enhancement(cli): Shell autocomplete for the Vector CLI

src/app.rs

@@ -1,6 +1,6 @@
 use crate::{
     cli::{handle_config_errors, Color, LogFormat, Opts, RootOpts, SubCommand},
-    config, generate, graph, heartbeat, list, metrics,
+    completion, config, generate, graph, heartbeat, list, metrics,
     signal::{self, SignalTo},
     topology::{self, RunningTopology},
     trace, unit_test, validate,
@@ -143,6 +143,8 @@ impl Application {
                         SubCommand::Validate(v) => validate::validate(&v, color).await,
                         #[cfg(feature = "vrl-cli")]
                         SubCommand::Vrl(s) => vrl_cli::cmd::cmd(&s),
+
+                        SubCommand::Completion(c) => completion::cmd(&c),
                     };
 
                     return Err(code);

src/cli.rs

@@ -1,4 +1,4 @@
-use crate::{config, generate, get_version, graph, list, unit_test, validate};
+use crate::{completion, config, generate, get_version, graph, list, unit_test, validate};
 use std::path::PathBuf;
 use structopt::{clap::AppSettings, StructOpt};
 
@@ -205,6 +205,9 @@ pub enum SubCommand {
     /// Vector Remap Language CLI
     #[cfg(feature = "vrl-cli")]
     Vrl(vrl_cli::Opts),
+
+    /// Output autocompletion scripts for the Vector CLI.
+    Completion(completion::Opts),
 }
 
 #[derive(Debug, Clone, PartialEq)]

src/completion.rs

@@ -0,0 +1,15 @@
+use crate::cli::Opts as RootOpts;
+use structopt::{clap::Shell, StructOpt};
+
+#[derive(StructOpt, Debug)]
+#[structopt(rename_all = "kebab-case")]
+pub struct Opts {
+    #[structopt(name = "SHELL", possible_values = &Shell::variants())]
+    shell: Shell,
+}
+
+pub fn cmd(opts: &Opts) -> exitcode::ExitCode {
+    RootOpts::clap().gen_completions_to("vector", opts.shell, &mut std::io::stdout());
+
+    exitcode::OK
+}

src/lib.rs

@@ -25,6 +25,7 @@ extern crate vrl_cli;
 #[macro_use]
 pub mod config;
 pub mod cli;
+pub mod completion;
 pub mod conditions;
 pub mod dns;
 #[cfg(feature = "docker")]