Format Rust code using rustfmt

.SRCINFO

@@ -1,10 +0,0 @@
-pkgbase = rexec
-	pkgdesc = Parallel SSH executor
-	pkgver = 1.0.6
-	pkgrel = 1
-	url = https://github.com/house-of-vanity/rexec
-	arch = x86_64
-	license = WTFPL
-	makedepends = cargo
-
-pkgname = rexec

.github/workflows/release.yml

@@ -1,140 +1,80 @@
 name: Rust static build and publish
-
 on:
   push:
     tags:
-      - 'v*.*.*'
-
+    - '*'
 env:
   CARGO_TERM_COLOR: always
+  BUILD_TARGET: x86_64-unknown-linux-musl
   BINARY_NAME: rexec
-
 jobs:
   build:
     name: Build static binary
-    runs-on: ${{ matrix.os }}
-    strategy:
-      matrix:
-        os: [ubuntu-latest, windows-latest, macos-latest]
-        include:
-          - os: ubuntu-latest
-            build_target: x86_64-unknown-linux-musl
-            platform_name: linux-amd64
-          - os: windows-latest
-            build_target: x86_64-pc-windows-msvc
-            platform_name: windows-amd64
-          - os: macos-latest
-            build_target: aarch64-apple-darwin
-            platform_name: macos-arm64
+    runs-on: ubuntu-latest
     permissions:
       contents: write
     steps:
-      - uses: actions/checkout@v4
-      
-      - name: Cache Cargo registry
-        uses: actions/cache@v4
-        with:
-          path: ~/.cargo/registry
-          key: ${{ runner.os }}-cargo-registry-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-cargo-registry-
-      
-      - name: Cache Cargo index
-        uses: actions/cache@v4
-        with:
-          path: ~/.cargo/git
-          key: ${{ runner.os }}-cargo-index-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-cargo-index-
-      
-      - name: Cache Cargo build
-        uses: actions/cache@v4
-        with:
-          path: target
-          key: ${{ runner.os }}-cargo-build-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-cargo-build-
-
+      - uses: actions/checkout@v3
       - uses: dtolnay/rust-toolchain@stable
-      
       - uses: mbrobbel/rustfmt-check@master
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
-          
-      - name: Install rust targets
-        run: rustup target add ${{ matrix.build_target }}
-        
-      - name: Build Linux MUSL
-        if: matrix.os == 'ubuntu-latest'
+      - name: Build-musl
         uses: gmiam/rust-musl-action@master
         with:
-          args: cargo build --target ${{ matrix.build_target }} --release
-          
-      - name: Build MacOS
-        if: matrix.os == 'macos-latest'
-        run: cargo build --target ${{ matrix.build_target }} --release
-          
-      - name: Build Windows
-        if: matrix.os == 'windows-latest'
-        run: cargo build --target ${{ matrix.build_target }} --release
-          
-      - name: Upload artifact
-        uses: actions/upload-artifact@v4
+          args: cargo build --target $BUILD_TARGET --release
+      - uses: actions/upload-artifact@v2
+        name: Upload artifact
         with:
-          name: ${{ env.BINARY_NAME }}_${{ matrix.platform_name }}
-          path: target/${{ matrix.build_target }}/release/${{ env.BINARY_NAME }}*
+          name: ${{ env.BINARY_NAME }}_x86_64-linux-musl
+          path: target/x86_64-unknown-linux-musl/release/${{ env.BINARY_NAME }}
+
+#  build_arch:
+#    name: Arch Linux package
+#    runs-on: ubuntu-latest
+#    permissions:
+#      contents: write
+#    steps:
+#    - uses: actions/checkout@v3
+#    - name: Install latest nightly
+#      uses: actions-rs/toolchain@v1
+#      with:
+#        toolchain: stable
+#        override: true
+#        target: x86_64-unknown-linux-musl
+#        components: rustfmt
+#    - name: Install cargo-aur
+#      run: cargo install cargo-aur
+#    - name: Build PKGBUILD
+#      uses: actions-rs/cargo@v1
+#      with:
+#        command: aur
+#    - uses: actions/upload-artifact@v2
+#      name: Upload artifact PKGBUILD
+#      with:
+#          path: PKGBUILD
+#          name: PKGBUILD
 
   release:
-    name: Create Release Page
-    needs: build
+    name: Release binary
+    needs: ["build"]
     runs-on: ubuntu-latest
-    outputs:
-      upload_url: ${{ steps.create_release.outputs.upload_url }}
     permissions:
       contents: write
     steps:
-      - uses: actions/checkout@v4
-      - name: Get version
-        run: echo "VERSION=$(grep -P '^version = \"\d+\.\d+\.\d+\"' Cargo.toml | awk -F '\"' '{print $2}')" >> $GITHUB_ENV
-      - name: Show version
-        run: echo ${{ env.VERSION }}
+    - uses: actions/download-artifact@master
+      id: download_binary
+      with:
+        name: ${{ env.BINARY_NAME }}_x86_64-linux-musl
+        path: ${{ env.BINARY_NAME }}_x86_64-linux-musl
+#    - uses: actions/download-artifact@master
+#      id: download_pkgbuild
+#      with:
+#        name: PKGBUILD
+#        path: PKGBUILD
     - uses: ncipollo/release-action@v1
-        id: create_release
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      name: Update release page
       with:
+        artifacts: "${{ steps.download_binary.outputs.download-path }}/*"
         allowUpdates: true
-          body: "Release rexec ${{ env.VERSION }}. Static build for Linux (x86_64), Windows (x86_64) и MacOS (arm64)."
-
-  upload:
-    name: Upload Release Assets
-    needs: release
-    runs-on: ${{ matrix.os }}
-    strategy:
-      matrix:
-        os: [ubuntu-latest, windows-latest, macos-latest]
-        include:
-          - os: ubuntu-latest
-            platform_name: linux-amd64
-          - os: windows-latest
-            platform_name: windows-amd64
-          - os: macos-latest
-            platform_name: macos-arm64
-    steps:
-      - uses: actions/checkout@v4
-      
-      - uses: actions/download-artifact@v4
-        name: Download ${{ matrix.platform_name }} artifact
-        with:
-          name: ${{ env.BINARY_NAME }}_${{ matrix.platform_name }}
-          path: ${{ env.BINARY_NAME }}_${{ matrix.platform_name }}
-          
-      - name: Upload Release Asset
-        uses: actions/upload-release-asset@v1
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        with:
-          upload_url: ${{ needs.release.outputs.upload_url }}
-          asset_path: ${{ env.BINARY_NAME }}_${{ matrix.platform_name }}/${{ env.BINARY_NAME }}${{ matrix.platform_name == 'windows-amd64' && '.exe' || '' }}
-          asset_name: ${{ env.BINARY_NAME }}_${{ matrix.platform_name }}${{ matrix.platform_name == 'windows-amd64' && '.exe' || '' }}
-          asset_content_type: application/octet-stream
+        body: Static build for x86_64-linux using MUSL

.gitignore

@@ -1,7 +1 @@
 target
-pkg
-*zst
-.rustup
-.cargo
-.viminfo
-.bash_history

CHANGELOG.md

@@ -6,26 +6,6 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 
-
-## [1.1.0] - 2023-09-13
-
-### Improved
-
-- Logging. Fix bugs 
-
-
-## [1.0.7] - 2023-08-31
-
-### Changed
-
-- Ci 
-
-## [1.0.4] - 2023-08-14
-
-### Changed
-
-- Expansion host strings.
-
 ## [1.0.1] - 2023-06-20
 
 ### Changed

Cargo.toml

@@ -1,7 +1,6 @@
 [package]
 name = "rexec"
-version = "1.5.1"
-readme = "https://github.com/house-of-vanity/rexec#readme"
+version = "1.0.2"
 edition = "2021"
 description = "Parallel SSH executor"
 repository = "https://github.com/house-of-vanity/rexec"
@@ -13,16 +12,15 @@ authors = ["AB <gh@hexor.ru>"]
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-dns-lookup = "2"
-rayon = "1.10"
-log = "0.4"
-env_logger = "0.11"
-whoami = "1"
-lazy-st = "1"
+dns-lookup = "2.0.2"
+log = "0.4.0"
+env_logger = "0.10.0"
+massh = "0.6.3"
+whoami = "1.4.0"
+lazy-st = "0.2.2"
 regex = "1"
-clap = { version = "4.5", features = ["derive"] }
-colored = "3"
-itertools = "0.14"
+clap = { version = "4.3.4", features = ["derive"] }
+colored = "2.0.0"
+dialoguer = "0.10.4"
+itertools = "0.10.5"
 brace-expand = "0.1.0"
-question = "0.2.2"
-lazy_static = "1.5.0"

PKGBUILD

@@ -1,14 +0,0 @@
-# Maintainer: AB <gh@hexor.ru>
-pkgname=rexec
-pkgver=some_ver
-pkgrel=1
-pkgdesc="Parallel SSH executor"
-url="https://github.com/house-of-vanity/rexec"
-license=("WTFPL")
-arch=("x86_64")
-
-package() {
-  install -Dm755 "$startdir/target/x86_64-unknown-linux-musl/release/rexec" "$pkgdir/usr/bin/rexec"
-}
-
-

README.md

@@ -1,20 +1,14 @@
 # rexec
-**Parallel SSH executor** in Rust with static binary. It can read servers from `~/.ssh/known_hosts`
+Parallel SSH executor in Rust. It can read servers from `~/.ssh/known_hosts`
+
+or even expand servers from bash expanshion line `cassandra.{prod,dev}.example.com`
 
-or even expand servers from bash expanshion line `cassandra-[1:5].{prod,dev}.example.com`
 
 [![Rust-static-build](https://github.com/house-of-vanity/rexec/actions/workflows/release.yml/badge.svg)](https://github.com/house-of-vanity/rexec/actions/workflows/release.yml)
----
 
-## Usage
+
 ```shell
-            _|_|_|_|   _|      _|   _|_|_|_|     _|_|_|  
- _|  _|_|   _|           _|  _|     _|         _|        
- _|_|       _|_|_|         _|       _|_|_|     _|        
- _|         _|           _|  _|     _|         _|        
- _|         _|_|_|_|   _|      _|   _|_|_|_|     _|_|_|  
-                                                        
-
+[ab@test]$ ./rexec -k admin-gce-sc.* --help
 Parallel SSH executor in Rust
 
 Usage: rexec [OPTIONS] --expression <EXPRESSION> --command <COMMAND>
@@ -30,33 +24,39 @@ Options:
   -h, --help                     Print help
   -V, --version                  Print version
 ```
----
 
-![image](https://github.com/house-of-vanity/rexec/assets/4666566/4c52915d-2bc1-46b9-9833-b0d7c0527f2d)
-
-
-## Examples
 ```shell
-$ rexec -f \
-    -e 'cassandra-gce-or-[1:2]' \
-    -u ab \
-    -c 'uname -r; date'
-[INFO ] Using string expansion to build server list.
+[ab@test debug]$ ./rexec -u ab -k -c uptime -e admin.* -f
 [INFO ] Matched hosts:
-[INFO ] cassandra-gce-or-1.prod.example.com [2.22.123.79]
-[INFO ] cassandra-gce-or-2.prod.example.com [2.22.123.158]
-Continue on following 2 servers? y
-[INFO ] Run command on 2 servers.
+[INFO ] admin-gce-sc-1.lca-prod.** [35.211.27.195]
+[INFO ] admin-gce-sc-1.mmk-prod.** [35.211.79.202]
+[ERROR] admin-gce-sc-1.led-prod.** couldn't be resolved.
+[INFO ] admin-gce-sc-1.msq-dev.** [35.211.0.24]
+[ERROR] admin-gce-sc-1.hui-dev.** couldn't be resolved.
     
-cassandra-gce-or-1.prod.example.com
-Exit code [0] / stdout 45 bytes / stderr 0 bytes
-STDOUT
-║ 5.15.0-1040-gcp
-║ Thu Sep  7 13:44:40 UTC 2023
+[INFO ] Run command on 3 servers.
 
-cassandra-gce-or-2.prod.example.com
-Exit code [0] / stdout 45 bytes / stderr 0 bytes
-STDOUT
-║ 5.15.0-1040-gcp
-║ Thu Sep  7 13:44:40 UTC 2023
+
+[INFO ] admin.gnb-prod.**
+Code 0 
+STDOUT:                                                    
+ 23:31:21 up 294 days, 14:14,  0 users,  load average: 0.53, 0.64, 0.52
+
+STDERR:
+                                                                                                                       
+[INFO ] admin.abe-prod.**
+Code 0 
+STDOUT:                                                    
+ 23:31:22 up 154 days,  9:24,  0 users,  load average: 0.31, 0.25, 0.18
+                                                           
+STDERR:
+
+[INFO ] admin-gce-be-1.toy-prod.**
+Code 0                                                     
+STDOUT:
+ 23:31:22 up 98 days,  6:20,  0 users,  load average: 0.88, 0.74, 0.80
+                             
+STDERR:
+no server running on /tmp/tmux-1019/default                                                                            
+open terminal failed: not a terminal
 ```

src/main.rs

@@ -1,64 +1,45 @@
+#[macro_use]
 extern crate log;
 
+use std::collections::HashMap;
 use std::fs::read_to_string;
 use std::hash::Hash;
-use std::io::{BufRead, BufReader};
 use std::net::IpAddr;
-use std::process::{self, Command, Stdio};
-use std::sync::{Arc, Mutex};
-use std::thread;
+use std::process;
 
 use clap::Parser;
 use colored::*;
+use dialoguer::Confirm;
 use dns_lookup::lookup_host;
 use env_logger::Env;
 use itertools::Itertools;
-use lazy_static::lazy_static;
-use log::{error, info, warn};
-use question::{Answer, Question};
-use rayon::prelude::*;
+use log::{error, info};
+use massh::{MasshClient, MasshConfig, MasshHostConfig, SshAuth};
 use regex::Regex;
 
-// Global state to track the currently open block
-lazy_static! {
-    static ref CURRENT_BLOCK: Arc<Mutex<Option<String>>> = Arc::new(Mutex::new(None));
-}
-
-// Define command-line arguments using the clap library
+// Define args
 #[derive(Parser, Debug)]
 #[command(author = "AB ab@hexor.ru", version, about = "Parallel SSH executor in Rust", long_about = None)]
 struct Args {
-    /// Username for SSH connections (defaults to current system user)
-    #[arg(short = 'u', short_alias = 'l', long, default_value_t = whoami::username())]
+    #[arg(short, long, default_value_t = whoami::username())]
     username: String,
 
-    /// Flag to use known_hosts file for server discovery instead of pattern expansion
-    #[arg(
-        short,
-        long,
-        help = "Use known_hosts to build servers list instead of string expansion."
-    )]
+    #[arg(short, long, help = "Use known_hosts to build servers list")]
     known_hosts: bool,
 
-    /// Server name patterns with expansion syntax
-    /// Examples: 'web-[1:12]-io-{prod,dev}' expands to multiple servers
     #[arg(
         short,
         long,
-        num_args = 1..,
-        help = "Expression to build server list. List and range expansion are supported. Example: 'web-[1:12]-io-{prod,dev}'"
+        help = "Expression to build server list. List and range expansion available. Example: 'web-[1:12]-io-{prod,dev}'"
     )]
-    expression: Vec<String>,
+    expression: String,
 
-    /// Command to execute on each server
     #[arg(short, long, help = "Command to execute on servers")]
     command: String,
 
-    /// Display only exit codes without command output
     #[arg(long, default_value_t = false, help = "Show exit code ONLY")]
     code: bool,
 
-    /// Skip confirmation prompt before executing commands
     #[arg(
         short = 'f',
         long,
@@ -67,104 +48,21 @@ struct Args {
     )]
     noconfirm: bool,
 
-    /// Maximum number of parallel SSH connections
     #[arg(short, long, default_value_t = 100)]
     parallel: i32,
 }
 
-/// Host representation for both known_hosts entries and expanded patterns
+// Represent line from known_hosts file
 #[derive(Debug, Default, Clone, PartialEq, Eq, Hash)]
 struct Host {
-    /// Hostname or IP address as a string
     name: String,
-    /// Resolved IP address (if available)
     ip: Option<IpAddr>,
 }
 
-/// Find common domain suffix across all hostnames to simplify output display
-///
-/// This function analyzes all hostnames to identify a common domain suffix
-/// which can be shortened during display to improve readability.
-///
-/// # Arguments
-/// * `hostnames` - A slice of strings containing all server hostnames
-///
-/// # Returns
-/// * `Option<String>` - The common suffix if found, or None
-fn find_common_suffix(hostnames: &[String]) -> Option<String> {
-    if hostnames.is_empty() {
-        return None;
-    }
-
-    // Don't truncate if only one host
-    if hostnames.len() == 1 {
-        return None;
-    }
-
-    let first = &hostnames[0];
-
-    // Start with assumption that the entire first hostname is the common suffix
-    let mut common = first.clone();
-
-    // Iterate through remaining hostnames, reducing the common part
-    for hostname in hostnames.iter().skip(1) {
-        // Exit early if no common part remains
-        if common.is_empty() {
-            return None;
-        }
-
-        // Find common suffix with current hostname
-        let mut new_common = String::new();
-
-        // Search for common suffix by comparing characters from right to left
-        let mut common_chars = common.chars().rev();
-        let mut hostname_chars = hostname.chars().rev();
-
-        loop {
-            match (common_chars.next(), hostname_chars.next()) {
-                (Some(c1), Some(c2)) if c1 == c2 => new_common.insert(0, c1),
-                _ => break,
-            }
-        }
-
-        common = new_common;
-    }
-
-    // Ensure the common part is a valid domain suffix (starts with a dot)
-    if common.is_empty() || !common.starts_with('.') {
-        return None;
-    }
-
-    // Return the identified common suffix
-    Some(common)
-}
-
-/// Shorten hostname by removing the common suffix and replacing with an asterisk
-///
-/// # Arguments
-/// * `hostname` - The original hostname
-/// * `common_suffix` - Optional common suffix to remove
-///
-/// # Returns
-/// * `String` - Shortened hostname or original if no common suffix
-fn shorten_hostname(hostname: &str, common_suffix: &Option<String>) -> String {
-    match common_suffix {
-        Some(suffix) if hostname.ends_with(suffix) => {
-            let short_name = hostname[..hostname.len() - suffix.len()].to_string();
-            format!("{}{}", short_name, "*")
-        }
-        _ => hostname.to_string(),
-    }
-}
-
-/// Read and parse the SSH known_hosts file to extract server names
-///
-/// # Returns
-/// * `Vec<Host>` - List of hosts found in the known_hosts file
+// Read known_hosts file
 fn read_known_hosts() -> Vec<Host> {
     let mut result: Vec<Host> = Vec::new();
 
-    // Read known_hosts file from the user's home directory
     for line in read_to_string(format!("/home/{}/.ssh/known_hosts", whoami::username()))
         .unwrap()
         .lines()
@@ -179,91 +77,51 @@ fn read_known_hosts() -> Vec<Host> {
     result
 }
 
-/// Expand a numeric range in the format [start:end] to a list of strings
-///
-/// # Arguments
-/// * `start` - Starting number (inclusive)
-/// * `end` - Ending number (inclusive)
-///
-/// # Returns
-/// * `Vec<String>` - List of numbers as strings
-fn expand_range(start: i32, end: i32) -> Vec<String> {
-    (start..=end).map(|i| i.to_string()).collect()
-}
-
-/// Expand a comma-separated list in the format {item1,item2,item3} to a list of strings
-///
-/// # Arguments
-/// * `list` - Comma-separated string to expand
-///
-/// # Returns
-/// * `Vec<String>` - List of expanded items
-fn expand_list(list: &str) -> Vec<String> {
-    list.split(',').map(|s| s.to_string()).collect()
-}
-
-/// Expand a server pattern string with range and list notation into individual hostnames
-///
-/// Supports two expansion types:
-/// - Range expansion: server-[1:5] → server-1, server-2, server-3, server-4, server-5
-/// - List expansion: server-{prod,dev} → server-prod, server-dev
-///
-/// # Arguments
-/// * `s` - Pattern string to expand
-///
-/// # Returns
-/// * `Vec<Host>` - List of expanded Host objects
-fn expand_string(s: &str) -> Vec<Host> {
+fn expand_string(string: String) -> Vec<Host> {
+    let mut result: Vec<String> = Vec::new();
+    let mut _result: Vec<String> = Vec::new();
     let mut hosts: Vec<Host> = Vec::new();
-    let mut result = vec![s.to_string()];
 
-    // First expand all range expressions [start:end]
-    while let Some(r) = result.iter().find(|s| s.contains('[')) {
-        let r = r.clone();
-        let start = r.find('[').unwrap();
-        let end = match r[start..].find(']') {
-            None => {
-                error!("Error parsing host expression. Wrong range expansion '[a:b]'");
-                process::exit(1);
+    if let Some(open_bracket_index) = string.find('[') {
+        if let Some(close_bracket_index) = string.find(']') {
+            let prefix = &string[..open_bracket_index];
+            let range = &string[open_bracket_index + 1..close_bracket_index];
+            let postfix = &string[close_bracket_index + 1..];
+
+            let parts: Vec<&str> = range.split(':').collect();
+
+            if parts.len() == 2 {
+                if let Ok(start) = parts[0].parse::<u32>() {
+                    if let Ok(end) = parts[1].parse::<u32>() {
+                        for num in start..=end {
+                            _result.push(format!("{}{}{}", prefix, num, postfix));
                         }
-            Some(s) => s + start,
-        };
-        let colon = match r[start..end].find(':') {
-            None => {
-                error!("Error parsing host expression. Missing colon in range expansion '[a:b]'");
-                process::exit(1);
                     }
-            Some(c) => c + start,
-        };
-        let low = r[start + 1..colon].parse::<i32>().unwrap();
-        let high = r[colon + 1..end].parse::<i32>().unwrap();
-        result.retain(|s| s != &r);
-        for val in expand_range(low, high) {
-            let new_str = format!("{}{}{}", &r[..start], val, &r[end + 1..]);
-            result.push(new_str);
+                }
+            }
+        }
+    } else {
+        _result.push(String::from(string));
+    }
+
+    for string in _result {
+        if let Some(open_brace_index) = string.find('{') {
+            if let Some(close_brace_index) = string.find('}') {
+                let prefix = &string[..open_brace_index];
+                let list = &string[open_brace_index + 1..close_brace_index];
+                let postfix = &string[close_brace_index + 1..];
+
+                let items: Vec<&str> = list.split(',').collect();
+
+                for item in items {
+                    result.push(format!("{}{}{}", prefix, item, postfix));
+                }
+            }
+        } else {
+            result.push(String::from(string));
         }
     }
 
-    // Then expand all list expressions {item1,item2}
-    while let Some(r) = result.iter().find(|s| s.contains('{')) {
-        let r = r.clone();
-        let start = r.find('{').unwrap();
-        let end = match r.find('}') {
-            None => {
-                error!("Error parsing host expression. Wrong range expansion '{{one,two}}'");
-                process::exit(1);
-            }
-            Some(s) => s,
-        };
-        let list = &r[start + 1..end];
-        result.retain(|s| s != &r);
-        for val in expand_list(list) {
-            let new_str = format!("{}{}{}", &r[..start], val, &r[end + 1..]);
-            result.push(new_str);
-        }
-    }
-
-    // Convert all expanded strings to Host objects
     for hostname in result {
         hosts.push(Host {
             name: hostname.to_string(),
@@ -273,354 +131,121 @@ fn expand_string(s: &str) -> Vec<Host> {
     hosts
 }
 
-/// Execute a command on a single host using the system SSH client
-///
-/// This function runs an SSH command using the system's SSH client,
-/// capturing and displaying output in real-time with proper formatting.
-///
-/// # Arguments
-/// * `hostname` - Target server hostname
-/// * `username` - SSH username
-/// * `command` - Command to execute
-/// * `common_suffix` - Optional common suffix for hostname display formatting
-/// * `code_only` - Whether to display only exit codes
-///
-/// # Returns
-/// * `Result<i32, String>` - Exit code on success or error message
-fn execute_ssh_command(
-    hostname: &str,
-    username: &str,
-    command: &str,
-    common_suffix: &Option<String>,
-    code_only: bool,
-) -> Result<i32, String> {
-    let display_name = shorten_hostname(hostname, common_suffix);
-
-    // Build the SSH command with appropriate options
-    let mut ssh_cmd = Command::new("ssh");
-    ssh_cmd
-        .arg("-o")
-        .arg("StrictHostKeyChecking=no")
-        .arg("-o")
-        .arg("BatchMode=yes")
-        .arg(format!("{}@{}", username, hostname))
-        .arg(command)
-        .stdout(Stdio::piped())
-        .stderr(Stdio::piped());
-
-    // Execute the command
-    let mut child = match ssh_cmd.spawn() {
-        Ok(child) => child,
-        Err(e) => return Err(format!("Failed to start SSH process: {}", e)),
-    };
-
-    // Function to handle output lines with proper block management
-    let handle_output = |line: String, display_name: &str, code_only: bool, is_stderr: bool| {
-        if !code_only {
-            let mut current_block = CURRENT_BLOCK.lock().unwrap();
-
-            // Check if we need to close the previous block and open a new one
-            match current_block.as_ref() {
-                Some(open_host) if open_host != display_name => {
-                    // Close the previous block
-                    println!("└ {} ┘", open_host.yellow());
-                    // Open new block
-                    println!("┌ {} ┐", display_name.yellow());
-                    *current_block = Some(display_name.to_string());
-                }
-                None => {
-                    // Open new block
-                    println!("┌ {} ┐", display_name.yellow());
-                    *current_block = Some(display_name.to_string());
-                }
-                Some(_) => {
-                    // Same host, continue with current block
-                }
-            }
-
-            // Print the log line with colored separator based on stream type
-            let separator = if is_stderr {
-                "│".red()
-            } else {
-                "│".green()
-            };
-            println!(
-                "{} {} {} {}",
-                separator,
-                display_name.yellow(),
-                separator,
-                line
-            );
-        }
-    };
-
-    // Capture and display stdout in real-time using a dedicated thread
-    let stdout = child.stdout.take().unwrap();
-    let display_name_stdout = display_name.clone();
-    let code_only_stdout = code_only;
-    let stdout_thread = thread::spawn(move || {
-        let reader = BufReader::new(stdout);
-
-        for line in reader.lines() {
-            match line {
-                Ok(line) => {
-                    handle_output(line, &display_name_stdout, code_only_stdout, false);
-                    // false = stdout
-                }
-                Err(_) => break,
-            }
-        }
-    });
-
-    // Capture and display stderr in real-time using a dedicated thread
-    let stderr = child.stderr.take().unwrap();
-    let display_name_stderr = display_name.clone();
-    let code_only_stderr = code_only;
-    let stderr_thread = thread::spawn(move || {
-        let reader = BufReader::new(stderr);
-
-        for line in reader.lines() {
-            match line {
-                Ok(line) => {
-                    handle_output(line, &display_name_stderr, code_only_stderr, true);
-                    // true = stderr
-                }
-                Err(_) => break,
-            }
-        }
-    });
-
-    // Wait for command to complete
-    let status = match child.wait() {
-        Ok(status) => status,
-        Err(e) => return Err(format!("Failed to wait for SSH process: {}", e)),
-    };
-
-    // Wait for stdout and stderr threads to complete
-    stdout_thread.join().unwrap();
-    stderr_thread.join().unwrap();
-
-    // Close the block if this host was the last one to output
-    if !code_only {
-        let mut current_block = CURRENT_BLOCK.lock().unwrap();
-        if let Some(open_host) = current_block.as_ref() {
-            if open_host == &display_name {
-                println!("└ {} ┘", display_name.yellow());
-                *current_block = None;
-            }
-        }
-    }
-
-    // Format exit code with color (green for success, red for failure)
-    let exit_code = status.code().unwrap_or(-1);
-    let code_string = if exit_code == 0 {
-        format!("{}", exit_code.to_string().green())
-    } else {
-        format!("{}", exit_code.to_string().red())
-    };
-
-    // For code-only mode, just show hostname and exit code
-    if code_only {
-        println!("{}: [{}]", display_name.yellow(), code_string);
-    }
-
-    Ok(exit_code)
-}
-
-/// Main entry point for the application
 fn main() {
-    // Initialize logging with minimal formatting (no timestamp, no target)
     env_logger::Builder::from_env(Env::default().default_filter_or("info"))
         .format_timestamp(None)
         .format_target(false)
         .init();
-
-    // Parse command-line arguments
     let args = Args::parse();
 
-    // Build the list of target hosts based on user selection method
     let hosts = if args.known_hosts {
-        // Use regex pattern matching against known_hosts file
         info!("Using ~/.ssh/known_hosts to build server list.");
         let known_hosts = read_known_hosts();
-        let mut all_hosts = Vec::new();
-        for expression in args.expression.iter() {
-            let re = match Regex::new(expression) {
+        // Build regex
+        let re = match Regex::new(&args.expression) {
             Ok(result) => result,
             Err(e) => {
                 error!("Error parsing regex. {}", e);
                 process::exit(1);
             }
         };
-            let matched: Vec<Host> = known_hosts
-                .clone()
+        // match hostnames from known_hosts to regex
+        known_hosts
             .into_iter()
             .filter(|r| re.is_match(&r.name.clone()))
-                .collect();
-            all_hosts.extend(matched);
-        }
-        all_hosts
+            .collect()
     } else {
-        // Use pattern expansion syntax (ranges and lists)
         info!("Using string expansion to build server list.");
-        let mut all_hosts = Vec::new();
-        for expression in args.expression.iter() {
-            all_hosts.extend(expand_string(expression));
-        }
-        all_hosts
+        expand_string(args.expression)
     };
 
-    // Remove duplicate hosts while preserving original order
+    // Dedup hosts from known_hosts file
     let matched_hosts: Vec<_> = hosts.into_iter().unique().collect();
 
-    // Log parallelism setting if not using the default
-    if args.parallel != 100 {
-        warn!("Parallelism: {} thread{}", &args.parallel, {
-            if args.parallel != 1 {
-                "s."
-            } else {
-                "."
-            }
-        });
-    }
-
-    // Store hosts with their original indices to preserve ordering
-    let mut host_with_indices: Vec<(Host, usize)> = Vec::new();
-    for (idx, host) in matched_hosts.iter().enumerate() {
-        host_with_indices.push((host.clone(), idx));
-    }
-
+    // Build MasshHostConfig hostnames list
+    let mut massh_hosts: Vec<MasshHostConfig> = vec![];
+    let mut hosts_and_ips: HashMap<IpAddr, String> = HashMap::new();
     info!("Matched hosts:");
-
-    // Perform DNS resolution for all hosts in parallel
-    // Results are stored with original indices to maintain order
-    let resolved_ips_with_indices = Arc::new(Mutex::new(Vec::<(String, IpAddr, usize)>::new()));
-
-    host_with_indices
-        .par_iter()
-        .for_each(|(host, idx)| match lookup_host(&host.name) {
-            Ok(ips) if !ips.is_empty() => {
-                let ip = ips[0];
-                let mut results = resolved_ips_with_indices.lock().unwrap();
-                results.push((host.name.clone(), ip, *idx));
-            }
-            Ok(_) => {
-                let mut results = resolved_ips_with_indices.lock().unwrap();
-                results.push((
-                    host.name.clone(),
-                    IpAddr::V4(std::net::Ipv4Addr::new(0, 0, 0, 0)),
-                    *idx,
-                ));
-            }
+    for host in matched_hosts.iter() {
+        let ip = match lookup_host(&host.name) {
+            Ok(ip) => ip[0],
             Err(_) => {
-                let mut results = resolved_ips_with_indices.lock().unwrap();
-                results.push((
-                    host.name.clone(),
-                    IpAddr::V4(std::net::Ipv4Addr::new(0, 0, 0, 0)),
-                    *idx,
-                ));
-            }
-        });
-
-    // Sort hosts by original index to maintain consistent display order
-    let mut resolved_hosts = resolved_ips_with_indices.lock().unwrap().clone();
-    resolved_hosts.sort_by_key(|(_, _, idx)| *idx);
-
-    // Display all matched hosts with their resolved IPs
-    for (hostname, ip, _) in &resolved_hosts {
-        if ip.is_unspecified() {
-            error!("DNS resolve failed: {}", hostname.red());
-        } else {
-            info!("{} [{}]", hostname, ip);
+                error!("{} couldn't be resolved.", &host.name.red());
+                continue;
             }
+        };
+        info!("{} [{}]", &host.name, ip);
+        hosts_and_ips.insert(ip, host.name.clone());
+        massh_hosts.push(MasshHostConfig {
+            addr: ip,
+            auth: None,
+            port: None,
+            user: None,
+        })
     }
+    // Build MasshConfig using massh_hosts vector
+    let config = MasshConfig {
+        default_auth: SshAuth::Agent,
+        default_port: 22,
+        default_user: args.username,
+        threads: args.parallel as u64,
+        timeout: 0,
+        hosts: massh_hosts,
+    };
+    let massh = MasshClient::from(&config);
 
-    // Filter out hosts that couldn't be resolved
-    let valid_hosts: Vec<(String, IpAddr, usize)> = resolved_hosts
-        .into_iter()
-        .filter(|(_, ip, _)| !ip.is_unspecified())
-        .collect();
-
-    // Exit if no valid hosts remain
-    if valid_hosts.is_empty() {
-        error!("No valid hosts to connect to");
-        process::exit(1);
-    }
-
-    // Find common domain suffix to optimize display
-    let hostnames: Vec<String> = valid_hosts
-        .iter()
-        .map(|(hostname, _, _)| hostname.clone())
-        .collect();
-    let common_suffix = find_common_suffix(&hostnames);
-
-    // Inform user about display optimization if common suffix found
-    if let Some(suffix) = &common_suffix {
-        info!(
-            "Common domain suffix found: '{}' (will be displayed as '*')",
-            suffix
-        );
-    }
-
-    // Ask for confirmation before proceeding (unless --noconfirm is specified)
-    if !args.noconfirm
-        && match Question::new(&*format!(
+    // Ask for confirmation
+    if args.noconfirm == true
+        || Confirm::new()
+            .with_prompt(format!(
                 "Continue on following {} servers?",
-            &valid_hosts.len()
+                &config.hosts.len()
             ))
-        .confirm()
+            .interact()
+            .unwrap()
     {
-            Answer::YES => true,
-            Answer::NO => {
+        info!("\n");
+        info!("Run command on {} servers.", &config.hosts.len());
+        info!("\n");
+
+        // Run a command on all the configured hosts.
+        // Receive the result of the command for each host and print its output.
+        let rx = massh.execute(args.command);
+
+        while let Ok((host, result)) = rx.recv() {
+            let ip: String = host.split('@').collect::<Vec<_>>()[1]
+                .split(':')
+                .collect::<Vec<_>>()[0]
+                .to_string();
+            let ip = ip.parse::<IpAddr>().unwrap();
+            info!(
+                "{}",
+                hosts_and_ips
+                    .get(&ip)
+                    .unwrap_or(&"Couldn't parse IP".to_string())
+                    .to_string()
+                    .yellow()
+                    .bold()
+                    .to_string()
+            );
+            let output = match result {
+                Ok(output) => output,
+                Err(e) => {
+                    error!("Can't access server: {}", e);
+                    continue;
+                }
+            };
+            if output.exit_status == 0 {
+                println!("Code {}", output.exit_status);
+            } else {
+                error!("Code {}", output.exit_status);
+            };
+            if !args.code {
+                println!("STDOUT:\n{}", String::from_utf8(output.stdout).unwrap());
+                println!("STDERR:\n{}", String::from_utf8(output.stderr).unwrap());
+            }
+        }
+    } else {
         warn!("Stopped");
-                process::exit(0);
-            }
-            _ => unreachable!(),
-        }
-    {
-        info!("Run command on {} servers.", &valid_hosts.len());
-    }
-
-    // Execute commands using system SSH client
-    let batch_size = args.parallel as usize;
-    let mut processed = 0;
-
-    while processed < valid_hosts.len() {
-        let end = std::cmp::min(processed + batch_size, valid_hosts.len());
-        let batch = &valid_hosts[processed..end];
-
-        // Create a thread for each host in the current batch
-        let mut handles = Vec::new();
-
-        for (hostname, _, _) in batch {
-            let hostname = hostname.clone();
-            let username = args.username.clone();
-            let command = args.command.clone();
-            let common_suffix_clone = common_suffix.clone();
-            let code_only = args.code;
-
-            // Execute SSH command in a separate thread
-            let handle = thread::spawn(move || {
-                match execute_ssh_command(
-                    &hostname,
-                    &username,
-                    &command,
-                    &common_suffix_clone,
-                    code_only,
-                ) {
-                    Ok(_) => (),
-                    Err(e) => error!("Error executing command on {}: {}", hostname, e),
-                }
-            });
-
-            handles.push(handle);
-        }
-
-        // Wait for all threads in this batch to complete
-        for handle in handles {
-            handle.join().unwrap();
-        }
-
-        processed = end;
     }
 }