mirror of
https://github.com/stefanprodan/podinfo.git
synced 2026-03-31 08:07:06 +00:00
129 lines
3.4 KiB
Go
129 lines
3.4 KiB
Go
package api
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import (
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"bytes"
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"context"
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"fmt"
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"io/ioutil"
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"net/http"
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"net/http/httptrace"
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"sync"
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"github.com/stefanprodan/podinfo/pkg/version"
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"go.opentelemetry.io/contrib/instrumentation/net/http/httptrace/otelhttptrace"
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"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
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"go.uber.org/zap"
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)
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// Echo godoc
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// @Summary Echo
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// @Description forwards the call to the backend service and echos the posted content
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// @Tags HTTP API
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// @Accept json
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// @Produce json
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// @Router /api/echo [post]
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// @Success 202 {object} api.MapResponse
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func (s *Server) echoHandler(w http.ResponseWriter, r *http.Request) {
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ctx, span := s.tracer.Start(r.Context(), "echoHandler")
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defer span.End()
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body, err := ioutil.ReadAll(r.Body)
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if err != nil {
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s.logger.Error("reading the request body failed", zap.Error(err))
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s.ErrorResponse(w, r, span, "invalid request body", http.StatusBadRequest)
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return
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}
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defer r.Body.Close()
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client := http.Client{Transport: otelhttp.NewTransport(http.DefaultTransport)}
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if len(s.config.BackendURL) > 0 {
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result := make([]string, len(s.config.BackendURL))
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var wg sync.WaitGroup
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wg.Add(len(s.config.BackendURL))
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for i, b := range s.config.BackendURL {
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go func(index int, backend string) {
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defer wg.Done()
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ctx = httptrace.WithClientTrace(ctx, otelhttptrace.NewClientTrace(ctx))
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ctx, cancel := context.WithTimeout(ctx, s.config.HttpClientTimeout)
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defer cancel()
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backendReq, err := http.NewRequestWithContext(ctx, "POST", backend, bytes.NewReader(body))
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if err != nil {
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s.logger.Error("backend call failed", zap.Error(err), zap.String("url", backend))
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return
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}
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// forward headers
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copyTracingHeaders(r, backendReq)
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backendReq.Header.Set("X-API-Version", version.VERSION)
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backendReq.Header.Set("X-API-Revision", version.REVISION)
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// call backend
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resp, err := client.Do(backendReq)
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if err != nil {
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s.logger.Error("backend call failed", zap.Error(err), zap.String("url", backend))
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result[index] = fmt.Sprintf("backend %v call failed %v", backend, err)
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return
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}
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defer resp.Body.Close()
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// copy error status from backend and exit
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if resp.StatusCode >= 400 {
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s.logger.Error("backend call failed", zap.Int("status", resp.StatusCode), zap.String("url", backend))
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result[index] = fmt.Sprintf("backend %v response status code %v", backend, resp.StatusCode)
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return
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}
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// forward the received body
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rbody, err := ioutil.ReadAll(resp.Body)
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if err != nil {
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s.logger.Error(
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"reading the backend request body failed",
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zap.Error(err),
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zap.String("url", backend))
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result[index] = fmt.Sprintf("backend %v call failed %v", backend, err)
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return
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}
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s.logger.Debug(
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"payload received from backend",
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zap.String("response", string(rbody)),
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zap.String("url", backend))
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result[index] = string(rbody)
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}(i, b)
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}
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wg.Wait()
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w.Header().Set("X-Color", s.config.UIColor)
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s.JSONResponse(w, r, result)
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} else {
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w.Header().Set("X-Color", s.config.UIColor)
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w.WriteHeader(http.StatusAccepted)
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w.Write(body)
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}
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}
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func copyTracingHeaders(from *http.Request, to *http.Request) {
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headers := []string{
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"x-request-id",
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"x-b3-traceid",
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"x-b3-spanid",
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"x-b3-parentspanid",
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"x-b3-sampled",
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"x-b3-flags",
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"x-ot-span-context",
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}
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for i := range headers {
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headerValue := from.Header.Get(headers[i])
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if len(headerValue) > 0 {
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to.Header.Set(headers[i], headerValue)
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}
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}
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}
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