fix(gui): Landscape config serialization (#855)

The Landscape ping service doesn't support https by default.

Additionally, wslpath can fool wsl-pro-service, when the path passed to
the command line is an empty path it outputs the current working
directory absolute path. Due systemd, cwd is `/`.


![image](https://github.com/user-attachments/assets/6d8cb161-cd06-48ea-9782-d7e478056fdd)

We should have wsl-pro-service checking for empty paths before invoking
wslpath for added correctness (users could well assemble a config file
by hand having `ssl_public_key = `), but it also makes sense to fix it
here, as we're aware of which fields are optional in the UI. But,
instead of treating this (or any path) field as special, I'm being more
generic, **filtering out any line in the INI configuration output that
could have empty values**, i.e., we won't output lines with this shape :
`key =`.

More test assertions were added validating those assumptions.

gui/packages/ubuntupro/lib/pages/landscape/landscape_model.dart

@@ -174,16 +174,20 @@ class LandscapeSaasConfig extends LandscapeConfig {
     if (!isComplete) return null;
     final uri = Uri.https(landscapeSaas);
 
+    final registrationKeyLine =
+        registrationKey.isEmpty ? '' : 'registration_key = $registrationKey';
+
     return '''
 [host]
 url = ${uri.replace(port: 6554).authority}
 [client]
 account_name = $accountName
-registration_key = $registrationKey
 url = ${uri.replace(path: '/message-system')}
-ping_url = ${uri.replace(path: '/ping')}
+ping_url = ${uri.replace(scheme: 'http').replace(path: '/ping')}
 log_level = info
-''';
+$registrationKeyLine
+'''
+        .trimRight();
   }
 }
 
@@ -262,18 +266,24 @@ class LandscapeSelfHostedConfig extends LandscapeConfig {
   @override
   String? config() {
     if (!isComplete) return null;
+
+    final sslKeyLine = sslKeyPath.isEmpty ? '' : 'ssl_public_key = $sslKeyPath';
+    final registrationKeyLine =
+        registrationKey.isEmpty ? '' : 'registration_key = $registrationKey';
+
     final uri = Uri.parse(_fqdn);
     return '''
 [host]
 url = ${uri.replace(port: 6554).authority}
 [client]
 account_name = $standalone
-registration_key = $registrationKey
 url = ${uri.replace(path: '/message-system')}
-ping_url = ${uri.replace(path: '/ping')}
+ping_url = ${uri.replace(scheme: 'http').replace(path: '/ping')}
 log_level = info
-ssl_public_key = $sslKeyPath
-''';
+$sslKeyLine
+$registrationKeyLine
+'''
+        .trimRight();
   }
 }
 

gui/packages/ubuntupro/pubspec.lock

@@ -440,6 +440,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "4.2.0"
+  ini:
+    dependency: "direct dev"
+    description:
+      name: ini
+      sha256: "12a76c53591ffdf86d1265be3f986888a6dfeb34a85957774bc65912d989a173"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.1.0"
   integration_test:
     dependency: "direct dev"
     description: flutter

gui/packages/ubuntupro/pubspec.yaml

@@ -72,6 +72,7 @@ dev_dependencies:
   flutter_lints: ^4.0.0
   flutter_test:
     sdk: flutter
+  ini: ^2.1.0
   integration_test:
     sdk: flutter
   nested: ^1.0.0

gui/packages/ubuntupro/test/pages/landscape/landscape_data_model_test.dart

@@ -1,4 +1,5 @@
 import 'package:flutter_test/flutter_test.dart';
+import 'package:ini/ini.dart';
 
 import 'package:ubuntupro/pages/landscape/landscape_model.dart';
 
@@ -30,7 +31,11 @@ void main() {
         c.accountName = tc.account;
         expect(c.accountNameError, tc.wantError);
         expect(c.isComplete, tc.wantComplete);
-        expect(c.config(), tc.wantConfig);
+        final raw = c.config();
+        expect(raw, tc.wantConfig);
+        if (raw != null) {
+          expectINI(raw);
+        }
       });
     }
   });
@@ -114,7 +119,11 @@ void main() {
         expect(c.fqdnError, tc.wantFqdnError);
         expect(c.fileError, tc.wantFileError);
         expect(c.isComplete, tc.wantComplete);
-        expect(c.config(), tc.wantConfig);
+        final raw = c.config();
+        expect(raw, tc.wantConfig);
+        if (raw != null) {
+          expectINI(raw);
+        }
       });
     }
   });
@@ -177,6 +186,25 @@ void main() {
   });
 }
 
+void expectINI(String raw) {
+  final config = Config.fromStrings(raw.split('\n'));
+  expectNoEmptyValuesInINI(config);
+  expectUrlSchemes(config);
+}
+
+void expectNoEmptyValuesInINI(Config config) {
+  for (final o in config.items('client')!) {
+    expect(o[1], isNotEmpty);
+  }
+}
+
+void expectUrlSchemes(Config config) {
+  final url = Uri.parse(config.get('client', 'url')!);
+  expect(url.scheme, 'https');
+  final ping = Uri.parse(config.get('client', 'ping_url')!);
+  expect(ping.scheme, 'http');
+}
+
 const saasURL = 'https://landscape.canonical.com';
 const customConf = './test/testdata/landscape/custom.conf';
 const notFoundPath = './test/testdata/landscape/notfound.txt';