try to support nested cli command definitions

src/bin/pbs-datastore.rs

@@ -17,24 +17,8 @@ fn print_cli_usage() {
     eprintln!("Usage: TODO");
 }
 
-type CliCommandDefinition = HashMap<String, CliCommand>;
 
-fn run_cli_command(def: &CliCommandDefinition) -> Result<(), Error> {
-
-    let mut args: Vec<String> = std::env::args().skip(1).collect();
-
-    if args.len() < 1 {
-        bail!("no command specified.");
-    }
-
-    let command = args.remove(0);
-
-    let cli_cmd = match def.get(&command) {
-        Some(cmd) => cmd,
-        None => {
-            bail!("no such command '{}'", command);
-        }
-    };
+fn handle_simple_command(cli_cmd: &CliCommand, args: Vec<String>) -> Result<(), Error> {
 
     let (params, rest) = getopts::parse_arguments(
         &args, &cli_cmd.arg_param, &cli_cmd.info.parameters)?;
@@ -50,35 +34,95 @@ fn run_cli_command(def: &CliCommandDefinition) -> Result<(), Error> {
     Ok(())
 }
 
+fn handle_nested_command(def: &HashMap<String, CmdDef>, mut args: Vec<String>) -> Result<(), Error> {
+
+    if args.len() < 1 {
+        let mut cmds: Vec<&String> = def.keys().collect();
+        cmds.sort();
+
+        let list = cmds.iter().fold(String::new(),|mut s,item| {
+            if !s.is_empty() { s+= ", "; }
+            s += item;
+            s
+        });
+
+        bail!("expected command argument, but no command specified.\nPossible commands: {}", list);
+    }
+
+    let command = args.remove(0);
+
+    let sub_cmd = match def.get(&command) {
+        Some(cmd) => cmd,
+        None => {
+            bail!("no such command '{}'", command);
+        }
+    };
+
+    match sub_cmd {
+        CmdDef::Simple(cli_cmd) => {
+            handle_simple_command(cli_cmd, args)?;
+        }
+        CmdDef::Nested(map) => {
+            handle_nested_command(map, args)?;
+        }
+    }
+
+    Ok(())
+}
+
+fn run_cli_command(def: &CmdDef) -> Result<(), Error> {
+
+    let args: Vec<String> = std::env::args().skip(1).collect();
+
+    match def {
+        CmdDef::Simple(cli_cmd) => handle_simple_command(cli_cmd, args),
+        CmdDef::Nested(map) => handle_nested_command(map, args),
+    }
+}
+
 struct CliCommand {
     info: ApiMethod,
     arg_param: Vec<&'static str>,
     fixed_param: Vec<&'static str>,
 }
 
+enum CmdDef {
+    Simple(CliCommand),
+    Nested(HashMap<String, CmdDef>),
+}
+
+fn datastore_commands() -> CmdDef {
+
+    let mut cmd_def = HashMap::new();
+
+    cmd_def.insert("list".to_owned(), CmdDef::Simple(CliCommand {
+        info: api3::config::datastore::get(),
+        arg_param: vec![],
+        fixed_param: vec![],
+    }));
+
+    cmd_def.insert("create".to_owned(), CmdDef::Simple(CliCommand {
+        info: api3::config::datastore::post(),
+        arg_param: vec!["name", "path"],
+        fixed_param: vec![],
+    }));
+
+    cmd_def.insert("remove".to_owned(), CmdDef::Simple(CliCommand {
+        info: api3::config::datastore::delete(),
+        arg_param: vec!["name"],
+        fixed_param: vec![],
+    }));
+
+    CmdDef::Nested(cmd_def)
+}
+
 fn main() {
 
     let mut cmd_def = HashMap::new();
 
-    cmd_def.insert("list".to_owned(), CliCommand {
-        info: api3::config::datastore::get(),
-        arg_param: vec![],
-        fixed_param: vec![],
-    });
+    cmd_def.insert("datastore".to_owned(), datastore_commands());
 
-    cmd_def.insert("create".to_owned(), CliCommand {
-        info: api3::config::datastore::post(),
-        arg_param: vec!["name", "path"],
-        fixed_param: vec![],
-    });
-
-    cmd_def.insert("remove".to_owned(), CliCommand {
-        info: api3::config::datastore::delete(),
-        arg_param: vec!["name"],
-        fixed_param: vec![],
-    });
-
-    if let Err(err) = run_cli_command(&cmd_def) {
+    if let Err(err) = run_cli_command(&CmdDef::Nested(cmd_def)) {
         eprintln!("Error: {}", err);
         print_cli_usage();
         std::process::exit(-1);