Module: McptaskRailsRunner::Binary

Defined in:
lib/mcptask_rails_runner/binary.rb

Overview

Locates, installs and executes the bundled Go binary.

Constant Summary collapse

GEM_ROOT = 
File.expand_path("../..", __dir__)
SUPPORTED_PLATFORMS = 
%w[
  arm64-darwin
  x86_64-darwin
  aarch64-linux
  x86_64-linux
  x64-mingw-ucrt
].freeze
INSTALL_DIR =

Where the binary is installed to live, outside every gem directory.

The scheduled job runs this path, and it has to be one that survives a bundle update: a job pointing into gems/mcptask-rails-runner--/libexec dies the moment the gem is bumped, at 08:00, in a log nobody reads. Under the runner's own ~/.mcptask rather than /usr/local/bin, because bundle install has no sudo and a gem cannot write there. The Go side knows the same path — see InstalledBinary in internal/install/schedule.go.

File.join(Dir.home, ".mcptask", "bin")
VERSION_LINE =

The line mcptask_runner version prints the version on.

/Version:\s*(\S+)/

Class Method Summary collapse

Class Method Details

.bundled_path(gem_root: GEM_ROOT) ⇒ Object

The copy that ships inside this gem, which is the one the Gemfile pins.

Raises:



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# File 'lib/mcptask_rails_runner/binary.rb', line 49

def bundled_path(gem_root: GEM_ROOT)
  exe = File.join(gem_root, "libexec", executable_name)
  return exe if File.file?(exe)

  raise Error, <<~MSG
    mcptask_runner binary not found at #{exe}.

    The platform gem for #{Gem::Platform.local} was probably not installed.
    Supported platforms: #{SUPPORTED_PLATFORMS.join(', ')}.

    On a supported platform, re-run `bundle install` (and make sure the
    platform is in Gemfile.lock: `bundle lock --add-platform #{Gem::Platform.local}`).
    On an unsupported platform, install the binary from
    https://github.com/jchsoft/mcptask-releases and point the
    MCPTASK_RUNNER_BIN environment variable at it.
  MSG
end

.copy(source, target) ⇒ Object

Written beside the target and renamed into place: a half-copied binary over a working one is a scheduled job that fails on a corrupt file, and the rename also sidesteps the ETXTBSY a running copy would give.



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# File 'lib/mcptask_rails_runner/binary.rb', line 146

def copy(source, target)
  FileUtils.mkdir_p(File.dirname(target))
  staged = "#{target}.new"
  FileUtils.cp(source, staged)
  FileUtils.chmod(0o755, staged)
  File.rename(staged, target)
end

.exec!(*args) ⇒ Object

Replaces the current process, so the binary's exit code and signal handling reach the caller (rake) unchanged.



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# File 'lib/mcptask_rails_runner/binary.rb', line 114

def exec!(*args)
  Kernel.exec(path, *args)
end

.exec_installed!(*args) ⇒ Object

Installs the binary outside the gem first, then runs that copy.

Used by install and update, the two tasks that generate the scheduled job: the job runs whichever binary is executing them, so it has to be the copy at the version-free path rather than the one inside this gem.



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# File 'lib/mcptask_rails_runner/binary.rb', line 123

def exec_installed!(*args)
  Kernel.exec(install!, *args)
end

.executable_name ⇒ Object 



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# File 'lib/mcptask_rails_runner/binary.rb', line 34

def executable_name
  Gem.win_platform? ? "mcptask_runner.exe" : "mcptask_runner"
end

.install!(install_dir: INSTALL_DIR, gem_root: GEM_ROOT, out: $stdout) ⇒ Object

Copies the bundled binary out of the gem, and returns what to run.

The gem bootstraps the binary; it does not host it. Everything the scheduled job touches has to outlive bundle update, and a gem directory does not — so install and update put a copy where nothing but they will ever move it. A copy rather than a symlink: a link into the gem's libexec dangles on the same bundle update, which is the identical 08:00 failure moved one step along, and Windows wants a privilege for symlinks besides.

Teaching the launcher to run bundle exec rake instead would fix the path and put bundler and Gemfile.lock back into the 08:00 path — the layer the Go port set out to remove.

Newest wins, and says so. A host with several projects has several gem versions and one installed binary, so a project pinning an older gem must not quietly drag the machine's runner backwards.



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# File 'lib/mcptask_rails_runner/binary.rb', line 88

def install!(install_dir: INSTALL_DIR, gem_root: GEM_ROOT, out: $stdout)
  override = ENV["MCPTASK_RUNNER_BIN"]
  unless override.nil? || override.empty?
    out.puts "[mcptask_runner] MCPTASK_RUNNER_BIN is set — running #{override} " \
             "and leaving #{installed_path(install_dir: install_dir)} alone."
    return override
  end

  source = bundled_path(gem_root: gem_root)
  target = installed_path(install_dir: install_dir)

  existing = installed_version(target)
  if existing && existing > Gem::Version.new(VERSION)
    out.puts "[mcptask_runner] #{target} already holds #{existing}, which is newer than this " \
             "gem's #{VERSION} — keeping it. Delete that file to install this gem's binary instead."
    return target
  end

  copy(source, target)
  out.puts "[mcptask_runner] installed mcptask_runner #{VERSION} into #{target}" \
           "#{existing ? " (replacing #{existing})" : ''}."
  target
end

.installed_path(install_dir: INSTALL_DIR) ⇒ Object

The version-free path the installed copy lives at.



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# File 'lib/mcptask_rails_runner/binary.rb', line 68

def installed_path(install_dir: INSTALL_DIR)
  File.join(install_dir, executable_name)
end

.installed_version(target) ⇒ Object

What the installed copy reports about itself, or nil when there is none — or when it cannot be asked, which a stray file at that path cannot be.

Asked of the binary rather than recorded in a marker file beside it: the binary is what actually runs at 08:00, and a marker can only be right about installs that went through here.



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# File 'lib/mcptask_rails_runner/binary.rb', line 133

def installed_version(target)
  return nil unless File.file?(target)

  banner = IO.popen([target, "version"], err: File::NULL, &:read)
  raw = banner.to_s[VERSION_LINE, 1]
  raw && Gem::Version.new(raw)
rescue StandardError
  nil
end

.path(gem_root: GEM_ROOT) ⇒ Object

Absolute path to the binary this gem runs. Never resolved through PATH: the binary shares the mcptask_runner name with the legacy gem's rake namespace, and a PATH lookup could pick up a stale or wrong install.



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# File 'lib/mcptask_rails_runner/binary.rb', line 41

def path(gem_root: GEM_ROOT)
  override = ENV["MCPTASK_RUNNER_BIN"]
  return override unless override.nil? || override.empty?

  bundled_path(gem_root: gem_root)
end