tart login: better error when an improperly formatted host is provided (#863)

* tart login: better error when an improperly formatted host is provided

* Revert old behavior w.r.t. URLComponents()

Sources/tart/Commands/Login.swift

@@ -49,9 +49,10 @@ struct Login: AsyncParsableCommand {
     ])
 
     if !noValidate {
+      let registry = try Registry(host: host, namespace: "", insecure: insecure,
+                                  credentialsProviders: [credentialsProvider])
+
       do {
-        let registry = try Registry(host: host, namespace: "", insecure: insecure,
-                                    credentialsProviders: [credentialsProvider])
         try await registry.ping()
       } catch {
         throw RuntimeError.InvalidCredentials("invalid credentials: \(error)")

Sources/tart/OCI/Registry.swift

@@ -112,11 +112,11 @@ class Registry {
     return host
   }
 
-  init(urlComponents: URLComponents,
+  init(baseURL: URL,
        namespace: String,
        credentialsProviders: [CredentialsProvider] = [EnvironmentCredentialsProvider(), DockerConfigCredentialsProvider(), KeychainCredentialsProvider()]
   ) throws {
-    baseURL = urlComponents.url!
+    self.baseURL = baseURL
     self.namespace = namespace
     self.credentialsProviders = credentialsProviders
   }
@@ -130,7 +130,17 @@ class Registry {
     let proto = insecure ? "http" : "https"
     let baseURLComponents = URLComponents(string: proto + "://" + host + "/v2/")!
 
-    try self.init(urlComponents: baseURLComponents, namespace: namespace, credentialsProviders: credentialsProviders)
+    guard let baseURL = baseURLComponents.url else {
+      var hint = ""
+
+      if host.hasPrefix("http://") || host.hasPrefix("https://") {
+        hint += ", make sure that it doesn't start with http:// or https://"
+      }
+
+      throw RuntimeError.ImproperlyFormattedHost(host, hint)
+    }
+
+    try self.init(baseURL: baseURL, namespace: namespace, credentialsProviders: credentialsProviders)
   }
 
   func ping() async throws {

Sources/tart/VMStorageHelper.swift

@@ -61,6 +61,7 @@ enum RuntimeError : Error {
   case PIDLockFailed(_ message: String)
   case FailedToParseRemoteName(_ message: String)
   case VMTerminationFailed(_ message: String)
+  case ImproperlyFormattedHost(_ host: String, _ hint: String)
   case InvalidCredentials(_ message: String)
   case VMDirectoryAlreadyInitialized(_ message: String)
   case ExportFailed(_ message: String)
@@ -107,6 +108,8 @@ extension RuntimeError : CustomStringConvertible {
       return "failed to parse remote name: \(cause)"
     case .VMTerminationFailed(let message):
       return message
+    case .ImproperlyFormattedHost(let host, let hint):
+      return "improperly formatted host \"\(host)\" was provided\(hint)"
     case .InvalidCredentials(let message):
       return message
     case .VMDirectoryAlreadyInitialized(let message):

Tests/TartTests/Util/RegistryRunner.swift

@@ -39,7 +39,7 @@ class RegistryRunner {
     let port = try Self.dockerCmd("inspect", containerID, "--format", "{{(index (index .NetworkSettings.Ports \"5000/tcp\") 0).HostPort}}")
       .trimmingCharacters(in: CharacterSet.newlines)
 
-    registry = try Registry(urlComponents: URLComponents(string: "http://127.0.0.1:\(port)/v2/")!,
+    registry = try Registry(baseURL: URL(string: "http://127.0.0.1:\(port)/v2/")!,
                             namespace: "vm-image")
 
     // Wait for the Docker Registry to start