Nick Craig-Wood
8d8b82ba6f
Add fshttp.SetFaultInjector, which installs a function consulted by every Transport before a request is sent. The injector can synthesise an error status code or a transport error for chosen requests. The request body is drained and closed as a real round trip would, but nothing reaches the server. This lets the integration tests check that backends cope with a transient failure part way through an upload - in particular that a retry re-sends the same data rather than an already consumed or freed buffer - without needing a fake server for each backend.
68 lines
1.8 KiB
Go
68 lines
1.8 KiB
Go
package fshttp
|
|
|
|
import (
|
|
"fmt"
|
|
"io"
|
|
"net/http"
|
|
"sync"
|
|
)
|
|
|
|
// FaultInjector decides whether to fail req instead of sending it.
|
|
//
|
|
// It returns a non-zero HTTP status code to synthesise an error
|
|
// response, a non-nil error to fail the request at the transport, or
|
|
// (0, nil) to send the request normally. When a fault is injected the
|
|
// request body is drained and closed as it would be by a real round
|
|
// trip, but nothing is sent to the server.
|
|
type FaultInjector func(req *http.Request) (statusCode int, err error)
|
|
|
|
var (
|
|
faultInjectorMu sync.RWMutex
|
|
faultInjector FaultInjector
|
|
)
|
|
|
|
// SetFaultInjector installs f as the fault injector for every Transport,
|
|
// or removes it if f is nil.
|
|
//
|
|
// This is intended for tests which need to check how callers cope with
|
|
// transient HTTP failures, such as whether an upload is retried
|
|
// correctly after a 5xx.
|
|
func SetFaultInjector(f FaultInjector) {
|
|
faultInjectorMu.Lock()
|
|
defer faultInjectorMu.Unlock()
|
|
faultInjector = f
|
|
}
|
|
|
|
// injectFault consults the fault injector and returns the synthesised
|
|
// response or error for req, or (nil, nil) if it should be sent.
|
|
func injectFault(req *http.Request) (*http.Response, error) {
|
|
faultInjectorMu.RLock()
|
|
f := faultInjector
|
|
faultInjectorMu.RUnlock()
|
|
if f == nil {
|
|
return nil, nil
|
|
}
|
|
statusCode, err := f(req)
|
|
if statusCode == 0 && err == nil {
|
|
return nil, nil
|
|
}
|
|
if req.Body != nil {
|
|
_, _ = io.Copy(io.Discard, req.Body)
|
|
_ = req.Body.Close()
|
|
}
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return &http.Response{
|
|
Status: fmt.Sprintf("%d %s", statusCode, http.StatusText(statusCode)),
|
|
StatusCode: statusCode,
|
|
Proto: "HTTP/1.1",
|
|
ProtoMajor: 1,
|
|
ProtoMinor: 1,
|
|
Header: make(http.Header),
|
|
Body: http.NoBody,
|
|
ContentLength: 0,
|
|
Request: req,
|
|
}, nil
|
|
}
|