SNOW-829454: Async API Example (#813)

cmd/async/.gitignore

@@ -0,0 +1 @@
+async

cmd/async/Makefile

@@ -0,0 +1,16 @@
+include ../../gosnowflake.mak
+CMD_TARGET=async
+
+## Install
+install: cinstall
+
+## Run
+run: crun
+
+## Lint
+lint: clint
+
+## Format source codes
+fmt: cfmt
+
+.PHONY: install run lint fmt

cmd/async/async.go

@@ -0,0 +1,148 @@
+package main
+
+import (
+	"context"
+	"database/sql"
+	"database/sql/driver"
+	"flag"
+	"fmt"
+	sf "github.com/snowflakedb/gosnowflake"
+	"io"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func getDSN() (string, *sf.Config, error) {
+	env := func(k string, failOnMissing bool) string {
+		if value := os.Getenv(k); value != "" {
+			return value
+		}
+		if failOnMissing {
+			log.Fatalf("%v environment variable is not set.", k)
+		}
+		return ""
+	}
+
+	account := env("SNOWFLAKE_TEST_ACCOUNT", true)
+	user := env("SNOWFLAKE_TEST_USER", true)
+	password := env("SNOWFLAKE_TEST_PASSWORD", true)
+	host := env("SNOWFLAKE_TEST_HOST", false)
+	portStr := env("SNOWFLAKE_TEST_PORT", false)
+	protocol := env("SNOWFLAKE_TEST_PROTOCOL", false)
+
+	port := 443 // snowflake default port
+	var err error
+	if len(portStr) > 0 {
+		port, err = strconv.Atoi(portStr)
+		if err != nil {
+			return "", nil, err
+		}
+	}
+
+	cfg := &sf.Config{
+		Account:  account,
+		User:     user,
+		Password: password,
+		Host:     host,
+		Port:     port,
+		Protocol: protocol,
+	}
+
+	dsn, err := sf.DSN(cfg)
+	return dsn, cfg, err
+}
+
+func main() {
+	if !flag.Parsed() {
+		flag.Parse()
+	}
+
+	dsn, cfg, err := getDSN()
+	if err != nil {
+		log.Fatalf("failed to create DSN from Config: %v, err: %v", cfg, err)
+	}
+
+	db, err := sql.Open("snowflake", dsn)
+	if err != nil {
+		log.Fatalf("failed to connect. %v, err: %v", dsn, err)
+	}
+	defer db.Close()
+
+	fmt.Println("Lets simulate long running query by passing execution logic as a function")
+	driverRows := runAsyncDriverQuery(db, "CALL SYSTEM$WAIT(10, 'SECONDS')")
+	fmt.Println("The query is running asynchronously - you can continue your workflow after starting the query")
+	printDriverRowsResult(driverRows)
+
+	fmt.Println("Lets simulate long running query using the standard sql package")
+	sqlRows := runAsyncSQLQuery(db, "CALL SYSTEM$WAIT(10, 'SECONDS')")
+	fmt.Println("The query is running asynchronously - you can continue your workflow after starting the query")
+	printSQLRowsResult(sqlRows)
+}
+
+func runAsyncDriverQuery(db *sql.DB, query string) driver.Rows {
+	// Enable asynchronous mode
+	ctx := sf.WithAsyncMode(context.Background())
+
+	// Establish a connection
+	conn, _ := db.Conn(ctx)
+	var rows driver.Rows
+
+	// Unwrap connection
+	err := conn.Raw(func(x interface{}) error {
+		var err error
+		// Execute asynchronous query
+		rows, err = x.(driver.QueryerContext).QueryContext(ctx, query, nil)
+
+		return err
+	})
+
+	if err != nil {
+		log.Fatalf("unable to run the query. err: %v", err)
+	}
+
+	return rows
+}
+
+func runAsyncSQLQuery(db *sql.DB, query string) *sql.Rows {
+	// Enable asynchronous mode
+	ctx := sf.WithAsyncMode(context.Background())
+
+	// Execute asynchronous query
+	rows, err := db.QueryContext(ctx, query)
+
+	if err != nil {
+		log.Fatalf("unable to run the query. err: %v", err)
+	}
+
+	return rows
+}
+
+func printDriverRowsResult(rows driver.Rows) {
+	fmt.Println(strings.Join(rows.Columns(), ", "))
+
+	dest := make([]driver.Value, 1)
+	for rows.Next(dest) != io.EOF {
+		for val := range dest {
+			fmt.Printf("%v\n", dest[val])
+		}
+	}
+}
+
+func printSQLRowsResult(rows *sql.Rows) {
+	cols, err := rows.Columns()
+	if err != nil {
+		log.Fatalf("failed to get columns. err: %v", err)
+	}
+	fmt.Println(strings.Join(cols, ", "))
+
+	var val string
+	for rows.Next() {
+		err := rows.Scan(&val)
+		if err != nil {
+			log.Fatalf("failed to scan rows. err: %v", err)
+		}
+		fmt.Printf("%v\n", val)
+	}
+}