[pbs-devel] [PATCH proxmox v6 1/2] router: cli: add confirmation helper

[Wolfgang Bumiller]

Some minor cleanups & doc nits:

On Fri, Apr 26, 2024 at 02:37:15PM GMT, Gabriel Goller wrote:
> Add confirmation helper that outputs a prompt and lets the user
> confirm or deny it.
> Implemented to close #4763.
> 
> Co-authored-by: Thomas Lamprecht <t.lamprecht at proxmox.com>
> Signed-off-by: Gabriel Goller <g.goller at proxmox.com>
> ---
>  proxmox-router/Cargo.toml     |   1 +
>  proxmox-router/src/cli/mod.rs | 113 +++++++++++++++++++++++++++++++++-
>  2 files changed, 113 insertions(+), 1 deletion(-)
> 
> diff --git a/proxmox-router/Cargo.toml b/proxmox-router/Cargo.toml
> index dcd71a4..0b9d361 100644
> --- a/proxmox-router/Cargo.toml
> +++ b/proxmox-router/Cargo.toml
> @@ -19,6 +19,7 @@ percent-encoding.workspace = true
>  serde_json.workspace = true
>  serde.workspace = true
>  unicode-width ="0.1.8"
> +regex.workspace = true
>  
>  # cli:
>  tokio = { workspace = true, features = [], optional = true }
> diff --git a/proxmox-router/src/cli/mod.rs b/proxmox-router/src/cli/mod.rs
> index 7df94ad..d13caa5 100644
> --- a/proxmox-router/src/cli/mod.rs
> +++ b/proxmox-router/src/cli/mod.rs
> @@ -12,7 +12,11 @@
>  //! - Ability to create interactive commands (using ``rustyline``)
>  //! - Supports complex/nested commands
>  
> -use std::collections::HashMap;
> +use std::{
> +    collections::HashMap,
> +    io::{self, Write},
> +};
> +use anyhow::bail;
>  
>  use crate::ApiMethod;
>  
> @@ -61,6 +65,113 @@ pub fn init_cli_logger(env_var_name: &str, default_log_level: &str) {
>      .init();
>  }
>  
> +#[derive(PartialEq, Debug)]

This is essentially a bool, so +Clone+Copy please. Also maybe +Eq?

> +/// Use for simple yes or no questions, where booleans can be confusing, especially if there's a
> +/// default response to consider. The implementation provides query helper for the CLI.
> +pub enum Confirmation {
> +    Yes,
> +    No,
> +}
> +
> +impl Confirmation {
> +    /// Get the formatted choice for the query prompt, with self being the highlighted (default)
> +    /// one displayed as upper case.
> +    pub fn default_choice_str(&self) -> &'static str {

^ With +Copy all the methods can drop the `&` and be self-consuming.

> +        match self {
> +            Self::Yes => "Y/n",
> +            Self::No => "y/N",
> +        }
> +    }
> +
> +    /// Returns true if the answer is Yes
> +    pub fn is_yes(&self) -> bool {
> +        *self == Self::Yes
> +    }
> +
> +    /// Returns true if the answer is No
> +    pub fn is_no(&self) -> bool {
> +        *self == Self::No
> +    }
> +
> +    /// Parse an input string reference as yes or no confirmation.
> +    ///
> +    /// The input string is checked verbatim if it is exactly one of the single chars 'y', 'Y',
> +    /// 'n', or 'N'. You must trim the string before calling, if needed, or use one of the query
> +    /// helper functions.
> +    ///
> +    /// ```
> +    /// use proxmox_router::cli::Confirmation;
> +    ///
> +    /// let answer = Confirmation::from_str("y");
> +    /// assert!(answer.expect("valid").is_yes());
> +    ///
> +    /// let answer = Confirmation::from_str("N");
> +    /// assert!(answer.expect("valid").is_no());
> +    ///
> +    /// let answer = Confirmation::from_str("bogus");
> +    /// assert!(answer.is_err());
> +    /// ```
> +    pub fn from_str(input: &str) -> Result<Self, anyhow::Error> {
> +        match input.trim() {
> +            "y" | "Y" => Ok(Self::Yes),
> +            "n" | "N" => Ok(Self::No),
> +            _ => bail!("unexpected choice '{input}'! Use 'y' or 'n'"),
> +        }
> +    }
> +
> +    /// Parse a input string reference as yes or no confirmation, allowing a fallback default
> +    /// answer if the user enters an empty choice.
> +    ///
> +    /// The input string is checked verbatim if it is exactly one of the single chars 'y', 'Y',
> +    /// 'n', or 'N'. The empty string maps to the default. You must trim the string before calling,
> +    /// if needed, or use one of the query helper functions.
> +    ///
> +    /// ```
> +    /// use proxmox_router::cli::Confirmation;
> +    ///
> +    /// let answer = Confirmation::from_str_with_default("", Confirmation::No);
> +    /// assert!(answer.expect("valid").is_no());
> +    ///
> +    /// let answer = Confirmation::from_str_with_default("n", Confirmation::Yes);
> +    /// assert!(answer.expect("valid").is_no());
> +    ///
> +    /// let answer = Confirmation::from_str_with_default("yes", Confirmation::Yes);
> +    /// assert!(answer.is_err()); // full-word answer not allowed for now.
> +    /// ```
> +    pub fn from_str_with_default(input: &str, default: Self) -> Result<Self, anyhow::Error> {
> +        match input.trim() {
> +            "y" | "Y" => Ok(Self::Yes),
> +            "n" | "N" => Ok(Self::No),
> +            "" => Ok(default),
> +            _ => bail!("unexpected choice '{input}'! Use enter for default or use 'y' or 'n'"),
> +        }
> +    }
> +
> +    /// Print a query prompt with available yes no choices and returns the String the user enters.
> +    fn read_line(query: &str, choices: &str) -> Result<String, io::Error> {
> +        print!("{query} [{choices}]: ");
> +
> +        io::stdout().flush()?;
> +        let stdin = io::stdin();
> +        let mut line = String::new();
> +        stdin.read_line(&mut line)?;
> +        Ok(line)
> +    }
> +
> +    /// Print a query prompt and parse the white-space trimmed answer using from_str.

Please add backticks around `from_str`.

> +    pub fn query(query: &str) -> Result<Self, anyhow::Error> {
> +        let line = Self::read_line(query, "y/n")?;
> +        Confirmation::from_str(line.trim())
> +    }
> +
> +    /// Print a query prompt and parse the answer using from_str_with_default, falling back to the

Please add backticks around `from_str_with_default`.

> +    /// default_answer if the user provided an empty string.
> +    pub fn query_with_default(query: &str, default_answer: Self) -> Result<Self, anyhow::Error> {
> +        let line = Self::read_line(query, default_answer.default_choice_str())?;
> +        Confirmation::from_str_with_default(line.trim(), default_answer)
> +    }
> +}