Implement an option to control the installation of the kitty bootstrap script

kittens/ssh/main.py

@@ -156,6 +156,8 @@ def make_tarfile(ssh_opts: SSHOptions, base_env: Dict[str, str], compression: st
         env['KITTY_LOGIN_SHELL'] = ssh_opts.login_shell
     if ssh_opts.cwd:
         env['KITTY_LOGIN_CWD'] = ssh_opts.cwd
+    if ssh_opts.remote_kitty != 'no':
+        env['KITTY_REMOTE'] = ssh_opts.remote_kitty
     env_script = serialize_env(env, base_env)
     buf = io.BytesIO()
     with tarfile.open(mode=f'w:{compression}', fileobj=buf, encoding='utf-8') as tf:
@@ -171,6 +173,7 @@ def make_tarfile(ssh_opts: SSHOptions, base_env: Dict[str, str], compression: st
                 f'{arcname}/ssh/*',          # bootstrap files are sent as command line args
                 f'{arcname}/zsh/kitty.zsh',  # present for legacy compat not needed by ssh kitten
             ))
+        if ssh_opts.remote_kitty != 'no':
             arcname = 'home/' + rd + '/kitty'
             add_data_as_file(tf, arcname + '/version', str_version.encode('ascii'))
             tf.add(shell_integration_dir + '/ssh/kitty', arcname=arcname + '/bin/kitty', filter=normalize_tarinfo)

kittens/ssh/options/definition.py

@@ -102,6 +102,19 @@ The working directory on the remote host to change to. Env vars in this
 value are expanded. The default is empty so no changing is done, which
 usually means the home directory is used.
 ''')
+
+opt('remote_kitty', 'if-needed', choices=('if-needed', 'no', 'yes'), long_text='''
+Make kitty available on the remote server. Useful to run kittens such as the
+icat kitten to display images or the transfer file kitten to transfer files.
+Only works if the remote server has an architecture for which pre-compiled
+kitty binaries are available. Note that kitty is not actually copied to the
+remote server, instead a small bootstrap script is copied which will download
+and run kitty when kitty is first executed on the remote server. A value of
+:code:`needed` means kitty is installed only if not already present in the
+system-wide PATH. A value of :code:`yes` means that kitty is installed even if
+already present, and the installed kitty takes precedence. Finally, :code:`no`
+means no kitty is installed on the remote machine.
+''')
 egr()  # }}}
 
 agr('ssh', 'SSH configuration')  # {{{

kittens/ssh/options/parse.py

@@ -38,6 +38,14 @@ class Parser:
     def remote_dir(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
         ans['remote_dir'] = relative_dir(val)
 
+    def remote_kitty(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
+        val = val.lower()
+        if val not in self.choices_for_remote_kitty:
+            raise ValueError(f"The value {val} is not a valid choice for remote_kitty")
+        ans["remote_kitty"] = val
+
+    choices_for_remote_kitty = frozenset(('if-needed', 'no', 'yes'))
+
     def share_connections(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
         ans['share_connections'] = to_bool(val)
 

kittens/ssh/options/types.py

@@ -5,8 +5,10 @@ import kittens.ssh.copy
 
 if typing.TYPE_CHECKING:
     choices_for_askpass = typing.Literal['unless-set', 'ssh', 'native']
+    choices_for_remote_kitty = typing.Literal['if-needed', 'no', 'yes']
 else:
     choices_for_askpass = str
+    choices_for_remote_kitty = str
 
 option_names = (  # {{{
  'askpass',
@@ -17,6 +19,7 @@ option_names = (  # {{{
  'interpreter',
  'login_shell',
  'remote_dir',
+ 'remote_kitty',
  'share_connections',
  'shell_integration')  # }}}
 
@@ -28,6 +31,7 @@ class Options:
     interpreter: str = 'sh'
     login_shell: str = ''
     remote_dir: str = '.local/share/kitty-ssh-kitten'
+    remote_kitty: choices_for_remote_kitty = 'if-needed'
     share_connections: bool = True
     shell_integration: str = 'inherited'
     copy: typing.Dict[str, kittens.ssh.copy.CopyInstruction] = {}

shell-integration/ssh/bootstrap-utils.sh

@@ -169,6 +169,24 @@ fi' > "$sh_script"
     exec "$login_shell"
 }
 
+install_kitty_bootstrap() {
+    case "$(command uname)" in
+        Linux) ;;
+        Darwin) ;;
+        *) return ;;
+    esac
+    kitty_exists="n"
+    command -v kitty 2> /dev/null > /dev/null && kitty_exists="y"
+    if [ "$kitty_remote" = "yes" -o "$kitty_remote-$kitty_exists" = "if-needed-n" ]; then
+        kitty_dir="$data_dir/kitty/bin"
+        if [ "$kitty_exists" = "y" ]; then
+            export PATH="$kitty_dir:$PATH"
+        else
+            export PATH="$PATH:$kitty_dir"
+        fi
+    fi
+}
+
 prepare_for_exec() {
     if [ -n "$leading_data" ]; then
         # clear current line as it might have things echoed on it from leading_data
@@ -177,6 +195,7 @@ prepare_for_exec() {
         printf "\r\033[K" > /dev/tty
     fi
     [ -f "$HOME/.terminfo/kitty.terminfo" ] || die "Incomplete extraction of ssh data"
+    install_kitty_bootstrap
 
     [ -n "$login_shell" ] || using_getent || using_id || using_python || using_perl || using_passwd || using_shell_env || login_shell="sh"
     shell_name=$(command basename $login_shell)

shell-integration/ssh/bootstrap.py

@@ -258,6 +258,19 @@ def exec_with_shell_integration():
         exec_bash_with_integration()
 
 
+def install_kitty_bootstrap():
+    kitty_remote = os.environ.pop('KITTY_REMOTE', '')
+    if os.uname().sysname not in ('Linux', 'Darwin'):
+        return
+    kitty_exists = shutil.which('kitty')
+    if kitty_remote == 'yes' or (kitty_remote == 'if-needed' and not kitty_exists):
+        kitty_dir = os.path.join(data_dir, 'kitty', 'bin')
+        if kitty_exists:
+            os.environ['PATH'] = kitty_dir + os.pathsep + os.environ['PATH']
+        else:
+            os.environ['PATH'] = os.environ['PATH'] + os.pathsep + kitty_dir
+
+
 def main():
     global tty_file_obj, login_shell
     # the value of O_CLOEXEC below is on macOS which is most likely to not have
@@ -271,6 +284,7 @@ def main():
     finally:
         cleanup()
     cwd = os.environ.pop('KITTY_LOGIN_CWD', '')
+    install_kitty_bootstrap()
     if cwd:
         os.chdir(cwd)
     ksi = frozenset(filter(None, os.environ.get('KITTY_SHELL_INTEGRATION', '').split()))

shell-integration/ssh/bootstrap.sh

@@ -106,6 +106,8 @@ untar_and_read_env() {
     unset KITTY_LOGIN_SHELL
     login_cwd="$KITTY_LOGIN_CWD"
     unset KITTY_LOGIN_CWD
+    kitty_remote="$KITTY_REMOTE"
+    unset KITTY_REMOTE
     compile_terminfo "$tdir/home"
     mv_files_and_dirs "$tdir/home" "$HOME"
     [ -e "$tdir/root" ] && mv_files_and_dirs "$tdir/root" ""