[AUX-N]: Add preferred assignments functionality by GwnDaan · Pull Request #655 · Open-Agriculture/AgIsoStack-plus-plus

GwnDaan · 2026-01-01T13:30:46Z

This PR adds the functionality for auxiliary assignments to work. One needs to register a store and load callback in the application to make the assignments persistent.

Copilot

Pull request overview

This PR adds preferred auxiliary function assignment functionality to the Virtual Terminal Client, enabling applications to persist auxiliary input device assignments through user-provided callback functions. The implementation follows ISO 11783 specifications with proper state machine handling, timeout/retry logic, and device lifetime management.

Introduced state machine states for sending and waiting for auxiliary preferred assignment responses with retry logic (up to 3 attempts)
Added callback mechanism for loading and storing auxiliary function assignments, allowing applications to implement persistent storage
Implemented device timeout monitoring (300ms per ISO 11783-6) with automatic cleanup of offline devices

Reviewed changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated 10 comments.

File	Description
isobus/include/isobus/isobus/isobus_virtual_terminal_client.hpp	Added new state machine states, callback typedefs, timeout constants, retry counter, and modified struct to support timestamp tracking; corrected typo in documentation
isobus/src/isobus_virtual_terminal_client.cpp	Implemented callback setter, state machine logic for preferred assignments with retry/timeout handling, device timeout monitoring, assignment message construction with serialization, and storage callback invocations
examples/virtual_terminal/aux_functions/main.cpp	Added example implementation of load/store callbacks using in-memory map storage, and enabled Debug logging to demonstrate the new functionality
.gitignore	Added exclusion for `.claude` directory

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isobus/src/isobus_virtual_terminal_client.cpp

Copilot · 2026-01-01T13:34:59Z

isobus/src/isobus_virtual_terminal_client.cpp

+		std::vector<std::uint8_t> buffer = {
+			static_cast<std::uint8_t>(Function::PreferredAssignmentCommand)
+		};
+
+		/// @todo make the load operation asynchronous
+		// Load stored assignments into pending storage if callback is registered
+		if (nullptr != auxiliaryAssignmentLoadCallback)
+		{
+			buffer.push_back(static_cast<std::uint8_t>(devices.size()));
+			for (const AssignedAuxiliaryInputDevice &device : devices)
+			{
+				buffer.push_back(static_cast<std::uint8_t>(device.name));
+				buffer.push_back(static_cast<std::uint8_t>(device.name >> 8));
+				buffer.push_back(static_cast<std::uint8_t>(device.name >> 16));
+				buffer.push_back(static_cast<std::uint8_t>(device.name >> 24));
+				buffer.push_back(static_cast<std::uint8_t>(device.name >> 32));
+				buffer.push_back(static_cast<std::uint8_t>(device.name >> 40));
+				buffer.push_back(static_cast<std::uint8_t>(device.name >> 48));
+				buffer.push_back(static_cast<std::uint8_t>(device.name >> 56));
+				buffer.push_back(static_cast<std::uint8_t>(device.modelIdentificationCode));
+				buffer.push_back(static_cast<std::uint8_t>(device.modelIdentificationCode >> 8));
+
+				auto loadedAssignments = auxiliaryAssignmentLoadCallback(device.name, device.modelIdentificationCode, auxiliaryAssignmentCallbackContext);
+				LOG_DEBUG("[AUX-N]: Loaded " + isobus::to_string(loadedAssignments.size()) + " stored assignments for device, awaiting VT confirmation.");
+
+				buffer.push_back(static_cast<std::uint8_t>(loadedAssignments.size()));
+				for (const AssignedAuxiliaryFunction &function : loadedAssignments)
+				{
+					buffer.push_back(static_cast<std::uint8_t>(function.functionObjectID));
+					buffer.push_back(static_cast<std::uint8_t>(function.functionObjectID >> 8));
+					buffer.push_back(static_cast<std::uint8_t>(function.inputObjectID));
+					buffer.push_back(static_cast<std::uint8_t>(function.inputObjectID >> 8));
+				}
+			}


The buffer is constructed with repeated push_back operations for serialization. For better performance, consider pre-calculating the required buffer size and using reserve() before the loop, or using a more efficient serialization method. The current approach may cause multiple reallocations as the buffer grows, especially when there are many devices and assignments.

Copilot · 2026-01-01T13:34:59Z

isobus/src/isobus_virtual_terminal_client.cpp

+		else
+		{
+			buffer.push_back(0);
+			LOG_WARNING("[AUX-N] Sending preferred assignemnts, but no auxiliary assignment load callback registered.");


Spelling error: "assignemnts" should be "assignments"

Suggested change

LOG_WARNING("[AUX-N] Sending preferred assignemnts, but no auxiliary assignment load callback registered.");

LOG_WARNING("[AUX-N] Sending preferred assignments, but no auxiliary assignment load callback registered.");

Copilot · 2026-01-01T13:34:59Z

isobus/src/isobus_virtual_terminal_client.cpp

 										{
 											hasError = true;
-											LOG_WARNING("[AUX-N]: Unable to store preferred assignment due to unsupported function type: " + isobus::to_string(functionType));
+											LOG_WARNING("[AUX-N]: Unable to to handle assignment due to unsupported function type: " + isobus::to_string(functionType));


Spelling error: "to to handle" should be "to handle" (duplicate "to")

Suggested change

LOG_WARNING("[AUX-N]: Unable to to handle assignment due to unsupported function type: " + isobus::to_string(functionType));

LOG_WARNING("[AUX-N]: Unable to handle assignment due to unsupported function type: " + isobus::to_string(functionType));

Copilot · 2026-01-01T13:34:59Z

examples/virtual_terminal/aux_functions/main.cpp


 	isobus::CANStackLogger::set_can_stack_logger_sink(&logger);
-	isobus::CANStackLogger::set_log_level(isobus::CANStackLogger::LoggingLevel::Info); // Change this to Debug to see more information
+	isobus::CANStackLogger::set_log_level(isobus::CANStackLogger::LoggingLevel::Debug); // Change this to Debug to see more information


The log level has been changed from Info to Debug. While this may be helpful for development and testing of the new auxiliary assignment functionality, consider whether this should remain in the example code permanently, as it will generate significantly more log output for users. A comment explaining why Debug level is recommended for this example would be helpful.

Suggested change

isobus::CANStackLogger::set_log_level(isobus::CANStackLogger::LoggingLevel::Debug); // Change this to Debug to see more information

// Use Debug level here so this example shows detailed VT and auxiliary assignment activity.

// This will generate significantly more log output; for production use, consider using Info instead.

isobus::CANStackLogger::set_log_level(isobus::CANStackLogger::LoggingLevel::Debug);

isobus/src/isobus_virtual_terminal_client.cpp

Copilot · 2026-01-01T13:35:00Z

isobus/src/isobus_virtual_terminal_client.cpp

+							LOG_WARNING("[AUX-N]: Preferred Assignment OK response timeout (attempt " +
+							            isobus::to_string(static_cast<int>(auxiliaryAssignmentRetryCount)) +
+							            "/3). Retrying...");


The log message is potentially confusing. The retry count is incremented before logging (line 1707), so when it shows "attempt 1/3", this is actually the 2nd send attempt (1st retry). Consider adjusting the log message to clarify this is a retry count, not an attempt count. For example: "Retrying (retry 1/2)" or incrementing after the log to show "attempt 2/3".

Suggested change

LOG_WARNING("[AUX-N]: Preferred Assignment OK response timeout (attempt " +

isobus::to_string(static_cast<int>(auxiliaryAssignmentRetryCount)) +

"/3). Retrying...");

LOG_WARNING("[AUX-N]: Preferred Assignment OK response timeout (retry " +

isobus::to_string(static_cast<int>(auxiliaryAssignmentRetryCount)) +

"/2). Retrying...");

Copilot · 2026-01-01T13:35:00Z

isobus/src/isobus_virtual_terminal_client.cpp

+									{
+										parentVT->auxiliaryAssignmentRetryCount++;
+										LOG_WARNING("[AUX-N]: Retrying preferred assignment (attempt " +
+										            isobus::to_string(static_cast<int>(parentVT->auxiliaryAssignmentRetryCount)) + "/3)...");


The log message shows "attempt X/3" but this could be inconsistent with line 1708-1710. Here the retry count is incremented first (line 2732) before logging, so the attempt number shown may be confusing to users. Consider using consistent messaging across both locations.

Suggested change

isobus::to_string(static_cast<int>(parentVT->auxiliaryAssignmentRetryCount)) + "/3)...");

isobus::to_string(static_cast<int>(parentVT->auxiliaryAssignmentRetryCount + 1U)) + "/3)...");

Copilot · 2026-01-01T13:35:00Z

isobus/src/isobus_virtual_terminal_client.cpp

+									if (parentVT->get_is_connected())
+									{
+										// Send preferred assignments to VT for confirmation
+										if (parentVT->send_auxiliary_functions_preferred_assignment({ inputDevice }))
+										{
+											LOG_DEBUG("[AUX-N]: Successfully sent preferred assignments for new device.");
+										}
+										else
+										{
+											LOG_WARNING("[AUX-N]: Failed to send preferred assignments for new device.");
+										}
+									}


When a new auxiliary input device is detected and the VT is already connected, preferred assignments are sent immediately (line 3341) without going through the state machine. This bypasses the retry logic and timeout handling that exists in the SendAuxiliaryPreferredAssignment and WaitForPreferredAssignmentResponse states. Consider whether this needs retry logic or if the direct send is intentional for this specific case.

Copilot · 2026-01-01T13:35:01Z

isobus/include/isobus/isobus/isobus_virtual_terminal_client.hpp

+			std::uint64_t name; ///< The NAME of the unit
+			std::uint16_t modelIdentificationCode; ///< The model identification code


The const qualifiers were removed from the name and modelIdentificationCode fields. While this change is necessary to support the timestamp updates (line 3354), consider whether these fields should still be conceptually immutable. If a device's NAME or model ID should never change after creation, consider alternative designs such as using the timestamp field as mutable while keeping these fields const, or using a key-based lookup structure.

sonarqubecloud · 2026-01-01T13:38:50Z

Quality Gate passed

Issues
13 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
5.5% Duplication on New Code

See analysis details on SonarQube Cloud

GwnDaan added 2 commits December 31, 2025 18:07

feat(aux-n): add load/store for preferred assignments

ab73394

feat(aux-n): add retry mechanism for sending preferred assignments

6223fc0

GwnDaan requested a review from Copilot January 1, 2026 13:30

Copilot started reviewing on behalf of GwnDaan January 1, 2026 13:31 View session

Copilot AI reviewed Jan 1, 2026

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[AUX-N]: Add preferred assignments functionality#655

[AUX-N]: Add preferred assignments functionality#655
GwnDaan wants to merge 2 commits intomainfrom
daan/aux-n-persistent-preferred-assignments

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	LOG_WARNING("[AUX-N] Sending preferred assignemnts, but no auxiliary assignment load callback registered.");
	LOG_WARNING("[AUX-N] Sending preferred assignments, but no auxiliary assignment load callback registered.");

	LOG_WARNING("[AUX-N]: Unable to to handle assignment due to unsupported function type: " + isobus::to_string(functionType));
	LOG_WARNING("[AUX-N]: Unable to handle assignment due to unsupported function type: " + isobus::to_string(functionType));

	isobus::to_string(static_cast<int>(parentVT->auxiliaryAssignmentRetryCount)) + "/3)...");
	isobus::to_string(static_cast<int>(parentVT->auxiliaryAssignmentRetryCount + 1U)) + "/3)...");

		std::uint64_t name; ///< The NAME of the unit
		std::uint16_t modelIdentificationCode; ///< The model identification code

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sonarqubecloud bot commented Jan 1, 2026

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