14 +210,8 @@ class Config
# Build database_url from db.* if it's not set directly
if config.database_url.to_s.empty?
if db = config.db
config.database_url = URI.new(
scheme: "postgres",
user: db.user,
password: db.password,
host: db.host,
port: db.port,
path: db.dbname,
)
db.scheme = "postgres"
config.database_url = db.to_uri
else
puts "Config: Either database_url or db.* is required"
exit(1)

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@ -0,0 +1,14 @@
require "../cache/store_type"
module Invidious::Config
struct CacheConfig
include YAML::Serializable
@[YAML::Field(converter: IV::Config::URIConverter)]
property url : URI? = URI.new
# Required because of YAML serialization
def initialize
end
end
end