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metrics.go
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/
metrics.go
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package filters
import (
"compress/gzip"
"errors"
"fmt"
"github.com/loft-sh/vcluster/pkg/metrics"
"github.com/loft-sh/vcluster/pkg/server/handler"
requestpkg "github.com/loft-sh/vcluster/pkg/util/request"
dto "github.com/prometheus/client_model/go"
"github.com/prometheus/common/expfmt"
"io/ioutil"
corev1 "k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/runtime/serializer"
"k8s.io/apiserver/pkg/endpoints/handlers/responsewriters"
"k8s.io/apiserver/pkg/endpoints/request"
"net/http"
"net/http/httptest"
ctrl "sigs.k8s.io/controller-runtime"
"sigs.k8s.io/controller-runtime/pkg/client"
"strings"
)
func WithInjectedMetrics(h http.Handler, localManager ctrl.Manager, virtualManager ctrl.Manager, targetNamespace string) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
info, ok := request.RequestInfoFrom(req.Context())
if !ok {
requestpkg.FailWithStatus(w, req, http.StatusInternalServerError, fmt.Errorf("request info is missing"))
return
}
if info.IsResourceRequest == false && (info.Path == "/metrics/cadvisor" || info.Path == "/metrics/probes" || info.Path == "/metrics/resource" || info.Path == "/metrics/resource/v1alpha1") {
out, err := gatherMetrics(req, localManager, virtualManager.GetClient(), targetNamespace, info.Path)
if err != nil {
requestpkg.FailWithStatus(w, req, http.StatusInternalServerError, err)
return
}
w.Header().Set("Content-Type", string(expfmt.Negotiate(req.Header)))
w.WriteHeader(http.StatusOK)
w.Write(out)
return
}
h.ServeHTTP(w, req)
})
}
func gatherMetrics(req *http.Request, localManager ctrl.Manager, vClient client.Client, targetNamespace, path string) ([]byte, error) {
nodes := &corev1.NodeList{}
err := vClient.List(req.Context(), nodes)
if err != nil {
return nil, err
}
req.Header.Del("Authorization")
returnMetrics := []*dto.MetricFamily{}
for _, node := range nodes.Items {
h, err := handler.Handler("", localManager.GetConfig())
if err != nil {
return nil, err
}
clonedRequest := req.Clone(req.Context())
clonedRequest.URL.Path = fmt.Sprintf("/api/v1/nodes/%s/proxy%s", node.Name, path)
code, _, data, err := executeRequest(clonedRequest, h)
if err != nil {
return nil, err
} else if code != http.StatusOK {
return nil, errors.New(string(data))
}
nodeMetrics, err := metrics.Decode(data)
if err != nil {
return nil, err
}
nodeMetrics, err = metrics.Rewrite(req.Context(), nodeMetrics, targetNamespace, vClient)
if err != nil {
return nil, err
}
labelName := "node"
nodeName := node.Name
metrics.AddLabels(nodeMetrics, []*dto.LabelPair{
{
Name: &labelName,
Value: &nodeName,
},
})
metrics.Merge(nodeMetrics, &returnMetrics)
}
return metrics.Encode(returnMetrics, expfmt.Negotiate(req.Header))
}
func WithMetricsRewrite(h http.Handler, localManager ctrl.Manager, virtualManager ctrl.Manager, targetNamespace string) http.Handler {
s := serializer.NewCodecFactory(virtualManager.GetScheme())
return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
info, ok := request.RequestInfoFrom(req.Context())
if !ok {
requestpkg.FailWithStatus(w, req, http.StatusInternalServerError, fmt.Errorf("request info is missing"))
return
}
if metricsApplies(info) {
// authorization was done here already so we will just go forward with the rewrite
req.Header.Del("Authorization")
h, err := handler.Handler("", localManager.GetConfig())
if err != nil {
requestpkg.FailWithStatus(w, req, http.StatusInternalServerError, err)
return
}
code, header, data, err := executeRequest(req, h)
if err != nil {
responsewriters.ErrorNegotiated(err, s, corev1.SchemeGroupVersion, w, req)
return
} else if code != http.StatusOK {
writeWithHeader(w, code, header, data)
return
}
// now rewrite the metrics
newData, err := rewritePrometheusMetrics(req, data, targetNamespace, virtualManager.GetClient())
if err != nil {
responsewriters.ErrorNegotiated(err, s, corev1.SchemeGroupVersion, w, req)
return
}
w.Header().Set("Content-Type", string(expfmt.Negotiate(req.Header)))
w.WriteHeader(code)
w.Write(newData)
return
}
h.ServeHTTP(w, req)
})
}
func writeWithHeader(w http.ResponseWriter, code int, header http.Header, body []byte) {
// delete old header
for k := range w.Header() {
w.Header().Del(k)
}
for k, v := range header {
for _, s := range v {
w.Header().Add(k, s)
}
}
w.WriteHeader(code)
w.Write(body)
}
func rewritePrometheusMetrics(req *http.Request, data []byte, targetNamespace string, vClient client.Client) ([]byte, error) {
metricsFamilies, err := metrics.Decode(data)
if err != nil {
return nil, err
}
metricsFamilies, err = metrics.Rewrite(req.Context(), metricsFamilies, targetNamespace, vClient)
if err != nil {
return nil, err
}
return metrics.Encode(metricsFamilies, expfmt.Negotiate(req.Header))
}
func executeRequest(req *http.Request, h http.Handler) (int, http.Header, []byte, error) {
clonedRequest := req.Clone(req.Context())
fakeWriter := httptest.NewRecorder()
h.ServeHTTP(fakeWriter, clonedRequest)
// Check that the server actually sent compressed data
var responseBytes []byte
switch fakeWriter.Header().Get("Content-Encoding") {
case "gzip":
reader, err := gzip.NewReader(fakeWriter.Body)
if err != nil {
return 0, nil, nil, err
}
responseBytes, err = ioutil.ReadAll(reader)
if err != nil {
return 0, nil, nil, err
}
fakeWriter.Header().Del("Content-Encoding")
default:
responseBytes = fakeWriter.Body.Bytes()
}
return fakeWriter.Code, fakeWriter.Header(), responseBytes, nil
}
func metricsApplies(r *request.RequestInfo) bool {
if r.IsResourceRequest == false {
return false
}
return r.APIGroup == corev1.SchemeGroupVersion.Group &&
r.APIVersion == corev1.SchemeGroupVersion.Version &&
r.Resource == "nodes" &&
r.Subresource == "proxy" &&
(strings.HasSuffix(r.Path, "/metrics/cadvisor") || strings.HasSuffix(r.Path, "/metrics/probes") || strings.HasSuffix(r.Path, "/metrics/resource") || strings.HasSuffix(r.Path, "/metrics/resource/v1alpha1"))
}