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.
103 lines
2.6 KiB
Go
103 lines
2.6 KiB
Go
package fshttp
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import (
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"context"
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"errors"
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"io"
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"net/http"
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"net/http/httptest"
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"strings"
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"sync/atomic"
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"testing"
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"github.com/stretchr/testify/assert"
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"github.com/stretchr/testify/require"
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)
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// trackingBody records whether a request body was read to EOF and closed
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type trackingBody struct {
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io.Reader
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eof bool
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closed bool
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}
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func (b *trackingBody) Read(p []byte) (n int, err error) {
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n, err = b.Reader.Read(p)
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if err == io.EOF {
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b.eof = true
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}
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return n, err
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}
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func (b *trackingBody) Close() error {
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b.closed = true
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return nil
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}
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func TestFaultInjector(t *testing.T) {
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var hits atomic.Int32
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server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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hits.Add(1)
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_, _ = io.Copy(io.Discard, r.Body)
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w.WriteHeader(http.StatusNoContent)
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}))
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defer server.Close()
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ctx := context.Background()
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client := NewClientCustom(ctx, nil)
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injectErr := errors.New("injected error")
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// Fail the first request with a status code and the second with an
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// error, then let everything through
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var calls atomic.Int32
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SetFaultInjector(func(req *http.Request) (int, error) {
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switch calls.Add(1) {
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case 1:
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return http.StatusInternalServerError, nil
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case 2:
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return 0, injectErr
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}
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return 0, nil
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})
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defer SetFaultInjector(nil)
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do := func() (*trackingBody, *http.Response, error) {
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body := &trackingBody{Reader: strings.NewReader("hello")}
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req, err := http.NewRequestWithContext(ctx, "PUT", server.URL, body)
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require.NoError(t, err)
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resp, err := client.Do(req)
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if err == nil {
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_ = resp.Body.Close()
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}
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return body, resp, err
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}
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body, resp, err := do()
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require.NoError(t, err)
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assert.Equal(t, http.StatusInternalServerError, resp.StatusCode)
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assert.Equal(t, "500 Internal Server Error", resp.Status)
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assert.True(t, body.eof, "body should be drained")
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assert.True(t, body.closed, "body should be closed")
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assert.Equal(t, int32(0), hits.Load(), "server should not see a faulted request")
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body, _, err = do()
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require.ErrorIs(t, err, injectErr)
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assert.True(t, body.eof, "body should be drained")
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assert.True(t, body.closed, "body should be closed")
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assert.Equal(t, int32(0), hits.Load(), "server should not see a faulted request")
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_, resp, err = do()
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require.NoError(t, err)
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assert.Equal(t, http.StatusNoContent, resp.StatusCode)
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assert.Equal(t, int32(1), hits.Load())
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// Removing the injector lets requests through
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SetFaultInjector(nil)
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_, resp, err = do()
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require.NoError(t, err)
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assert.Equal(t, http.StatusNoContent, resp.StatusCode)
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assert.Equal(t, int32(2), hits.Load())
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assert.Equal(t, int32(3), calls.Load())
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}
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