Add docs example for upsert streamed

Author: jrauh01

database/example_upsert_streamed_test.go

@@ -0,0 +1,83 @@
+package database
+
+import (
+	"context"
+	"fmt"
+	"github.com/creasty/defaults"
+	"github.com/icinga/icinga-go-library/logging"
+	"github.com/icinga/icinga-go-library/utils"
+	"go.uber.org/zap/zapcore"
+	"golang.org/x/sync/errgroup"
+	"time"
+)
+
+func ExampleUpsertStreamed() {
+	var (
+		testEntites = []MockEntity{
+			{Id: 1, Name: "test1", Age: 10, Email: "[email protected]"},
+			{Id: 2, Name: "test2", Age: 20, Email: "[email protected]"},
+		}
+		g, ctx         = errgroup.WithContext(context.Background())
+		entities       = make(chan MockEntity, len(testEntites))
+		defaultOptions Options
+	)
+
+	logs, err := logging.NewLoggingFromConfig(
+		"Icinga Kubernetes",
+		logging.Config{Level: zapcore.DebugLevel, Output: "console", Interval: time.Second * 10},
+	)
+	if err != nil {
+		utils.PrintErrorThenExit(err, 1)
+	}
+
+	log := logs.GetLogger()
+
+	err = defaults.Set(&defaultOptions)
+	if err != nil {
+		log.Fatalf("cannot set default options: %v", err)
+	}
+
+	db, err := NewDbFromConfig(
+		&Config{Type: "sqlite", Database: ":memory:example-upsert", Options: defaultOptions},
+		logs.GetChildLogger("database"),
+		RetryConnectorCallbacks{},
+	)
+	if err != nil {
+		log.Fatalf("cannot create database: %v", err)
+	}
+
+	_, err = db.Query("CREATE TABLE IF NOT EXISTS mock_entity (id INTEGER PRIMARY KEY, name VARCHAR(255), age INTEGER, email VARCHAR(255))")
+	if err != nil {
+		log.Fatalf("cannot create table in db: %v", err)
+	}
+
+	g.Go(func() error {
+		return UpsertStreamed(ctx, db, entities)
+	})
+
+	for _, entity := range testEntites {
+		entities <- entity
+	}
+
+	close(entities)
+
+	time.Sleep(time.Second)
+
+	testSelect := &[]MockEntity{}
+
+	err = db.Select(testSelect, "SELECT * FROM mock_entity")
+	if err != nil {
+		log.Fatalf("cannot select from db: %v", err)
+	}
+
+	fmt.Println(*testSelect)
+
+	if err = g.Wait(); err != nil {
+		log.Fatalf("upsert error: %v", err)
+	}
+
+	_ = db.Close()
+
+	// Output:
+	// [{1 test1 10 [email protected]} {2 test2 20 [email protected]}]
+}