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package api
import (
"fmt"
"math"
"strconv"
"strings"
"time"
"github.com/gin-gonic/gin"
"github.com/prometheus/client_golang/prometheus"
"github.com/rs/zerolog/log"
)
// Only use base path as label value (e.g.: /api/repos) because of time series cardinality
// See https://prometheus.io/docs/practices/naming/#labels
func getBasePath(c *gin.Context) string {
segment0, err := getURLSegment(c.Request.URL.Path, 0)
if err != nil {
return "/"
}
segment1, err := getURLSegment(c.Request.URL.Path, 1)
if err != nil {
return *segment0
}
return *segment0 + *segment1
}
func getURLSegment(url string, idx int) (*string, error) {
urlSegments := strings.Split(url, "/")
// Remove segment at index 0 because it's an empty string
urlSegments = urlSegments[1:cap(urlSegments)]
if len(urlSegments) <= idx {
return nil, fmt.Errorf("index %d out of range, only has %d url segments", idx, len(urlSegments))
}
segmentAtIndex := urlSegments[idx]
s := fmt.Sprintf("/%s", segmentAtIndex)
return &s, nil
}
func instrumentHandlerInFlight(g *prometheus.GaugeVec, pathFunc func(*gin.Context) string) func(*gin.Context) {
return func(c *gin.Context) {
g.WithLabelValues(c.Request.Method, pathFunc(c)).Inc()
defer g.WithLabelValues(c.Request.Method, pathFunc(c)).Dec()
c.Next()
}
}
func instrumentHandlerCounter(counter *prometheus.CounterVec, pathFunc func(*gin.Context) string) func(*gin.Context) {
return func(c *gin.Context) {
c.Next()
counter.WithLabelValues(strconv.Itoa(c.Writer.Status()), c.Request.Method, pathFunc(c)).Inc()
}
}
func instrumentHandlerRequestSize(obs prometheus.ObserverVec, pathFunc func(*gin.Context) string) func(*gin.Context) {
return func(c *gin.Context) {
c.Next()
obs.WithLabelValues(strconv.Itoa(c.Writer.Status()), c.Request.Method, pathFunc(c)).Observe(float64(c.Request.ContentLength))
}
}
func instrumentHandlerResponseSize(obs prometheus.ObserverVec, pathFunc func(*gin.Context) string) func(*gin.Context) {
return func(c *gin.Context) {
c.Next()
var responseSize = math.Max(float64(c.Writer.Size()), 0)
obs.WithLabelValues(strconv.Itoa(c.Writer.Status()), c.Request.Method, pathFunc(c)).Observe(responseSize)
}
}
func instrumentHandlerDuration(obs prometheus.ObserverVec, pathFunc func(*gin.Context) string) func(*gin.Context) {
return func(c *gin.Context) {
now := time.Now()
c.Next()
obs.WithLabelValues(strconv.Itoa(c.Writer.Status()), c.Request.Method, pathFunc(c)).Observe(time.Since(now).Seconds())
}
}
// JSONLogger is a gin middleware that takes an instance of Logger and uses it for writing access
// logs that include error messages if there are any.
func JSONLogger() gin.HandlerFunc {
return func(c *gin.Context) {
// Start timer
start := time.Now()
path := c.Request.URL.Path
raw := c.Request.URL.RawQuery
// Process request
c.Next()
ts := time.Now()
if raw != "" {
path = path + "?" + raw
}
errorMessage := strings.TrimSuffix(c.Errors.ByType(gin.ErrorTypePrivate).String(), "\n")
l := log.With().Str("remote", c.ClientIP()).Logger().
With().Str("method", c.Request.Method).Logger().
With().Str("path", path).Logger().
With().Str("protocol", c.Request.Proto).Logger().
With().Str("code", fmt.Sprint(c.Writer.Status())).Logger().
With().Str("latency", ts.Sub(start).String()).Logger().
With().Str("agent", c.Request.UserAgent()).Logger()
if c.Writer.Status() >= 400 && c.Writer.Status() < 500 {
l.Warn().Msg(errorMessage)
} else if c.Writer.Status() >= 500 {
l.Error().Msg(errorMessage)
} else {
l.Info().Msg(errorMessage)
}
}
}
|
