add self-update script

main.go

@@ -5,6 +5,7 @@ import (
 	"crypto/x509"
 	"encoding/pem"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"net/http"
 	"os"
@@ -291,6 +292,37 @@ func ReadOSRelease(configfile string) map[string]string {
 	return ConfigParams
 }
 
+// download file: taken as is from StackOverflow
+func downloadFile(filepath string, url string) (err error) {
+
+	// Create the file
+	out, err := os.Create(filepath)
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+
+	// Get the data
+	resp, err := http.Get(url)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	// Check server response
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("bad status: %s", resp.Status)
+	}
+
+	// Writer the body to file
+	_, err = io.Copy(out, resp.Body)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
 func main() {
 
 	OSInfo := ReadOSRelease("/etc/os-release")
@@ -343,6 +375,7 @@ Options:
   --key-destination=KEYDESTINATION              Key Destination [default: %v/<cert-name>.key]
   --ca-destination=CADESTINATION                CA Destination [default: %v/COMODO_<type>.crt]
   --wildcard                                    The certificate type is wildcard
+  --update                                      Self-updates the tool and exit
 `, CertBase, CertBase, KeyBase, CertBase)
 
 	arguments, _ := docopt.Parse(usage, nil, true, appVersion, false)
@@ -352,6 +385,18 @@ Options:
 		appExit(0)
 	}
 
+	if arguments["--wildcard"] == true {
+		ArtifactoryBase := "https://artifactory.software.geant.org/artifactory/acme-downloader"
+		ArtifactName := fmt.Sprintf("acme-downloader_%v_%v", runtime.GOOS, runtime.GOARCH)
+		ToolName := os.Args[0]
+		ArtifactURL := fmt.Sprintf("%v/%v", ArtifactoryBase, ArtifactName)
+		if runtime.GOOS == "windows" {
+			ArtifactURL = fmt.Sprintf("%v/%v.exe", ArtifactoryBase, ArtifactName)
+		}
+		downloadFile(ToolName, ArtifactURL)
+		fmt.Printf("%v updated successfully!\n", ToolName)
+	}
+
 	if runtime.GOOS == "windows" {
 		tmpCertificateDestination = "C:\\tmp\\acme-downloader\\cert\\amce_cert.pem"
 		tmpFullchainDestination = "C:\\tmp\\acme-downloader\\cert\\amce_fullchain.pem"