feat: add example for InfluxDB client with pre-configured HTTP client (#224)

Author: NguyenHoangSon96

examples/WithPreConfigHttp/with_pre_configured_http_client.go

@@ -0,0 +1,139 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/InfluxCommunity/influxdb3-go/v2/influxdb3"
+)
+
+func main() {
+	// Retrieve credentials from environment variables.
+	url := os.Getenv("INFLUX_URL")
+	token := os.Getenv("INFLUX_TOKEN")
+	database := os.Getenv("INFLUX_DATABASE")
+
+	timeout := 10 * time.Second
+	maxIdleConnections := 10
+
+	transport := http.DefaultTransport.(*http.Transport).Clone()
+	transport.IdleConnTimeout = 90 * time.Second
+	transport.MaxIdleConns = maxIdleConnections
+	transport.MaxIdleConnsPerHost = maxIdleConnections
+
+	dialer := &net.Dialer{
+		Timeout:   timeout,
+		KeepAlive: 30 * time.Second,
+	}
+	transport.DialContext = dialer.DialContext
+
+	httpClient := &http.Client{
+		Timeout:   timeout,
+		Transport: transport,
+	}
+
+	/*
+		Creating an Influxdb client with a pre-configured Http client.
+		Warning: If you also set ClientConfig.MaxIdleConnections or ClientConfig.IdleConnectionTimeout,...
+		It will override these properties in your pre-configured Http client
+	*/
+	config := influxdb3.ClientConfig{
+		Host:       url,
+		Token:      token,
+		Database:   database,
+		HTTPClient: httpClient,
+	}
+	client, err := influxdb3.New(config)
+	if err != nil {
+		panic(err)
+	}
+
+	// Close the client when finished and raise any errors.
+	defer func(client *influxdb3.Client) {
+		err := client.Close()
+		if err != nil {
+			panic(err)
+		}
+	}(client)
+
+	// Create a Point using the full params constructor.
+	p := influxdb3.NewPoint("stat",
+		map[string]string{"location": "Paris"},
+		map[string]any{
+			"temperature": 24.5,
+			"humidity":    40,
+		},
+		time.Now())
+
+	// Write the point synchronously.
+	err = client.WritePoints(context.Background(), []*influxdb3.Point{p})
+	if err != nil {
+		panic(err)
+	}
+
+	// Create a Point using the fluent interface (method chaining).
+	p = influxdb3.NewPointWithMeasurement("stat").
+		SetTag("location", "London").
+		SetField("temperature", 17.1).
+		SetField("humidity", 65).
+		SetTimestamp(time.Now())
+
+	// Write the point synchronously.
+	err = client.WritePoints(context.Background(), []*influxdb3.Point{p})
+	if err != nil {
+		panic(err)
+	}
+
+	// Construct data as a custom type.
+	sensorData := struct {
+		Table string    `lp:"measurement"`
+		Unit  string    `lp:"tag,location"`
+		Temp  float64   `lp:"field,temperature"`
+		Humid int64     `lp:"field,humidity"`
+		Time  time.Time `lp:"timestamp"`
+	}{"stat", "Madrid", 33.8, 35, time.Now()}
+
+	// Write the data.
+	err = client.WriteData(context.Background(), []any{sensorData})
+	if err != nil {
+		panic(err)
+	}
+
+	// Provide data as a line protocol string.
+	line := fmt.Sprintf("stat,location=Berlin temperature=%f,humidity=%di", 20.1, 55)
+
+	// Write the line protocol string.
+	err = client.Write(context.Background(), []byte(line))
+	if err != nil {
+		panic(err)
+	}
+
+	// Prepare an SQL query
+	query := `
+    SELECT *
+    FROM stat
+    WHERE time >= now() - interval '5 minutes'
+    AND location IN ('Paris', 'London', 'Madrid')
+  `
+
+	// Run the query (with client timeout)
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+	iterator, err := client.Query(ctx, query)
+	if err != nil {
+		panic(err)
+	}
+	for iterator.Next() {
+		// The query iterator returns each row as a map[string]any.
+		// The keys are the column names, allowing you to access the values by column name.
+		value := iterator.Value()
+		fmt.Printf("%s at %v:\n", value["location"],
+			(value["time"].(time.Time)).Format(time.RFC822))
+		fmt.Printf("  temperature: %f\n", value["temperature"])
+		fmt.Printf("  humidity   : %d%%\n", value["humidity"])
+	}
+}