Format Rust code using rustfmt

\\?\D:\a\rexec\rexec\src\main.rs

@@ -0,0 +1,745 @@
+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 clap::Parser;
+use colored::*;
+use dns_lookup::lookup_host;
+use env_logger::Env;
+use itertools::Itertools;
+use log::{error, info, warn};
+use massh::{MasshClient, MasshConfig, MasshHostConfig, SshAuth};
+use question::{Answer, Question};
+use rayon::prelude::*;
+use regex::Regex;
+
+// Define command-line arguments using the clap library
+#[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, 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."
+    )]
+    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}'"
+    )]
+    expression: Vec<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,
+        default_value_t = false,
+        help = "Don't ask for confirmation"
+    )]
+    noconfirm: bool,
+
+    /// Maximum number of parallel SSH connections
+    #[arg(short, long, default_value_t = 100)]
+    parallel: i32,
+
+    /// Use the embedded SSH client library instead of system SSH command
+    #[arg(
+        long,
+        help = "Use embedded SSH client instead of system SSH. Does not support 'live output'.",
+        default_value_t = false
+    )]
+    embedded_ssh: bool,
+}
+
+/// Host representation for both known_hosts entries and expanded patterns
+#[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
+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()
+    {
+        let line = line.split(" ").collect::<Vec<&str>>();
+        let hostname = line[0];
+        result.push(Host {
+            name: hostname.to_string(),
+            ip: None,
+        })
+    }
+    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> {
+    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);
+            }
+            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);
+        }
+    }
+
+    // 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(),
+            ip: None,
+        })
+    }
+    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
+///
+/// # 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>,
+) -> Result<i32, String> {
+    let display_name = shorten_hostname(hostname, common_suffix);
+
+    // Display execution start message with shortened hostname
+    println!("\n{} - STARTED", display_name.yellow().bold());
+
+    // 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)),
+    };
+
+    // 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 stdout_thread = thread::spawn(move || {
+        let reader = BufReader::new(stdout);
+        let prefix = format!("{}", "│".green());
+
+        for line in reader.lines() {
+            match line {
+                Ok(line) => println!("{} {} - {}", prefix, display_name_stdout.yellow(), line),
+                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 stderr_thread = thread::spawn(move || {
+        let reader = BufReader::new(stderr);
+        let prefix = format!("{}", "║".red());
+
+        for line in reader.lines() {
+            match line {
+                Ok(line) => println!("{} {} - {}", prefix, display_name_stderr.yellow(), line),
+                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();
+
+    // 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())
+    };
+
+    // Display completion message
+    println!(
+        "{} - COMPLETED (Exit code: [{}])",
+        display_name.yellow().bold(),
+        code_string
+    );
+
+    Ok(exit_code)
+}
+
+/// Execute commands on multiple hosts using the massh library (embedded SSH)
+///
+/// This function handles batch processing of hosts to maintain the original order
+/// while executing commands in parallel using the massh library.
+///
+/// # Arguments
+/// * `hosts` - Vector of (hostname, IP address, original index) tuples
+/// * `username` - SSH username
+/// * `command` - Command to execute
+/// * `parallel` - Maximum number of parallel connections
+/// * `code_only` - Whether to display only exit codes
+/// * `common_suffix` - Optional common suffix for hostname display formatting
+fn execute_with_massh(
+    hosts: &[(String, IpAddr, usize)],
+    username: &str,
+    command: &str,
+    parallel: i32,
+    code_only: bool,
+    common_suffix: &Option<String>,
+) {
+    // Create a lookup table for host data using IP addresses as keys
+    let mut hosts_and_ips: HashMap<IpAddr, (String, usize)> = HashMap::new();
+    let mut massh_hosts: Vec<MasshHostConfig> = Vec::new();
+
+    for (hostname, ip, idx) in hosts {
+        hosts_and_ips.insert(*ip, (hostname.clone(), *idx));
+        massh_hosts.push(MasshHostConfig {
+            addr: *ip,
+            auth: None,
+            port: None,
+            user: None,
+        });
+    }
+
+    // Process hosts in batches to respect parallelism setting while maintaining order
+    let batch_size = parallel as usize;
+    let mut processed = 0;
+
+    while processed < massh_hosts.len() {
+        let end = std::cmp::min(processed + batch_size, massh_hosts.len());
+
+        // Create a new config and vector for this batch
+        let mut batch_hosts = Vec::new();
+        for host in &massh_hosts[processed..end] {
+            batch_hosts.push(MasshHostConfig {
+                addr: host.addr,
+                auth: None,
+                port: None,
+                user: None,
+            });
+        }
+
+        // Create a new MasshClient for this batch with appropriate configuration
+        let batch_config = MasshConfig {
+            default_auth: SshAuth::Agent,
+            default_port: 22,
+            default_user: username.to_string(),
+            threads: batch_hosts.len() as u64,
+            timeout: 0,
+            hosts: batch_hosts,
+        };
+
+        let batch_massh = MasshClient::from(&batch_config);
+
+        // Execute the command on all hosts in this batch
+        let rx = batch_massh.execute(command.to_string());
+
+        // Collect all results from this batch before moving to the next
+        let mut batch_results = Vec::new();
+
+        while let Ok((host, result)) = rx.recv() {
+            // Extract IP address from the massh result
+            let ip: String = host.split('@').collect::<Vec<_>>()[1]
+                .split(':')
+                .collect::<Vec<_>>()[0]
+                .to_string();
+            let ip = ip.parse::<IpAddr>().unwrap();
+
+            // Lookup the original hostname and index
+            if let Some((hostname, idx)) = hosts_and_ips.get(&ip) {
+                batch_results.push((hostname.clone(), ip, result, *idx));
+            } else {
+                error!("Unexpected IP address in result: {}", ip);
+            }
+        }
+
+        // Sort results by original index to maintain consistent display order
+        batch_results.sort_by_key(|(_, _, _, idx)| *idx);
+
+        // Display results for each host in the batch
+        for (hostname, _ip, result, _) in batch_results {
+            let display_name = shorten_hostname(&hostname, common_suffix);
+
+            // Display hostname with consistent formatting
+            println!("\n{}", display_name.yellow().bold().to_string());
+
+            // Handle execution result
+            let output = match result {
+                Ok(output) => output,
+                Err(e) => {
+                    error!("Can't access server: {}", e);
+                    continue;
+                }
+            };
+
+            // Format exit code with color
+            let code_string = if output.exit_status == 0 {
+                format!("{}", output.exit_status.to_string().green())
+            } else {
+                format!("{}", output.exit_status.to_string().red())
+            };
+
+            // Display summary of command execution
+            println!(
+                "{}",
+                format!(
+                    "Exit code [{}] / stdout {} bytes / stderr {} bytes",
+                    code_string,
+                    output.stdout.len(),
+                    output.stderr.len()
+                )
+                .bold()
+            );
+
+            // Display command output if not in code-only mode
+            if !code_only {
+                // Display stdout with appropriate formatting
+                match String::from_utf8(output.stdout) {
+                    Ok(stdout) => match stdout.as_str() {
+                        "" => {}
+                        _ => {
+                            let prefix = if output.exit_status != 0 {
+                                format!("{}", "│".cyan())
+                            } else {
+                                format!("{}", "│".green())
+                            };
+                            for line in stdout.lines() {
+                                println!("{} {} - {}", prefix, display_name.yellow(), line);
+                            }
+                        }
+                    },
+                    Err(_) => {}
+                }
+                // Display stderr with appropriate formatting
+                match String::from_utf8(output.stderr) {
+                    Ok(stderr) => match stderr.as_str() {
+                        "" => {}
+                        _ => {
+                            for line in stderr.lines() {
+                                println!("{} {} - {}", "║".red(), display_name.yellow(), line);
+                            }
+                        }
+                    },
+                    Err(_) => {}
+                }
+            }
+        }
+
+        processed = end;
+    }
+}
+
+/// 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) {
+                Ok(result) => result,
+                Err(e) => {
+                    error!("Error parsing regex. {}", e);
+                    process::exit(1);
+                }
+            };
+            let matched: Vec<Host> = known_hosts
+                .clone()
+                .into_iter()
+                .filter(|r| re.is_match(&r.name.clone()))
+                .collect();
+            all_hosts.extend(matched);
+        }
+        all_hosts
+    } 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
+    };
+
+    // Remove duplicate hosts while preserving original order
+    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));
+    }
+
+    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,
+                ));
+            }
+            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);
+        }
+    }
+
+    // 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!(
+            "Continue on following {} servers?",
+            &valid_hosts.len()
+        ))
+        .confirm()
+        {
+            Answer::YES => true,
+            Answer::NO => {
+                warn!("Stopped");
+                process::exit(0);
+            }
+            _ => unreachable!(),
+        }
+    {
+        info!("Run command on {} servers.", &valid_hosts.len());
+    }
+
+    // Execute commands using selected method (system SSH or embedded library)
+    if !args.embedded_ssh {
+        // Use system SSH client (default behavior)
+        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();
+
+                // Execute SSH command in a separate thread
+                let handle = thread::spawn(move || {
+                    match execute_ssh_command(&hostname, &username, &command, &common_suffix_clone)
+                    {
+                        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;
+        }
+    } else {
+        // Use the embedded massh library implementation
+        execute_with_massh(
+            &valid_hosts,
+            &args.username,
+            &args.command,
+            args.parallel,
+            args.code,
+            &common_suffix,
+        );
+    }
+}