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Add console support
Signed-off-by: Cong Wang <cwang@multikernel.io>
1 parent 293bf14 commit f2f1906

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‎src/kerf/cli.py‎

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@@ -26,6 +26,7 @@
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from .unload.main import unload
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from .delete.main import delete
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from .show.main import show
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from .console.main import console
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@click.group()
@@ -48,6 +49,7 @@ def main(ctx, debug):
4849
main.add_command(unload)
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main.add_command(delete)
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main.add_command(show)
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main.add_command(console)
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if __name__ == "__main__":

‎src/kerf/console/__init__.py‎

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@@ -0,0 +1,21 @@
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# Copyright 2025 Multikernel Technologies, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""
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Console attachment subcommand implementation.
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"""
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from .main import console, run_console
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__all__ = ["console", "run_console"]

‎src/kerf/console/main.py‎

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@@ -0,0 +1,235 @@
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# Copyright 2025 Multikernel Technologies, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""
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Console attachment subcommand implementation for mktty device.
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"""
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import os
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import select
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import sys
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import termios
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import tty
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from pathlib import Path
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from typing import Optional
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import click
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from ..models import InstanceState
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from ..utils import get_instance_id_from_name, get_instance_name_from_id, get_instance_status
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MKTTY_DEVICE = "/dev/mktty"
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CTRL_CLOSE_BRACKET = 0x1D # Ctrl+]
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def run_console(instance_id: int, instance_name: str, verbose: bool = False) -> int:
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"""
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Attach to a running instance's console via mktty device.
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Args:
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instance_id: The instance ID to attach to
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instance_name: The instance name (for display purposes)
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verbose: Enable verbose output
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Returns:
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0 on success, non-zero on error
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"""
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# Check if mktty device exists
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if not Path(MKTTY_DEVICE).exists():
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click.echo(f"Error: Console device {MKTTY_DEVICE} not found", err=True)
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click.echo("Make sure the mktty kernel module is loaded", err=True)
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return 1
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# Check if stdin is a tty
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if not sys.stdin.isatty():
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click.echo("Error: stdin is not a terminal", err=True)
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return 1
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click.echo(f"Connecting to console for instance '{instance_name}' (ID: {instance_id})...")
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click.echo("Escape sequence: Ctrl+] followed by . to detach")
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click.echo("")
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# Open mktty device
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try:
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mktty_fd = os.open(MKTTY_DEVICE, os.O_RDWR)
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except OSError as e:
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click.echo(f"Error: Failed to open {MKTTY_DEVICE}: {e}", err=True)
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if e.errno == 13: # EACCES
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click.echo("Note: This operation may require root privileges", err=True)
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return 1
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try:
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# Write instance ID to mktty device to initiate connection
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instance_id_str = f"{instance_id}\n"
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os.write(mktty_fd, instance_id_str.encode("utf-8"))
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# Save terminal settings
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stdin_fd = sys.stdin.fileno()
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stdout_fd = sys.stdout.fileno()
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old_settings = termios.tcgetattr(stdin_fd)
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try:
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# Enter raw mode
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tty.setraw(stdin_fd)
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# State for detach sequence detection
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saw_ctrl_bracket = False
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# I/O loop
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while True:
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readable, _, _ = select.select([stdin_fd, mktty_fd], [], [], 0.1)
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for fd in readable:
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if fd == stdin_fd:
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# Read from stdin
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data = os.read(stdin_fd, 1)
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if not data:
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# EOF on stdin
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return 0
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byte = data[0]
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# Check for detach sequence: Ctrl+] followed by .
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if saw_ctrl_bracket:
106+
if byte == ord('.'):
107+
# Detach sequence complete
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return 0
109+
else:
110+
# Not a detach sequence, send the buffered Ctrl+]
111+
os.write(mktty_fd, bytes([CTRL_CLOSE_BRACKET]))
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saw_ctrl_bracket = False
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# Fall through to send current byte
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115+
if byte == CTRL_CLOSE_BRACKET:
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# Start of potential detach sequence
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saw_ctrl_bracket = True
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else:
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# Send to mktty device
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os.write(mktty_fd, data)
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elif fd == mktty_fd:
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# Read from mktty device
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try:
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data = os.read(mktty_fd, 4096)
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if data:
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# Translate \n to \r\n for proper terminal display
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# in raw mode (kernel outputs \n, terminal needs \r\n)
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# First normalize any existing \r\n to \n, then convert
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data = data.replace(b'\r\n', b'\n').replace(b'\n', b'\r\n')
131+
os.write(stdout_fd, data)
132+
except OSError:
133+
# Device closed or error
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return 0
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finally:
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# Restore terminal settings
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termios.tcsetattr(stdin_fd, termios.TCSADRAIN, old_settings)
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click.echo("")
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click.echo("Disconnected from console.")
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finally:
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os.close(mktty_fd)
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return 0
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@click.command(name="console")
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@click.argument("name", required=False)
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@click.option("--id", type=int, help="Instance ID (alternative to name)")
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@click.option("--verbose", "-v", is_flag=True, help="Verbose output")
152+
def console(name: Optional[str], id: Optional[int], verbose: bool):
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"""
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Attach to a running instance's console.
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Connect to the console of a running multikernel instance via the mktty
157+
device. All input including Ctrl+C is passed through to the spawn kernel.
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159+
To detach from the console, press Ctrl+] followed by . (period).
160+
161+
Examples:
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163+
kerf console web-server
164+
kerf console --id=1
165+
"""
166+
try:
167+
if not name and id is None:
168+
click.echo("Error: Either instance name or --id must be provided", err=True)
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click.echo("Usage: kerf console <name> or kerf console --id=<id>", err=True)
170+
sys.exit(2)
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172+
instance_name = None
173+
instance_id = None
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175+
if name:
176+
# Use name, convert to ID
177+
instance_name = name
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instance_id = get_instance_id_from_name(name)
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if instance_id is None:
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click.echo(f"Error: Instance '{name}' not found", err=True)
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click.echo("Check available instances in /sys/fs/multikernel/instances/", err=True)
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sys.exit(1)
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if verbose:
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click.echo(f"Instance name: {name} (ID: {instance_id})")
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else:
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# Use ID directly, need to find name
189+
instance_id = id
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191+
if instance_id < 1 or instance_id > 511:
192+
click.echo(f"Error: --id must be between 1 and 511 (got {instance_id})", err=True)
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sys.exit(2)
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195+
instance_name = get_instance_name_from_id(instance_id)
196+
if not instance_name:
197+
click.echo(f"Error: Instance with ID {instance_id} not found", err=True)
198+
click.echo("Check available instances in /sys/fs/multikernel/instances/", err=True)
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sys.exit(1)
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if verbose:
202+
click.echo(f"Instance name: {instance_name} (ID: {instance_id})")
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# Check instance status - must be active
205+
status = get_instance_status(instance_name)
206+
if status is None:
207+
click.echo(f"Error: Failed to read status for instance '{instance_name}'", err=True)
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sys.exit(1)
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if status.lower() != InstanceState.ACTIVE.value:
211+
click.echo(
212+
f"Error: Instance '{instance_name}' is not active (status: '{status}')",
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err=True,
214+
)
215+
click.echo(
216+
f"Console attachment requires the instance to be in '{InstanceState.ACTIVE.value}' state.",
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err=True,
218+
)
219+
click.echo(f"Start the instance with: kerf exec {instance_name}", err=True)
220+
sys.exit(1)
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if verbose:
223+
click.echo(f"Instance status: {status}")
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# Run the console
226+
result = run_console(instance_id, instance_name, verbose)
227+
sys.exit(result)
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229+
except Exception as e:
230+
click.echo(f"Unexpected error: {e}", err=True)
231+
if verbose:
232+
import traceback
233+
234+
traceback.print_exc()
235+
sys.exit(1)

‎src/kerf/exec/main.py‎

Lines changed: 14 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -103,18 +103,23 @@ def boot_multikernel(mk_id: int) -> int:
103103
@click.command(name="exec")
104104
@click.argument("name", required=False)
105105
@click.option("--id", type=int, help="Multikernel instance ID to boot (alternative to name)")
106+
@click.option("--console", "attach_console", is_flag=True, help="Attach to console after boot")
106107
@click.option("--verbose", "-v", is_flag=True, help="Verbose output")
107-
def exec_cmd(name: Optional[str], id: Optional[int], verbose: bool):
108+
def exec_cmd(name: Optional[str], id: Optional[int], attach_console: bool, verbose: bool):
108109
"""
109110
Boot a multikernel instance using the reboot syscall.
110111
111112
This command boots a previously loaded multikernel instance by name or ID using
112113
the reboot syscall with the MULTIKERNEL command.
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Use --console to immediately attach to the instance's console after boot.
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Press Ctrl+] followed by . to detach from the console.
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Examples:
115119
116120
kerf exec web-server
117121
kerf exec --id=1
122+
kerf exec web-server --console
118123
"""
119124
try:
120125
if not name and id is None:
@@ -217,6 +222,14 @@ def exec_cmd(name: Optional[str], id: Optional[int], verbose: bool):
217222
else:
218223
click.echo("✓ Boot command executed successfully")
219224

225+
# Attach to console if requested
226+
if attach_console:
227+
from ..console import run_console
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229+
console_result = run_console(instance_id, instance_name, verbose)
230+
if console_result != 0:
231+
sys.exit(console_result)
232+
220233
# Note: If successful, this syscall will reboot the system and boot the
221234
# specified multikernel instance, so we may not reach this point.
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‎src/kerf/load/main.py‎

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Original file line numberDiff line numberDiff line change
@@ -214,6 +214,7 @@ def kexec_file_load(
214214
@click.option("--netmask", default="255.255.255.0", help="Network mask (default: 255.255.255.0)")
215215
@click.option("--nic", help="Network interface name (e.g., eth0)")
216216
@click.option("--hostname", help="Hostname for spawn kernel")
217+
@click.option("--console", "console_device", help="Console device (e.g., mktty0)")
217218
@click.option("--verbose", "-v", is_flag=True, help="Verbose output")
218219
def load( # pylint: disable=too-many-arguments,too-many-positional-arguments,too-many-locals
219220
ctx: click.Context,
@@ -230,6 +231,7 @@ def load( # pylint: disable=too-many-arguments,too-many-positional-arguments,to
230231
netmask: str,
231232
nic: Optional[str],
232233
hostname: Optional[str],
234+
console_device: Optional[str],
233235
verbose: bool,
234236
):
235237
"""
@@ -267,6 +269,10 @@ def load( # pylint: disable=too-many-arguments,too-many-positional-arguments,to
267269
# Load with DHCP
268270
kerf load web-server --kernel=/boot/vmlinuz --image=nginx:latest \\
269271
--ip=dhcp --nic=eth0
272+
273+
# Load with console enabled
274+
kerf load web-server --kernel=/boot/vmlinuz --image=nginx:latest \\
275+
--console=mktty0
270276
"""
271277
try:
272278
if not name and id is None:
@@ -463,6 +469,12 @@ def load( # pylint: disable=too-many-arguments,too-many-positional-arguments,to
463469
if verbose:
464470
click.echo(f"Network config: {ip_param}")
465471

472+
# Add console device if specified
473+
if console_device:
474+
cmdline_parts.append(f"console={console_device}")
475+
if verbose:
476+
click.echo(f"Console: console={console_device}")
477+
466478
cmdline_str = " ".join(cmdline_parts)
467479

468480
if verbose:

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