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ruby - Faraday::ConnectionFailed 的意外行为

问题描述

我正在为一个 API 编写一个客户端，该 API 从Faraday::ConnectionFailed和Faraday::TimeoutError重试相同的方法MAX_RETRIES时间。

这是涉及的主要方法：

def benchmark_request(path)
  retries ||= 0
  request_start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)

  response = yield

  total_request_seconds = (Process.clock_gettime(Process::CLOCK_MONOTONIC) - request_start_time)
  Rails.logger.info "client request took (#{total_request_seconds}s): #{ENV['API_PATH_PREFIX']}#{path}"

  response
rescue Faraday::ConnectionFailed, Faraday::TimeoutError => e
  retries += 1
  retry if retries <= MAX_RETRIES
end

调用的方法是：

 def get(path, params = {})
   benchmark_request(path) { token.get("#{ENV['API_PATH_PREFIX']}#{path}", params) }
 end

token.get来自oauth2正在使用的宝石Faraday

这是有趣的一点。我写了 2 个规范，每个我想处理的异常都有 1 个。

context 'when the endpoint raises a ConnectionFailed' do
  let(:token_expires_at) { 1.hour.from_now.to_i }
  let(:response_body) { '' }
  let(:response_status) { 200 }

  before do
    allow(token).to receive(:get).and_raise(Faraday::ConnectionFailed)
    described_class.get(api_endpoint)
  end

  it 'is called MAX_RETRIES times' do
    expect(token).to have_received(:get).exactly(3).times
  end
end

context 'when the endpoint raises a TimeoutError' do
  let(:token_expires_at) { 1.hour.from_now.to_i }
  let(:response_body) { '' }
  let(:response_status) { 200 }

  before do
    allow(token).to receive(:get).and_raise(Faraday::TimeoutError)
    described_class.get(api_endpoint)
  end

  it 'is called MAX_RETRIES times' do
    expect(token).to have_received(:get).exactly(3).times
  end
end

测试测试ConnectionFailed失败，测试测试TimeoutError为绿色。引发的异常是：

1) Client::Base.get when the endpoint raises a ConnectionFailed is called MAX_RETRIES times
 Failure/Error: token.get(path, params)

 ArgumentError:
   wrong number of arguments (given 0, expected 1..2)
 # /home/ngw/.rvm/gems/ruby-2.6.2/gems/faraday-0.15.4/lib/faraday/error.rb:7:in `initialize'
 # ./app/lib/client/base.rb:13:in `get'
 # ./spec/lib/client/base_spec.rb:111:in `block (4 levels) in <top (required)>'

这显然是关于如何初始化异常。

有人知道吗？

标签： rubyapihttpfaraday

解决方案

这是因为 Farady::ConnectionFailed 继承自 Faraday::Error 类，该类def initialize至少需要一个参数。在此处 (Error)和此处 (ConnectionFailed)检查源。

TimeoutError 有效，因为它的默认值设置exc为"timeout" here。

乍一看很难发现，我完全理解你也迷路了。

正如@MikeRogers0 在他的解决方案中提到的那样，您必须在and_raise.

我希望你会发现这个答案有帮助。

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