faas/gateway/metrics/add_metrics.go
Alex Ellis bd39b9267a Update comments
- updates comments and adds where missing
- updates locks so that unlock is done via defer instead of
at the end of the statement
- extracts timeout variable in two places
- remove makeClient() unused method from metrics package

No-harm changes tested via go build.

Signed-off-by: Alex Ellis (VMware) <alexellis2@gmail.com>
2018-10-03 13:16:28 +01:00

108 lines
2.7 KiB
Go

package metrics
import (
"encoding/json"
"fmt"
"io/ioutil"
"log"
"net/http"
"net/http/httptest"
"net/url"
"strconv"
"github.com/openfaas/faas/gateway/requests"
)
// AddMetricsHandler wraps a http.HandlerFunc with Prometheus metrics
func AddMetricsHandler(handler http.HandlerFunc, prometheusQuery PrometheusQueryFetcher) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
recorder := httptest.NewRecorder()
handler.ServeHTTP(recorder, r)
upstreamCall := recorder.Result()
if upstreamCall.Body == nil {
log.Println("Upstream call had empty body.")
return
}
defer upstreamCall.Body.Close()
if recorder.Code != http.StatusOK {
w.Header().Set("Content-Type", "text/plain")
w.WriteHeader(http.StatusInternalServerError)
w.Write([]byte(fmt.Sprintf("Error pulling metrics from provider/backend. Status code: %d", recorder.Code)))
return
}
upstreamBody, _ := ioutil.ReadAll(upstreamCall.Body)
var functions []requests.Function
err := json.Unmarshal(upstreamBody, &functions)
if err != nil {
log.Printf("Metrics upstream error: %s", err)
w.Header().Set("Content-Type", "text/plain")
w.WriteHeader(http.StatusInternalServerError)
w.Write([]byte("Error parsing metrics from upstream provider/backend."))
return
}
expr := url.QueryEscape(`sum(gateway_function_invocation_total{function_name=~".*", code=~".*"}) by (function_name, code)`)
// expr := "sum(gateway_function_invocation_total%7Bfunction_name%3D~%22.*%22%2C+code%3D~%22.*%22%7D)+by+(function_name%2C+code)"
results, fetchErr := prometheusQuery.Fetch(expr)
if fetchErr != nil {
log.Printf("Error querying Prometheus API: %s\n", fetchErr.Error())
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(http.StatusOK)
w.Write(upstreamBody)
return
}
mixIn(&functions, results)
bytesOut, marshalErr := json.Marshal(functions)
if marshalErr != nil {
log.Println(marshalErr)
return
}
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(http.StatusOK)
w.Write(bytesOut)
}
}
func mixIn(functions *[]requests.Function, metrics *VectorQueryResponse) {
if functions == nil {
return
}
// Ensure values are empty first.
for i := range *functions {
(*functions)[i].InvocationCount = 0
}
for i, function := range *functions {
for _, v := range metrics.Data.Result {
if v.Metric.FunctionName == function.Name {
metricValue := v.Value[1]
switch metricValue.(type) {
case string:
// log.Println("String")
f, strconvErr := strconv.ParseFloat(metricValue.(string), 64)
if strconvErr != nil {
log.Printf("Unable to convert value for metric: %s\n", strconvErr)
continue
}
(*functions)[i].InvocationCount += f
break
}
}
}
}
}