法拉第的意外行为::连接失败

Question

我正在为一个 API 编写一个客户端，该客户端从Faraday::ConnectionFailed中拯救出来，Faraday::TimeoutError重试相同的方法MAX_RETRIES次。

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

调用的方法为：

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

token.get来自使用Faraday的oauth2宝石

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？

Answer 1

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

我通过将第二个参数传递给and_raise方法来解决此问题。我认为这是因为法拉第的异常类略有不同。

Answer 2

发生这种情况是因为Farady：：ConnectionFailed继承自Faraday：：Error class，该类在其def initialize中至少需要一个参数。在此处(错误(和此处(连接失败(检查源。

超时错误之所以有效，是因为它为exc设置了默认值以在此处"timeout"。

第一眼很难发现，我完全理解你也迷路了。

正如@MikeRogers0在他的解决方案中提到的，您必须在and_raise中使用第二个参数。

我希望这个答案对您有所帮助。