From 4fd86fbc75670878308fd6a56b7778334b52ccd8 Mon Sep 17 00:00:00 2001
From: Paul Buetow <paul@buetow.org>
Date: Mon, 25 May 2026 20:05:15 +0300
Subject: refactor(manager): extract focused collaborators from Manager God
 Class

Extract VM lifecycle, SSH execution, WireGuard setup, model switching,
end-to-end inference tests, and provisioning orchestration into separate
collaborator classes. Manager becomes a thin facade (~80 lines).

Also fixes CLI edge-cases: status/model-list when no VMs are active,
and threads --vllm/--ollama flags through the provisioning pipeline.
---
 lib/hyperstack/ssh_runner.rb | 126 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 126 insertions(+)
 create mode 100644 lib/hyperstack/ssh_runner.rb

(limited to 'lib/hyperstack/ssh_runner.rb')

diff --git a/lib/hyperstack/ssh_runner.rb b/lib/hyperstack/ssh_runner.rb
new file mode 100644
index 0000000..f41859d
--- /dev/null
+++ b/lib/hyperstack/ssh_runner.rb
@@ -0,0 +1,126 @@
+# frozen_string_literal: true
+
+require 'open3'
+require 'socket'
+
+module HyperstackVM
+  # Executes commands over SSH and manages host-key trust.
+  class SshRunner
+    def initialize(config:, out:)
+      @config = config
+      @out = out
+    end
+
+    def run(host, remote_script)
+      Open3.capture3(*command(host), stdin_data: remote_script)
+    end
+
+    def run_streaming(host, remote_script)
+      combined = +''
+      Open3.popen2e(*command(host)) do |stdin, output, wait_thr|
+        stdin.write(remote_script)
+        stdin.close
+        output.each do |line|
+          combined << line
+          @out.print(line)
+        end
+        return [combined, wait_thr.value]
+      end
+    end
+
+    def tcp_open?(host, port)
+      Socket.tcp(host, port, connect_timeout: @config.ssh_connect_timeout) do |sock|
+        sock.close
+        true
+      end
+    rescue Errno::ECONNREFUSED, Errno::ETIMEDOUT, Errno::EHOSTUNREACH,
+           Errno::ENETUNREACH, SocketError, IOError
+      false
+    end
+
+    def command(host)
+      cmd = [
+        'ssh',
+        '-o', 'BatchMode=yes',
+        '-o', 'StrictHostKeyChecking=yes',
+        '-o', "UserKnownHostsFile=#{@config.ssh_known_hosts_path}",
+        '-o', "ConnectTimeout=#{@config.ssh_connect_timeout}",
+        '-p', @config.ssh_port.to_s
+      ]
+      if File.exist?(@config.ssh_private_key_path)
+        cmd.concat(['-i', @config.ssh_private_key_path])
+      else
+        warn_out("SSH private key #{@config.ssh_private_key_path} does not exist; falling back to default ssh-agent identity.")
+      end
+      cmd << "#{@config.ssh_username}@#{host}"
+      cmd << 'bash -se'
+      cmd
+    end
+
+    # Trust / known-hosts management
+
+    def ensure_trusted_host(host)
+      scanned = scan_host_keys(host)
+      return false if scanned.empty?
+
+      existing = known_host_entries
+      if existing.empty?
+        write_known_host_entries(scanned)
+        puts "Pinned SSH host key for #{host} in #{@config.ssh_known_hosts_path}."
+        return true
+      end
+
+      return true if existing == scanned
+
+      warn_out("SSH host key mismatch for #{host}. Replacing cached key (VM was likely recreated).")
+      write_known_host_entries(scanned)
+      true
+    end
+
+    def scan_host_keys(host)
+      stdout, stderr, status = Open3.capture3(
+        'ssh-keyscan', '-T', @config.ssh_connect_timeout.to_s,
+        '-p', @config.ssh_port.to_s, host
+      )
+      unless status.success?
+        warn_out("ssh-keyscan not ready yet: #{stderr.strip}") unless stderr.to_s.strip.empty?
+        return []
+      end
+      stdout.lines.map(&:strip).reject { |l| l.empty? || l.start_with?('#') }.sort.uniq
+    rescue Errno::ENOENT
+      raise Error, 'ssh-keyscan is required to pin SSH host keys but was not found in PATH.'
+    end
+
+    def delete_known_hosts_file
+      File.delete(@config.ssh_known_hosts_path) if File.exist?(@config.ssh_known_hosts_path)
+    rescue Errno::EACCES => e
+      raise Error, "Cannot delete SSH known_hosts file #{@config.ssh_known_hosts_path}: #{e.message}"
+    end
+
+    def known_host_entries
+      path = @config.ssh_known_hosts_path
+      return [] unless File.exist?(path)
+
+      File.readlines(path, chomp: true).map(&:strip).reject(&:empty?).sort.uniq
+    rescue Errno::EACCES => e
+      raise Error, "Cannot read SSH known_hosts file #{path}: #{e.message}"
+    end
+
+    def write_known_host_entries(entries)
+      path = @config.ssh_known_hosts_path
+      FileUtils.mkdir_p(File.dirname(path))
+      temp = "#{path}.tmp"
+      File.write(temp, "#{entries.join("\n")}\n")
+      File.chmod(0o600, temp)
+      File.rename(temp, path)
+    rescue Errno::EACCES => e
+      raise Error, "Cannot write SSH known_hosts file #{path}: #{e.message}"
+    end
+
+    private
+
+    def warn_out(msg)
+      @out.puts("WARN: #{msg}")
+    end
+  end
+end
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