client: add rough example for using the client

omaha/client/example_test.go

@@ -0,0 +1,100 @@
+// Copyright 2017 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package client
+
+import (
+	"fmt"
+	"os"
+	//"os/signal"
+	"syscall"
+
+	"github.com/coreos/go-omaha/omaha"
+)
+
+func Example() {
+	// Launch a dummy server for our client to talk to.
+	s, err := omaha.NewTrivialServer("127.0.0.1:0")
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	defer s.Destroy()
+	go s.Serve()
+
+	// Configure our client. userID should be random but preserved
+	// across restarts. version is the current version of our app.
+	var (
+		serverURL = "http://" + s.Addr().String()
+		userID    = "8b10fc6d-30ca-49b2-b1a2-8185f03d522b"
+		appID     = "5ca607f8-61b5-4692-90ce-30380ba05a98"
+		version   = "1.0.0"
+	)
+	c, err := NewAppClient(serverURL, userID, appID, version)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	// Client version is the name and version of this updater.
+	c.SetClientVersion("example-0.0.1")
+
+	// Use SIGUSR1 to trigger immediate update checks.
+	sigc := make(chan os.Signal, 1)
+	//signal.Notify(sigc, syscall.SIGUSR1)
+	sigc <- syscall.SIGUSR1 // Fake it
+
+	//for {
+	var source string
+	select {
+	case <-sigc:
+		source = "ondemandupdate"
+	case <-c.NextPing():
+		source = "scheduler"
+	}
+
+	// TODO: pass source to UpdateCheck
+	_ = source
+	// If updates are disabled call c.Ping() instead.
+	update, err := c.UpdateCheck()
+	if err != nil {
+		fmt.Println(err)
+		//continue
+		return
+	}
+
+	// Download new application version.
+	c.Event(&omaha.EventRequest{
+		Type:   omaha.EventTypeUpdateDownloadFinished,
+		Result: omaha.EventResultSuccess,
+	})
+
+	// Install new application version here.
+	c.Event(&omaha.EventRequest{
+		Type:   omaha.EventTypeUpdateComplete,
+		Result: omaha.EventResultSuccess,
+	})
+
+	// Restart, new application is now running.
+	c.SetVersion(update.Manifest.Version)
+	c.Event(&omaha.EventRequest{
+		Type:   omaha.EventTypeUpdateComplete,
+		Result: omaha.EventResultSuccessReboot,
+	})
+
+	//}
+
+	// Output:
+	// omaha: update status noupdate
+}