open-vault/helper/metricsutil/metricsutil.go

132 lines
3.4 KiB
Go

package metricsutil
import (
"bytes"
"encoding/json"
"fmt"
"net/http"
"strings"
"github.com/armon/go-metrics"
"github.com/hashicorp/vault/sdk/logical"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/expfmt"
)
const (
OpenMetricsMIMEType = "application/openmetrics-text"
PrometheusSchemaMIMEType = "prometheus/telemetry"
// ErrorContentType is the content type returned by an error response.
ErrorContentType = "text/plain"
)
const (
PrometheusMetricFormat = "prometheus"
)
type MetricsHelper struct {
inMemSink *metrics.InmemSink
PrometheusEnabled bool
}
func NewMetricsHelper(inMem *metrics.InmemSink, enablePrometheus bool) *MetricsHelper {
return &MetricsHelper{inMem, enablePrometheus}
}
func FormatFromRequest(req *logical.Request) string {
acceptHeaders := req.Headers["Accept"]
if len(acceptHeaders) > 0 {
acceptHeader := acceptHeaders[0]
if strings.HasPrefix(acceptHeader, OpenMetricsMIMEType) {
return PrometheusMetricFormat
}
// Look for prometheus accept header
for _, header := range acceptHeaders {
if strings.Contains(header, PrometheusSchemaMIMEType) {
return PrometheusMetricFormat
}
}
}
return ""
}
func (m *MetricsHelper) ResponseForFormat(format string) *logical.Response {
switch format {
case PrometheusMetricFormat:
return m.PrometheusResponse()
case "":
return m.GenericResponse()
default:
return &logical.Response{
Data: map[string]interface{}{
logical.HTTPContentType: ErrorContentType,
logical.HTTPRawBody: fmt.Sprintf("metric response format \"%s\" unknown", format),
logical.HTTPStatusCode: http.StatusBadRequest,
},
}
}
}
func (m *MetricsHelper) PrometheusResponse() *logical.Response {
resp := &logical.Response{
Data: map[string]interface{}{
logical.HTTPContentType: ErrorContentType,
logical.HTTPStatusCode: http.StatusBadRequest,
},
}
if !m.PrometheusEnabled {
resp.Data[logical.HTTPRawBody] = "prometheus is not enabled"
return resp
}
metricsFamilies, err := prometheus.DefaultGatherer.Gather()
if err != nil && len(metricsFamilies) == 0 {
resp.Data[logical.HTTPRawBody] = fmt.Sprintf("no prometheus metrics could be decoded: %s", err)
return resp
}
// Initialize a byte buffer.
buf := &bytes.Buffer{}
defer buf.Reset()
e := expfmt.NewEncoder(buf, expfmt.FmtText)
for _, mf := range metricsFamilies {
err := e.Encode(mf)
if err != nil {
resp.Data[logical.HTTPRawBody] = fmt.Sprintf("error during the encoding of metrics: %s", err)
return resp
}
}
resp.Data[logical.HTTPContentType] = string(expfmt.FmtText)
resp.Data[logical.HTTPRawBody] = buf.Bytes()
resp.Data[logical.HTTPStatusCode] = http.StatusOK
return resp
}
func (m *MetricsHelper) GenericResponse() *logical.Response {
resp := &logical.Response{
Data: map[string]interface{}{
logical.HTTPContentType: ErrorContentType,
logical.HTTPStatusCode: http.StatusBadRequest,
},
}
summary, err := m.inMemSink.DisplayMetrics(nil, nil)
if err != nil {
resp.Data[logical.HTTPRawBody] = fmt.Sprintf("error while fetching the in-memory metrics: %s", err)
return resp
}
content, err := json.Marshal(summary)
if err != nil {
resp.Data[logical.HTTPRawBody] = fmt.Sprintf("error while marshalling the in-memory metrics: %s", err)
return resp
}
resp.Data[logical.HTTPContentType] = "application/json"
resp.Data[logical.HTTPRawBody] = content
resp.Data[logical.HTTPStatusCode] = http.StatusOK
return resp
}