CLI auto-completions (informalsystems#1789)

cli: Add completions command using clap_complete

.changelog/unreleased/improvements/ibc-relayer-cli/1789-cli-completions.md

@@ -0,0 +1,2 @@
+- Add `completions` CLI command to generate shell auto-completion scripts.
+  ([#1789](https://github.com/informalsystems/ibc-rs/pull/1789)) 

relayer-cli/Cargo.toml

@@ -33,6 +33,7 @@ ibc-telemetry    = { version = "0.10.0", path = "../telemetry", optional = true
 ibc-relayer-rest = { version = "0.10.0", path = "../relayer-rest", optional = true }
 
 clap = { version = "3.0", features = ["cargo"] }
+clap_complete = "3.0"
 serde = { version = "1.0", features = ["serde_derive"] }
 tokio = { version = "1.0", features = ["full"] }
 tracing = "0.1.29"

relayer-cli/src/commands.rs

@@ -5,22 +5,7 @@
 //! See the `impl Configurable` below for how to specify the path to the
 //! application's configuration file.
 
-use core::time::Duration;
-use std::path::PathBuf;
-
-use abscissa_core::clap::Parser;
-use abscissa_core::{config::Override, Command, Configurable, FrameworkError, Runnable};
-use tracing::{error, info};
-
-use crate::DEFAULT_CONFIG_PATH;
-use ibc_relayer::config::Config;
-
-use self::{
-    config::ConfigCmd, create::CreateCmds, health::HealthCheckCmd, keys::KeysCmd,
-    listen::ListenCmd, misbehaviour::MisbehaviourCmd, query::QueryCmd, start::StartCmd, tx::TxCmd,
-    update::UpdateCmds, upgrade::UpgradeCmds, version::VersionCmd,
-};
-
+mod completions;
 mod config;
 mod create;
 mod health;
@@ -34,6 +19,22 @@ mod update;
 mod upgrade;
 mod version;
 
+use self::{
+    completions::CompletionsCmd, config::ConfigCmd, create::CreateCmds, health::HealthCheckCmd,
+    keys::KeysCmd, listen::ListenCmd, misbehaviour::MisbehaviourCmd, query::QueryCmd,
+    start::StartCmd, tx::TxCmd, update::UpdateCmds, upgrade::UpgradeCmds, version::VersionCmd,
+};
+
+use core::time::Duration;
+use std::path::PathBuf;
+
+use abscissa_core::clap::Parser;
+use abscissa_core::{config::Override, Command, Configurable, FrameworkError, Runnable};
+use tracing::{error, info};
+
+use crate::DEFAULT_CONFIG_PATH;
+use ibc_relayer::config::Config;
+
 /// Default configuration file path
 pub fn default_config_file() -> Option<PathBuf> {
     dirs_next::home_dir().map(|home| home.join(DEFAULT_CONFIG_PATH))
@@ -86,6 +87,10 @@ pub enum CliCmd {
 
     /// Performs a health check of all chains in the the config
     HealthCheck(HealthCheckCmd),
+
+    /// Generate auto-complete scripts for different shells.
+    #[clap(display_order = 1000)]
+    Completions(CompletionsCmd),
 }
 
 /// This trait allows you to define how application configuration is loaded.

relayer-cli/src/commands/completions.rs

@@ -0,0 +1,20 @@
+use crate::entry::EntryPoint;
+use abscissa_core::clap::Parser;
+use abscissa_core::Runnable;
+use clap::IntoApp;
+use clap_complete::Shell;
+use std::io;
+
+#[derive(Debug, Parser)]
+pub struct CompletionsCmd {
+    #[clap(arg_enum)]
+    shell: Shell,
+}
+
+impl Runnable for CompletionsCmd {
+    fn run(&self) {
+        let mut app = EntryPoint::into_app();
+        let app_name = app.get_name().to_owned();
+        clap_complete::generate(self.shell, &mut app, app_name, &mut io::stdout());
+    }
+}

relayer/src/chain.rs

@@ -1,7 +1,6 @@
 use alloc::sync::Arc;
 use core::convert::TryFrom;
 
-use prost_types::Any;
 use tendermint::block::Height;
 use tokio::runtime::Runtime as TokioRuntime;