promware

README

promware

A simple, configurable middleware for recording request metrics with Prometheus

🛠 Installation

Make sure to have Go installed (Version 1.16 or higher).

Install promware with go get:

$ go get -u github.com/imbue11235/promware

💻 Usage

With standard library

middleware := promware.Default()

handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    w.WriteHeader(http.StatusOK)
    fmt.Fprintln(w, "hello world")
})

mux := http.NewServeMux()
mux.Handle("/metrics", promhttp.Handler())
mux.Handle("/", middleware(handler))

http.ListenAndServe("<addr>", mux)

Options

middleware := promware.New(
    // Skip depending on request data 
    promware.WithSkipFunc(func(r *http.Request) bool {
        return r.URL.Path == "/something"
    })
    	
    // Set subsystem
    promware.WithSubsystem("my-subsystem")
    
    // Set namespace 
    promware.WithNamespace("my-namespace")
    
    // Add request counter, set name
    promware.WithRequestCounter("total-requests")
    
    // Add latency histogram, set name and buckets
    promware.WithLatencyHistogram("request-latency", []float64{0.5, 1, 2})
)

📜 License

This project is licensed under the MIT license.

Documentation

Index

• func WithDefaultLatencyHistogram() option
• func WithDefaultRequestCounter() option
• func WithLatencyHistogram(name string, buckets []float64) option
• func WithNamespace(namespace string) option
• func WithRequestCounter(name string) option
• func WithSkipFunc(skipFunc SkipFunc) option
• func WithSubsystem(name string) option
• type Middleware
  • func Default() Middleware
  • func New(options ...option) Middleware
• type SkipFunc

Functions

func WithDefaultLatencyHistogram

func WithDefaultLatencyHistogram() option

WithDefaultLatencyHistogram creates a latency histogram collector with the name `request_duration_seconds`

func WithDefaultRequestCounter

func WithDefaultRequestCounter() option

WithDefaultRequestCounter creates a request counter with the default name `requests_total`

func WithLatencyHistogram

func WithLatencyHistogram(name string, buckets []float64) option

WithLatencyHistogram creates a latency histogram collector with a given name

func WithNamespace

func WithNamespace(namespace string) option

WithNamespace sets the namespace of the prometheus collectors

func WithRequestCounter

func WithRequestCounter(name string) option

WithRequestCounter creates a new request counter collector with a given name

func WithSkipFunc

func WithSkipFunc(skipFunc SkipFunc) option

func WithSubsystem

func WithSubsystem(name string) option

WithSubsystem sets the subsystem of the prometheus collectors

Types

type Middleware

type Middleware func(next http.Handler) http.Handler

Middleware is responsible for creating a middleware handler func

func Default

func Default() Middleware

Default creates a new middleware with default collectors attached

func New

func New(options ...option) Middleware

New creates a new prometheus middleware from given options. Note: the middleware has no prometheus collectors attached per default. If you want the default collectors, use Default

type SkipFunc

type SkipFunc func(r *http.Request) bool

SkipFunc allows for certain requests to be skipped based on information obtained from the http.Request, e.g. URLPath.