Pushing changes for testing harness before my next meeting. Adding working exec library and sample code

Signed-off-by: Kris Nóva <kris@nivenly.com>

examples/app_upload_download_photo.go

@@ -0,0 +1,20 @@
+package main
+
+import (
+	sampleapp "github.com/kris-nova/client-go/sample-app"
+	"github.com/kris-nova/logger"
+)
+
+func main() {
+	logger.Level = 4
+	app := sampleapp.New()
+	var err error
+	err = app.Start()
+	if err != nil {
+		logger.Critical(err.Error())
+	}
+	err = app.Stop()
+	if err != nil {
+		logger.Critical(err.Error())
+	}
+}

examples/common.go

@@ -0,0 +1,30 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	photoprism "github.com/kris-nova/client-go"
+
+	"github.com/kris-nova/logger"
+)
+
+// format string, a ...interface{}
+func halt(code int, msg string, a ...interface{}) {
+	str := fmt.Sprintf(msg, a...)
+	logger.Critical(str)
+	os.Exit(code)
+}
+
+func auth() photoprism.ClientAuthenticator {
+	user := os.Getenv("PHOTOPRISM_USER")
+	if user == "" {
+		halt(1, "Missing PHOTOPRISM_USER")
+	}
+	pass := os.Getenv("PHOTOPRISM_PASS")
+	if pass == "" {
+		halt(2, "Missing PHOTOPRISM_PASS")
+	}
+	auth := photoprism.NewClientAuthLogin(user, pass)
+	return auth
+}

examples/download_photo.go

@@ -5,29 +5,15 @@ import (
 	"os"
 
 	photoprism "github.com/kris-nova/client-go"
-
-	"github.com/kris-nova/logger"
 )
 
-// format string, a ...interface{}
-func halt(code int, msg string, a ...interface{}) {
-	str := fmt.Sprintf(msg, a...)
-	logger.Critical(str)
-	os.Exit(code)
-}
-
 func main() {
-	user := os.Getenv("PHOTOPRISM_USER")
-	if user == "" {
-		halt(1, "Missing PHOTOPRISM_USER")
+	uuid := os.Getenv("PHOTOPRISM_ID")
+	if uuid == "" {
+		halt(2, "Missing PHOTOPRISM_UUID")
 	}
-	pass := os.Getenv("PHOTOPRISM_PASS")
-	if pass == "" {
-		halt(2, "Missing PHOTOPRISM_PASS")
-	}
-	login := photoprism.NewClientAuthLogin("username", "password")
-	photoclient := photoprism.New(login)
-	photo, err := photoclient.V1().GetPhoto("123")
+	client := photoprism.New(auth())
+	photo, err := client.V1().GetPhoto(uuid)
 	if err != nil {
 		halt(3, "Error fetching photo: %v", err)
 	}