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https://github.com/gravitational/teleport.git
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rosstimothy
fa3bb9ac59
The `http.Client.Transport` created in `newWebClient` wraps a chain of `http.RoundTripper` over an underlying `http.Transport`. Since we cannot guarantee that each `http.RoundTipper` has a `CloseIdleConnections` method the usage of `defer clt.CloseIdleConnections()` does not guarantee that the http connections created during Find/Ping/etc are closed. To prevent leaking connections implementations of `http.RoundTripper` have added a `CloseIdleConnections` method added that forwards the request on to the wrapped interface. The `otelhttp.Transport` does not implement this method either so care has been taken to wrap it in a `http.RoundTripper` which will call the root transport in `enforceCloseIdleConnections`. An upstream issue has been filed with otelhttp: https://github.com/open-telemetry/opentelemetry-go-contrib/issues/3543 to get the method added to their `Transport` implementation. This wasn't noticed prior to upgrading to go1.20 becuase prior to [this](https://github.com/golang/go/commit/4e7e7ae1406c70d9cc0809ec11105a55a60a0b70) commit the `ReadHeaderTimeout` set on the Proxy web api http.Server would cause the connection to appear idle and get terminated by the server. `TestWebClientClosesIdleConnections` was added to capture the leak in connections as reported in #22757 and prevent any regressions.
62 lines
1.8 KiB
Go
62 lines
1.8 KiB
Go
// Copyright 2022 Gravitational, Inc
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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 breaker
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import (
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"net/http"
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)
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// RoundTripper wraps a http.RoundTripper with a CircuitBreaker
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type RoundTripper struct {
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tripper http.RoundTripper
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cb *CircuitBreaker
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}
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// NewRoundTripper returns a RoundTripper
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func NewRoundTripper(cb *CircuitBreaker, tripper http.RoundTripper) *RoundTripper {
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return &RoundTripper{
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tripper: tripper,
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cb: cb,
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}
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}
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// CloseIdleConnections ensures idle connections of the wrapped
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// [http.RoundTripper] are closed.
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func (t *RoundTripper) CloseIdleConnections() {
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type closeIdler interface {
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CloseIdleConnections()
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}
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if tr, ok := t.tripper.(closeIdler); ok {
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tr.CloseIdleConnections()
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}
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}
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// RoundTrip forwards the request on to the provided http.RoundTripper if
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// the CircuitBreaker allows it
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func (t *RoundTripper) RoundTrip(request *http.Request) (*http.Response, error) {
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v, err := t.cb.Execute(func() (interface{}, error) {
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//nolint:bodyclose // The interface{} conversion to *http.Response trips the linter even though this
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// is merely a pass through function. Closing the body here would prevent the actual
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// consumer to not be able to read it. Copying here to satisfy the linter seems wasteful.
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return t.tripper.RoundTrip(request)
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})
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if v == nil {
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return nil, err
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}
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return v.(*http.Response), err
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}
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