无法创建在 Go 中以错误响应导致重试的处理程序
我正在尝试验证go-retryablehttp执行是否按照指定的配置执行重试。
验证方法是创建一个测试
创建一个可重试的客户端
创建一个新请求
使用错误处理程序创建一个新服务器
服务请求
验证重试次数。
以上是我试图在下面的代码块中捕获的内容
//function that returns 500 error
func InternalServerErrorHandler(w http.ResponseWriter, r *http.Request) {
http.Error(w, fmt.Sprintf("test_%d_body", http.StatusInternalServerError), http.StatusInternalServerError)
}
func TestCreateToolsClient(t *testing.T) {
//create a new server
ts := httptest.NewServer(http.HandlerFunc(InternalServerErrorHandler))
defer ts.Close()
//create a request
request, err := retryablehttp.NewRequest(http.MethodGet, ts.URL, nil)
if err != nil {
log.Fatal(err)
}
//create a retryable client
var options retryablehttp.Options
options.RetryWaitMin = 10 * time.Millisecond
options.RetryWaitMax = 50 * time.Millisecond
options.RetryMax = 6
options.Timeout = 60000 * time.Millisecond
retryableClient := retryablehttp.NewClient(options)
retryCount := -1
// to verify from stdout if the # of retry actually is getting counted
retryableClient.RequestLogHook = func(req *http.Request, retryNumber int) {
retryCount = retryNumber
log.Println("Retrying")
}
//execute the request
response, err := retryableClient.Do(request)
if err != nil {
return
}
//verify
require.Equal(t, http.StatusInternalServerError, response.StatusCode)
require.Equal(t, 2, retryCount)
}
我的理解是
retryableClient.Do(request)如果有错误，每个都应该采取时间=超时鉴于处理程序返回错误，它应该使重试尝试等于
options.RetryMax = 6次数
我尝试调试代码，结果
// Attempt the request resp, err = c.HTTPClient.Do(req.Request)
这里有 err as nil。
不确定我做错了什么。
我在这里创建了一个围棋游乐场
四季花海浏览 91回答 1
1回答
-
翻过高山走不出你
好的，我想通了。在这里用解决方案去游乐场我的 go 版本是 Go 1.17。如果您在 go playground（Go 版本 1.19）中运行上述代码，重试有效。对于 Go 1.17，retryable-http(v1.0.2) 不处理状态错误代码func DefaultRetryPolicy() func(ctx context.Context, resp *http.Response, err error) (bool, error) { return func(ctx context.Context, resp *http.Response, err error) (bool, error) { // do not retry on context.Canceled or context.DeadlineExceeded //fmt.Printf("jkajsuiohsd %v\n", ctx.Err()) if ctx.Err() != nil { return false, ctx.Err() } if err != nil { if v, ok := err.(*url.Error); ok { // Don't retry if the error was due to too many redirects. if redirectsErrorRegex.MatchString(v.Error()) { return false, nil } // Don't retry if the error was due to an invalid protocol scheme. if schemeErrorRegex.MatchString(v.Error()) { return false, nil } // Don't retry if the error was due to TLS cert verification failure. if _, ok := v.Err.(x509.UnknownAuthorityError); ok { return false, nil } } // The error is likely recoverable so retry. return true, nil } //EXPECT HANDLING BASED ON STATUS CODES, BUT ABSENT return false, nil }}对于 Go 1.19，retryable-http(v2.1) 实现了如下baseRetryPolicy所示的功能func baseRetryPolicy(resp *http.Response, err error) (bool, error) { if err != nil { if v, ok := err.(*url.Error); ok { // Don't retry if the error was due to too many redirects. if redirectsErrorRe.MatchString(v.Error()) { return false, v } // Don't retry if the error was due to an invalid protocol scheme. if schemeErrorRe.MatchString(v.Error()) { return false, v } // Don't retry if the error was due to TLS cert verification failure. if notTrustedErrorRe.MatchString(v.Error()) { return false, v } if _, ok := v.Err.(x509.UnknownAuthorityError); ok { return false, v } } // The error is likely recoverable so retry. return true, nil } // 429 Too Many Requests is recoverable. Sometimes the server puts // a Retry-After response header to indicate when the server is // available to start processing request from client. if resp.StatusCode == http.StatusTooManyRequests { return true, nil } // Check the response code. We retry on 500-range responses to allow // the server time to recover, as 500's are typically not permanent // errors and may relate to outages on the server side. This will catch // invalid response codes as well, like 0 and 999. //THIS PART HERE FLAGS RETRIES ON STATUS CODES! if resp.StatusCode == 0 || (resp.StatusCode >= 500 && resp.StatusCode != http.StatusNotImplemented) { return true, fmt.Errorf("unexpected HTTP status %s", resp.Status) } return false, nil}最后，有以下选项。移动到 1.19尝试使用 go-retryablehttp v2.01如果您要使用 Go.17，请通过如下更新 CheckRetry 函数来创建自定义重试策略。func TestCreateToolsClient(t *testing.T) { ts := httptest.NewServer(http.HandlerFunc(InternalServerErrorHandler)) defer ts.Close() request, err := retryablehttp.NewRequest(http.MethodGet, ts.URL, nil) if err != nil { log.Fatal(err) } var options retryablehttp.Options options.RetryWaitMin = 10 * time.Millisecond options.RetryWaitMax = 50 * time.Millisecond options.RetryMax = 6 options.Timeout = 60 * time.Second //options.Timeout = 30000 * time.Millisecond retryableClient := retryablehttp.NewClient(options) retryCount := -1 // to verify from stdout if the # of retry actually is getting counted retryableClient.RequestLogHook = func(req *http.Request, retryNumber int) { retryCount = retryNumber log.Println("Retrying") } // A regular expression to match the error returned by net/http when the // configured number of redirects is exhausted. This error isn't typed // specifically so we resort to matching on the error string. redirectsErrorRe := regexp.MustCompile(`stopped after \d+ redirects\z`) // A regular expression to match the error returned by net/http when the // scheme specified in the URL is invalid. This error isn't typed // specifically so we resort to matching on the error string. schemeErrorRe := regexp.MustCompile(`unsupported protocol scheme`) // A regular expression to match the error returned by net/http when the // TLS certificate is not trusted. This error isn't typed // specifically so we resort to matching on the error string. notTrustedErrorRe := regexp.MustCompile(`certificate is not trusted`) retryableClient.CheckRetry = func(_ context.Context, resp *http.Response, err error) (bool, error) { if err != nil { if v, ok := err.(*url.Error); ok { // Don't retry if the error was due to too many redirects. if redirectsErrorRe.MatchString(v.Error()) { return false, v } // Don't retry if the error was due to an invalid protocol scheme. if schemeErrorRe.MatchString(v.Error()) { return false, v } // Don't retry if the error was due to TLS cert verification failure. if notTrustedErrorRe.MatchString(v.Error()) { return false, v } if _, ok := v.Err.(x509.UnknownAuthorityError); ok { return false, v } } // The error is likely recoverable so retry. return true, nil } // 429 Too Many Requests is recoverable. Sometimes the server puts // a Retry-After response header to indicate when the server is // available to start processing request from client. if resp.StatusCode == http.StatusTooManyRequests { return true, nil } // Check the response code. We retry on 500-range responses to allow // the server time to recover, as 500's are typically not permanent // errors and may relate to outages on the server side. This will catch // invalid response codes as well, like 0 and 999. if resp.StatusCode == 0 || (resp.StatusCode >= 500 && resp.StatusCode != http.StatusNotImplemented) { return true, fmt.Errorf("unexpected HTTP status %s", resp.Status) } return false, nil }
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