v1.2.2

Bug Fixes

Backend.AI Auto-detection Improvements (#66, #67)

• Fixed Backend.AI environment auto-detection to properly distinguish between SSH single-host mode and multi-node command execution
• Added comprehensive host detection heuristics:
  • Special hostname detection: localhost, localhost.localdomain
  • IPv4 address validation: 127.0.0.1, 192.168.x.x, etc.
  • User@host format detection (contains @)
  • Host:port format detection (contains :)
  • SSH URI format detection (starts with ssh://)
  • FQDN detection (multiple . and no spaces)
  • IPv6 format detection (starts with [)
• Users can now naturally use bssh localhost "command" in Backend.AI environments
• IPv4 addresses now work directly without special syntax

Improvements

Host Detection Logic

• Extracted testable looks_like_host_specification() function for better maintainability
• Added is_ipv4_address() helper with strict validation (4 octets, each 0-255)
• Performance optimized with early returns for most common patterns
• Added 16 comprehensive unit tests covering all detection patterns and edge cases

Documentation

• Updated ARCHITECTURE.md with detailed host detection heuristics documentation
• Added usage examples for SSH single-host mode in Backend.AI environments
• Documented detection order and performance optimizations

Technical Details

Test Coverage

• Added 16 new tests for host specification detection
• Total test count: 402 tests (all passing)
• Test categories:
  • IPv4 validation (valid and invalid patterns)
  • Localhost variations
  • User@host, host:port, SSH URI formats
  • FQDN and IPv6 detection
  • Edge cases (empty strings, invalid inputs, special characters)
  • Performance verification (early return optimization)
  • Internationalized domain names

Implementation Details

• Heuristic-based approach balances pragmatism and safety
• Early return optimization: most common patterns checked first
• localhost check: O(1) string comparison
• IPv4 validation: O(4) = O(1) split + parse
• Overall performance impact: < 1μs per call

Files Modified

• src/app/initialization.rs: Added detection functions
• src/app/initialization_tests.rs: Added comprehensive tests
• src/app/mod.rs: Added test module reference
• src/main.rs: Changed cli to mut cli for initialization
• ARCHITECTURE.md: Updated documentation

Example Usage

export BACKENDAI_CLUSTER_HOSTS="node1,node2,node3"

# SSH single-host mode (all now work!)
bssh localhost "whoami"              # ✅ 1 node
bssh 127.0.0.1 "whoami"              # ✅ 1 node
bssh 192.168.1.100 "whoami"          # ✅ 1 node
bssh user@host "whoami"              # ✅ 1 node
bssh host:22 "whoami"                # ✅ 1 node
bssh server.example.com "whoami"     # ✅ 1 node

# Multi-node mode (still works)
bssh "whoami"                        # ✅ 3 nodes

CI/CD Improvements

None

Dependencies

None

Breaking Changes

None

Known Issues

Simple Hostname Limitation: Simple hostnames without indicators (e.g., bssh myserver "command") cannot be automatically distinguished from commands. Use one of these methods:

• bssh user@myserver "command" (add user@)
• bssh myserver:22 "command" (add port)
• bssh -H myserver "command" (explicit -H flag)

This limitation is minimal as localhost and all IP addresses now work directly.

What's Changed

• fix: Add host detection heuristic for Backend.AI auto-detection (#66) by @inureyes in #67

Full Changelog: v1.2.1...v1.2.2