mirror of
https://github.com/alibaba/higress.git
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124 lines
3.2 KiB
Go
124 lines
3.2 KiB
Go
// Copyright (c) 2022 Alibaba Group Holding Ltd.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package util
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import (
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"context"
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"crypto/tls"
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"fmt"
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"io"
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"net/http"
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"time"
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)
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const (
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defaultInitialInterval = 500 * time.Millisecond
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defaultMaxInterval = 60 * time.Second
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)
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type HTTPFetcher struct {
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client *http.Client
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initialBackoff time.Duration
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requestMaxRetry int
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bufferSize int64
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}
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// NewHTTPFetcher create a new HTTP remote fetcher.
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func NewHTTPFetcher(requestTimeout time.Duration, requestMaxRetry int, bufferSize int64) *HTTPFetcher {
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if requestTimeout == 0 {
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requestTimeout = 5 * time.Second
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}
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transport := http.DefaultTransport.(*http.Transport).Clone()
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// nolint: gosec
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// This is only when a user explicitly sets a flag to enable insecure mode
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transport.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
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return &HTTPFetcher{
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client: &http.Client{
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Timeout: requestTimeout,
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},
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initialBackoff: defaultInitialInterval,
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requestMaxRetry: requestMaxRetry,
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bufferSize: bufferSize,
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}
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}
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// Fetch downloads with HTTP get.
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func (f *HTTPFetcher) Fetch(ctx context.Context, url string) ([]byte, error) {
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c := f.client
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delayInterval := f.initialBackoff
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attempts := 0
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var lastError error
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for attempts < f.requestMaxRetry {
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attempts++
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req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
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if err != nil {
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return nil, err
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}
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resp, err := c.Do(req)
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if err != nil {
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lastError = err
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if ctx.Err() != nil {
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// If there is context timeout, exit this loop.
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return nil, fmt.Errorf("download failed after %v attempts, last error: %v", attempts, lastError)
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}
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delayInterval = delayInterval + f.initialBackoff
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if delayInterval > defaultMaxInterval {
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break
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}
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time.Sleep(delayInterval)
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continue
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}
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if resp.StatusCode == http.StatusOK {
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body, err := io.ReadAll(io.LimitReader(resp.Body, f.bufferSize))
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if err != nil {
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return nil, err
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}
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err = resp.Body.Close()
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if err != nil {
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return nil, err
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}
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return body, err
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}
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lastError = fmt.Errorf("download request failed: status code %v", resp.StatusCode)
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if retryable(resp.StatusCode) {
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_, err := io.ReadAll(io.LimitReader(resp.Body, f.bufferSize))
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if err != nil {
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return nil, err
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}
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err = resp.Body.Close()
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delayInterval = delayInterval + f.initialBackoff
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if delayInterval > defaultMaxInterval {
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break
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}
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time.Sleep(delayInterval)
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continue
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}
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err = resp.Body.Close()
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break
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}
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return nil, fmt.Errorf("download failed after %v attempts, last error: %v", attempts, lastError)
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}
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func retryable(code int) bool {
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return code >= 500 &&
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!(code == http.StatusNotImplemented ||
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code == http.StatusHTTPVersionNotSupported ||
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code == http.StatusNetworkAuthenticationRequired)
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}
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