First version

2022-09-26 23:25:10 +03:00 · 2022-09-26 23:25:10 +03:00 · 3805b8267a
commit 3805b8267a
parent 8b28b22064
5 changed files with 188 additions and 0 deletions
--- a/go.mod
+++ b/go.mod
@ -0,0 +1,5 @@
+module git.dm1sh.ru/dm1sh/gotemptracker
+
+go 1.19
+
+require github.com/lib/pq v1.10.7
--- a/go.sum
+++ b/go.sum
@ -0,0 +1,2 @@
+github.com/lib/pq v1.10.7 h1:p7ZhMD+KsSRozJr34udlUrhboJwWAgCg34+/ZZNvZZw=
+github.com/lib/pq v1.10.7/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
--- a/index.gohtml
+++ b/index.gohtml
@ -0,0 +1,49 @@
+<!DOCTYPE html>
+<html>
+
+<head>
+	<meta charset="utf-8">
+	<meta name="viewport" content="width=device-width, initial-scale=1">
+	<title>gotemptracker</title>
+</head>
+
+<body>
+	<h1>This is the first step to quantified selt, brought in by Golang app with PostgreSQL database</h1>
+	<form method="post">
+		<label>Temperature:</label><br />
+		<input type="number" step="0.1" name="value">
+		<input type="submit">
+	</form>
+
+	<canvas id="tempChart" style="width:100%;max-width:700px"></canvas>
+
+	<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js">
+	</script>
+
+	<script>
+		const vals = [
+			{{range .}}
+				{{.Value}},
+			{{end}}
+		];
+
+		const dates = [
+			{{range .}}
+				{{.CreatedAt.Format "2006-01-02"}},
+			{{end}}
+		];
+
+		new Chart("tempChart", {
+			type: "line",
+			data: {
+				labels: dates,
+				datasets: [{
+					data: vals
+				}]
+			}
+		});
+	</script>
+
+</body>
+
+</html>
--- a/main.go
+++ b/main.go
@ -0,0 +1,66 @@
+package main
+
+import (
+	"html/template"
+	"log"
+	"net/http"
+	"os"
+	"strconv"
+
+	"git.dm1sh.ru/dm1sh/gotemptracker/models"
+)
+
+func getEnv(name, default_val string) string {
+	val := os.Getenv(name)
+
+	if val == "" {
+		return default_val
+	}
+
+	return val
+}
+
+var tmpl *template.Template
+
+func indexHandler(w http.ResponseWriter, r *http.Request) {
+	if r.Method == http.MethodPost {
+		strvalue := r.FormValue("value")
+
+		value, err := strconv.ParseFloat(strvalue, 32)
+		if err != nil {
+			http.Error(w, "Expected floating point value", http.StatusBadRequest)
+		}
+
+		models.InsertMeasurement(value)
+	}
+
+	measurements, err := models.AllMeasurements()
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	err = tmpl.Execute(w, measurements)
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+func main() {
+	tmpl = template.Must(template.ParseFiles("index.gohtml"))
+
+	err := models.InitDB(getEnv("DB_CONNECTION_STRING", "postgres://gotemptracker:gotemptracker@localhost:5432/gotemptracker?sslmode=disable"))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	http.HandleFunc("/", indexHandler)
+
+	port := getEnv("PORT", "80")
+
+	log.Printf("Listening on %s\n", port)
+
+	if err := http.ListenAndServe(":"+port, nil); err != nil {
+		log.Fatal(err)
+	}
+}
--- a/models/models.go
+++ b/models/models.go
@ -0,0 +1,66 @@
+package models
+
+import (
+	"database/sql"
+	"time"
+
+	_ "github.com/lib/pq"
+)
+
+var db *sql.DB
+
+type Measurement struct {
+	CreatedAt time.Time
+	Value     float32
+}
+
+func InitDB(dataSourceName string) (err error) {
+	db, err = sql.Open("postgres", dataSourceName)
+	if err != nil {
+		return err
+	}
+
+	if err = db.Ping(); err != nil {
+		return err
+	}
+
+	_, err = db.Exec(`
+		CREATE TABLE IF NOT EXISTS measurements (
+			created_at TIMESTAMP,
+			value NUMERIC (3, 1)
+		)
+	`)
+	return err
+}
+
+func AllMeasurements() (measurements []Measurement, err error) {
+	rows, err := db.Query("SELECT * FROM measurements")
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	for rows.Next() {
+		var measurement Measurement
+
+		err = rows.Scan(&measurement.CreatedAt, &measurement.Value)
+		if err != nil {
+			return nil, err
+		}
+
+		measurements = append(measurements, measurement)
+	}
+	if err = rows.Err(); err != nil {
+		return nil, err
+	}
+
+	return measurements, nil
+}
+
+func InsertMeasurement(value float64) (err error) {
+	_, err = db.Exec(`
+		INSERT INTO measurements VALUES (current_timestamp, $1)
+	`, value)
+
+	return err
+}