Refactor CLI parsing: clap derive + improved errors.

**Big refactoring!**

As suggested, more declarative code is used to define CLI.

NOTE: Errors like 'missing argument' or 'u64 parse error'
are handled by `clap` natively now.

kairos-cli/Cargo.toml

@@ -14,9 +14,10 @@ edition = "2021"
 
 [dependencies]
 casper-types = { version = "4.0.1", features = ["std"] } # TODO: Change `std` -> `std-fs-io` in the future version.
-clap = "4.4.18"
+clap = { version = "4.4.18", features = ["derive"] }
 hex = "0.4.3"
 thiserror = "1.0.56"
 
 [dev-dependencies]
 assert_cmd = "2.0.13"
+predicates = "3.1.0"

kairos-cli/bin/commands/deposit.rs

@@ -1,31 +1,24 @@
-use crate::common::{amount, private_key};
+use crate::common::args::{AmountArg, PrivateKeyPathArg};
 use crate::crypto::signer::CasperSigner;
 use crate::error::CliError;
-use clap::{ArgMatches, Command};
 
-pub struct Deposit;
+use clap::Parser;
 
-impl Deposit {
-    pub const NAME: &'static str = "deposit";
-    pub const ABOUT: &'static str = "Deposits funds into your account";
-
-    pub fn new_cmd() -> Command {
-        Command::new(Self::NAME)
-            .about(Self::ABOUT)
-            .arg(amount::arg())
-            .arg(private_key::arg())
-    }
-
-    pub fn run(matches: &ArgMatches) -> Result<String, CliError> {
-        let _amount = amount::get(matches)?;
-        let private_key = private_key::get(matches)?;
+#[derive(Parser, Debug)]
+pub struct Args {
+    #[clap(flatten)]
+    amount: AmountArg,
+    #[clap(flatten)]
+    private_key_path: PrivateKeyPathArg,
+}
 
-        let _signer = CasperSigner::from_key(private_key);
+pub fn run(args: Args) -> Result<String, CliError> {
+    let _amount: u64 = args.amount.field;
+    let _signer = CasperSigner::from_key_pathbuf(args.private_key_path.field)?;
 
-        // TODO: Create transaction and sign it with `signer`.
+    // TODO: Create transaction and sign it with `signer`.
 
-        // TODO: Send transaction to the network, using Rust SDK.
+    // TODO: Send transaction to the network, using Rust SDK.
 
-        Ok("ok".to_string())
-    }
+    Ok("ok".to_string())
 }

kairos-cli/bin/commands/mod.rs

@@ -1,7 +1,15 @@
-mod deposit;
-mod transfer;
-mod withdraw;
+pub mod deposit;
+pub mod transfer;
+pub mod withdraw;
 
-pub use deposit::Deposit;
-pub use transfer::Transfer;
-pub use withdraw::Withdraw;
+use clap::Subcommand;
+
+#[derive(Subcommand)]
+pub enum Command {
+    #[command(about = "Deposits funds into your account")]
+    Deposit(deposit::Args),
+    #[command(about = "Transfers funds to another account")]
+    Transfer(transfer::Args),
+    #[command(about = "Withdraws funds from your account")]
+    Withdraw(withdraw::Args),
+}

kairos-cli/bin/commands/transfer.rs

@@ -1,59 +1,31 @@
-use crate::common::{amount, private_key};
+use crate::common::args::{AmountArg, PrivateKeyPathArg};
 use crate::crypto::public_key::CasperPublicKey;
 use crate::crypto::signer::CasperSigner;
 use crate::error::CliError;
-use clap::{Arg, ArgMatches, Command};
+use crate::utils::parse_hex_string;
 
-pub struct Transfer;
+use clap::Parser;
 
-const ARG_NAME: &str = "recipient";
-const ARG_SHORT: char = 'r';
-const ARG_VALUE_NAME: &str = "PUBLIC_KEY";
+type StdVec<E> = Vec<E>;
 
-pub mod recipient {
-    use super::*;
-
-    pub fn arg() -> Arg {
-        Arg::new(ARG_NAME)
-            .long(ARG_NAME)
-            .short(ARG_SHORT)
-            .required(true)
-            .value_name(ARG_VALUE_NAME)
-    }
-
-    pub fn get(matches: &ArgMatches) -> Result<CasperPublicKey, CliError> {
-        let value = matches
-            .get_one::<String>("recipient")
-            .map(String::as_str)
-            .unwrap();
-
-        CasperPublicKey::from_hex(value).map_err(|error| CliError::CryptoError { error })
-    }
+#[derive(Parser)]
+pub struct Args {
+    #[arg(long, short, value_name = "PUBLIC_KEY", value_parser = parse_hex_string)]
+    recipient: StdVec<u8>,
+    #[clap(flatten)]
+    amount: AmountArg,
+    #[clap(flatten)]
+    private_key_path: PrivateKeyPathArg,
 }
 
-impl Transfer {
-    pub const NAME: &'static str = "transfer";
-    pub const ABOUT: &'static str = "Transfers funds to another account";
-
-    pub fn new_cmd() -> Command {
-        Command::new(Self::NAME)
-            .about(Self::ABOUT)
-            .arg(recipient::arg())
-            .arg(amount::arg())
-            .arg(private_key::arg())
-    }
-
-    pub fn run(matches: &ArgMatches) -> Result<String, CliError> {
-        let _recipient = recipient::get(matches)?;
-        let _amount = amount::get(matches)?;
-        let private_key = private_key::get(matches)?;
-
-        let _signer = CasperSigner::from_key(private_key);
+pub fn run(args: Args) -> Result<String, CliError> {
+    let _recipient = CasperPublicKey::from_bytes(args.recipient.as_ref())?;
+    let _amount: u64 = args.amount.field;
+    let _signer = CasperSigner::from_key_pathbuf(args.private_key_path.field)?;
 
-        // TODO: Create transaction and sign it with `signer`.
+    // TODO: Create transaction and sign it with `signer`.
 
-        // TODO: Send transaction to the network, using Rust SDK.
+    // TODO: Send transaction to the network, using Rust SDK.
 
-        Ok("ok".to_string())
-    }
+    Ok("ok".to_string())
 }

kairos-cli/bin/commands/withdraw.rs

@@ -1,31 +1,24 @@
-use crate::common::{amount, private_key};
+use crate::common::args::{AmountArg, PrivateKeyPathArg};
 use crate::crypto::signer::CasperSigner;
 use crate::error::CliError;
-use clap::{ArgMatches, Command};
 
-pub struct Withdraw;
+use clap::Parser;
 
-impl Withdraw {
-    pub const NAME: &'static str = "withdraw";
-    pub const ABOUT: &'static str = "Withdraws funds from your account";
-
-    pub fn new_cmd() -> Command {
-        Command::new(Self::NAME)
-            .about(Self::ABOUT)
-            .arg(amount::arg())
-            .arg(private_key::arg())
-    }
-
-    pub fn run(matches: &ArgMatches) -> Result<String, CliError> {
-        let _amount = amount::get(matches)?;
-        let private_key = private_key::get(matches)?;
+#[derive(Parser)]
+pub struct Args {
+    #[clap(flatten)]
+    amount: AmountArg,
+    #[clap(flatten)]
+    private_key_path: PrivateKeyPathArg,
+}
 
-        let _signer = CasperSigner::from_key(private_key);
+pub fn run(args: Args) -> Result<String, CliError> {
+    let _amount: u64 = args.amount.field;
+    let _signer = CasperSigner::from_key_pathbuf(args.private_key_path.field)?;
 
-        // TODO: Create transaction and sign it with `signer`.
+    // TODO: Create transaction and sign it with `signer`.
 
-        // TODO: Send transaction to the network, using Rust SDK.
+    // TODO: Send transaction to the network, using Rust SDK.
 
-        Ok("ok".to_string())
-    }
+    Ok("ok".to_string())
 }

kairos-cli/bin/common/args.rs

@@ -1,61 +1,15 @@
-use crate::error::CliError;
-use clap::{Arg, ArgMatches};
+use std::path::PathBuf;
 
-pub mod amount {
-    use super::*;
+use clap::Args;
 
-    const ARG_NAME: &str = "amount";
-    const ARG_SHORT: char = 'a';
-    const ARG_VALUE_NAME: &str = "NUM_MOTES";
-
-    pub fn arg() -> Arg {
-        Arg::new(ARG_NAME)
-            .long(ARG_NAME)
-            .short(ARG_SHORT)
-            .required(true)
-            .value_name(ARG_VALUE_NAME)
-    }
-
-    pub fn get(matches: &ArgMatches) -> Result<u64, CliError> {
-        let value = matches
-            .get_one::<String>(ARG_NAME)
-            .map(String::as_str)
-            .ok_or(CliError::MissingArgument { context: ARG_NAME })?;
-
-        let amount = value
-            .parse::<u64>()
-            .map_err(|_| CliError::FailedToParseU64 { context: "amount" })?;
-
-        Ok(amount)
-    }
+#[derive(Args, Debug)]
+pub struct AmountArg {
+    #[arg(name = "amount", long, short, value_name = "NUM_MOTES")]
+    pub field: u64,
 }
 
-pub mod private_key {
-    use crate::crypto::private_key::CasperPrivateKey;
-
-    use super::*;
-
-    const ARG_NAME: &str = "private-key";
-    const ARG_SHORT: char = 'k';
-    const ARG_VALUE_NAME: &str = "FILE_PATH";
-
-    pub fn arg() -> Arg {
-        Arg::new(ARG_NAME)
-            .long(ARG_NAME)
-            .short(ARG_SHORT)
-            .required(true)
-            .value_name(ARG_VALUE_NAME)
-    }
-
-    pub fn get(matches: &ArgMatches) -> Result<CasperPrivateKey, CliError> {
-        let value = matches
-            .get_one::<String>(ARG_NAME)
-            .map(String::as_str)
-            .ok_or(CliError::MissingArgument { context: ARG_NAME })?;
-
-        let private_key =
-            CasperPrivateKey::from_file(value).map_err(|error| CliError::CryptoError { error })?;
-
-        Ok(private_key)
-    }
+#[derive(Args, Debug)]
+pub struct PrivateKeyPathArg {
+    #[arg(name = "private-key", long, short = 'k', value_name = "FILE_PATH")]
+    pub field: PathBuf,
 }

kairos-cli/bin/common/mod.rs

@@ -1,4 +1 @@
-mod args;
-
-pub use args::amount;
-pub use args::private_key;
+pub mod args;

kairos-cli/bin/crypto/error.rs

@@ -2,9 +2,13 @@ use thiserror::Error;
 
 #[derive(Error, Debug)]
 pub enum CryptoError {
-    /// Failed to parse a public key from a formatted string.
+    /// Unable to load a file from the given path.
+    #[error("failed to load key from file")]
+    KeyLoad,
+    /// Failed to parse a public key from a raw data.
     #[error("failed to parse private key")]
-    FailedToParseKey {},
-    #[error("failed to serialize signature/key")]
-    Serialization {},
+    FailedToParseKey,
+    /// Invalid public key (hexdigest) or other encoding related error.
+    #[error("failed to serialize/deserialize '{context}'")]
+    Serialization { context: &'static str },
 }

kairos-cli/bin/crypto/private_key.rs

@@ -1,11 +1,18 @@
+use casper_types::file_utils::read_file;
+
 use crate::crypto::error::CryptoError;
 
 pub struct CasperPrivateKey(pub casper_types::SecretKey);
 
 impl CasperPrivateKey {
     pub fn from_file(file_path: &str) -> Result<Self, CryptoError> {
-        let secret_key = casper_types::SecretKey::from_file(file_path)
-            .map_err(|_e| CryptoError::FailedToParseKey {})?;
+        let data = read_file(file_path).map_err(|_e| CryptoError::KeyLoad)?;
+        let secret_key =
+            casper_types::SecretKey::from_pem(data).map_err(|_e| CryptoError::FailedToParseKey)?;
         Ok(Self(secret_key))
     }
 }
+
+pub fn parse_private_key(file_path: &str) -> Result<CasperPrivateKey, CryptoError> {
+    CasperPrivateKey::from_file(file_path)
+}