Merge pull request #1 from metonymic-smokey/develop

Use real time temperature data

README.md

@@ -1,2 +1,7 @@
 # prom-exporter
 Repo for learning how to implement Prometheus exporter
+
+### Instructions to run:    
+* Have Prometheus running on port 9090 and make sure port 2112 is not in use.   
+* Async exporter: `go run async.go temp.go`.     
+* Sync exporter: `go run sync.go temp.go`.     

async.go

@@ -1,25 +1,35 @@
 package main
 
 import (
-	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"net/http"
 	"time"
 
+	"github.com/gorilla/mux"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
-func recordMetrics(temp float64) {
-	go func() {
-		for {
-			opsProcessed.Inc()
-			jobsInQueue.Set(temp)
+func recordMetrics() {
+	for {
+		dat, err := getTempData()
+		if err != nil {
+			fmt.Println(err)
 			time.Sleep(2 * time.Second)
+			continue
 		}
-	}()
+		if len(dat.Data.Timestep) == 0 {
+			continue
+		}
+
+		for _, interval := range dat.Data.Timestep[0].TempVal {
+			jobsInQueue.Set(interval.Values.Temp)
+		}
+
+		opsProcessed.Inc()
+		time.Sleep(2 * time.Second)
+	}
 }
 
 var opsProcessed = promauto.NewGauge(
@@ -36,49 +46,29 @@ var jobsInQueue = promauto.NewGauge(
 	},
 )
 
-type Temperature struct {
-	Temp float64 `json:"temperature"`
-}
+var httpDuration = promauto.NewHistogramVec(prometheus.HistogramOpts{
+	Name: "http_response_time_seconds",
+	Help: "Duration of HTTP requests.",
+}, []string{"path"})
 
-type Final struct {
-	StartTime string      `json:"startTime"`
-	Values    Temperature `json:"values"`
-}
+func prometheusMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		route := mux.CurrentRoute(r)
+		path, _ := route.GetPathTemplate()
 
-type Interval struct {
-	Timestep  string  `json:"timestep"`
-	StartTime string  `json:"startTime"`
-	EndTime   string  `json:"endTime"`
-	TempVal   []Final `json:"intervals"`
-}
+		timer := prometheus.NewTimer(httpDuration.WithLabelValues(path))
 
-type Timelines struct {
-	Timestep []Interval `json:"timelines"`
-}
-
-type Response struct {
-	Data Timelines `json:"data"`
+		timer.ObserveDuration()
+	})
 }
 
 func main() {
-	url := fmt.Sprintf("https://api.tomorrow.io/v4/timelines?location=%f,%f&fields=temperature&timesteps=%s&units=%s", 73.98529171943665, 40.75872069597532, "1h", "metric")
-
-	req, _ := http.NewRequest("GET", url, nil)
-	req.Header.Add("apikey", "APIKEY")
-	res, _ := http.DefaultClient.Do(req)
-	defer res.Body.Close()
-
-	body, _ := ioutil.ReadAll(res.Body)
+	go recordMetrics()
 
-	var dat Response
-	if err := json.Unmarshal(body, &dat); err != nil {
-		panic(err)
-	}
-
-	for _, interval := range dat.Data.Timestep[0].TempVal {
-		recordMetrics(interval.Values.Temp)
-	}
+	router := mux.NewRouter()
+	router.Use(prometheusMiddleware)
 
-	http.Handle("/metrics", promhttp.Handler())
+	//http.Handle("/metrics", promhttp.Handler())
+	router.Path("/metrics").Handler(promhttp.Handler())
 	http.ListenAndServe(":2112", nil)
 }

go.mod

@@ -4,6 +4,7 @@ go 1.16
 
 require (
 	github.com/google/go-cmp v0.5.6 // indirect
+	github.com/gorilla/mux v1.8.0
 	github.com/prometheus/client_golang v1.11.0
 	golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1 // indirect
 )

go.sum

@@ -39,6 +39,8 @@ github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/
 github.com/google/go-cmp v0.5.6 h1:BKbKCqvP6I+rmFHt06ZmyQtvB8xAkWdhFyr0ZUNZcxQ=
 github.com/google/go-cmp v0.5.6/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
+github.com/gorilla/mux v1.8.0 h1:i40aqfkR1h2SlN9hojwV5ZA91wcXFOvkdNIeFDP5koI=
+github.com/gorilla/mux v1.8.0/go.mod h1:DVbg23sWSpFRCP0SfiEN6jmj59UnW/n46BH5rLB71So=
 github.com/jpillora/backoff v1.0.0/go.mod h1:J/6gKK9jxlEcS3zixgDgUAsiuZ7yrSoa/FX5e0EB2j4=
 github.com/json-iterator/go v1.1.6/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
 github.com/json-iterator/go v1.1.10/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=

sync.go

@@ -1,9 +1,11 @@
 package main
 
 import (
+	"fmt"
 	"log"
 	"math/rand"
 	"net/http"
+	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
@@ -15,12 +17,26 @@ type CityStats struct {
 
 //temperature by country
 func (c *CityStats) TemperatureAndHumidity() (
-	tempByCity map[string]int, humidityByCity map[string]float64,
+	tempByCity map[string]float64, humidityByCity map[string]float64,
 ) {
-	tempByCity = map[string]int{
-		"bangalore": rand.Intn(100),
-		"london":    rand.Intn(1000),
+	// get real time API temp data here
+	tempByCity = make(map[string]float64)
+	dat, err := getTempData()
+	if err != nil {
+		fmt.Println(err)
+		return
 	}
+	if len(dat.Data.Timestep) == 0 {
+		fmt.Println("empty result!")
+		return
+	}
+
+	cities := []string{"bangalore", "london"}
+
+	for ind, interval := range dat.Data.Timestep[0].TempVal {
+		tempByCity[cities[ind%2]] = interval.Values.Temp
+	}
+
 	humidityByCity = map[string]float64{
 		"bangalore": rand.Float64(),
 		"london":    rand.Float64(),
@@ -43,14 +59,23 @@ var (
 		"humidity of a city as a fraction",
 		[]string{"city"}, nil,
 	)
+	httpDuration = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Name:    "http_response_time_seconds",
+		Help:    "Duration of HTTP requests.",
+		Buckets: prometheus.LinearBuckets(20, 5, 5),
+	})
 )
 
 func (cc CityStatsCollector) Describe(ch chan<- *prometheus.Desc) {
 	prometheus.DescribeByCollect(cc, ch)
 }
 
 func (cc CityStatsCollector) Collect(ch chan<- prometheus.Metric) {
+	begin := time.Now()
 	tempByCity, humidityByCity := cc.CityStats.TemperatureAndHumidity()
+	duration := time.Since(begin)
+	httpDuration.Observe(float64(duration))
+
 	for city, temp := range tempByCity {
 		ch <- prometheus.MustNewConstMetric(
 			tempDesc,
@@ -88,6 +113,7 @@ func main() {
 	reg.MustRegister(
 		prometheus.NewProcessCollector(prometheus.ProcessCollectorOpts{}),
 		prometheus.NewGoCollector(),
+		httpDuration,
 	)
 
 	http.Handle("/metrics", promhttp.HandlerFor(reg, promhttp.HandlerOpts{}))

temp.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+)
+
+type Temperature struct {
+	Temp float64 `json:"temperature"`
+}
+
+type Final struct {
+	StartTime string      `json:"startTime"`
+	Values    Temperature `json:"values"`
+}
+
+type Interval struct {
+	Timestep  string  `json:"timestep"`
+	StartTime string  `json:"startTime"`
+	EndTime   string  `json:"endTime"`
+	TempVal   []Final `json:"intervals"`
+}
+
+type Timelines struct {
+	Timestep []Interval `json:"timelines"`
+}
+
+type Response struct {
+	Data Timelines `json:"data"`
+}
+
+func getTempData() (Response, error) {
+	url := fmt.Sprintf("https://api.tomorrow.io/v4/timelines?location=%f,%f&fields=temperature&timesteps=%s&units=%s", 73.98529171943665, 40.75872069597532, "1h", "metric")
+
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return Response{}, errors.New("error in GET request")
+	}
+	req.Header.Add("apikey", "APIKEY")
+	res, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return Response{}, err
+	}
+	defer res.Body.Close()
+
+	body, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		return Response{}, errors.New("error reading response")
+	}
+
+	var dat Response
+	if err := json.Unmarshal(body, &dat); err != nil {
+		return Response{}, errors.New("error unmarshalling JSON")
+	}
+
+	return dat, nil
+}