pulumi/sdk/go/common/util/httputil/http.go

125 lines
3.9 KiB
Go

// Copyright 2016-2018, Pulumi Corporation.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package httputil
import (
"context"
"net/http"
"strings"
"time"
"github.com/pulumi/pulumi/sdk/v3/go/common/util/contract"
"github.com/pulumi/pulumi/sdk/v3/go/common/util/retry"
)
// RetryOpts defines options to configure the retry behavior.
// Leave nil for defaults.
type RetryOpts struct {
// These fields map directly to util.Acceptor.
Delay *time.Duration
Backoff *float64
MaxDelay *time.Duration
MaxRetryCount *int
// HandshakeTimeoutsOnly indicates whether we should only be retrying timeouts that occur during the TLS handshake.
// These timeouts are safe to retry even on POST requests, since we know the actual request hasn't been sent yet.
HandshakeTimeoutsOnly bool
}
// DoWithRetry calls client.Do, and in the case of an error, retries the operation again after a slight delay.
// Uses the default retry delays, starting at 100ms and ramping up to ~1.3s.
func DoWithRetry(req *http.Request, client *http.Client) (*http.Response, error) {
var opts RetryOpts
return doWithRetry(req, client, opts)
}
// DoWithRetryOpts calls client.Do, but retrying 500s (even for POSTs). Using the provided delays.
func DoWithRetryOpts(req *http.Request, client *http.Client, opts RetryOpts) (*http.Response, error) {
return doWithRetry(req, client, opts)
}
func doWithRetry(req *http.Request, client *http.Client, opts RetryOpts) (*http.Response, error) {
contract.Assertf(req.ContentLength == 0 || req.GetBody != nil,
"Retryable request must have no body or rewindable body")
inRange := func(test, lower, upper int) bool {
return lower <= test && test <= upper
}
// maxRetryCount is the number of times to try an http request before
// giving up an returning the last error.
maxRetryCount := 5
if opts.MaxRetryCount != nil {
maxRetryCount = *opts.MaxRetryCount
}
acceptor := retry.Acceptor{
// If the opts field is nil, retry.Until will provide defaults.
Delay: opts.Delay,
Backoff: opts.Backoff,
MaxDelay: opts.MaxDelay,
Accept: func(try int, _ time.Duration) (bool, interface{}, error) {
if try > 0 && req.GetBody != nil {
// Reset request body, if present, for retries.
rc, bodyErr := req.GetBody()
if bodyErr != nil {
return false, nil, bodyErr
}
req.Body = rc
}
res, resErr := client.Do(req)
if opts.HandshakeTimeoutsOnly {
if resErr != nil && strings.Contains(resErr.Error(), "net/http: TLS handshake timeout") {
// If we have a handshake timeout, we can retry the request.
return false, nil, nil
}
return true, res, resErr
}
if resErr == nil && !inRange(res.StatusCode, 500, 599) {
return true, res, nil
}
if try >= (maxRetryCount - 1) {
return true, res, resErr
}
// Close the response body, if present, since our caller can't.
if resErr == nil {
contract.IgnoreError(res.Body.Close())
}
return false, nil, nil
},
}
_, res, err := retry.Until(context.Background(), acceptor)
if err != nil {
return nil, err
}
return res.(*http.Response), nil
}
// GetWithRetry issues a GET request with the given client, and in the case of an error, retries the operation again
// after a slight delay.
func GetWithRetry(url string, client *http.Client) (*http.Response, error) {
req, err := http.NewRequest("GET", url, nil)
if err != nil {
return nil, err
}
return DoWithRetry(req, client)
}