gitpod/components/openvsx-proxy/pkg/modifyresponse.go
2022-12-08 13:05:19 -03:00

115 lines
3.3 KiB
Go

// Copyright (c) 2021 Gitpod GmbH. All rights reserved.
// Licensed under the GNU Affero General Public License (AGPL).
// See License.AGPL.txt in the project root for license information.
package pkg
import (
"bytes"
"fmt"
"io/ioutil"
"net/http"
"strconv"
"time"
"unicode/utf8"
"github.com/gitpod-io/gitpod/common-go/log"
"github.com/sirupsen/logrus"
)
func (o *OpenVSXProxy) ModifyResponse(r *http.Response) error {
reqid := r.Request.Context().Value(REQUEST_ID_CTX).(string)
key, ok := r.Request.Context().Value(REQUEST_CACHE_KEY_CTX).(string)
logFields := logrus.Fields{
LOG_FIELD_FUNC: "response_handler",
LOG_FIELD_REQUEST_ID: reqid,
LOG_FIELD_REQUEST: key,
LOG_FIELD_STATUS: strconv.Itoa(r.StatusCode),
"response_content_length": r.Header.Get("Content-Length"),
}
start := time.Now()
defer func(ts time.Time) {
duration := time.Since(ts)
o.metrics.DurationResponseProcessingHistogram.Observe(duration.Seconds())
log.
WithFields(logFields).
WithFields(o.DurationLogFields(duration)).
Info("processing response finished")
}(start)
log.WithFields(logFields).Debug("handling response")
o.metrics.IncStatusCounter(r.Request, strconv.Itoa(r.StatusCode))
if !ok {
return nil
}
if key == "" {
log.WithFields(logFields).Error("cache key header is missing - sending response as is")
return nil
}
rawBody, err := ioutil.ReadAll(r.Body)
if err != nil {
log.WithFields(logFields).WithError(err).Error("error reading response raw body")
return err
}
r.Body.Close()
if r.StatusCode >= 500 || r.StatusCode == http.StatusTooManyRequests || r.StatusCode == http.StatusRequestTimeout {
// use cache if exists
bodyLogField := "(binary)"
if utf8.Valid(rawBody) {
bodyStr := string(rawBody)
truncatedSuffix := ""
if len(bodyStr) > 500 {
truncatedSuffix = "... [truncated]"
}
bodyLogField = fmt.Sprintf("%.500s%s", bodyStr, truncatedSuffix)
}
log.
WithFields(logFields).
WithField("body", bodyLogField).
Warn("error from upstream server - trying to use cached response")
cached, ok, err := o.ReadCache(key)
if err != nil {
log.WithFields(logFields).WithError(err).Error("cannot read from cache")
return nil
}
if !ok {
log.WithFields(logFields).Debug("cache has no entry for key")
return nil
}
r.Header = cached.Header
if v := r.Header.Get("Access-Control-Allow-Origin"); v != "" && v != "*" {
r.Header.Set("Access-Control-Allow-Origin", r.Header.Get("Origin"))
}
r.Body = ioutil.NopCloser(bytes.NewBuffer(cached.Body))
r.ContentLength = int64(len(cached.Body))
r.StatusCode = cached.StatusCode
log.WithFields(logFields).Debug("used cache response due to an upstream error")
o.metrics.BackupCacheServeCounter.Inc()
return nil
}
// no error (status code < 500)
cacheObj := &CacheObject{
Header: r.Header,
Body: rawBody,
StatusCode: r.StatusCode,
}
err = o.StoreCache(key, cacheObj)
if err != nil {
log.WithFields(logFields).WithError(err).Error("error storing response to cache")
} else {
log.WithFields(logFields).Debug("successfully stored response to cache")
}
r.Body = ioutil.NopCloser(bytes.NewBuffer(rawBody))
r.ContentLength = int64(len(rawBody))
r.Header.Set("Content-Length", strconv.Itoa(len(rawBody)))
return nil
}