95 lines
2.9 KiB
Ruby
95 lines
2.9 KiB
Ruby
module Gitlab
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module RepositoryCacheAdapter
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extend ActiveSupport::Concern
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class_methods do
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# Wraps around the given method and caches its output in Redis and an instance
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# variable.
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#
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# This only works for methods that do not take any arguments.
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def cache_method(name, fallback: nil, memoize_only: false)
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original = :"_uncached_#{name}"
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alias_method(original, name)
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define_method(name) do
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cache_method_output(name, fallback: fallback, memoize_only: memoize_only) do
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__send__(original) # rubocop:disable GitlabSecurity/PublicSend
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end
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end
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end
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end
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# RepositoryCache to be used. Should be overridden by the including class
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def cache
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raise NotImplementedError
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end
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# List of cached methods. Should be overridden by the including class
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def cached_methods
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raise NotImplementedError
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end
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# Caches the supplied block both in a cache and in an instance variable.
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#
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# The cache key and instance variable are named the same way as the value of
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# the `key` argument.
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#
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# This method will return `nil` if the corresponding instance variable is also
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# set to `nil`. This ensures we don't keep yielding the block when it returns
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# `nil`.
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#
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# key - The name of the key to cache the data in.
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# fallback - A value to fall back to in the event of a Git error.
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def cache_method_output(key, fallback: nil, memoize_only: false, &block)
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ivar = cache_instance_variable_name(key)
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if instance_variable_defined?(ivar)
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instance_variable_get(ivar)
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else
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# If the repository doesn't exist and a fallback was specified we return
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# that value inmediately. This saves us Rugged/gRPC invocations.
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return fallback unless fallback.nil? || cache.repository.exists?
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begin
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value =
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if memoize_only
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yield
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else
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cache.fetch(key, &block)
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end
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instance_variable_set(ivar, value)
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rescue Gitlab::Git::Repository::NoRepository
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# Even if the above `#exists?` check passes these errors might still
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# occur (for example because of a non-existing HEAD). We want to
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# gracefully handle this and not cache anything
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fallback
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end
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end
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end
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# Expires the caches of a specific set of methods
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def expire_method_caches(methods)
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methods.each do |key|
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unless cached_methods.include?(key.to_sym)
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Rails.logger.error "Requested to expire non-existent method '#{key}' for Repository"
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next
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end
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cache.expire(key)
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ivar = cache_instance_variable_name(key)
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remove_instance_variable(ivar) if instance_variable_defined?(ivar)
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end
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end
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private
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def cache_instance_variable_name(key)
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:"@#{key.to_s.tr('?!', '')}"
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end
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end
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end
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