Refactoring: command dispatch, internal type error, reduce duplication in CLI parser definitions

Author: michaelklishin

Cargo.lock

@@ -0,0 +1,76 @@
+// Copyright (C) 2023-2025 RabbitMQ Core Team ([email protected])
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use crate::errors::CommandRunError;
+use clap::ArgMatches;
+use std::fmt::Display;
+use std::str::FromStr;
+
+type CommandResult<T> = Result<T, CommandRunError>;
+
+pub trait ArgMatchesExt {
+    fn str_arg(&self, name: &str) -> &String;
+    fn string_arg(&self, name: &str) -> String;
+
+    fn required_string(&self, name: &str) -> CommandResult<String>;
+    fn optional_string(&self, name: &str) -> Option<String>;
+    fn optional_typed<T: Clone + Send + Sync + 'static>(&self, name: &str) -> Option<T>;
+    fn optional_typed_or<T: Clone + Send + Sync + 'static>(&self, name: &str, default: T) -> T;
+    fn parse_required<T: FromStr>(&self, name: &str) -> CommandResult<T>
+    where
+        T::Err: Display;
+}
+
+impl ArgMatchesExt for ArgMatches {
+    fn str_arg(&self, name: &str) -> &String {
+        self.get_one::<String>(name).unwrap()
+    }
+
+    fn string_arg(&self, name: &str) -> String {
+        self.get_one::<String>(name).cloned().unwrap()
+    }
+
+    fn required_string(&self, name: &str) -> CommandResult<String> {
+        self.get_one::<String>(name).cloned().ok_or_else(|| {
+            CommandRunError::MissingRequiredArgument {
+                name: name.to_string(),
+            }
+        })
+    }
+
+    fn optional_string(&self, name: &str) -> Option<String> {
+        self.get_one::<String>(name).cloned()
+    }
+
+    fn optional_typed<T: Clone + Send + Sync + 'static>(&self, name: &str) -> Option<T> {
+        self.get_one::<T>(name).cloned()
+    }
+
+    fn optional_typed_or<T: Clone + Send + Sync + 'static>(&self, name: &str, default: T) -> T {
+        self.get_one::<T>(name).cloned().unwrap_or(default)
+    }
+
+    fn parse_required<T: FromStr>(&self, name: &str) -> CommandResult<T>
+    where
+        T::Err: Display,
+    {
+        let value = self.required_string(name)?;
+        value
+            .parse::<T>()
+            .map_err(|e| CommandRunError::InvalidArgumentValue {
+                name: name.to_string(),
+                message: e.to_string(),
+            })
+    }
+}