update changelog

Reviewed-on: #9

.gitignore

@@ -22,6 +22,9 @@ go.work
 
 # vscode Go debugging files
 __debug_*
+ntppool-exporter
+bin/
 
 # vscode editor config
 .vscode/
+

.woodpecker/docker-deploy.yml

@@ -0,0 +1,35 @@
+when:
+  - event: [pull_request, tag]
+  
+
+steps:
+  docker-deploy-pr:
+    when:
+      - event: pull_request
+    image: woodpeckerci/plugin-docker-buildx
+    settings:
+      dockerfile: Dockerfile
+      platforms: linux/arm/v7,linux/arm64/v8,linux/amd64
+      repo: lauralani/ntppool-exporter
+      registry: https://index.docker.io/v1/
+      tag: pr-${CI_COMMIT_PULL_REQUEST}
+      username: lauralani
+      password:
+        from_secret: dockerhub_token
+  
+
+  docker-deploy-tag:
+    when:
+      event: tag
+    image: woodpeckerci/plugin-docker-buildx
+    settings:
+      dockerfile: Dockerfile
+      platforms: linux/arm/v7,linux/arm64/v8,linux/amd64
+      repo: lauralani/ntppool-exporter
+      registry: https://index.docker.io/v1/
+      auto_tag: true
+      username: lauralani
+      password:
+        from_secret: dockerhub_token
+
+  

.woodpecker/golang-test.yml

@@ -0,0 +1,9 @@
+when:
+  - event: push
+
+steps:
+  test:
+    image: golang:1.22-bullseye
+    commands:
+      - go mod download
+      - go test -v ./...

CHANGELOG.md

@@ -6,16 +6,35 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Changed
+- changed docker base image to gcr.io/distroless/static-debian12
+
+## [0.2.0] - 2024-04-19
+### ⚠️ Breaking Changes
+- renamed the score metric from `ntppool_score` to `ntppool_server_score`
+- removed unneccessary `server` label in metrics
+
+### Added
+- added in-memory cache to reduce API strain (#4)
+
+### Changed
+- fixed some debug logs
+- update readme to reflect new repo
+
+## [0.1.1] - 2024-04-17
+### Fixed
+- Fix nil references when http request fails (#2)
 
 ## [0.1.0] - 2024-04-17
 
 ### Added
-
 - This CHANGELOG file to document all significant changes
 - LICENSE
 - CONTRIBUTING guidelines
 - MAINTAINERS file
 - minimal implementation of the exporter
 
-[unreleased]: https://gitlab.com/adoralaura/ntppool-exporter/compare/v0.1.0...HEAD
-[0.1.0]: https://gitlab.com/adoralaura/ntppool-exporter/releases/tag/v0.1.0
+[unreleased]: https://gitlab.com/adoralaura/ntppool-exporter/compare/0.2.0...HEAD
+[0.2.0]: https://gitlab.com/adoralaura/ntppool-exporter/compare/0.1.1...0.2.0
+[0.1.1]: https://gitlab.com/adoralaura/ntppool-exporter/compare/0.1.0...0.1.1
+[0.1.0]: https://gitlab.com/adoralaura/ntppool-exporter/releases/tag/0.1.0

CONTRIBUTING.md

@@ -1,12 +1,12 @@
 # Contributing
 
-We use GitLab to manage reviews of pull requests.
+I use my own [Forgejo Instance](https://code.lila.network) to manage issues and pull requests.
 
 * If you have a trivial fix or improvement, go ahead and create a pull request,
   addressing (with `@...`) the maintainer of this repository (see
   [MAINTAINERS.md](MAINTAINERS.md)) in the description of the pull request.
 
-* If you plan to do something more involved, first please create [a new issue](https://gitlab.com/adoralaura/ntppool-exporter/-/issues/new).
+* If you plan to do something more involved, first please [send me a mail]( mailto:adora@lila.network?subject=%5Bntppool-exporter%5D).
 
 # What to contribute
 

Dockerfile

@@ -1,8 +1,9 @@
-FROM golang:1.22-alpine AS dev
+FROM golang:1.22-bullseye AS dev
 
 COPY . /var/app
 WORKDIR /var/app
 
+
 ENV GO111MODULE="on" \
     CGO_ENABLED=0 \
     GOOS=linux
@@ -13,12 +14,13 @@ ENTRYPOINT ["sh"]
 
 FROM dev as build
 
+RUN DEBIAN_FRONTEND=noninteractive apt-get install --no-install-recommends --assume-yes ca-certificates
 RUN go mod download && go mod verify
-RUN go build -o ntppool-exporter main.go$
+RUN go build -o ntppool-exporter main.go
 RUN chmod +x ntppool-exporter
 
 
-FROM scratch AS prod
+FROM gcr.io/distroless/static-debian12 AS prod
 
 WORKDIR /app
 COPY --from=build /var/app/ntppool-exporter /bin/

Makefile

@@ -0,0 +1,3 @@
+
+test:
+	go test ./...

README.md

@@ -2,16 +2,13 @@
 
 This exporter is @adoralaura s try to display server scores from servers in [ntppool.org](https://www.ntppool.org) in a format which [Prometheus](https://prometheus.io/) can ingest.
 
-
-
-
-
 # Usage
 
 ## Installation
 
-Binaries can be downloaded soon from the [GitLab releases page](https://gitlab.com/adoralaura/ntppool-exporter/-/releases) and need no
-special installation
+Pre-built docker images can be found at [Docker Hub](https://hub.docker.com/r/lauralani/ntppool-exporter). A sample `docker-compose.yml` can be [found here](docker-compose.yml).
+
+Binaries can be built by cloning this repository and run `go build main.go` with [Golang](https://go.dev/) installed.
 
 ## Running
 

VERSION

@@ -1 +0,0 @@
-0.1.0

cache/cache.go

@@ -0,0 +1,93 @@
+/*
+Copyright 2024 Adora Laura Kalb <adora@lila.network>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package cache
+
+import (
+	"net/netip"
+	"sync"
+	"time"
+)
+
+var (
+	GlobalScoreCache  *ScoreCache
+	cacheExpiredAfter = 5 * time.Minute
+)
+
+type ServerScore struct {
+	expiresAt time.Time
+	Score     float64
+}
+
+type ScoreCache struct {
+	stop chan struct{}
+
+	mu sync.RWMutex
+
+	scores map[netip.Addr]ServerScore
+}
+
+type CacheMissError struct{}
+
+func (m *CacheMissError) Error() string {
+	return "User is not in cache!"
+}
+
+func newCacheMissError() *CacheMissError {
+	return &CacheMissError{}
+}
+
+func NewScoreCache() *ScoreCache {
+	lc := &ScoreCache{
+		scores: make(map[netip.Addr]ServerScore),
+		stop:   make(chan struct{}),
+	}
+
+	return lc
+}
+
+func (sc *ScoreCache) Add(score float64, ip netip.Addr, ts time.Time) {
+	ssc := ServerScore{Score: score, expiresAt: ts.Add(cacheExpiredAfter)}
+	sc.mu.Lock()
+	sc.scores[ip] = ssc
+	sc.mu.Unlock()
+}
+
+func (lc *ScoreCache) Get(ip netip.Addr) (ServerScore, error) {
+	now := time.Now()
+	lc.mu.RLock()
+
+	cachedScore, ok := lc.scores[ip]
+	if !ok {
+		lc.mu.RUnlock()
+		return ServerScore{}, newCacheMissError()
+	}
+	lc.mu.RUnlock()
+
+	if now.After(cachedScore.expiresAt) {
+		lc.delete(ip)
+		return ServerScore{}, newCacheMissError()
+	}
+
+	return cachedScore, nil
+}
+
+func (lc *ScoreCache) delete(ip netip.Addr) {
+	lc.mu.Lock()
+
+	delete(lc.scores, ip)
+	lc.mu.Unlock()
+}

cache/cache_test.go

@@ -0,0 +1,49 @@
+/*
+Copyright 2024 Adora Laura Kalb <adora@lila.network>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package cache
+
+import (
+	"net/netip"
+	"testing"
+	"time"
+)
+
+func TestCacheGet(t *testing.T) {
+	const testFloat = 1.23456
+	cache := NewScoreCache()
+	cache.Add(testFloat, netip.MustParseAddr("1.2.3.4"), time.Now().Add(5*time.Minute))
+
+	score, _ := cache.Get(netip.MustParseAddr("1.2.3.4"))
+	if score.Score != testFloat {
+		t.Fatalf("cache.Get(\"1.2.3.4\") = %f, want %f", score.Score, testFloat)
+	}
+}
+
+func TestCacheMiss(t *testing.T) {
+	now := time.Now()
+	const testFloat = 1.23456
+
+	expiredTime := now.Add(-(time.Minute * 10))
+
+	cache := NewScoreCache()
+	cache.Add(testFloat, netip.MustParseAddr("1.2.3.4"), expiredTime)
+
+	_, err := cache.Get(netip.MustParseAddr("1.2.3.4"))
+	if err == nil {
+		t.Fatalf("cache.Get(\"1.2.3.4\") = got nil, want error")
+	}
+}

collector/collector.go

@@ -27,6 +27,7 @@ import (
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
 	"github.com/prometheus/client_golang/prometheus"
+	"golang.adora.codes/ntppool-exporter/cache"
 	"golang.adora.codes/ntppool-exporter/models"
 )
 
@@ -52,7 +53,7 @@ func (c Collector) Describe(ch chan<- *prometheus.Desc) {
 
 // Collect implements Prometheus.Collector.
 func (c Collector) Collect(ch chan<- prometheus.Metric) {
-	logger := log.With(c.logger, "scraper")
+	logger := log.With(c.logger, "module", "scraper")
 	level.Debug(logger).Log("msg", "Starting scrape")
 	start := time.Now()
 	c.collect(ch, logger)
@@ -61,7 +62,24 @@ func (c Collector) Collect(ch chan<- prometheus.Metric) {
 }
 
 func (c Collector) collect(ch chan<- prometheus.Metric, logger log.Logger) {
-	httpError := false
+	score, err := cache.GlobalScoreCache.Get(c.target)
+	if err == nil {
+		level.Debug(logger).Log("msg", "Serving score from cache",
+			"server", c.target.String(), "score", score.Score)
+
+		serverScoreMetric := prometheus.NewDesc("ntppool_server_score",
+			"Shows the server score currently assigned at ntppool.org",
+			nil, nil)
+
+		m1 := prometheus.MustNewConstMetric(serverScoreMetric, prometheus.GaugeValue, score.Score)
+		m1 = prometheus.NewMetricWithTimestamp(time.Now(), m1)
+		ch <- m1
+		return
+	}
+
+	level.Debug(logger).Log("msg", "Cache miss, querying API",
+		"server", c.target.String())
+
 	var serverApiScore float64 = 0
 	const apiEndpoint = "https://www.ntppool.org/scores/"
 	const apiQuery = "/json?limit=1&monitor=24"
@@ -73,19 +91,20 @@ func (c Collector) collect(ch chan<- prometheus.Metric, logger log.Logger) {
 
 	if err != nil {
 		level.Error(logger).Log("msg", "Error sending HTTP request", "url", url, "message", err)
-		httpError = true
+		return
 	}
 	res, err := client.Do(req)
 	if err != nil {
-		level.Error(logger).Log("msg", "Error in HTTP response", "status", res.Status)
-		httpError = true
+		level.Error(logger).Log("msg", "Error in HTTP response", "error", err)
+		return
+
 	}
 	defer res.Body.Close()
 
 	body, err := io.ReadAll(res.Body)
 	if err != nil {
 		level.Error(logger).Log("msg", "Error reading HTTP response body", "error", err)
-		httpError = true
+		return
 	}
 
 	var response models.ApiResponse
@@ -93,17 +112,19 @@ func (c Collector) collect(ch chan<- prometheus.Metric, logger log.Logger) {
 	err = json.Unmarshal(body, &response)
 	if err != nil {
 		level.Error(logger).Log("msg", "Error unmarshaling JSON body", "error", err)
-		httpError = true
+		return
 	}
 
-	if !httpError {
-		serverApiScore = response.History[0].Score
-	}
+	serverApiScore = response.History[0].Score
+
+	cache.GlobalScoreCache.Add(serverApiScore, c.target, time.Now())
+	level.Debug(logger).Log("msg", "Added score to cache",
+		"server", c.target.String(), "score", score.Score)
 
 	// TODO: Test or delete
-	serverScoreMetric := prometheus.NewDesc("ntppool_score",
+	serverScoreMetric := prometheus.NewDesc("ntppool_server_score",
 		"Shows the server score currently assigned at ntppool.org",
-		nil, prometheus.Labels{"server": c.target.String()})
+		nil, nil)
 
 	// TODO: Test or delete
 	//c.metrics.NtpppolServerScore.Add(serverApiScore)

docker-compose.yml

@@ -0,0 +1,8 @@
+services:
+  ntppool_exporter:
+    image: lauralani/ntppool-exporter:latest
+    restart: always
+    ports:
+      - '127.0.0.1:43609:43609'
+    # Add this to enable debug logging:
+    # command: --log.level=debug 

helpers/helpers.go

@@ -0,0 +1,25 @@
+/*
+Copyright 2024 Adora Laura Kalb <adora@lila.network>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package helpers
+
+import (
+	"time"
+)
+
+func UnixToTime(i int64) time.Time {
+	return time.Unix(i, 0)
+}

main.go

@@ -20,6 +20,7 @@ import (
 	"net/http"
 	"net/netip"
 	"os"
+	"time"
 
 	"github.com/alecthomas/kingpin/v2"
 	"github.com/go-kit/log"
@@ -32,11 +33,13 @@ import (
 	"github.com/prometheus/common/version"
 	"github.com/prometheus/exporter-toolkit/web"
 	webflag "github.com/prometheus/exporter-toolkit/web/kingpinflag"
+	"golang.adora.codes/ntppool-exporter/cache"
 	"golang.adora.codes/ntppool-exporter/collector"
 )
 
 const (
-	namespace = "ntppool"
+	namespace  = "ntppool"
+	appVersion = "0.2.0"
 )
 
 var (
@@ -87,6 +90,7 @@ func handler(w http.ResponseWriter, r *http.Request, logger log.Logger, exporter
 }
 
 func main() {
+	version.Version = appVersion
 	promlogConfig := &promlog.Config{}
 	flag.AddFlags(kingpin.CommandLine, promlogConfig)
 	kingpin.Version(version.Print("ntppool_exporter"))
@@ -94,7 +98,9 @@ func main() {
 	kingpin.Parse()
 	logger := promlog.New(promlogConfig)
 
-	level.Info(logger).Log("msg", "Starting ntppool_exporter", "version", version.Info())
+	cache.GlobalScoreCache = cache.NewScoreCache()
+
+	level.Info(logger).Log("msg", "Starting ntppool_exporter", "version", appVersion)
 	level.Info(logger).Log("build_context", version.BuildContext())
 
 	exporterMetrics := collector.Metrics{
@@ -146,7 +152,12 @@ func main() {
 		http.Handle("/", landingPage)
 	}
 
-	srv := &http.Server{}
+	srv := &http.Server{
+		ReadHeaderTimeout: 15 * time.Second,
+		ReadTimeout:       15 * time.Second,
+		WriteTimeout:      10 * time.Second,
+		IdleTimeout:       30 * time.Second,
+	}
 	if err := web.ListenAndServe(srv, toolkitFlags, logger); err != nil {
 		level.Error(logger).Log("msg", "Error starting HTTP server", "err", err)
 		os.Exit(1)

models/api_response.go

@@ -34,8 +34,8 @@ type ApiResponse struct {
 }
 
 type ApiResponseHistory struct {
-	Timestamp int     `json:"ts"`
-	Step      int     `json:"step"`
-	Score     float64 `json:"score"`
-	MonitorID int     `json:"monitor_id"`
+	TimestampInt int64   `json:"ts"`
+	Step         int     `json:"step"`
+	Score        float64 `json:"score"`
+	MonitorID    int     `json:"monitor_id"`
 }