mirror of https://github.com/grafana/grafana
K8s: Add Aggregation to Backend Service (#81591)
Co-authored-by: Charandas Batra <charandas.batra@grafana.com>pull/82215/head^2
Todd Treece
2 years ago
committed by
GitHub
parent
6d5211e172
commit
d6e6298103
@ -0,0 +1,14 @@ |
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apiVersion: apiregistration.k8s.io/v1 |
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kind: APIService |
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metadata: |
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name: v0alpha1.example.grafana.app |
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spec: |
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version: v0alpha1 |
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insecureSkipTLSVerify: true |
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group: example.grafana.app |
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groupPriorityMinimum: 1000 |
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versionPriority: 15 |
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service: |
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name: example-apiserver |
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namespace: grafana |
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port: 7443 |
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@ -0,0 +1,7 @@ |
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apiVersion: service.grafana.app/v0alpha1 |
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kind: ExternalName |
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metadata: |
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name: example-apiserver |
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namespace: grafana |
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spec: |
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host: localhost |
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@ -0,0 +1,132 @@ |
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package responsewriter |
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import ( |
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"bufio" |
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"fmt" |
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"io" |
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"net/http" |
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"k8s.io/apiserver/pkg/endpoints/responsewriter" |
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"k8s.io/klog/v2" |
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) |
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var _ responsewriter.CloseNotifierFlusher = (*ResponseAdapter)(nil) |
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var _ http.ResponseWriter = (*ResponseAdapter)(nil) |
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var _ io.ReadCloser = (*ResponseAdapter)(nil) |
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func WrapHandler(handler http.Handler) func(req *http.Request) (*http.Response, error) { |
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// ignore the lint error because the response is passed directly to the client,
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// so the client will be responsible for closing the response body.
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//nolint:bodyclose
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return func(req *http.Request) (*http.Response, error) { |
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w := NewAdapter(req) |
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resp := w.Response() |
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go func() { |
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handler.ServeHTTP(w, req) |
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if err := w.CloseWriter(); err != nil { |
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klog.Errorf("error closing writer: %v", err) |
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} |
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}() |
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return resp, nil |
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} |
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} |
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// ResponseAdapter is an implementation of [http.ResponseWriter] that allows conversion to a [http.Response].
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type ResponseAdapter struct { |
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req *http.Request |
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res *http.Response |
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reader io.ReadCloser |
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writer io.WriteCloser |
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buffered *bufio.ReadWriter |
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} |
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// NewAdapter returns an initialized [ResponseAdapter].
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func NewAdapter(req *http.Request) *ResponseAdapter { |
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r, w := io.Pipe() |
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writer := bufio.NewWriter(w) |
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reader := bufio.NewReader(r) |
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buffered := bufio.NewReadWriter(reader, writer) |
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return &ResponseAdapter{ |
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req: req, |
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res: &http.Response{ |
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Proto: req.Proto, |
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ProtoMajor: req.ProtoMajor, |
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ProtoMinor: req.ProtoMinor, |
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Header: make(http.Header), |
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}, |
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reader: r, |
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writer: w, |
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buffered: buffered, |
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} |
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} |
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// Header implements [http.ResponseWriter].
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// It returns the response headers to mutate within a handler.
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func (ra *ResponseAdapter) Header() http.Header { |
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return ra.res.Header |
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} |
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// Write implements [http.ResponseWriter].
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func (ra *ResponseAdapter) Write(buf []byte) (int, error) { |
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return ra.buffered.Write(buf) |
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} |
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// Read implements [io.Reader].
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func (ra *ResponseAdapter) Read(buf []byte) (int, error) { |
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return ra.buffered.Read(buf) |
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} |
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// WriteHeader implements [http.ResponseWriter].
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func (ra *ResponseAdapter) WriteHeader(code int) { |
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ra.res.StatusCode = code |
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ra.res.Status = fmt.Sprintf("%03d %s", code, http.StatusText(code)) |
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} |
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// Flush implements [http.Flusher].
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func (ra *ResponseAdapter) Flush() { |
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if ra.buffered.Writer.Buffered() == 0 { |
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return |
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} |
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if err := ra.buffered.Writer.Flush(); err != nil { |
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klog.Error("Error flushing response buffer: ", "error", err) |
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} |
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} |
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// Response returns the [http.Response] generated by the [http.Handler].
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func (ra *ResponseAdapter) Response() *http.Response { |
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// make sure to set the status code to 200 if the request is a watch
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// this is to ensure that client-go uses a streamwatcher:
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// https://github.com/kubernetes/client-go/blob/76174b8af8cfd938018b04198595d65b48a69334/rest/request.go#L737
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if ra.res.StatusCode == 0 && ra.req.URL.Query().Get("watch") == "true" { |
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ra.WriteHeader(http.StatusOK) |
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} |
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ra.res.Body = ra |
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return ra.res |
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} |
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// Decorate implements [responsewriter.UserProvidedDecorator].
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func (ra *ResponseAdapter) Unwrap() http.ResponseWriter { |
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return ra |
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} |
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// CloseNotify implements [http.CloseNotifier].
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func (ra *ResponseAdapter) CloseNotify() <-chan bool { |
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ch := make(chan bool) |
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go func() { |
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<-ra.req.Context().Done() |
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ch <- true |
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}() |
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return ch |
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} |
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// Close implements [io.Closer].
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func (ra *ResponseAdapter) Close() error { |
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return ra.reader.Close() |
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} |
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// CloseWriter should be called after the http.Handler has returned.
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func (ra *ResponseAdapter) CloseWriter() error { |
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ra.Flush() |
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return ra.writer.Close() |
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} |
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@ -0,0 +1,136 @@ |
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package responsewriter_test |
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import ( |
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"io" |
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"math/rand" |
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"net/http" |
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"testing" |
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"time" |
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grafanaresponsewriter "github.com/grafana/grafana/pkg/services/apiserver/endpoints/responsewriter" |
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"github.com/stretchr/testify/require" |
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) |
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func TestResponseAdapter(t *testing.T) { |
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t.Run("should handle synchronous write", func(t *testing.T) { |
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client := &http.Client{ |
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Transport: &roundTripperFunc{ |
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ready: make(chan struct{}), |
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// ignore the lint error because the response is passed directly to the client,
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// so the client will be responsible for closing the response body.
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//nolint:bodyclose
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fn: grafanaresponsewriter.WrapHandler(http.HandlerFunc(syncHandler)), |
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}, |
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} |
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close(client.Transport.(*roundTripperFunc).ready) |
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req, err := http.NewRequest("GET", "http://localhost/test", nil) |
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require.NoError(t, err) |
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resp, err := client.Do(req) |
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require.NoError(t, err) |
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defer func() { |
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err := resp.Body.Close() |
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require.NoError(t, err) |
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}() |
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bodyBytes, err := io.ReadAll(resp.Body) |
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require.NoError(t, err) |
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require.Equal(t, "OK", string(bodyBytes)) |
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}) |
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t.Run("should handle synchronous write", func(t *testing.T) { |
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generateRandomStrings(10) |
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client := &http.Client{ |
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Transport: &roundTripperFunc{ |
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ready: make(chan struct{}), |
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// ignore the lint error because the response is passed directly to the client,
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// so the client will be responsible for closing the response body.
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//nolint:bodyclose
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fn: grafanaresponsewriter.WrapHandler(http.HandlerFunc(asyncHandler)), |
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}, |
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} |
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close(client.Transport.(*roundTripperFunc).ready) |
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req, err := http.NewRequest("GET", "http://localhost/test?watch=true", nil) |
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require.NoError(t, err) |
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resp, err := client.Do(req) |
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require.NoError(t, err) |
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defer func() { |
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err := resp.Body.Close() |
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require.NoError(t, err) |
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}() |
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// ensure that watch request is a 200
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require.Equal(t, http.StatusOK, resp.StatusCode) |
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// limit to 100 bytes to test the reader buffer
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buf := make([]byte, 100) |
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// holds the read bytes between iterations
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cache := []byte{} |
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for i := 0; i < 10; { |
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n, err := resp.Body.Read(buf) |
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require.NoError(t, err) |
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if n == 0 { |
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continue |
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} |
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cache = append(cache, buf[:n]...) |
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if len(cache) >= len(randomStrings[i]) { |
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str := cache[:len(randomStrings[i])] |
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require.Equal(t, randomStrings[i], string(str)) |
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cache = cache[len(randomStrings[i]):] |
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i++ |
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} |
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} |
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}) |
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} |
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func syncHandler(w http.ResponseWriter, r *http.Request) { |
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w.WriteHeader(http.StatusOK) |
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_, _ = w.Write([]byte("OK")) |
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} |
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func asyncHandler(w http.ResponseWriter, r *http.Request) { |
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w.WriteHeader(http.StatusOK) |
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for _, s := range randomStrings { |
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time.Sleep(100 * time.Millisecond) |
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// write the current iteration
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_, _ = w.Write([]byte(s)) |
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w.(http.Flusher).Flush() |
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} |
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} |
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var randomStrings = []string{} |
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func generateRandomStrings(n int) { |
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for i := 0; i < n; i++ { |
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randomString := generateRandomString(1000 * (i + 1)) |
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randomStrings = append(randomStrings, randomString) |
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} |
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} |
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func generateRandomString(n int) string { |
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gen := rand.New(rand.NewSource(time.Now().UnixNano())) |
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var chars = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789") |
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b := make([]rune, n) |
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for i := range b { |
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b[i] = chars[gen.Intn(len(chars))] |
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} |
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return string(b) |
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} |
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type roundTripperFunc struct { |
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ready chan struct{} |
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fn func(req *http.Request) (*http.Response, error) |
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} |
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func (f *roundTripperFunc) RoundTrip(req *http.Request) (*http.Response, error) { |
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if f.fn == nil { |
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<-f.ready |
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} |
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res, err := f.fn(req) |
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return res, err |
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} |
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