Gin Web Framework Prometheus metrics exporter
$ go get github.com/zsais/go-gin-prometheus
package main
import (
"github.com/gin-gonic/gin"
"github.com/zsais/go-gin-prometheus"
)
func main() {
r := gin.New()
// NewWithConfig is the recommended way to initialize the middleware
p := ginprometheus.NewWithConfig(ginprometheus.Config{
Subsystem: "gin",
})
p.Use(r)
r.GET("/", func(c *gin.Context) {
c.JSON(200, "Hello world!")
})
r.Run(":29090")
}See the example.go file
It is possible to add custom labels to all metrics.
package main
import (
"github.com/gin-gonic/gin"
"github.com/zsais/go-gin-prometheus"
)
func main() {
r := gin.New()
// NewWithConfig is the recommended way to initialize the middleware
p := ginprometheus.NewWithConfig(ginprometheus.Config{
Subsystem: "gin",
CustomLabels: map[string]string{
"custom_label": "custom_value",
},
})
p.Use(r)
r.GET("/", func(c *gin.Context) {
c.JSON(200, "Hello world!")
})
r.Run(":29090")
}By default, this middleware reads the entire request body to calculate the request size. This can be expensive for large request bodies. You can disable this behavior by setting the DisableBodyReading option to true. When disabled, the middleware will use the ContentLength header to determine the request size.
package main
import (
"github.com/gin-gonic/gin"
"github.com/zsais/go-gin-prometheus"
)
func main() {
r := gin.New()
// NewWithConfig is the recommended way to initialize the middleware
p := ginprometheus.NewWithConfig(ginprometheus.Config{
Subsystem: "gin",
DisableBodyReading: true,
})
p.Use(r)
r.GET("/", func(c *gin.Context) {
c.JSON(200, "Hello world!")
})
r.Run(":29090")
}The request counter (requests_total) has a url label which,
although desirable, can become problematic in cases where your
application uses templated routes expecting a great number of
variations, as Prometheus explicitly recommends against metrics having
high cardinality dimensions:
https://prometheus.io/docs/practices/naming/#labels
If you have for instance a /customer/:name templated route and you
don't want to generate a time series for every possible customer name,
you could supply this mapping function to the middleware:
package main
import (
"strings"
"github.com/gin-gonic/gin"
"github.com/zsais/go-gin-prometheus"
)
func main() {
r := gin.New()
// NewWithConfig is the recommended way to initialize the middleware
p := ginprometheus.NewWithConfig(ginprometheus.Config{
Subsystem: "gin",
})
p.ReqCntURLLabelMappingFn = func(c *gin.Context) string {
url := c.Request.URL.Path
for _, p := range c.Params {
if p.Key == "name" {
url = strings.Replace(url, p.Value, ":name", 1)
break
}
}
return url
}
p.Use(r)
r.GET("/", func(c *gin.Context) {
c.JSON(200, "Hello world!")
})
r.Run(":29090")
}which would map /customer/alice and /customer/bob to their
template /customer/:name, and thus preserve a low cardinality for
our metrics.
The default branch of this repository will soon be renamed from master to main. To update your local clone after this change has been made, you can use the following commands:
git fetch origin
git checkout main
git branch -u origin/main
git branch -d master