feat: Add --connect-timeout option for connection timeout (pdsh -t compatibility)

[inureyes]

Summary

Add a new --connect-timeout option to bssh that sets the SSH connection timeout separately from the command execution timeout. This is a prerequisite for pdsh compatibility mode.

Parent Issue

Part of #91 (pdsh compatibility mode) - Phase 1: New Options for Feature Parity

Background

pdsh distinguishes between two types of timeouts:

• -t seconds: Connection timeout (how long to wait for SSH connection, default 10s)
• -u seconds: Command timeout (how long to allow command to run)

Currently bssh has --timeout which controls command execution timeout, but lacks a separate connection timeout option. This distinction is important for:

• Slow networks where connection takes longer
• Fast operations where command should timeout quickly but connection can take time
• Fine-grained control over failure modes

Current Behavior

// In src/ssh/client.rs
const DEFAULT_CONNECT_TIMEOUT: Duration = Duration::from_secs(30);

The connection timeout is currently hardcoded at 30 seconds.

Proposed Implementation

CLI Interface

# Default: 30s connection timeout
bssh -H "node1,node2" "uptime"

# Custom connection timeout
bssh -H "node1,node2" --connect-timeout 10 "uptime"

# Combined with command timeout
bssh -H "node1,node2" --connect-timeout 5 --timeout 60 "long-command"

Option Definition

#[arg(
    long = "connect-timeout",
    default_value = "30",
    value_name = "SECONDS",
    help = "SSH connection timeout in seconds [default: 30]"
)]
pub connect_timeout: u64,

Implementation Tasks

• Add --connect-timeout option to Cli struct in src/cli.rs
• Pass connection timeout to SSH client configuration
• Modify src/ssh/client.rs to accept configurable timeout
• Update executor to use CLI-provided timeout
• Add unit tests for timeout behavior
• Update help text and examples

Acceptance Criteria

• --connect-timeout N sets SSH connection timeout to N seconds
• Default remains 30 seconds for backward compatibility
• Connection timeout is independent of --timeout (command timeout)
• Timeout of 0 should be disallowed or mean "no timeout" (needs decision)
• Clear error message when connection times out
• Works correctly with parallel connections

Technical Considerations

• Currently tokio::time::timeout wraps the connect call
• May need to propagate timeout value through connection chain
• Consider if this should also apply to authentication timeout

Notes

• Using --connect-timeout (long form only) to avoid conflict with -t (which is --tty in bssh)
• In pdsh compatibility mode, -t will map to --connect-timeout

Related

• Parent: feat: Add pdsh compatibility mode for drop-in replacement #91

[inureyes]

Implementation Complete

The --connect-timeout option has been fully implemented with all code review issues fixed.

Changes Made

Commit 4c6ffe0: feat: Add --connect-timeout option for SSH connection timeout

• Added --connect-timeout CLI option with default value of 30 seconds
• Integrated with executor and SSH client layers
• Works with exec and ping commands

Commit e068545: fix: Propagate connect_timeout through all SSH connection paths

• Fixed jump host connections to use user-specified timeout
• Propagated timeout to all file transfer operations (upload/download)
• Added validation to reject value of 0 (minimum is 1 second)
• Updated help text

Usage

# Default 30 second connection timeout
bssh -H "node1,node2" "uptime"

# Custom connection timeout
bssh --connect-timeout 10 -H "node1,node2" "uptime"

# Combined with command timeout
bssh --connect-timeout 5 --timeout 60 -H "node1,node2" "long-command"

Acceptance Criteria Met

• --connect-timeout N sets SSH connection timeout to N seconds
• Default remains 30 seconds for backward compatibility
• Connection timeout is independent of --timeout (command timeout)
• Timeout of 0 is disallowed (minimum value validation)
• Clear error message when connection times out
• Works correctly with parallel connections
• Works with jump host connections
• Works with file transfer operations