Provide adapters for mailgun and modernprogram.

README.md

@@ -1 +1,118 @@
-# Prometheus Groupcache exporter
+[![license](http:https://img.shields.io/badge/license-MIT-blue.svg)](https://github.com/udhos/groupcache_exporter/blob/main/LICENSE)
+[![Go Report Card](https://goreportcard.com/badge/github.com/udhos/groupcache_exporter)](https://goreportcard.com/report/github.com/udhos/groupcache_exporter)
+[![Go Reference](https://pkg.go.dev/badge/github.com/udhos/groupcache_exporter.svg)](https://pkg.go.dev/github.com/udhos/groupcache_exporter)
+
+# Prometheus Groupcache exporter
+
+This exporter implements the prometheus.Collector interface in order to expose Prometheus metrics for [groupcache](https://github.com/golang/groupcache).
+
+# Example for mailgun groupcache
+
+```golang
+import "github.com/grafana/groupcache_exporter/groupcache/mailgun"
+
+// ...
+
+appName := filepath.Base(os.Args[0])
+
+cache := startGroupcache()
+
+//
+// expose prometheus metrics
+//
+{
+ metricsRoute := "/metrics"
+ metricsPort := ":3000"
+
+ log.Printf("starting metrics server at: %s %s", metricsPort, metricsRoute)
+
+ mailgun := mailgun.New(cache)
+ labels := map[string]string{
+ "app": appName,
+ }
+ namespace := ""
+ collector := groupcache_exporter.NewExporter(namespace, labels, mailgun)
+
+ prometheus.MustRegister(collector)
+
+ go func() {
+ http.Handle(metricsRoute, promhttp.Handler())
+ log.Fatal(http.ListenAndServe(metricsPort, nil))
+ }()
+}
+```
+
+Full example: [./examples/groupcache/mailgun](./examples/groupcache/mailgun)
+
+# Example for modernprogram groupcache
+
+```golang
+import "github.com/grafana/groupcache_exporter/groupcache/modernprogram"
+
+// ...
+
+appName := filepath.Base(os.Args[0])
+
+cache := startGroupcache()
+
+//
+// expose prometheus metrics
+//
+{
+ metricsRoute := "/metrics"
+ metricsPort := ":3000"
+
+ log.Printf("starting metrics server at: %s %s", metricsPort, metricsRoute)
+
+ modernprogram := modernprogram.New(cache)
+ labels := map[string]string{
+ "app": appName,
+ }
+ namespace := ""
+ collector := groupcache_exporter.NewExporter(namespace, labels, modernprogram)
+
+ prometheus.MustRegister(collector)
+
+ go func() {
+ http.Handle(metricsRoute, promhttp.Handler())
+ log.Fatal(http.ListenAndServe(metricsPort, nil))
+ }()
+}
+```
+
+Full example: [./examples/groupcache/modernprogram](./examples/groupcache/modernprogram)
+
+# Testing
+
+## Build
+
+ go install ./...
+
+## Run example application
+
+ groupcache-exporter-mailgun
+
+## Query the metrics endpoint
+
+```bash
+curl -s localhost:3000/metrics | grep -E ^groupcache
+groupcache_cache_bytes{app="groupcache-exporter-mailgun",group="files",type="hot"} 0
+groupcache_cache_bytes{app="groupcache-exporter-mailgun",group="files",type="main"} 2954
+groupcache_cache_evictions_total{app="groupcache-exporter-mailgun",group="files",type="hot"} 0
+groupcache_cache_evictions_total{app="groupcache-exporter-mailgun",group="files",type="main"} 1
+groupcache_cache_gets_total{app="groupcache-exporter-mailgun",group="files",type="hot"} 4
+groupcache_cache_gets_total{app="groupcache-exporter-mailgun",group="files",type="main"} 16
+groupcache_cache_hits_total{app="groupcache-exporter-mailgun",group="files",type="hot"} 0
+groupcache_cache_hits_total{app="groupcache-exporter-mailgun",group="files",type="main"} 12
+groupcache_cache_items{app="groupcache-exporter-mailgun",group="files",type="hot"} 0
+groupcache_cache_items{app="groupcache-exporter-mailgun",group="files",type="main"} 1
+groupcache_gets_total{app="groupcache-exporter-mailgun",group="files"} 14
+groupcache_hits_total{app="groupcache-exporter-mailgun",group="files"} 12
+groupcache_loads_deduped_total{app="groupcache-exporter-mailgun",group="files"} 2
+groupcache_loads_total{app="groupcache-exporter-mailgun",group="files"} 2
+groupcache_local_load_errs_total{app="groupcache-exporter-mailgun",group="files"} 0
+groupcache_local_load_total{app="groupcache-exporter-mailgun",group="files"} 2
+groupcache_peer_errors_total{app="groupcache-exporter-mailgun",group="files"} 0
+groupcache_peer_loads_total{app="groupcache-exporter-mailgun",group="files"} 0
+groupcache_server_requests_total{app="groupcache-exporter-mailgun",group="files"} 0
+```

build.sh

@@ -0,0 +1,23 @@
+#!/bin/bash
+
+go install golang.org/x/vuln/cmd/govulncheck@latest
+
+gofmt -s -w .
+
+revive ./...
+
+gocyclo -over 15 .
+
+go mod tidy
+
+govulncheck ./...
+
+go env -w CGO_ENABLED=1
+
+go test -race ./...
+
+go env -w CGO_ENABLED=0
+
+go install ./...
+
+go env -u CGO_ENABLED

examples/groupcache-exporter-mailgun/groupcache.go

@@ -0,0 +1,71 @@
+package main
+
+import (
+ "context"
+ "log"
+ "net/http"
+ "os"
+ "time"
+
+ "github.com/mailgun/groupcache/v2"
+)
+
+func startGroupcache() *groupcache.Group {
+
+ ttl := time.Minute
+
+ log.Printf("groupcache ttl: %v", ttl)
+
+ //
+ // create groupcache pool
+ //
+
+ groupcachePort := ":5000"
+
+ myURL := "http:https://127.0.0.1" + groupcachePort
+
+ log.Printf("groupcache my URL: %s", myURL)
+
+ pool := groupcache.NewHTTPPoolOpts(myURL, &groupcache.HTTPPoolOptions{})
+
+ //
+ // start groupcache server
+ //
+
+ serverGroupCache := &http.Server{Addr: groupcachePort, Handler: pool}
+
+ go func() {
+ log.Printf("groupcache server: listening on %s", groupcachePort)
+ err := serverGroupCache.ListenAndServe()
+ log.Printf("groupcache server: exited: %v", err)
+ }()
+
+ pool.Set(myURL)
+
+ //
+ // create cache
+ //
+
+ var groupcacheSizeBytes int64 = 1_000_000
+
+ // https://talks.golang.org/2013/oscon-dl.slide#46
+ //
+ // 64 MB max per-node memory usage
+ cache := groupcache.NewGroup("files", groupcacheSizeBytes, groupcache.GetterFunc(
+ func(ctx context.Context, key string, dest groupcache.Sink) error {
+
+ log.Printf("getter: loading: key:%s, ttl:%v", key, ttl)
+
+ data, errFile := os.ReadFile(key)
+ if errFile != nil {
+ return errFile
+ }
+
+ expire := time.Now().Add(ttl)
+ dest.SetBytes(data, expire)
+
+ return nil
+ }))
+
+ return cache
+}

examples/groupcache-exporter-mailgun/main.go

@@ -0,0 +1,62 @@
+// Package main implements the example.
+package main
+
+import (
+ "context"
+ "log"
+ "net/http"
+ "os"
+ "path/filepath"
+ "time"
+
+ "github.com/grafana/groupcache_exporter"
+ "github.com/grafana/groupcache_exporter/groupcache/mailgun"
+ "github.com/mailgun/groupcache/v2"
+ "github.com/prometheus/client_golang/prometheus"
+ "github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+func main() {
+
+ appName := filepath.Base(os.Args[0])
+
+ cache := startGroupcache()
+
+ //
+ // expose prometheus metrics
+ //
+ {
+ metricsRoute := "/metrics"
+ metricsPort := ":3000"
+
+ log.Printf("starting metrics server at: %s %s", metricsPort, metricsRoute)
+
+ mailgun := mailgun.New(cache)
+ labels := map[string]string{
+ "app": appName,
+ }
+ namespace := ""
+ collector := groupcache_exporter.NewExporter(namespace, labels, mailgun)
+
+ prometheus.MustRegister(collector)
+
+ go func() {
+ http.Handle(metricsRoute, promhttp.Handler())
+ log.Fatal(http.ListenAndServe(metricsPort, nil))
+ }()
+ }
+
+ //
+ // query cache periodically
+ //
+
+ const interval = 5 * time.Second
+
+ for {
+ var dst []byte
+ cache.Get(context.TODO(), "/etc/passwd", groupcache.AllocatingByteSliceSink(&dst))
+ log.Printf("cache answer: %d bytes, sleeping %v", len(dst), interval)
+ time.Sleep(interval)
+ }
+
+}

examples/groupcache-exporter-modernprogram/groupcache.go

@@ -0,0 +1,71 @@
+package main
+
+import (
+ "context"
+ "log"
+ "net/http"
+ "os"
+ "time"
+
+ "github.com/modernprogram/groupcache/v2"
+)
+
+func startGroupcache() *groupcache.Group {
+
+ ttl := time.Minute
+
+ log.Printf("groupcache ttl: %v", ttl)
+
+ //
+ // create groupcache pool
+ //
+
+ groupcachePort := ":5000"
+
+ myURL := "http:https://127.0.0.1" + groupcachePort
+
+ log.Printf("groupcache my URL: %s", myURL)
+
+ pool := groupcache.NewHTTPPoolOpts(myURL, &groupcache.HTTPPoolOptions{})
+
+ //
+ // start groupcache server
+ //
+
+ serverGroupCache := &http.Server{Addr: groupcachePort, Handler: pool}
+
+ go func() {
+ log.Printf("groupcache server: listening on %s", groupcachePort)
+ err := serverGroupCache.ListenAndServe()
+ log.Printf("groupcache server: exited: %v", err)
+ }()
+
+ pool.Set(myURL)
+
+ //
+ // create cache
+ //
+
+ var groupcacheSizeBytes int64 = 1_000_000
+
+ // https://talks.golang.org/2013/oscon-dl.slide#46
+ //
+ // 64 MB max per-node memory usage
+ cache := groupcache.NewGroup("files", groupcacheSizeBytes, groupcache.GetterFunc(
+ func(ctx context.Context, key string, dest groupcache.Sink) error {
+
+ log.Printf("getter: loading: key:%s, ttl:%v", key, ttl)
+
+ data, errFile := os.ReadFile(key)
+ if errFile != nil {
+ return errFile
+ }
+
+ expire := time.Now().Add(ttl)
+ dest.SetBytes(data, expire)
+
+ return nil
+ }))
+
+ return cache
+}