Support generation of shell completions (#54)

## Description

For #37

This was surprisingly easy. Following the same semantics as `kubectl`.

Docs will be added via c97f6ac in #36.
We can copy parts of `kubectl` docs

You can try it out with `source <(stackablectl completion bash)` (for bash)

Author: sbernauer

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Added
+
+- Support generation of shell completions ([#54](https://github.com/stackabletech/stackablectl/pull/54))
+
 ### Changed
 
 - Update Rust and Go libs ([#46](https://github.com/stackabletech/stackablectl/pull/46))

Cargo.lock

@@ -10,6 +10,7 @@ repository = "https://github.com/stackabletech/stackablectl"
 [dependencies]
 cached = "0.37"
 clap = { version = "3.2", features = ["derive", "cargo"] }
+clap_complete = "3.2"
 env_logger = "0.9"
 indexmap = { version = "1.9", features = ["serde"] }
 lazy_static = "1.4"

Cargo.toml

@@ -1,57 +1,72 @@
 use crate::{operator::CliCommandOperator, release::CliCommandRelease, stack::CliCommandStack};
-use clap::{ArgEnum, Parser};
+use clap::{ArgEnum, Command, Parser, ValueHint};
+use clap_complete::{generate, Generator, Shell};
 use log::LevelFilter;
+use std::io;
 
 #[derive(Parser)]
 #[clap(author, version, about)]
 pub struct CliArgs {
     #[clap(subcommand)]
     pub cmd: CliCommand,
 
-    /// Log level. One of Error, Warn, Info, Debug or Trace
-    #[clap(short, long, default_value = "Info")]
-    pub log_level: LevelFilter,
+    /// Log level.
+    #[clap(short, long, arg_enum, default_value = "info")]
+    pub log_level: LogLevel,
 
     /// Namespace where to deploy the products and operators
-    #[clap(short, long, default_value = "default")]
+    #[clap(short, long, default_value = "default", value_hint = ValueHint::Other)]
     pub namespace: String,
 
+    /// Overwrite the URL of the stable helm repo
+    ///
     /// If you don't have access to the Stackable Helm repos you can mirror the repo and provide the URL here
     /// (e.g. <https://my.repo/repository/stackable-stable/>).
     #[clap(
         long,
-        default_value = "https://repo.stackable.tech/repository/helm-stable"
+        default_value = "https://repo.stackable.tech/repository/helm-stable",
+        value_hint = ValueHint::Url,
     )]
     pub helm_repo_stackable_stable: String,
 
+    /// Overwrite the URL of the test helm repo
+    ///
     /// If you don't have access to the Stackable Helm repos you can mirror the repo and provide the URL here
     /// (e.g. <https://my.repo/repository/stackable-test/>).
     #[clap(
         long,
-        default_value = "https://repo.stackable.tech/repository/helm-test"
+        default_value = "https://repo.stackable.tech/repository/helm-test",
+        value_hint = ValueHint::Url,
     )]
     pub helm_repo_stackable_test: String,
 
+    /// Overwrite the URL of the dev helm repo
+    ///
     /// If you don't have access to the Stackable Helm repos you can mirror the repo and provide the URL here
     /// (e.g. <https://my.repo/repository/stackable-dev/>).
     #[clap(
         long,
-        default_value = "https://repo.stackable.tech/repository/helm-dev"
+        default_value = "https://repo.stackable.tech/repository/helm-dev",
+        value_hint = ValueHint::Url,
     )]
     pub helm_repo_stackable_dev: String,
 
+    /// Adds a YAML file containing custom releases
+    ///
     /// If you don't have access to the Stackable GitHub repos or you want to maintain your own releases you can specify additional YAML files containing release information.
     /// Have a look [here](https://raw.githubusercontent.com/stackabletech/stackablectl/main/releases.yaml) for the structure.
     /// Can either be an URL or a path to a file e.g. `https://my.server/my-releases.yaml` or '/etc/my-releases.yaml' or `C:\Users\Sebastian\my-releases.yaml`.
     /// Can be specified multiple times.
-    #[clap(long, multiple_occurrences(true))]
+    #[clap(long, multiple_occurrences(true), value_hint = ValueHint::FilePath)]
     pub additional_release_files: Vec<String>,
 
+    /// Adds a YAML file containing custom stacks
+    ///
     /// If you don't have access to the Stackable GitHub repos or you want to maintain your own stacks you can specify additional YAML files containing stack information.
     /// Have a look [here](https://raw.githubusercontent.com/stackabletech/stackablectl/main/stacks.yaml) for the structure.
     /// Can either be an URL or a path to a file e.g. `https://my.server/my-stacks.yaml` or '/etc/my-stacks.yaml' or `C:\Users\Sebastian\my-stacks.yaml`.
     /// Can be specified multiple times.
-    #[clap(long, multiple_occurrences(true))]
+    #[clap(long, multiple_occurrences(true), value_hint = ValueHint::FilePath)]
     pub additional_stack_files: Vec<String>,
 }
 
@@ -68,6 +83,9 @@ pub enum CliCommand {
     /// This subcommand interacts with stacks, which are ready-to-use combinations of products.
     #[clap(subcommand, alias("s"), alias("st"))]
     Stack(CliCommandStack),
+
+    /// Output shell completion code for the specified shell.
+    Completion(CliCommandCompletion),
 }
 
 #[derive(Clone, Parser, ArgEnum)]
@@ -76,3 +94,35 @@ pub enum OutputType {
     Json,
     Yaml,
 }
+
+#[derive(Clone, Copy, Parser, Debug, ArgEnum)]
+pub enum LogLevel {
+    Error,
+    Warn,
+    Info,
+    Debug,
+    Trace,
+}
+
+impl From<LogLevel> for LevelFilter {
+    fn from(val: LogLevel) -> Self {
+        match val {
+            LogLevel::Error => LevelFilter::Error,
+            LogLevel::Warn => LevelFilter::Warn,
+            LogLevel::Info => LevelFilter::Info,
+            LogLevel::Debug => LevelFilter::Debug,
+            LogLevel::Trace => LevelFilter::Trace,
+        }
+    }
+}
+
+#[derive(Parser)]
+pub struct CliCommandCompletion {
+    // Shell to generate the completions for
+    #[clap(arg_enum, value_parser)]
+    pub shell: Shell,
+}
+
+pub fn print_completions<G: Generator>(gen: G, cmd: &mut Command) {
+    generate(gen, cmd, cmd.get_name().to_string(), &mut io::stdout());
+}

src/arguments.rs

@@ -47,7 +47,7 @@ pub fn handle_common_cli_args(args: &CliArgs) {
         args.helm_repo_stackable_dev.clone(),
     );
 
-    *(LOG_LEVEL.lock().unwrap()) = args.log_level;
+    *(LOG_LEVEL.lock().unwrap()) = args.log_level.into();
 
     let namespace = &args.namespace;
     if namespace != "default" {

src/helm.rs

@@ -1,6 +1,6 @@
 use crate::arguments::CliCommand;
 use arguments::CliArgs;
-use clap::Parser;
+use clap::{IntoApp, Parser};
 
 mod arguments;
 mod helm;
@@ -37,7 +37,7 @@ fn main() {
     env_logger::builder()
         .format_timestamp(None)
         .format_target(false)
-        .filter_level(args.log_level)
+        .filter_level(args.log_level.into())
         .init();
     helm::handle_common_cli_args(&args);
     release::handle_common_cli_args(&args);
@@ -47,5 +47,9 @@ fn main() {
         CliCommand::Operator(command) => command.handle(),
         CliCommand::Release(command) => command.handle(),
         CliCommand::Stack(command) => command.handle(),
+        CliCommand::Completion(command) => {
+            let mut cmd = CliArgs::command();
+            arguments::print_completions(command.shell, &mut cmd);
+        }
     }
 }

src/main.rs

@@ -1,5 +1,5 @@
 use crate::{arguments::OutputType, helm, helm::HELM_REPOS, kind, AVAILABLE_OPERATORS};
-use clap::Parser;
+use clap::{Parser, ValueHint};
 use indexmap::IndexMap;
 use log::{info, warn};
 use serde::Serialize;
@@ -16,6 +16,7 @@ pub enum CliCommandOperator {
     /// Show details of a specific operator
     #[clap(alias("desc"))]
     Describe {
+        #[clap(value_hint = ValueHint::Other)]
         operator: String,
         #[clap(short, long, arg_enum, default_value = "text")]
         output: OutputType,
@@ -26,7 +27,7 @@ pub enum CliCommandOperator {
         /// Space separated list of operators to install.
         /// Must have the form `name[=version]` e.g. `superset`, `superset=0.3.0`, `superset=0.3.0-nightly` or `superset=0.3.0-pr123`.
         /// You can get the available versions with `stackablectl operator list` or `stackablectl operator describe superset`
-        #[clap(multiple_occurrences(true), required = true)]
+        #[clap(multiple_occurrences(true), required = true, value_hint = ValueHint::Other)]
         operators: Vec<Operator>,
 
         /// If specified a local kubernetes cluster consisting of 4 nodes for testing purposes will be created.
@@ -39,15 +40,16 @@ pub enum CliCommandOperator {
         #[clap(
             long,
             default_value = "stackable-data-platform",
-            requires = "kind-cluster"
+            requires = "kind-cluster",
+            value_hint = ValueHint::Other,
         )]
         kind_cluster_name: String,
     },
     /// Uninstall a operator
     #[clap(alias("un"))]
     Uninstall {
         /// Space separated list of operators to uninstall.
-        #[clap(multiple_occurrences(true), required = true)]
+        #[clap(multiple_occurrences(true), required = true, value_hint = ValueHint::Other)]
         operators: Vec<String>,
     },
     /// List installed operators

src/operator.rs

@@ -1,6 +1,6 @@
 use crate::{arguments::OutputType, helpers, kind, operator, operator::Operator, CliArgs};
 use cached::proc_macro::cached;
-use clap::{ArgGroup, Parser};
+use clap::{ArgGroup, Parser, ValueHint};
 use indexmap::IndexMap;
 use lazy_static::lazy_static;
 use log::{error, info, warn};
@@ -24,6 +24,7 @@ pub enum CliCommandRelease {
     /// Show details of a specific release
     #[clap(alias("desc"))]
     Describe {
+        #[clap(value_hint = ValueHint::Other)]
         release: String,
         #[clap(short, long, arg_enum, default_value = "text")]
         output: OutputType,
@@ -37,17 +38,17 @@ pub enum CliCommandRelease {
     ))]
     Install {
         /// Name of the release to install
-        #[clap(required = true)]
+        #[clap(required = true, value_hint = ValueHint::Other)]
         release: String,
 
         /// Whitelist of product operators to install.
         /// Mutually exclusive with `--exclude-products`
-        #[clap(short, long)]
+        #[clap(short, long, value_hint = ValueHint::Other)]
         include_products: Vec<String>,
 
         /// Blacklist of product operators to install.
         /// Mutually exclusive with `--include-products`
-        #[clap(short, long)]
+        #[clap(short, long, value_hint = ValueHint::Other)]
         exclude_products: Vec<String>,
 
         /// If specified a local kubernetes cluster consisting of 4 nodes for testing purposes will be created.
@@ -60,15 +61,16 @@ pub enum CliCommandRelease {
         #[clap(
             long,
             default_value = "stackable-data-platform",
-            requires = "kind-cluster"
+            requires = "kind-cluster",
+            value_hint = ValueHint::Other,
         )]
         kind_cluster_name: String,
     },
     /// Uninstall a release
     #[clap(alias("un"))]
     Uninstall {
         /// Name of the release to uninstall
-        #[clap(required = true)]
+        #[clap(required = true, value_hint = ValueHint::Other)]
         release: String,
     },
 }