refactor(anchor): buffer bytes instead of string

Resolves Riley's comments, makes it so UTF-8 characters over 1 byte aren't destroyed

auto_start/auto_start_anchor.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 set -e
 
-SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+SCRIPT_DIR=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" &>/dev/null && pwd)
 
 # Wait for a network interface to be up (not necessarily online)
 while ! ip link show | grep -q "state UP"; do

auto_start/auto_start_headless_full.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 set -e
 
-SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+SCRIPT_DIR=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" &>/dev/null && pwd)
 
 # Wait for a network interface to be up (not necessarily online)
 while ! ip link show | grep -q "state UP"; do
@@ -26,4 +26,3 @@ source $SCRIPT_DIR/../install/setup.bash
 
 # Launch the ROS 2 node
 ros2 run headless_pkg headless_full
-

auto_start/start_rosbag.sh

@@ -1,12 +1,12 @@
 #!/usr/bin/env bash
 set -e
 
-SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+SCRIPT_DIR=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" &>/dev/null && pwd)
 
-[[ -z "$ANCHOR_WS" ]] && ANCHOR_WS="$SCRIPT_DIR/.."
+[[ -z $ANCHOR_WS ]] && ANCHOR_WS="$SCRIPT_DIR/.."
-[[ -z "$AUTONOMY_WS" ]] && AUTONOMY_WS="$HOME/rover-Autonomy"
+[[ -z $AUTONOMY_WS ]] && AUTONOMY_WS="$HOME/rover-Autonomy"
 BAG_LOCATION="$HOME/bags/autostart"
-[[ ! -d "$BAG_LOCATION" ]] && mkdir -p "$BAG_LOCATION"
+[[ ! -d $BAG_LOCATION ]] && mkdir -p "$BAG_LOCATION"
 
 # Wait for a network interface to be up (not necessarily online)
 while ! ip link show | grep -q "state UP"; do
@@ -16,7 +16,6 @@ done
 
 echo "[INFO] Network interface is up!"
 
-
 if command -v nixos-rebuild; then
   echo "[INFO] running on NixOS"
 else

flake.lock

@@ -24,16 +24,16 @@
         "nixpkgs": "nixpkgs"
       },
       "locked": {
-        "lastModified": 1770108954,
+        "lastModified": 1775216071,
-        "narHash": "sha256-VBj6bd4LPPSfsZJPa/UPPA92dOs6tmQo0XZKqfz/3W4=",
+        "narHash": "sha256-PrPW70Fh1uLx3JxNV/NLeXjUhgfrZmi7ac8LJOlS0q4=",
         "owner": "lopsided98",
         "repo": "nix-ros-overlay",
-        "rev": "3d05d46451b376e128a1553e78b8870c75d7753a",
+        "rev": "197a2b55c4ed24f8b885a5b20b65f426fb6d57ca",
         "type": "github"
       },
       "original": {
         "owner": "lopsided98",
-        "ref": "develop",
+        "ref": "master",
         "repo": "nix-ros-overlay",
         "type": "github"
       }

flake.nix

@@ -2,7 +2,7 @@
   description = "Development environment for ASTRA Anchor";
 
   inputs = {
-    nix-ros-overlay.url = "github:lopsided98/nix-ros-overlay/develop";
+    nix-ros-overlay.url = "github:lopsided98/nix-ros-overlay/master";
     nixpkgs.follows = "nix-ros-overlay/nixpkgs"; # IMPORTANT!!!
 
     treefmt-nix = {
@@ -31,6 +31,8 @@
           name = "ASTRA Anchor";
           packages = with pkgs; [
             colcon
+            socat
+            can-utils
             (python313.withPackages (
               p: with p; [
                 pyserial
@@ -96,7 +98,8 @@
     );
 
   nixConfig = {
-    extra-substituters = [ "https://ros.cachix.org" ];
+    # Cache to pull ros packages from
-    extra-trusted-public-keys = [ "ros.cachix.org-1:dSyZxI8geDCJrwgvCOHDoAfOm5sV1wCPjBkKL+38Rvo=" ];
+    extra-substituters = [ "https://ros.cachix.org" "https://attic.iid.ciirc.cvut.cz/ros" ];
+    extra-trusted-public-keys = [ "ros.cachix.org-1:dSyZxI8geDCJrwgvCOHDoAfOm5sV1wCPjBkKL+38Rvo=" "ros:JR95vUYsShSqfA1VTYoFt1Nz6uXasm5QrcOsGry9f6Q=" ];
   };
 }

scripts/reset-repo.bash

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+
+repo_root="$(git rev-parse --show-toplevel)"
+
+if [[ -z $repo_root ]]; then
+  echo "script must be run from within a git repo" >&2
+  exit 1
+fi
+
+cd $repo_root
+
+echo "this will nuke all of your current un-commited git changes, including any changes to submodules and any gitignored files. is this okay? (y/N)"
+read okay
+
+if [[ $okay != "y" ]]; then
+  echo "you didn't say exactly 'y'. aborting." >&2
+  exit 2
+fi
+
+echo
+
+echo "ok say goodbye to everything in this repo"
+git submodule deinit --all -f && echo "- submodules gone"
+git clean -fdx && echo "- gitignored changes gone"
+git add -A
+git reset HEAD --hard && echo "- everything else gone"
+git submodule update --init --recursive && echo "- brought the submodules back"
+echo
+
+echo "in theory that should've done it. let's make sure"
+status=$(git status --porcelain)
+echo $status
+if [[ -z $status ]]; then
+  echo "nice, all clean!"
+else
+  echo "uhh that's not supposed to be there. this is probably a bug in this script. good luck!" >&2
+  exit 3
+fi

scripts/test-connectors.bash

@@ -0,0 +1,463 @@
+#!/usr/bin/env bash
+
+# test script for anchor connectors (mock, serial, CAN)
+
+set -o pipefail
+
+repo_root="$(git rev-parse --show-toplevel)"
+
+if [[ -z $repo_root ]]; then
+  echo "script must be run from within the rover-ros2 repo" >&2
+  exit 1
+fi
+
+cd "$repo_root"
+
+# colors
+BOLD='\033[1m'
+RED='\033[1;31m'
+GREEN='\033[1;32m'
+YELLOW='\033[1;33m'
+NC='\033[0m'
+
+TESTS_PASSED=0
+TESTS_FAILED=0
+
+log() {
+  echo -e "${BOLD}${YELLOW}info:${NC} ${1}"
+}
+
+pass() {
+  echo -e "${BOLD}${GREEN}pass:${NC} ${1}"
+  TESTS_PASSED=$((TESTS_PASSED + 1))
+}
+
+fail() {
+  echo -e "${BOLD}${RED}fail:${NC} ${1}"
+  TESTS_FAILED=$((TESTS_FAILED + 1))
+}
+
+cleanup() {
+  log "cleaning up"
+  if [[ -n $ANCHOR_PID ]]; then
+    kill -INT -- -"$ANCHOR_PID" 2>/dev/null || true
+    wait "$ANCHOR_PID" 2>/dev/null || true
+  fi
+  if [[ -n $SOCAT_PID ]]; then
+    kill -INT "$SOCAT_PID" 2>/dev/null || true
+    wait "$SOCAT_PID" 2>/dev/null || true
+  fi
+  rm -f /tmp/ttyACM9 /tmp/ttyOUT 2>/dev/null || true
+}
+
+trap cleanup EXIT
+
+source_ros2() {
+  source install/setup.bash
+}
+
+wait_for_topic() {
+  local topic="$1"
+  local timeout="${2:-5}"
+  local count=0
+  while ! ros2 topic list 2>/dev/null | grep -q "^${topic}$"; do
+    sleep 0.5
+    count=$((count + 1))
+    if [[ $count -ge $((timeout * 2)) ]]; then
+      return 1
+    fi
+  done
+  return 0
+}
+
+# run a ROS pub/echo test
+# usage: ros_pubsub_test <echo_topic> <pub_topic> <msg_type> <msg_data>
+# returns the echo output via stdout
+ros_pubsub_test() {
+  local echo_topic="$1"
+  local pub_topic="$2"
+  local msg_type="$3"
+  local msg_data="$4"
+
+  timeout 5 bash -c "
+    ros2 topic echo --once $echo_topic &
+    ECHO_PID=\$!
+    sleep 0.5
+    ros2 topic pub --once $pub_topic $msg_type \"$msg_data\" >/dev/null 2>&1
+    wait \$ECHO_PID
+  " 2>/dev/null || true
+}
+
+test_mock_connector() {
+  log "testing mock connector"
+
+  log "starting anchor with mock connector"
+  setsid ros2 run anchor_pkg anchor --ros-args -p connector:=mock &
+  ANCHOR_PID=$!
+  sleep 2
+
+  if ! kill -0 "$ANCHOR_PID" 2>/dev/null; then
+    fail "mock connector: anchor failed to start"
+    return 1
+  fi
+
+  if ! wait_for_topic "/anchor/to_vic/relay" 10; then
+    fail "mock connector: topics not available"
+    kill -INT -- -"$ANCHOR_PID" 2>/dev/null || true
+    return 1
+  fi
+
+  log "anchor started successfully"
+
+  # test: relay -> debug
+  log "testing relay -> debug"
+  local output
+  output=$(ros_pubsub_test "/anchor/to_vic/debug" "/anchor/to_vic/relay" \
+    "astra_msgs/msg/VicCAN" '{mcu_name: \"core\", command_id: 50, data: [1.0, 2.0, 3.0, 4.0]}')
+
+  if [[ -n $output ]] && echo "$output" | grep -q "can_relay_tovic,core,50"; then
+    pass "mock connector: relay -> debug"
+  else
+    fail "mock connector: relay -> debug"
+  fi
+
+  # test: mock_mcu -> from_vic/core
+  log "testing mock_mcu (core) -> from_vic/core"
+  output=$(ros_pubsub_test "/anchor/from_vic/core" "/anchor/from_vic/mock_mcu" \
+    "astra_msgs/msg/VicCAN" '{mcu_name: \"core\", command_id: 10, data: [100.0, 200.0]}')
+
+  if [[ -n $output ]] && echo "$output" | grep -q "mcu_name: core" && echo "$output" | grep -q "command_id: 10"; then
+    pass "mock connector: mock_mcu -> from_vic/core"
+  else
+    fail "mock connector: mock_mcu -> from_vic/core"
+  fi
+
+  # test: mock_mcu -> from_vic/arm
+  log "testing mock_mcu (arm) -> from_vic/arm"
+  output=$(ros_pubsub_test "/anchor/from_vic/arm" "/anchor/from_vic/mock_mcu" \
+    "astra_msgs/msg/VicCAN" '{mcu_name: \"arm\", command_id: 55, data: [0.0, 450.0, 900.0, 0.0]}')
+
+  if [[ -n $output ]] && echo "$output" | grep -q "mcu_name: arm" && echo "$output" | grep -q "command_id: 55"; then
+    pass "mock connector: mock_mcu -> from_vic/arm"
+  else
+    fail "mock connector: mock_mcu -> from_vic/arm"
+  fi
+
+  # test: mock_mcu -> from_vic/bio
+  log "testing mock_mcu (citadel) -> from_vic/bio"
+  output=$(ros_pubsub_test "/anchor/from_vic/bio" "/anchor/from_vic/mock_mcu" \
+    "astra_msgs/msg/VicCAN" '{mcu_name: \"citadel\", command_id: 20, data: [5.0]}')
+
+  if echo "$output" | grep -q "mcu_name: citadel" && echo "$output" | grep -q "command_id: 20"; then
+    pass "mock connector: mock_mcu -> from_vic/bio"
+  else
+    fail "mock connector: mock_mcu -> from_vic/bio"
+  fi
+
+  # test: relay_string -> debug
+  log "testing relay_string -> debug"
+  output=$(ros_pubsub_test "/anchor/to_vic/debug" "/anchor/to_vic/relay_string" \
+    "std_msgs/msg/String" '{data: \"test_raw_string_data\"}')
+
+  if [[ -n $output ]] && echo "$output" | grep -q "test_raw_string_data"; then
+    pass "mock connector: relay_string -> debug"
+  else
+    fail "mock connector: relay_string -> debug"
+  fi
+
+  kill -INT -- -"$ANCHOR_PID" 2>/dev/null || true
+  wait "$ANCHOR_PID" 2>/dev/null || true
+  ANCHOR_PID=""
+}
+
+test_serial_connector() {
+  log "testing serial connector"
+
+  log "creating virtual serial ports with socat"
+  socat pty,raw,echo=0,link=/tmp/ttyACM9 pty,raw,echo=0,link=/tmp/ttyOUT 2>/dev/null &
+  SOCAT_PID=$!
+  sleep 2
+
+  if ! kill -0 "$SOCAT_PID" 2>/dev/null; then
+    fail "serial connector: failed to create virtual serial ports"
+    return 1
+  fi
+
+  log "starting anchor with serial connector (override: /tmp/ttyACM9)"
+  setsid ros2 run anchor_pkg anchor --ros-args -p connector:=serial -p serial_override:=/tmp/ttyACM9 &
+  ANCHOR_PID=$!
+  sleep 2
+
+  if ! kill -0 "$ANCHOR_PID" 2>/dev/null; then
+    fail "serial connector: anchor failed to start"
+    kill -INT "$SOCAT_PID" 2>/dev/null || true
+    return 1
+  fi
+
+  if ! wait_for_topic "/anchor/to_vic/relay" 10; then
+    fail "serial connector: topics not available"
+    kill -INT -- -"$ANCHOR_PID" 2>/dev/null || true
+    kill -INT "$SOCAT_PID" 2>/dev/null || true
+    return 1
+  fi
+
+  pass "serial connector: anchor starts with virtual serial"
+
+  # test: relay -> serial output (VicCAN encoding)
+  log "testing relay -> serial output"
+
+  local serial_out_file
+  serial_out_file=$(mktemp)
+
+  # Start head first (blocks waiting for input), then publish
+  timeout 5 head -n1 /tmp/ttyOUT >"$serial_out_file" &
+  local head_pid=$!
+  sleep 0.3
+  ros2 topic pub --once /anchor/to_vic/relay astra_msgs/msg/VicCAN \
+    '{mcu_name: "core", command_id: 30, data: [1.0, 2.0, 3.0, 4.0]}' >/dev/null 2>&1
+  wait $head_pid 2>/dev/null || true
+
+  local serial_out
+  serial_out=$(cat "$serial_out_file")
+  rm -f "$serial_out_file"
+
+  if [[ -n $serial_out ]] && echo "$serial_out" | grep -q "can_relay_tovic,core,30"; then
+    pass "serial connector: relay -> serial output"
+  else
+    fail "serial connector: relay -> serial output (got: $serial_out)"
+  fi
+
+  # test: serial input -> from_vic/core
+  log "testing serial input -> from_vic/core"
+
+  local output
+  output=$(timeout 5 bash -c '
+    ros2 topic echo --once /anchor/from_vic/core &
+    ECHO_PID=$!
+    sleep 0.5
+    echo "can_relay_fromvic,core,15,10.0,20.0,30.0,40.0" > /tmp/ttyOUT
+    sleep 0.5
+    echo "can_relay_fromvic,core,15,10.0,20.0,30.0,40.0" > /tmp/ttyOUT
+    wait $ECHO_PID
+  ' 2>/dev/null) || true
+
+  if echo "$output" | grep -q "mcu_name: core" && echo "$output" | grep -q "command_id: 15"; then
+    pass "serial connector: serial input -> from_vic/core"
+  else
+    fail "serial connector: serial input -> from_vic/core (got: $output)"
+  fi
+
+  # test: relay_string -> debug
+  log "testing relay_string -> debug"
+  output=$(ros_pubsub_test "/anchor/to_vic/debug" "/anchor/to_vic/relay_string" \
+    "std_msgs/msg/String" '{data: \"serial_test_string\"}')
+
+  if [[ -n $output ]] && echo "$output" | grep -q "serial_test_string"; then
+    pass "serial connector: relay_string -> debug"
+  else
+    fail "serial connector: relay_string -> debug"
+  fi
+
+  kill -INT -- -"$ANCHOR_PID" 2>/dev/null || true
+  wait "$ANCHOR_PID" 2>/dev/null || true
+  ANCHOR_PID=""
+  kill -INT "$SOCAT_PID" 2>/dev/null || true
+  wait "$SOCAT_PID" 2>/dev/null || true
+  SOCAT_PID=""
+}
+
+test_can_connector() {
+  log "testing CAN connector"
+
+  log "starting anchor with CAN connector (override: vcan0)"
+  setsid ros2 run anchor_pkg anchor --ros-args -p connector:=can -p can_override:=vcan0 &
+  ANCHOR_PID=$!
+  sleep 2
+
+  if ! kill -0 "$ANCHOR_PID" 2>/dev/null; then
+    fail "CAN connector: anchor failed to start"
+    return 1
+  fi
+
+  if ! wait_for_topic "/anchor/to_vic/relay" 10; then
+    fail "CAN connector: topics not available"
+    kill -INT -- -"$ANCHOR_PID" 2>/dev/null || true
+    return 1
+  fi
+
+  log "anchor started successfully"
+  sleep 1
+
+  # test: relay -> CAN bus
+  # core=1, int16x4=2, cmd=30 -> id = (1<<8)|(2<<6)|30 = 0x19E
+  log "testing relay -> CAN bus"
+
+  local output
+  output=$(timeout 8 bash -c '
+    candump -n 1 vcan0 &
+    DUMP_PID=$!
+    sleep 1
+    ros2 topic pub --once /anchor/to_vic/relay astra_msgs/msg/VicCAN "{mcu_name: \"core\", command_id: 30, data: [1, 2, 3, 4]}" >/dev/null 2>&1
+    sleep 0.5
+    ros2 topic pub --once /anchor/to_vic/relay astra_msgs/msg/VicCAN "{mcu_name: \"core\", command_id: 30, data: [1, 2, 3, 4]}" >/dev/null 2>&1
+    wait $DUMP_PID
+  ' 2>/dev/null) || true
+
+  if echo "$output" | grep -qi "19E"; then
+    pass "CAN connector: relay -> CAN bus"
+  else
+    fail "CAN connector: relay -> CAN bus (got: $output)"
+  fi
+
+  # test: CAN -> from_vic/core
+  log "testing CAN bus -> from_vic/core"
+
+  output=$(timeout 5 bash -c '
+    ros2 topic echo --once /anchor/from_vic/core &
+    ECHO_PID=$!
+    sleep 1
+    cansend vcan0 18F#000A0014001E0028
+    sleep 0.5
+    cansend vcan0 18F#000A0014001E0028
+    wait $ECHO_PID
+  ' 2>/dev/null) || true
+
+  if echo "$output" | grep -q "mcu_name: core" && echo "$output" | grep -q "command_id: 15"; then
+    pass "CAN connector: CAN -> from_vic/core"
+  else
+    fail "CAN connector: CAN -> from_vic/core"
+  fi
+
+  # test: CAN -> from_vic/arm
+  log "testing CAN bus -> from_vic/arm"
+
+  output=$(timeout 5 bash -c '
+    ros2 topic echo --once /anchor/from_vic/arm &
+    ECHO_PID=$!
+    sleep 1
+    cansend vcan0 294#00640096012C01F4
+    sleep 0.5
+    cansend vcan0 294#00640096012C01F4
+    wait $ECHO_PID
+  ' 2>/dev/null) || true
+
+  if echo "$output" | grep -q "mcu_name: arm" && echo "$output" | grep -q "command_id: 20"; then
+    pass "CAN connector: CAN -> from_vic/arm"
+  else
+    fail "CAN connector: CAN -> from_vic/arm"
+  fi
+
+  # test: CAN double data type (data_type_key=0)
+  log "testing CAN double data type"
+
+  output=$(timeout 8 bash -c '
+    ros2 topic echo --once /anchor/from_vic/core &
+    ECHO_PID=$!
+    sleep 1
+    cansend vcan0 105#3FF0000000000000
+    sleep 0.5
+    cansend vcan0 105#3FF0000000000000
+    sleep 0.5
+    cansend vcan0 105#3FF0000000000000
+    wait $ECHO_PID
+  ' 2>/dev/null) || true
+
+  if echo "$output" | grep -q "mcu_name: core" && echo "$output" | grep -q "command_id: 5"; then
+    pass "CAN connector: double data type"
+  else
+    fail "CAN connector: double data type"
+  fi
+
+  # test: CAN float32x2 data type (data_type_key=1)
+  log "testing CAN float32x2 data type"
+
+  output=$(timeout 8 bash -c '
+    ros2 topic echo --once /anchor/from_vic/core &
+    ECHO_PID=$!
+    sleep 1
+    cansend vcan0 14A#3F80000040000000
+    sleep 0.5
+    cansend vcan0 14A#3F80000040000000
+    sleep 0.5
+    cansend vcan0 14A#3F80000040000000
+    wait $ECHO_PID
+  ' 2>/dev/null) || true
+
+  if echo "$output" | grep -q "mcu_name: core" && echo "$output" | grep -q "command_id: 10"; then
+    pass "CAN connector: float32x2 data type"
+  else
+    fail "CAN connector: float32x2 data type"
+  fi
+
+  kill -INT -- -"$ANCHOR_PID" 2>/dev/null || true
+  wait "$ANCHOR_PID" 2>/dev/null || true
+  ANCHOR_PID=""
+}
+
+check_prerequisites() {
+  log "checking prerequisites"
+  local missing=0
+
+  if [[ ! -f install/setup.bash ]]; then
+    fail "install/setup.bash not found; run 'colcon build --symlink-install' first"
+    missing=1
+  fi
+
+  if ! command -v socat &>/dev/null; then
+    fail "socat not found; install it or use 'nix develop'"
+    missing=1
+  fi
+
+  if ! command -v cansend &>/dev/null || ! command -v candump &>/dev/null; then
+    fail "can-utils (cansend/candump) not found; install it or use 'nix develop'"
+    missing=1
+  fi
+
+  if ! ip link show vcan0 &>/dev/null; then
+    fail "vcan0 interface not found"
+    log "  create it with:"
+    log "    sudo ip link add dev vcan0 type vcan"
+    log "    sudo ip link set vcan0 up"
+    missing=1
+  elif ! ip link show vcan0 | grep -q ",UP"; then
+    fail "vcan0 exists but is not UP"
+    log "  enable it with: sudo ip link set vcan0 up"
+    missing=1
+  fi
+
+  if [[ $missing -eq 1 ]]; then
+    echo ""
+    log "prerequisites not met"
+    exit 1
+  fi
+
+  log "all prerequisites met"
+}
+
+main() {
+  echo ""
+  log "anchor connector test suite"
+  echo ""
+
+  check_prerequisites
+
+  log "sourcing ROS2 workspace"
+  source_ros2
+
+  test_mock_connector
+  test_serial_connector
+  test_can_connector
+
+  echo ""
+  log "test summary"
+  echo -e "${BOLD}${GREEN}passed:${NC} $TESTS_PASSED"
+  echo -e "${BOLD}${RED}failed:${NC} $TESTS_FAILED"
+  echo ""
+
+  if [[ $TESTS_FAILED -gt 0 ]]; then
+    exit 1
+  fi
+  exit 0
+}
+
+main "$@"

src/anchor_pkg/anchor_pkg/anchor_node.py

@@ -1,11 +1,9 @@
 from warnings import deprecated
 import rclpy
 from rclpy.node import Node
-from rclpy.executors import ExternalShutdownException
+from rclpy.executors import ExternalShutdownException, SingleThreadedExecutor
 from rcl_interfaces.msg import ParameterDescriptor, ParameterType
 
-import atexit
-
 from .connector import (
     Connector,
     MockConnector,
@@ -14,8 +12,7 @@ from .connector import (
     NoValidDeviceException,
     NoWorkingDeviceException,
 )
-from .convert import string_to_viccan
+from .convert import string_to_viccan, viccan_to_string
-import threading
 
 from astra_msgs.msg import VicCAN
 from std_msgs.msg import String
@@ -37,7 +34,7 @@ class Anchor(Node):
 
     Subscribers:
     * /anchor/from_vic/mock_mcu
-        - For testing without an actual MCU, publish ViCAN messages here as if they came from an MCU
+        - For testing without an actual MCU, publish VicCAN messages here as if they came from an MCU
     * /anchor/to_vic/relay
         - Core, Arm, and Bio publish VicCAN messages to this topic to send to the MCU
     * /anchor/to_vic/relay_string
@@ -154,7 +151,7 @@ class Anchor(Node):
         )
         # Debug publisher
         self.tovic_debug_pub_ = self.create_publisher(
-            VicCAN,
+            String,
             "/anchor/to_vic/debug",
             20,
         )
@@ -173,7 +170,7 @@ class Anchor(Node):
             20,
         )
         self.mock_mcu_sub_ = self.create_subscription(
-            String,
+            VicCAN,
             "/anchor/from_vic/mock_mcu",
             self.relay_fromvic,
             20,
@@ -181,15 +178,17 @@ class Anchor(Node):
         self.tovic_string_sub_ = self.create_subscription(
             String,
             "/anchor/to_vic/relay_string",
-            self.connector.write_raw,
+            self.write_connector_raw,
             20,
         )
 
-        # Close devices on exit
+        # poll at 100Hz for incoming data
-        atexit.register(self.cleanup)
+        self.read_timer_ = self.create_timer(0.01, self.read_connector)
 
-    def cleanup(self):
+    def destroy_node(self):
+        self.get_logger().info("closing connector")
         self.connector.cleanup()
+        super().destroy_node()
 
     def read_connector(self):
         """Check the connector for new data from the MCU, and publish string to appropriate topics"""
@@ -204,6 +203,11 @@ class Anchor(Node):
     def write_connector(self, msg: VicCAN):
         """Write to the connector and send a copy to /anchor/to_vic/debug"""
         self.connector.write(msg)
+        self.tovic_debug_pub_.publish(String(data=viccan_to_string(msg)))
+
+    def write_connector_raw(self, msg: String):
+        """Write raw string to the connector and send a copy to /anchor/to_vic/debug"""
+        self.connector.write_raw(msg)
         self.tovic_debug_pub_.publish(msg)
 
     @deprecated(
@@ -226,25 +230,26 @@ class Anchor(Node):
         """Relay a message from the MCU to the appropriate VicCAN topic"""
         if msg.mcu_name == "core":
             self.fromvic_core_pub_.publish(msg)
-        elif msg.mcu_name == "arm" or msg.mcu_name == "digit":
+        if msg.mcu_name == "arm" or msg.mcu_name == "digit":
             self.fromvic_arm_pub_.publish(msg)
-        elif msg.mcu_name == "citadel" or msg.mcu_name == "digit":
+        if msg.mcu_name == "citadel" or msg.mcu_name == "digit":
             self.fromvic_bio_pub_.publish(msg)
 
 
 def main(args=None):
-    try:
     rclpy.init(args=args)
     anchor_node = Anchor()
+    executor = SingleThreadedExecutor()
+    executor.add_node(anchor_node)
 
-        thread = threading.Thread(target=rclpy.spin, args=(anchor_node,), daemon=True)
+    try:
-        thread.start()
+        executor.spin()
-
-        rate = anchor_node.create_rate(100)  # 100 Hz -- arbitrary rate
-        while rclpy.ok():
-            anchor_node.read_connector()  # Check the connector for updates
-            rate.sleep()
     except (KeyboardInterrupt, ExternalShutdownException):
-        print("Caught shutdown signal, shutting down...")
+        pass
     finally:
+        # don't accept any more jobs
+        executor.shutdown()
+        # make the node quit processing things
+        anchor_node.destroy_node()
+        # shut down everything else
         rclpy.try_shutdown()

src/anchor_pkg/anchor_pkg/connector.py

@@ -1,5 +1,8 @@
 from abc import ABC, abstractmethod
+from time import monotonic
+from typing import TYPE_CHECKING
 from astra_msgs.msg import VicCAN
+from std_msgs.msg import String
 from rclpy.clock import Clock
 from rclpy.impl.rcutils_logger import RcutilsLogger
 from .convert import string_to_viccan as _string_to_viccan, viccan_to_string
@@ -19,8 +22,11 @@ KNOWN_USBS = [
     (0x10C4, 0xEA60),  # DOIT ESP32 Devkit V1
     (0x1A86, 0x55D3),  # ESP32 S3 Development Board
 ]
+
 BAUD_RATE = 115200
 
+SERIAL_READ_TIMEOUT = 0.5  # seconds
+
 MCU_IDS = [
     "broadcast",
     "core",
@@ -77,7 +83,7 @@ class Connector(ABC):
         pass
 
     @abstractmethod
-    def write_raw(self, msg: str):
+    def write_raw(self, msg: String):
         pass
 
     def cleanup(self):
@@ -95,6 +101,10 @@ class SerialConnector(Connector):
         ports = self._find_ports()
         mcu_name: str | None = None
 
+        # Serial buffering
+        self._serial_buffer: bytes = b""
+        self._last_read_time = monotonic()
+
         if serial_override:
             logger.warn(
                 f"using serial_override: `{serial_override}`! this will bypass several checks."
@@ -122,7 +132,7 @@ class SerialConnector(Connector):
         self.mcu_name = mcu_name
 
         # if we fail at this point, it should crash because we've already tested the port
-        self.serial_interface = serial.Serial(self.port, BAUD_RATE, timeout=1)
+        self.serial_interface = serial.Serial(self.port, BAUD_RATE, timeout=0)
 
     def _find_ports(self) -> list[str]:
         """
@@ -181,9 +191,66 @@ class SerialConnector(Connector):
 
         return None
 
+    def _try_readline(self) -> str | None:
+        """Attempts to read a full string from the MCU without blocking.
+
+        When pyserial is used with 'timeout=0', reads are performed non-blocking.
+        When used with interface.readline(), this breaks the assumption that a returned
+        string will be a completed attempt by the MCU to send a string; it may be
+        cut off between the start of the string and the newline, removing information
+        and rendering the string(s) useless; thus, to get around the downside of readline()
+        not waiting for a newline while still not blocking, this function manually
+        implements a serial input buffer and newline timeout.
+
+        If readline() returns a non-empty string, send it if it ends with a newline
+        (readline() will not read past any newline); otherwise, save the read string.
+        This buffered string should be pre-pended to the next readline() result.
+
+        If readline() does not receive a non-empty string after the last non-newline-
+        terminated readline() result within the manual timeout, send the contents of the
+        buffer as if it ended with a newline, and clear the buffer.
+
+        Returns:
+            str: A hopefully-complete string read from the MCU via the serial interface.
+        """
+        if TYPE_CHECKING:
+            assert type(self.serial_interface) == serial.Serial
+
+        # Warn on buffer timeout, as the only scenarios that would trigger this are
+        # a microcontroller output that isn't newline-terminated (bad), or the MCU is
+        # hanging (also bad).
+        if (
+            self._serial_buffer
+            and (monotonic() - self._last_read_time) > SERIAL_READ_TIMEOUT
+        ):
+            self.logger.warn(
+                f"Serial buffer timeout, last received '{self._serial_buffer}'."
+            )
+            result = self._serial_buffer
+            self._serial_buffer = b""
+            self._last_read_time = monotonic()
+            return str(result, "utf8").strip()
+
+        # No try-except here so caller catches it instead.
+        raw = self.serial_interface.readline()
+
+        # Empty or whitespace-only string
+        if not raw or not raw.strip():
+            return None
+
+        # Add to buffer or send finished buffer
+        if not (raw.endswith(b"\n") or raw.endswith(b"\r")):  # unfinished string
+            self._serial_buffer += raw
+            self._last_read_time = monotonic()
+            return None
+        else:
+            result = self._serial_buffer + raw
+            self._serial_buffer = b""
+            return str(result, "utf8").strip()
+
     def read(self) -> tuple[VicCAN | None, str | None]:
         try:
-            raw = str(self.serial_interface.readline(), "utf8")
+            raw = self._try_readline()
 
             if not raw:
                 return (None, None)
@@ -199,10 +266,10 @@ class SerialConnector(Connector):
             return (None, None)  # pretty much no other error matters
 
     def write(self, msg: VicCAN):
-        self.write_raw(viccan_to_string(msg))
+        self.write_raw(String(data=viccan_to_string(msg)))
 
-    def write_raw(self, msg: str):
+    def write_raw(self, msg: String):
-        self.serial_interface.write(bytes(msg, "utf8"))
+        self.serial_interface.write(bytes(msg.data, "utf8"))
 
     def cleanup(self):
         self.logger.info(f"closing serial port if open {self.port}")
@@ -411,8 +478,10 @@ class CANConnector(Connector):
             self.logger.error(f"CAN error while sending: {e}")
             raise DeviceClosedException("CAN bus closed unexpectedly")
 
-    def write_raw(self, msg: str):
+    def write_raw(self, msg: String):
-        self.logger.warn(f"write_raw is not supported for CANConnector. msg: {msg}")
+        self.logger.warn(
+            f"write_raw is not supported for CANConnector. msg: {msg.data}"
+        )
 
     def cleanup(self):
         try:
@@ -434,5 +503,5 @@ class MockConnector(Connector):
     def write(self, msg: VicCAN):
         pass
 
-    def write_raw(self, msg: str):
+    def write_raw(self, msg: String):
         pass

treefmt.nix

@@ -1,8 +1,9 @@
-{ pkgs, ... }:
+{ ... }:
 {
   projectRootFile = "flake.nix";
   programs = {
     nixfmt.enable = true;
     black.enable = true;
+    shfmt.enable = true;
   };
 }