mirror of
https://gitee.com/rulego/streamsql.git
synced 2026-04-03 11:16:48 +00:00
rulego-team
120 lines
3.7 KiB
Go
120 lines
3.7 KiB
Go
package main
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import (
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"fmt"
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"time"
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"github.com/rulego/streamsql"
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"github.com/rulego/streamsql/functions"
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"github.com/rulego/streamsql/utils/cast"
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)
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func main() {
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fmt.Println("=== StreamSQL 高级函数示例 ===")
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// 1. 注册自定义函数：温度华氏度转摄氏度
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err := functions.RegisterCustomFunction("fahrenheit_to_celsius", functions.TypeCustom, "温度转换", "华氏度转摄氏度", 1, 1,
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func(ctx *functions.FunctionContext, args []interface{}) (interface{}, error) {
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fahrenheit, err := cast.ToFloat64E(args[0])
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if err != nil {
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return nil, err
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}
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celsius := (fahrenheit - 32) * 5 / 9
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return celsius, nil
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})
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if err != nil {
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panic(fmt.Sprintf("注册自定义函数失败: %v", err))
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}
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fmt.Println("✓ 注册自定义函数：fahrenheit_to_celsius")
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// 2. 创建 StreamSQL 实例
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ssql := streamsql.New()
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defer ssql.Stop()
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// 3. 定义包含高级函数的 SQL
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sql := `
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SELECT
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device,
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AVG(abs(temperature - 20)) as avg_deviation,
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AVG(fahrenheit_to_celsius(temperature)) as avg_celsius,
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MAX(sqrt(humidity)) as max_sqrt_humidity
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FROM stream
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GROUP BY device, TumblingWindow('2s')
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WITH (TIMESTAMP='ts', TIMEUNIT='ss')
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`
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// 4. 执行 SQL
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err = ssql.Execute(sql)
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if err != nil {
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panic(fmt.Sprintf("执行SQL失败: %v", err))
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}
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fmt.Println("✓ SQL执行成功")
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// 5. 添加结果监听器
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ssql.AddSink(func(result []map[string]interface{}) {
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fmt.Printf("📊 聚合结果: %v\n", result)
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})
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// 6. 模拟传感器数据
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baseTime := time.Now()
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sensorData := []map[string]interface{}{
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{"device": "sensor1", "temperature": 68.0, "humidity": 25.0, "ts": baseTime.UnixMicro()}, // 20°C, 湿度25%
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{"device": "sensor1", "temperature": 86.0, "humidity": 36.0, "ts": baseTime.Unix()}, // 30°C, 湿度36%
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{"device": "sensor2", "temperature": 32.0, "humidity": 49.0, "ts": baseTime.Unix()}, // 0°C, 湿度49%
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{"device": "sensor2", "temperature": 104.0, "humidity": 64.0, "ts": baseTime.Unix()}, // 40°C, 湿度64%
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{"device": "temperature_probe", "temperature": 212.0, "humidity": 81.0, "ts": baseTime.Unix()}, // 100°C, 湿度81%
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}
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fmt.Println("\n🌡️ 发送传感器数据:")
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for _, data := range sensorData {
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fmt.Printf(" 设备: %s, 温度: %.1f°F, 湿度: %.1f%%\n",
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data["device"], data["temperature"], data["humidity"])
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ssql.Emit(data)
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}
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// 7. 等待处理完成
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fmt.Println("\n⏳ 等待窗口处理...")
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time.Sleep(3 * time.Second)
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// 8. 演示内置函数
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fmt.Println("\n🔧 内置函数演示:")
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// 数学函数
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fmt.Printf(" abs(-15.5) = %.1f\n", callFunction("abs", -15.5))
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fmt.Printf(" sqrt(16) = %.1f\n", callFunction("sqrt", 16.0))
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// 字符串函数
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fmt.Printf(" concat('Hello', ' ', 'World') = %s\n", callFunction("concat", "Hello", " ", "World"))
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fmt.Printf(" upper('streamsql') = %s\n", callFunction("upper", "streamsql"))
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fmt.Printf(" length('StreamSQL') = %d\n", callFunction("length", "StreamSQL"))
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// 转换函数
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fmt.Printf(" hex2dec('ff') = %d\n", callFunction("hex2dec", "ff"))
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fmt.Printf(" dec2hex(255) = %s\n", callFunction("dec2hex", 255))
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// 时间函数
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fmt.Printf(" now() = %d\n", callFunction("now"))
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// 9. 显示已注册的函数
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fmt.Println("\n📋 已注册的函数:")
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allFunctions := functions.ListAll()
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for name, fn := range allFunctions {
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fmt.Printf(" %s (%s): %s\n", name, fn.GetType(), fn.GetDescription())
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}
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fmt.Println("\n✅ 示例完成!")
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}
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// 辅助函数：调用函数并返回结果
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func callFunction(name string, args ...interface{}) interface{} {
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ctx := &functions.FunctionContext{
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Data: make(map[string]interface{}),
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}
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result, err := functions.Execute(name, ctx, args)
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if err != nil {
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return fmt.Sprintf("Error: %v", err)
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}
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return result
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}
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