94 lines
2.8 KiB
Ruby
94 lines
2.8 KiB
Ruby
module Gitlab
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module Cache
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# This module provides a simple way to cache values in RequestStore,
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# and the cache key would be based on the class name, method name,
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# optionally customized instance level values, optionally customized
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# method level values, and optional method arguments.
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#
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# A simple example:
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#
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# class UserAccess
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# extend Gitlab::Cache::RequestCache
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#
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# request_cache_key do
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# [user&.id, project&.id]
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# end
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#
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# request_cache def can_push_to_branch?(ref)
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# # ...
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# end
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# end
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#
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# This way, the result of `can_push_to_branch?` would be cached in
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# `RequestStore.store` based on the cache key. If RequestStore is not
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# currently active, then it would be stored in a hash saved in an
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# instance variable, so the cache logic would be the same.
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# Here's another example using customized method level values:
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#
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# class Commit
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# extend Gitlab::Cache::RequestCache
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#
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# def author
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# User.find_by_any_email(author_email.downcase)
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# end
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# request_cache(:author) { author_email.downcase }
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# end
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#
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# So that we could have different strategies for different methods
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#
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module RequestCache
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def self.extended(klass)
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return if klass < self
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extension = Module.new
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klass.const_set(:RequestCacheExtension, extension)
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klass.prepend(extension)
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end
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def request_cache_key(&block)
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if block_given?
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@request_cache_key = block
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else
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@request_cache_key
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end
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end
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def request_cache(method_name, &method_key_block)
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const_get(:RequestCacheExtension).module_eval do
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cache_key_method_name = "#{method_name}_cache_key"
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define_method(method_name) do |*args|
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store =
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if RequestStore.active?
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RequestStore.store
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else
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ivar_name = # ! and ? cannot be used as ivar name
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"@cache_#{method_name.to_s.tr('!?', "\u2605\u2606")}"
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instance_variable_get(ivar_name) ||
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instance_variable_set(ivar_name, {})
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end
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key = __send__(cache_key_method_name, args)
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store.fetch(key) { store[key] = super(*args) }
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end
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define_method(cache_key_method_name) do |args|
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klass = self.class
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instance_key = instance_exec(&klass.request_cache_key) if
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klass.request_cache_key
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method_key = instance_exec(&method_key_block) if method_key_block
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[klass.name, method_name, *instance_key, *method_key, *args]
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.join(':')
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end
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private cache_key_method_name
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end
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end
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end
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end
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end
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