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metrics: Add http_requests metric

pull/29/head
Daan Sprenkels 1 year ago
parent
commit
cf956501ac
4 changed files with 73 additions and 28 deletions
  1. +1
    -0
      go.sum
  2. +4
    -4
      handlers.go
  3. +35
    -24
      metrics.go
  4. +33
    -0
      router.go

+ 1
- 0
go.sum View File

@@ -41,6 +41,7 @@ github.com/prometheus/client_golang v0.9.1/go.mod h1:7SWBe2y4D6OKWSNQJUaRYU/AaXP
github.com/prometheus/client_golang v1.0.0/go.mod h1:db9x61etRT2tGnBNRi70OPL5FsnadC4Ky3P0J6CfImo=
github.com/prometheus/client_golang v1.1.0 h1:BQ53HtBmfOitExawJ6LokA4x8ov/z0SYYb0+HxJfRI8=
github.com/prometheus/client_golang v1.1.0/go.mod h1:I1FGZT9+L76gKKOs5djB6ezCbFQP1xR9D75/vuwEF3g=
github.com/prometheus/client_golang v1.2.1 h1:JnMpQc6ppsNgw9QPAGF6Dod479itz7lvlsMzzNayLOI=
github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910/go.mod h1:MbSGuTsp3dbXC40dX6PRTWyKYBIrTGTE9sqQNg2J8bo=
github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90 h1:S/YWwWx/RA8rT8tKFRuGUZhuA90OyIBpPCXkcbwU8DE=
github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=


+ 4
- 4
handlers.go View File

@@ -50,9 +50,9 @@ func (rl *rushlink) uploadFileGetHandler(w http.ResponseWriter, r *http.Request)
if badID {
renderError(w, r, http.StatusNotFound, "malformed file id")
return
} else {
panic(err)
}
// unexpected error
panic(err)
}

filePath := rl.fs.FilePath(fu.ID, fu.FileName)
@@ -62,9 +62,9 @@ func (rl *rushlink) uploadFileGetHandler(w http.ResponseWriter, r *http.Request)
log.Printf("error: %v should exist according to the database, but it doesn't", filePath)
renderError(w, r, http.StatusNotFound, "file not found")
return
} else {
panic(err)
}
// unexpected error
panic(err)
}
w.Header().Set("Content-Type", fu.ContentType)
io.Copy(w, file)


+ 35
- 24
metrics.go View File

@@ -10,34 +10,45 @@ import (
"github.com/gorilla/mux"
"github.com/pkg/errors"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promauto"
"github.com/prometheus/client_golang/prometheus/promhttp"
bolt "go.etcd.io/bbolt"
)

func StartMetricsServer(addr string, db *db.Database) {
var (
_ = promauto.NewGaugeFunc(prometheus.GaugeOpts{
Namespace: "rushlink",
Subsystem: "pastes",
Name: "urls_total",
Help: "The current amount of pastes in the database.",
}, func() float64 {
var metric float64
if err := db.Bolt.View(func(tx *bolt.Tx) error {
bucket := tx.Bucket([]byte("pastes"))
if bucket == nil {
return errors.New("bucket 'pastes' could not be found")
}
metric = float64(bucket.Stats().KeyN)
return nil
}); err != nil {
log.Printf("error: %v", errors.Wrap(err, "fetching pastes_total metric"))
return 0
}
return metric
})
)
const metricNamespace = "rushlink"

var metricRequestsTotalCounter = prometheus.NewCounterVec(prometheus.CounterOpts{
Namespace: metricNamespace,
Subsystem: "http",
Name: "requests_total",
Help: "How many HTTP requests processed, partitioned by status code and HTTP method.",
}, []string{"code", "method"})

func metricURLsTotal(database *db.Database) float64 {
var metric float64
if err := database.Bolt.View(func(tx *bolt.Tx) error {
bucket := tx.Bucket([]byte("pastes"))
if bucket == nil {
return errors.New("bucket 'pastes' could not be found")
}
metric = float64(bucket.Stats().KeyN)
return nil
}); err != nil {
log.Printf("error: %v", errors.Wrap(err, "fetching pastes_total metric"))
return 0
}
return metric
}

// StartMetricsServer starts sering Prometheus metrics exports on addr
func StartMetricsServer(addr string, database *db.Database, fs *db.FileStore) {
prometheus.MustRegister(metricRequestsTotalCounter)

prometheus.MustRegister(prometheus.NewGaugeFunc(prometheus.GaugeOpts{
Namespace: metricNamespace,
Subsystem: "pastes",
Name: "urls_total",
Help: "The current amount of pastes in the database.",
}, func() float64 { return metricURLsTotal(database) }))

router := mux.NewRouter()
router.Handle("/metrics", promhttp.Handler()).Methods("GET")


+ 33
- 0
router.go View File

@@ -5,6 +5,7 @@ import (
"log"
"net/http"
"runtime/debug"
"strconv"
"time"

"gitea.hashru.nl/dsprenkels/rushlink/internal/db"
@@ -37,6 +38,37 @@ func recoveryMiddleware(next http.Handler) http.Handler {
})
}

type statusResponseWriter struct {
Inner http.ResponseWriter
StatusCode int
}

func (w *statusResponseWriter) Header() http.Header {
return w.Inner.Header()
}

func (w *statusResponseWriter) Write(buf []byte) (int, error) {
if w.StatusCode == 0 {
w.WriteHeader(http.StatusOK)
}
return w.Inner.Write(buf)
}

func (w *statusResponseWriter) WriteHeader(statusCode int) {
w.StatusCode = statusCode
w.Inner.WriteHeader(statusCode)
}

func metricsMiddleware(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
srw := statusResponseWriter{Inner: w}
next.ServeHTTP(&srw, r)
status := strconv.Itoa(srw.StatusCode)
metricRequestsTotalCounter.WithLabelValues(status, r.Method).Inc()
})
}

// StartMainServer starts the main http server listening on addr.
func StartMainServer(addr string, db *db.Database, fs *db.FileStore) {
rl := rushlink{
db: db,
@@ -46,6 +78,7 @@ func StartMainServer(addr string, db *db.Database, fs *db.FileStore) {
// Initialize Gorilla router
router := mux.NewRouter()
router.Use(recoveryMiddleware)
router.Use(metricsMiddleware)
router.HandleFunc("/", rl.indexGetHandler).Methods("GET")
router.HandleFunc("/", rl.newPasteHandler).Methods("POST")
router.HandleFunc("/{key:[A-Za-z0-9-_]{4,}}", rl.viewPasteHandler).Methods("GET")


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