本帖最后由 keer_zu 于 2021-1-11 15:57 编辑
application Functions SDK
SDK是围绕“函数管道”的思想构建的。函数管道是按指定顺序处理数据的各种函数的集合。函数管道由配置中指定的触发器执行。toml。管道中的第一个函数被调用时带有触发管道的事件(例如events.Model)。管道中的每个后续调用都使用前一个函数的返回结果进行调用。让我们看一个简单的例子，它创建了一个管道来过滤特定的设备id，然后将数据转换为XML:
package main
import (
"fmt"
"github.com/edgexfoundry/app-functions-sdk-go/appsdk"
"github.com/edgexfoundry/app-functions-sdk-go/pkg/transforms"
"os"
)
func main() {
// 1) First thing to do is to create an instance of the EdgeX SDK, giving it a service key
edgexSdk := &appsdk.AppFunctionsSDK{
ServiceKey: "SimpleFilterXMLApp", // Key used by Registry (Aka Consul)
}
// 2) Next, we need to initialize the SDK
if err := edgexSdk.Initialize(); err != nil {
message := fmt.Sprintf("SDK initialization failed: %v\n", err)
if edgexSdk.LoggingClient != nil {
edgexSdk.LoggingClient.Error(message)
} else {
fmt.Println(message)
}
os.Exit(-1)
}
// 3) Shows how to access the application's specific configuration settings.
deviceNames, err := edgexSdk.GetAppSettingStrings("DeviceNames")
if err != nil {
edgexSdk.LoggingClient.Error(err.Error())
os.Exit(-1)
}
// 4) This is our pipeline configuration, the collection of functions to
// execute every time an event is triggered.
if err = edgexSdk.SetFunctionsPipeline(
transforms.NewFilter(deviceNames).FilterByDeviceName,
transforms.NewConversion().TransformToXML,
); err != nil {
edgexSdk.LoggingClient.Error(fmt.Sprintf("SDK SetPipeline failed: %v\n", err))
os.Exit(-1)
}
// 5) Lastly, we'll go ahead and tell the SDK to "start" and begin listening for events to trigger the pipeline.
err = edgexSdk.MakeItRun()
if err != nil {
edgexSdk.LoggingClient.Error("MakeItRun returned error: ", err.Error())
os.Exit(-1)
}
// Do any required cleanup here
os.Exit(0)
}
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