Split fallback_scheme into launch and connect choices

CHANGELOG.md

@@ -6,6 +6,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+
+- `replace_scheme` method to `Destination`
 
 ### Fixed
 
@@ -16,6 +19,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - `Map` implementation of `Display` now escapes `\` and `"`
 - `Map` implementation of `FromStr` now handles escaped `\` and `"`
+- Split `fallback_scheme` for `DistantManagerConfig` into
+  `launch_fallback_scheme` (defaulting to ssh) and `connect_fallback_scheme`
+  (defaulting to distant); this means that subsequent use of 
+  `distant client launch [user@]host[:port]` will now default to ssh instead of
+  failing due to lack of distant launch handler
 
 ## [0.17.1] - 2022-08-16
 ### Added

distant-core/src/manager/data/destination.rs

@@ -29,6 +29,14 @@ impl Destination {
         self.0.scheme().map(Scheme::as_str)
     }
 
+    /// Replaces the current scheme of the destination with the provided scheme, returning the old
+    /// scheme as a string if it existed
+    pub fn replace_scheme(&mut self, scheme: &str) -> Result<Option<String>, URIReferenceError> {
+        self.0
+            .set_scheme(Some(Scheme::try_from(scheme).map(Scheme::into_owned)?))
+            .map(|s| s.map(|s| s.to_string()))
+    }
+
     /// Returns the host of the destination as a string
     pub fn to_host_string(&self) -> String {
         // NOTE: We guarantee that there is a host for a destination during construction

distant-core/src/manager/server.rs

@@ -148,9 +148,9 @@ impl DistantManager {
             None => {
                 trace!(
                     "Using fallback scheme of {}",
-                    self.config.fallback_scheme.as_str()
+                    self.config.launch_fallback_scheme.as_str()
                 );
-                self.config.fallback_scheme.as_str()
+                self.config.launch_fallback_scheme.as_str()
             }
         }
         .to_lowercase();
@@ -193,9 +193,9 @@ impl DistantManager {
             None => {
                 trace!(
                     "Using fallback scheme of {}",
-                    self.config.fallback_scheme.as_str()
+                    self.config.connect_fallback_scheme.as_str()
                 );
-                self.config.fallback_scheme.as_str()
+                self.config.connect_fallback_scheme.as_str()
             }
         }
         .to_lowercase();

distant-core/src/manager/server/config.rs

@@ -2,8 +2,11 @@ use crate::{BoxedConnectHandler, BoxedLaunchHandler};
 use std::collections::HashMap;
 
 pub struct DistantManagerConfig {
-    /// Scheme to use when none is provided in a destination
+    /// Scheme to use when none is provided in a destination for launch
-    pub fallback_scheme: String,
+    pub launch_fallback_scheme: String,
+
+    /// Scheme to use when none is provided in a destination for connect
+    pub connect_fallback_scheme: String,
 
     /// Buffer size for queue of incoming connections before blocking
     pub connection_buffer_size: usize,
@@ -21,7 +24,12 @@ pub struct DistantManagerConfig {
 impl Default for DistantManagerConfig {
     fn default() -> Self {
         Self {
-            fallback_scheme: "distant".to_string(),
+            // Default to using ssh to launch distant
+            launch_fallback_scheme: "ssh".to_string(),
+
+            // Default to distant server when connecting
+            connect_fallback_scheme: "distant".to_string(),
+
             connection_buffer_size: 100,
             user: false,
             launch_handlers: HashMap::new(),

src/cli/commands/client.rs

@@ -421,7 +421,7 @@ impl ClientSubcommand {
                 config: launcher_config,
                 network,
                 format,
-                destination,
+                mut destination,
                 ..
             } => {
                 let network = network.merge(config.network);
@@ -445,6 +445,17 @@ impl ClientSubcommand {
                 // Grab the host we are connecting to for later use
                 let host = destination.to_host_string();
 
+                // If we have no scheme on launch, we need to fill it in with something
+                //
+                // TODO: Can we have the server support this instead of the client? Right now, the
+                //       server is failing because it cannot parse //localhost/ as it fails with
+                //       an invalid IPv4 or registered name character error on host
+                if destination.scheme().is_none() {
+                    destination
+                        .replace_scheme("ssh")
+                        .context("Failed to set a default scheme for a scheme-less destination")?;
+                }
+
                 // Start the server using our manager
                 debug!("Launching server at {} with {}", destination, extra);
                 let mut new_destination = client