Improve error handling for GetIdentity() and missing User address

cmd/salty-chat/chat.go

@@ -49,7 +49,11 @@ func init() {
 func chat(identity, uri string, user string) {
 	key, me, err := saltyim.GetIdentity(identity)
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "error reading identity %q: %s", identity, err)
+		fmt.Fprintf(os.Stderr, "error opening identity: %q", identity)
+		if me.IsZero() {
+			fmt.Fprintf(os.Stderr, "unable to find your user addressn in %q", identity)
+			fmt.Fprintln(os.Stderr, "tip: try adding # user: nick@domain to your identity")
+		}
 		os.Exit(2)
 	}
 

cmd/salty-chat/send.go

@@ -66,7 +66,12 @@ func send(identity, user string, args ...string) {
 
 	key, me, err := saltyim.GetIdentity(identity)
 	if err != nil {
-		log.Fatalf("error opening identity: %q", identity)
+		fmt.Fprintf(os.Stderr, "error opening identity: %q", identity)
+		if me.IsZero() {
+			fmt.Fprintf(os.Stderr, "unable to find your user addressn in %q", identity)
+			fmt.Fprintln(os.Stderr, "tip: try adding # user: nick@domain to your identity")
+		}
+		os.Exit(2)
 	}
 
 	var msg string

identity.go

@@ -1,6 +1,7 @@
 package saltyim
 
 import (
+	"fmt"
 	"log"
 	"os"
 
@@ -24,7 +25,7 @@ func GetIdentity(fn string) (*keys.EdX25519Key, Addr, error) {
 	id.Seek(0, 0)
 	me, err := ReadUser(id)
 	if err != nil {
-		log.Fatalf("error reading user from keyfile: %q", fn)
+		return key, Addr{}, fmt.Errorf("error reading user from keyfile: %q", fn)
 	}
 
 	return key, me, nil

lookup.go

@@ -17,6 +17,11 @@ type Addr struct {
 	Domain string
 }
 
+// IsZero returns true if the address is empty
+func (a Addr) IsZero() bool {
+	return a.User == "" && a.Domain == ""
+}
+
 func (a Addr) String() string {
 	return fmt.Sprint(a.User, "@", a.Domain)
 }