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Versions: 18
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Contents
require "cc/service/invocation/invocation_chain"
require "cc/service/invocation/with_retries"
require "cc/service/invocation/with_metrics"
require "cc/service/invocation/with_error_handling"
require "cc/service/invocation/with_return_values"
class CC::Service::Invocation
MIDDLEWARE = {
retries: WithRetries,
metrics: WithMetrics,
error_handling: WithErrorHandling,
return_values: WithReturnValues,
}.freeze
attr_reader :result
# Build a chain of invocation wrappers which eventually calls receive
# on the given service, then execute that chain.
#
# Order is important. Each call to #with, wraps the last.
#
# Usage:
#
# CC::Service::Invocation.invoke(service) do |i|
# i.with :retries, 3
# i.with :metrics, $statsd
# i.with :error_handling, Rails.logger
# end
#
# In the above example, service.receive could happen 4 times (once,
# then three retries) before an exception is re-raised up to the
# metrics collector, then up again to the error handling. If the order
# were reversed, the error handling middleware would prevent the other
# middleware from seeing any exceptions at all.
def self.invoke(service, &block)
instance = new(service, &block)
instance.result
end
def initialize(service)
@chain = InvocationChain.new { service.receive }
yield(self) if block_given?
@result = @chain.call
end
def with(middleware, *args)
if klass = MIDDLEWARE[middleware]
wrap(klass, *args)
end
end
def wrap(klass, *args)
@chain.wrap(klass, *args)
end
end
Version data entries
18 entries across 18 versions & 1 rubygems