Files
virtual-kubelet/node/api/metrics.go
2023-04-06 08:03:43 +01:00

68 lines
2.1 KiB
Go

// Copyright © 2017 The virtual-kubelet authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package api
import (
"bytes"
"context"
"net/http"
"github.com/pkg/errors"
dto "github.com/prometheus/client_model/go"
"github.com/prometheus/common/expfmt"
)
const (
PrometheusTextFormatContentType = "text/plain; version=0.0.4"
)
// PodMetricsResourceHandlerFunc defines the handler for getting pod metrics
type PodMetricsResourceHandlerFunc func(context.Context) ([]*dto.MetricFamily, error)
// HandlePodMetricsResource makes an HTTP handler for implementing the kubelet /metrics/resource endpoint
func HandlePodMetricsResource(h PodMetricsResourceHandlerFunc) http.HandlerFunc {
if h == nil {
return NotImplemented
}
return handleError(func(w http.ResponseWriter, req *http.Request) error {
metrics, err := h(req.Context())
if err != nil {
if isCancelled(err) {
return err
}
return errors.Wrap(err, "error getting status from provider")
}
// Convert metrics to Prometheus text format.
var buffer bytes.Buffer
enc := expfmt.NewEncoder(&buffer, expfmt.FmtText)
for _, mf := range metrics {
if err := enc.Encode(mf); err != nil {
return errors.Wrap(err, "could not convert metrics to prometheus text format")
}
}
// Set the response content type to "text/plain; version=0.0.4".
w.Header().Set("Content-Type", PrometheusTextFormatContentType)
// Write the metrics in Prometheus text format to the response writer.
if _, err := w.Write(buffer.Bytes()); err != nil {
return errors.Wrap(err, "could not write to client")
}
return nil
})
}