Fix AttributeError in health_reporter from dict iteration and missing Connection attributes

[Copilot]

The health reporter crashed with AttributeError: 'str' object has no attribute 'port_id' when collecting service metrics because it iterated over dict keys instead of values, and the Connection dataclass was missing bytes_read/bytes_written attributes.

Changes

• Added byte counters to Connection dataclass (serial_manager.py)

  • Added bytes_read and bytes_written fields (default 0)
  • Incremented counters in _read_continuously(), read_from_port(), and write_to_port()

• Fixed dict iteration

  • Changed for conn in active_connections → for conn in active_connections.values() in health_reporter.py and api/connections.py
  • get_active_connections() returns Dict[str, Connection]; iterating directly loops over keys (strings), not Connection objects

• Added tests (test_connection_bytes_tracking.py)

  • Verifies Connection has byte tracking attributes
  • Validates health reporter handles dict of connections correctly

Example

Before:

for conn in active_connections:  # conn is a string (port_id)
    print(conn.port_id)  # AttributeError: 'str' object has no attribute 'port_id'

After:

for conn in active_connections.values():  # conn is a Connection object
    print(conn.port_id)  # Works correctly
    print(conn.bytes_read)  # Now tracked

Original prompt

{"timestamp": "2026-01-05T17:32:15.680384+00:00", "level": "ERROR", "module": "src.health_reporter", "event": null, "message": "Error collecting service metrics: 'str' object has no attribute 'port_id'", "exc_info": "Traceback (most recent call last):\n File "/home/hyperloop/rpi-hub-server/src/health_reporter.py", line 219, in _collect_service_metrics\n "port_id": conn.port_id,\n ^^^^^^^^^^^^\nAttributeError: 'str' object has no attribute 'port_id'", "taskName": "Task-11"}

Created from VS Code.

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