Fix #4: lazy password evaluation

Closes #4 (closed)

Mimics django's lazy string behaviour.

funkwhale_cli/cli.py

@@ -88,6 +88,35 @@ RAW_DECORATOR = click.option(
     "--raw", is_flag=True, help="Directly output JSON returned by the happy"
 )
 
+class lazy_credential():
+    """
+    A proxy object to request access to the proxy object at the later possible point,
+    cf #4
+    """
+    def __init__(self, *args):
+        self.args = args
+        self._cached_value = None
+
+    @property
+    def value(self):
+        if self._cached_value:
+            return self._cached_value
+        v = keyring.get_password(*self.args)
+        self._cached_value = v
+        return v
+
+    def __str__(self):
+        return str(self.value)
+
+    def __eq__(self, other):
+        return self.value == other
+
+    def __repr__(self):
+        return str(self.value)
+
+    def __bool__(self):
+        return bool(self.value)
+
 
 def set_server(ctx, url, token):
     ctx.ensure_object(dict)
@@ -96,7 +125,7 @@ def set_server(ctx, url, token):
     ctx.obj["SERVER_NETLOC"] = parsed.netloc
     ctx.obj["SERVER_PROTOCOL"] = parsed.scheme
     try:
-        token = token or keyring.get_password(url, "_")
+        token = token or lazy_credential(url, "_")
     except ValueError as e:
         raise click.ClickException("Error while retrieving password from keyring: {}. Your password may be incorrect.".format(e.args[0]))
     except Exception as e: