Class: Google::Cloud::Core::GrpcBackoff

Inherits:
Object
  • Object
show all
Defined in:
lib/google/cloud/core/backoff.rb,
lib/google/cloud/core/grpc_backoff.rb

Overview

Backoff allows users to control how Google API calls are retried. If an API call fails the response will be checked to see if the call can be retried. If the response matches the criteria, then it will be retried with an incremental backoff. This means that an increasing delay will be added between each retried call. The first retry will be delayed one second, the second retry will be delayed two seconds, and so on.

Class Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ GrpcBackoff

Creates a new Backoff object to catch common errors when calling the Google API and handle the error by retrying the call.

Google::Cloud::Core::GrpcBackoff.new(options).execute do
  datastore.lookup lookup_ref
end



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# File 'lib/google/cloud/core/backoff.rb', line 66

def initialize options = {}
  @retries    = (options[:retries]    || GrpcBackoff.retries).to_i
  @grpc_codes = (options[:grpc_codes] || GrpcBackoff.grpc_codes).to_a
  @backoff    =  options[:backoff]    || GrpcBackoff.backoff
end

Class Attribute Details

.backoff ⇒ Object

The code to run when a backoff is handled. This must be a Proc and must take the number of retries as an argument.

Note: This method is undocumented and may change.



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# File 'lib/google/cloud/core/backoff.rb', line 51

def backoff
  @backoff
end

.grpc_codes ⇒ Object

The GRPC Status Codes that should be retried.

The default values are ‘14`.



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# File 'lib/google/cloud/core/backoff.rb', line 43

def grpc_codes
  @grpc_codes
end

.retries ⇒ Object

The number of times a retriable API call should be retried.

The default value is ‘3`.



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# File 'lib/google/cloud/core/backoff.rb', line 34

def retries
  @retries
end

Instance Method Details

#execute ⇒ Object 



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# File 'lib/google/cloud/core/backoff.rb', line 73

def execute
  current_retries = 0
  loop do
    begin
      return yield
    rescue GRPC::BadStatus => e
      raise e unless @grpc_codes.include?(e.code) &&
                     (current_retries < @retries)
      current_retries += 1
      @backoff.call current_retries
    end
  end
end