Catches exceptions and retries each request a limited number of times.
By default, it retries 2 times and handles only timeout exceptions. It can be configured with an arbitrary number of retries, a list of exceptions to handle, a retry interval, a percentage of randomness to add to the retry interval, and a backoff factor.
Examples
Faraday.new do |conn| conn.request :retry, max: 2, interval: 0.05, interval_randomness: 0.5, backoff_factor: 2 exceptions: [CustomException, 'Timeout::Error'] conn.adapter ... end
This example will result in a first interval that is random between 0.05 and 0.075 and a second interval that is random between 0.1 and 0.15
Public: Initialize middleware
Options: max - Maximum number of retries (default: 2) interval - Pause in seconds between retries (default: 0) interval_randomness - The maximum random interval amount expressed
as a float between 0 and 1 to use in addition to the interval. (default: 0)
backoff_factor - The amount to multiple each successive retry's
interval amount by in order to provide backoff (default: 1)
exceptions - The list of exceptions to handle. Exceptions can be
given as Class, Module, or String. (default: [Errno::ETIMEDOUT, Timeout::Error, Error::TimeoutError])
methods - A list of HTTP methods to retry without calling retry_if. Pass
an empty Array to call retry_if for all exceptions. (defaults to the idempotent HTTP methods in IDEMPOTENT_METHODS)
retry_if - block that will receive the env object and the exception raised
and should decide if the code should retry still the action or not independent of the retry count. This would be useful if the exception produced is non-recoverable or if the the HTTP method called is not idempotent. (defaults to return false)
# File lib/faraday/request/retry.rb, line 92 def initialize(app, options = nil) super(app) @options = Options.from(options) @errmatch = build_exception_matcher(@options.exceptions) end
Private: construct an exception matcher object.
An exception matcher for the rescue clause can usually be any object that responds to `===`, but for Ruby 1.8 it has to be a Class or Module.
# File lib/faraday/request/retry.rb, line 125 def build_exception_matcher(exceptions) matcher = Module.new (class << matcher; self; end).class_eval do define_method(:===) do |error| exceptions.any? do |ex| if ex.is_a? Module error.is_a? ex else error.class.to_s == ex.to_s end end end end matcher end
# File lib/faraday/request/retry.rb, line 105 def call(env) retries = @options.max request_body = env[:body] begin env[:body] = request_body # after failure env[:body] is set to the response body @app.call(env) rescue @errmatch => exception if retries > 0 && retry_request?(env, exception) retries -= 1 sleep sleep_amount(retries + 1) retry end raise end end
# File lib/faraday/request/retry.rb, line 98 def sleep_amount(retries) retry_index = @options.max - retries current_interval = @options.interval * (@options.backoff_factor ** retry_index) random_interval = rand * @options.interval_randomness.to_f * @options.interval current_interval + random_interval end
# File lib/faraday/request/retry.rb, line 143 def retry_request?(env, exception) @options.methods.include?(env[:method]) || @options.retry_if.call(env, exception) end