Add bash completions

Signed-off-by: itowlson <ivan.towlson@fermyon.com>

Author: itowlson

Cargo.lock

@@ -18,6 +18,7 @@ bindle = { workspace = true }
 bytes = "1.1"
 chrono = "0.4"
 clap = { version = "3.2.24", features = ["derive", "env"] }
+clap_complete = "3.1.4"
 clearscreen = "2.0.1"
 command-group = "2.1"
 comfy-table = "5.0"

Cargo.toml

@@ -129,6 +129,8 @@ enum SpinApp {
     Plugins(PluginCommands),
     #[clap(subcommand, hide = true)]
     Trigger(TriggerCommands),
+    #[clap(hide = true, name = "generate-bash-completions")]
+    GenerateBashCompletions,
     #[clap(external_subcommand)]
     External(Vec<String>),
     Watch(WatchCommand),
@@ -162,6 +164,11 @@ impl SpinApp {
             Self::External(cmd) => execute_external_subcommand(cmd, app).await,
             Self::Watch(cmd) => cmd.run().await,
             Self::Doctor(cmd) => cmd.run().await,
+            Self::GenerateBashCompletions => {
+                let mut cmd: clap::Command = SpinApp::into_app();
+                print_completions(clap_complete::Shell::Bash, &mut cmd);
+                Ok(())
+            }
         }
     }
 }
@@ -220,3 +227,7 @@ fn installed_plugin_help_entries() -> Vec<PluginHelpEntry> {
 fn hide_plugin_in_help(plugin: &spin_plugins::manifest::PluginManifest) -> bool {
     plugin.name().starts_with("trigger-")
 }
+
+fn print_completions<G: clap_complete::Generator>(gen: G, cmd: &mut clap::Command) {
+    clap_complete::generate(gen, cmd, cmd.get_name().to_string(), &mut std::io::stdout())
+}