144 lines
3.3 KiB
Go
144 lines
3.3 KiB
Go
package request
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import (
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"bytes"
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"io"
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"net/http"
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"net/http/httputil"
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"strconv"
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"strings"
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"time"
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"github.com/evcc-io/evcc/util"
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"github.com/prometheus/client_golang/prometheus"
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)
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type roundTripper struct {
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log *util.Logger
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base http.RoundTripper
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}
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var (
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LogHeaders bool
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LogMaxLen = 1024 * 8
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reqMetric *prometheus.SummaryVec
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resMetric *prometheus.CounterVec
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)
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func init() {
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labels := []string{"host"}
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reqMetric = prometheus.NewSummaryVec(prometheus.SummaryOpts{
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Namespace: "evcc",
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Subsystem: "http",
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Name: "request_duration_seconds",
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Help: "A summary of HTTP request durations",
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Objectives: map[float64]float64{
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0.5: 0.05, // 50th percentile with a max. absolute error of 0.05
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0.9: 0.01, // 90th percentile with a max. absolute error of 0.01
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0.99: 0.001, // 99th percentile with a max. absolute error of 0.001
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},
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}, labels)
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resMetric = prometheus.NewCounterVec(prometheus.CounterOpts{
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Namespace: "evcc",
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Subsystem: "http",
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Name: "request_total",
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Help: "Total count of HTTP requests",
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}, append(labels, "status"))
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prometheus.MustRegister(reqMetric, resMetric)
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}
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// NewTripper creates a logging roundtrip handler
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func NewTripper(log *util.Logger, base http.RoundTripper) http.RoundTripper {
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tripper := &roundTripper{
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log: log,
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base: base,
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}
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return tripper
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}
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// copy of http.drainBody
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func drainBody(b io.ReadCloser) (r1, r2 io.ReadCloser, err error) {
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if b == nil || b == http.NoBody {
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// No copying needed. Preserve the magic sentinel meaning of NoBody.
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return http.NoBody, http.NoBody, nil
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}
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var buf bytes.Buffer
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if _, err = buf.ReadFrom(b); err != nil {
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return nil, b, err
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}
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if err = b.Close(); err != nil {
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return nil, b, err
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}
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return io.NopCloser(&buf), io.NopCloser(bytes.NewReader(buf.Bytes())), nil
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}
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// dump http request/response body
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func dump(r io.ReadCloser, w *strings.Builder) error {
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body, err := io.ReadAll(r)
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if err != nil {
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return err
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}
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if w.Len() > 0 && len(body) > 0 {
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w.WriteString("\n--\n")
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}
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_, err = w.Write(bytes.TrimSpace(body[:min(LogMaxLen, len(body))]))
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return err
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}
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func (r *roundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
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r.log.TRACE.Printf("%s %s", req.Method, req.URL.String())
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// dump without headers
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var err error
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var save io.ReadCloser
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bld := new(strings.Builder)
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if LogHeaders {
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if body, err := httputil.DumpRequestOut(req, true); err == nil {
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bld.WriteString("\n")
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bld.Write(bytes.TrimSpace(body[:min(LogMaxLen, len(body))]))
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}
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} else {
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if save, req.Body, err = drainBody(req.Body); err == nil {
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err = dump(save, bld)
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}
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if err != nil {
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return nil, err
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}
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}
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startTime := time.Now()
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resp, err := r.base.RoundTrip(req)
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reqMetric.WithLabelValues(req.URL.Hostname()).Observe(time.Since(startTime).Seconds())
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if err == nil {
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resMetric.WithLabelValues(req.URL.Hostname(), strconv.Itoa(resp.StatusCode)).Add(1)
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if LogHeaders {
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if body, err := httputil.DumpResponse(resp, true); err == nil {
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bld.WriteString("\n\n")
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bld.Write(bytes.TrimSpace(body[:min(LogMaxLen, len(body))]))
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}
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} else {
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if save, resp.Body, err = drainBody(resp.Body); err == nil {
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err = dump(save, bld)
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}
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if err != nil {
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return nil, err
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}
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}
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} else {
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resMetric.WithLabelValues(req.URL.Hostname(), "999").Add(1)
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}
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if bld.Len() > 0 {
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r.log.TRACE.Println(bld.String())
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}
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return resp, err
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}
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