Rework to switch to using KUKSA.val databroker

Rework to use the "VAL" gRPC API from the KUKSA.val databroker
instead of the older server's WebSocket interface.  Some source
files have been renamed to match the class naming to provide
a bit more consistency.

Bug-AGL: SPEC-4762

Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Change-Id: Ib1ec31af439a9b2d5244e2232ea7be1ed9a2574c

17 files changed, 939 insertions, 720 deletions

diff --git a/src/hvac-can-helper.cpp b/src/HvacCanHelper.cpp
index 634f4b0..0c0f937 100644
--- a/src/hvac-can-helper.cpp
+++ b/src/HvacCanHelper.cpp
@@ -1,6 +1,10 @@
-// SPDX-License-Identifier: Apache-2.0
+/*
+ * Copyright (C) 2022,2023 Konsulko Group
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
-#include "hvac-can-helper.hpp"
+#include "HvacCanHelper.h"
 #include <iostream>
 #include <iomanip>
 #include <sstream>
diff --git a/src/hvac-can-helper.hpp b/src/HvacCanHelper.h
index 4175e6b..0787834 100644
--- a/src/hvac-can-helper.hpp
+++ b/src/HvacCanHelper.h
@@ -1,7 +1,11 @@
-// SPDX-License-Identifier: Apache-2.0
+/*
+ * Copyright (C) 2022,2023 Konsulko Group
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
-#ifndef _HVAC_CAN_HELPER_HPP
-#define _HVAC_CAN_HELPER_HPP
+#ifndef _HVAC_CAN_HELPER_H
+#define _HVAC_CAN_HELPER_H
 
 #include <cstdint>
 #include <string>
@@ -51,4 +55,4 @@ private:
 	uint8_t m_fan_speed;
 };
 
-#endif // _HVAC_CAN_HELPER_HPP
+#endif // _HVAC_CAN_HELPER_H
diff --git a/src/hvac-led-helper.cpp b/src/HvacLedHelper.cpp
index 3c86c81..54d4b2f 100644
--- a/src/hvac-led-helper.cpp
+++ b/src/HvacLedHelper.cpp
@@ -1,6 +1,10 @@
-// SPDX-License-Identifier: Apache-2.0
+/*
+ * Copyright (C) 2022,2023 Konsulko Group
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
-#include "hvac-led-helper.hpp"
+#include "HvacLedHelper.h"
 #include <iostream>
 #include <iomanip>
 #include <sstream>
diff --git a/src/hvac-led-helper.hpp b/src/HvacLedHelper.h
index 6f73aac..be94393 100644
--- a/src/hvac-led-helper.hpp
+++ b/src/HvacLedHelper.h
@@ -1,7 +1,11 @@
-// SPDX-License-Identifier: Apache-2.0
+/*
+ * Copyright (C) 2022,2023 Konsulko Group
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
-#ifndef _HVAC_LED_HELPER_HPP
-#define _HVAC_LED_HELPER_HPP
+#ifndef _HVAC_LED_HELPER_H
+#define _HVAC_LED_HELPER_H
 
 #include <cstdint>
 #include <string>
@@ -32,4 +36,4 @@ private:
 	uint8_t m_temp_right;
 };
 
-#endif // _HVAC_LED_HELPER_HPP
+#endif // _HVAC_LED_HELPER_H
diff --git a/src/HvacService.cpp b/src/HvacService.cpp
new file mode 100644
index 0000000..b53c5d8
--- /dev/null
+++ b/src/HvacService.cpp
@@ -0,0 +1,223 @@
+/*
+ * Copyright (C) 2022,2023 Konsulko Group
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "HvacService.h"
+#include <string>
+#include <sstream>
+#include <iostream>
+#include <algorithm>
+
+
+HvacService::HvacService(const KuksaConfig &config, GMainLoop *loop) :
+	m_loop(loop),
+	m_config(config),
+	m_can_helper(),
+	m_led_helper()
+{
+	// Create gRPC channel
+	std::string host = m_config.hostname();
+	host += ":";
+	std::stringstream ss;
+	ss << m_config.port();
+	host += ss.str();
+
+	std::shared_ptr<grpc::Channel> channel;
+	if (!m_config.caCert().empty()) {
+		grpc::SslCredentialsOptions options;
+		options.pem_root_certs = m_config.caCert();
+		if (!m_config.tlsServerName().empty()) {
+			grpc::ChannelArguments args;
+			auto target = m_config.tlsServerName();
+			std::cout << "Overriding TLS target name with " << target << std::endl;
+			args.SetString(GRPC_SSL_TARGET_NAME_OVERRIDE_ARG, target);
+			channel = grpc::CreateCustomChannel(host, grpc::SslCredentials(options), args);
+		} else {
+			channel = grpc::CreateChannel(host, grpc::SslCredentials(options));
+		}
+	} else {
+		channel = grpc::CreateChannel(host, grpc::InsecureChannelCredentials());
+	}
+
+	// Wait for the channel to be ready
+	std::cout << "Waiting for Databroker gRPC channel" << std::endl;
+	while (!channel->WaitForConnected(std::chrono::system_clock::now() +
+					  std::chrono::milliseconds(500))) ;
+	std::cout << "Databroker gRPC channel ready" << std::endl;
+
+	m_broker = new KuksaClient(channel, m_config);
+	if (m_broker) {
+		// Listen to actuator target updates
+		std::map<std::string, bool> signals;
+		signals["Vehicle.Cabin.HVAC.Station.Row1.Left.Temperature"] = true;
+		signals["Vehicle.Cabin.HVAC.Station.Row1.Left.FanSpeed"] = true;
+		signals["Vehicle.Cabin.HVAC.Station.Row1.Right.Temperature"] = true;
+		signals["Vehicle.Cabin.HVAC.Station.Row1.Right.FanSpeed"] = true;
+		m_broker->subscribe(signals,
+				    [this](const std::string &path, const Datapoint &dp) {
+					    HandleSignalChange(path, dp);
+				    },
+				    [this](const SubscribeRequest *request, const Status &s) {
+					    HandleSubscribeDone(request, s);
+				    });
+	}
+}
+
+HvacService::~HvacService()
+{
+	delete m_broker;
+}
+
+// Private
+
+void HvacService::HandleSignalChange(const std::string &path, const Datapoint &dp)
+{
+	if (m_config.verbose() > 1)
+		std::cout << "HvacService::HandleSignalChange: Value received for " << path << std::endl;
+
+	if (path == "Vehicle.Cabin.HVAC.Station.Row1.Left.Temperature") {
+		if (dp.has_int32()) {
+			int temp = dp.int32();
+			if (temp >= 0 && temp < 256)
+				set_left_temperature(temp);
+		}
+	} else if (path == "Vehicle.Cabin.HVAC.Station.Row1.Right.Temperature") {
+		if (dp.has_int32()) {
+			int temp = dp.int32();
+			if (temp >= 0 && temp < 256)
+				set_right_temperature(temp);
+		}
+	} else if (path == "Vehicle.Cabin.HVAC.Station.Row1.Left.FanSpeed") {
+		if (dp.has_uint32()) {
+			int speed = dp.uint32();
+			if (speed >= 0 && speed <= 100)
+				set_left_fan_speed(speed);
+		}
+	} else if (path == "Vehicle.Cabin.HVAC.Station.Row1.Right.FanSpeed") {
+		if (dp.has_uint32()) {
+			int speed = dp.uint32();
+			if (speed >= 0 && speed <= 100)
+				set_right_fan_speed(speed);
+		}
+	}
+	// else ignore
+}
+
+void HvacService::HandleSignalSetError(const std::string &path, const Error &error)
+{
+	std::cerr << "Error setting " << path << ": " << error.code() << " - " << error.reason() << std::endl;
+}
+
+void HvacService::HandleSubscribeDone(const SubscribeRequest *request, const Status &status)
+{
+	if (m_config.verbose())
+		std::cout << "Subscribe status = " << status.error_code() <<
+			" (" << status.error_message() << ")" << std::endl;
+
+	if (status.error_code() == grpc::CANCELLED) {
+		if (m_config.verbose())
+			std::cerr << "Subscribe canceled, assuming shutdown" << std::endl;
+		return;
+	}
+
+	// Queue up a resubcribe via the GLib event loop callback
+	struct resubscribe_data *data = new (struct resubscribe_data);
+	if (!data) {
+		std::cerr << "Could not create resubcribe_data" << std::endl;
+		exit(1);
+	}
+	data->self = this;
+	// Need to copy request since the one we have been handed is from the
+	// finished subscribe and will be going away.
+	data->request = new SubscribeRequest(*request);
+	if (!data->request) {
+		std::cerr << "Could not create resubscribe SubscribeRequest" << std::endl;
+		exit(1);
+	}
+
+	// NOTE: Waiting 100 milliseconds for now; it is possible that some
+	//       randomization and/or back-off may need to be added if many
+	//       subscribes are active, or switching to some other resubscribe
+	//       scheme altogether (e.g. post subscribes to a thread that waits
+	//       for the channel to become connected again).
+	g_timeout_add_full(G_PRIORITY_DEFAULT,
+			   100,
+			   resubscribe_cb,
+			   data,
+			   NULL);
+}
+
+void HvacService::Resubscribe(const SubscribeRequest *request)
+{
+	if (!(m_broker && request))
+		return;
+
+	m_broker->subscribe(request,
+			    [this](const std::string &path, const Datapoint &dp) {
+				    HandleSignalChange(path, dp);
+			    },
+			    [this](const SubscribeRequest *request, const Status &s) {
+				    HandleSubscribeDone(request, s);
+			    });
+}
+
+// NOTE: The following should perhaps be scheduling work via the GLib
+//       main loop to avoid potentially blocking threads from the gRPC
+//       pool.
+
+void HvacService::set_left_temperature(uint8_t temp)
+{
+	m_can_helper.set_left_temperature(temp);
+	m_led_helper.set_left_temperature(temp);
+
+	// Push out new value
+	m_broker->set("Vehicle.Cabin.HVAC.Station.Row1.Left.Temperature",
+		      (int) temp,
+		      [this](const std::string &path, const Error &error) {
+			      HandleSignalSetError(path, error);
+		      });
+}
+
+void HvacService::set_right_temperature(uint8_t temp)
+{
+	m_can_helper.set_right_temperature(temp);
+	m_led_helper.set_right_temperature(temp);
+
+	// Push out new value
+	m_broker->set("Vehicle.Cabin.HVAC.Station.Row1.Right.Temperature",
+		      (int) temp,
+		      [this](const std::string &path, const Error &error) {
+			      HandleSignalSetError(path, error);
+		      });
+}
+
+void HvacService::set_left_fan_speed(uint8_t speed)
+{
+	set_fan_speed(speed);
+
+	// Push out new value
+	m_broker->set("Vehicle.Cabin.HVAC.Station.Row1.Left.FanSpeed",
+		      speed,
+		      [this](const std::string &path, const Error &error) {
+			      HandleSignalSetError(path, error);
+		      });
+}
+
+void HvacService::set_right_fan_speed(uint8_t speed)
+{
+	set_fan_speed(speed);
+
+	// Push out new value
+	m_broker->set("Vehicle.Cabin.HVAC.Station.Row1.Right.FanSpeed",
+		      speed,
+		      [this](const std::string &path, const Error &error) {
+			      HandleSignalSetError(path, error);
+		      });
+}
+
+void HvacService::set_fan_speed(uint8_t speed)
+{
+	m_can_helper.set_fan_speed(speed);
+}
diff --git a/src/HvacService.h b/src/HvacService.h
new file mode 100644
index 0000000..756f6f3
--- /dev/null
+++ b/src/HvacService.h
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2022,2023 Konsulko Group
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef _HVAC_SERVICE_H
+#define _HVAC_SERVICE_H
+
+#include <glib.h>
+
+#include "KuksaConfig.h"
+#include "KuksaClient.h"
+#include "HvacCanHelper.h"
+#include "HvacLedHelper.h"
+
+class HvacService
+{
+public:
+	HvacService(const KuksaConfig &config, GMainLoop *loop = NULL);
+
+	~HvacService();
+
+	// Callback for KuksaClient subscribe API reconnect
+
+	static gboolean resubscribe_cb(gpointer data) {
+		struct resubscribe_data *d = (struct resubscribe_data*) data;
+		if (d && d->self) {
+			((HvacService*) d->self)->Resubscribe(d->request);
+		}
+		return FALSE;
+	}
+
+private:
+	struct resubscribe_data {
+		HvacService *self;
+		const SubscribeRequest *request;
+	};
+
+	GMainLoop *m_loop;
+	KuksaConfig m_config;
+	KuksaClient *m_broker;
+	HvacCanHelper m_can_helper;
+	HvacLedHelper m_led_helper;
+
+	void HandleSignalChange(const std::string &path, const Datapoint &dp);
+
+	void HandleSignalSetError(const std::string &path, const Error &error);
+
+	void HandleSubscribeDone(const SubscribeRequest *request, const Status &status);
+
+	void Resubscribe(const SubscribeRequest *request);
+
+	void set_left_temperature(uint8_t temp);
+
+	void set_right_temperature(uint8_t temp);
+
+	void set_left_fan_speed(uint8_t temp);
+
+	void set_right_fan_speed(uint8_t temp);
+
+	void set_fan_speed(uint8_t temp);
+};
+
+#endif // _HVAC_SERVICE_H
diff --git a/src/KuksaClient.cpp b/src/KuksaClient.cpp
new file mode 100644
index 0000000..844ce0e
--- /dev/null
+++ b/src/KuksaClient.cpp
@@ -0,0 +1,373 @@
+/*
+ * Copyright (C) 2023 Konsulko Group
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <string>
+#include <regex>
+#include <iterator>
+#include <mutex>
+
+#include "KuksaClient.h"
+
+using grpc::Channel;
+using grpc::ClientContext;
+using grpc::ClientReader;
+using grpc::Status;
+
+KuksaClient::KuksaClient(const std::shared_ptr< ::grpc::ChannelInterface>& channel, const KuksaConfig &config) :
+	m_config(config)
+{
+	m_stub = VAL::NewStub(channel);
+}
+
+void KuksaClient::get(const std::string &path, GetResponseCallback cb, const bool actuator)
+{
+	ClientContext *context = new ClientContext();
+	if (!context) {
+		handleCriticalFailure("Could not create ClientContext");
+		return;
+	}
+	std::string token = m_config.authToken();
+	if (!token.empty()) {
+		token.insert(0, std::string("Bearer "));
+		context->AddMetadata(std::string("authorization"), token);
+	}
+
+	GetRequest request;
+	auto entry = request.add_entries();
+	entry->set_path(path);
+	entry->add_fields(Field::FIELD_PATH);	
+	if (actuator)
+		entry->add_fields(Field::FIELD_ACTUATOR_TARGET);
+	else
+		entry->add_fields(Field::FIELD_VALUE);
+
+	GetResponse *response = new GetResponse();
+	if (!response) {
+		handleCriticalFailure("Could not create GetResponse");
+		return;
+	}
+
+	// NOTE: Using ClientUnaryReactor instead of the shortcut method
+	//       would allow getting detailed errors.
+	m_stub->async()->Get(context, &request, response,
+			     [this, cb, context, response](Status s) {
+				     if (s.ok())
+					     handleGetResponse(response, cb);
+				     delete response;
+				     delete context;
+			     });
+}
+
+// Since a set request needs a Datapoint with the appropriate type value,
+// checking the signal metadata to get the type would be a requirement for
+// a generic set call that takes a string as argument.  For now, assume
+// that set with a string is specifically for a signal of string type.
+
+void KuksaClient::set(const std::string &path, const std::string &value, SetResponseCallback cb, const bool actuator)
+{
+	Datapoint dp;
+	dp.set_string(value);
+	set(path, dp, cb, actuator);
+}
+
+void KuksaClient::set(const std::string &path, const int8_t value, SetResponseCallback cb, const bool actuator)
+{
+	Datapoint dp;
+	dp.set_int32(value);
+	set(path, dp, cb, actuator);
+}
+
+void KuksaClient::set(const std::string &path, const int16_t value, SetResponseCallback cb, const bool actuator)
+{
+	Datapoint dp;
+	dp.set_int32(value);
+	set(path, dp, cb, actuator);
+}
+
+void KuksaClient::set(const std::string &path, const int32_t value, SetResponseCallback cb, const bool actuator)
+{
+	Datapoint dp;
+	dp.set_int32(value);
+	set(path, dp, cb, actuator);
+}
+
+void KuksaClient::set(const std::string &path, const int64_t value, SetResponseCallback cb, const bool actuator)
+{
+	Datapoint dp;
+	dp.set_int64(value);
+	set(path, dp, cb, actuator);
+}
+
+void KuksaClient::set(const std::string &path, const uint8_t value, SetResponseCallback cb, const bool actuator)
+{
+	Datapoint dp;
+	dp.set_uint32(value);
+	set(path, dp, cb, actuator);
+}
+
+void KuksaClient::set(const std::string &path, const uint16_t value, SetResponseCallback cb, const bool actuator)
+{
+	Datapoint dp;
+	dp.set_uint32(value);
+	set(path, dp, cb, actuator);
+}
+
+void KuksaClient::set(const std::string &path, const uint32_t value, SetResponseCallback cb, const bool actuator)
+{
+	Datapoint dp;
+	dp.set_uint32(value);
+	set(path, dp, cb, actuator);
+}
+
+void KuksaClient::set(const std::string &path, const uint64_t value, SetResponseCallback cb, const bool actuator)
+{
+	Datapoint dp;
+	dp.set_uint64(value);
+	set(path, dp, cb, actuator);
+}
+
+void KuksaClient::set(const std::string &path, const float value, SetResponseCallback cb, const bool actuator)
+{
+	Datapoint dp;
+	dp.set_float_(value);
+	set(path, dp, cb, actuator);
+}
+
+void KuksaClient::set(const std::string &path, const double value, SetResponseCallback cb, const bool actuator)
+{
+	Datapoint dp;
+	dp.set_double_(value);
+	set(path, dp, cb, actuator);
+}
+
+void KuksaClient::subscribe(const std::string &path,
+			    SubscribeResponseCallback cb,
+			    const bool actuator,
+			    SubscribeDoneCallback done_cb)
+{
+	SubscribeRequest *request = new SubscribeRequest();
+	if (!request) {
+		handleCriticalFailure("Could not create SubscribeRequest");
+		return;
+	}
+
+	auto entry = request->add_entries();
+	entry->set_path(path);
+	entry->add_fields(Field::FIELD_PATH);	
+	if (actuator)
+		entry->add_fields(Field::FIELD_ACTUATOR_TARGET);
+	else
+		entry->add_fields(Field::FIELD_VALUE);
+
+	subscribe(request, cb, done_cb);
+}
+
+void KuksaClient::subscribe(const std::map<std::string, bool> signals,
+			    SubscribeResponseCallback cb,
+			    SubscribeDoneCallback done_cb)
+{
+	SubscribeRequest *request = new SubscribeRequest();
+	if (!request) {
+		handleCriticalFailure("Could not create SubscribeRequest");
+		return;
+	}
+
+	for(auto it = signals.cbegin(); it != signals.cend(); ++it) {
+		auto entry = request->add_entries();
+		entry->set_path(it->first);
+		entry->add_fields(Field::FIELD_PATH);	
+		if (it->second)
+			entry->add_fields(Field::FIELD_ACTUATOR_TARGET);
+		else
+			entry->add_fields(Field::FIELD_VALUE);
+	}
+
+	subscribe(request, cb, done_cb);
+}
+
+void KuksaClient::subscribe(const SubscribeRequest *request,
+			    SubscribeResponseCallback cb,
+			    SubscribeDoneCallback done_cb)
+{
+	if (!(request && cb))
+		return;
+
+	class Reader : public grpc::ClientReadReactor<SubscribeResponse> {
+	public:
+		Reader(VAL::Stub *stub,
+		       KuksaClient *client,
+		       KuksaConfig &config,
+		       const SubscribeRequest *request,
+		       SubscribeResponseCallback cb,
+		       SubscribeDoneCallback done_cb):
+			client_(client),
+			config_(config),
+			request_(request),
+			cb_(cb),
+			done_cb_(done_cb) {
+			std::string token = config_.authToken();
+			if (!token.empty()) {
+				token.insert(0, std::string("Bearer "));
+				context_.AddMetadata(std::string("authorization"), token);
+			}
+			stub->async()->Subscribe(&context_, request, this);
+			StartRead(&response_);
+			StartCall();
+		}
+		void OnReadDone(bool ok) override {
+			std::unique_lock<std::mutex> lock(mutex_);
+			if (ok) {
+				if (client_)
+					client_->handleSubscribeResponse(&response_, cb_);
+				StartRead(&response_);
+			}
+		}
+		void OnDone(const Status& s) override {
+			status_ = s;
+			if (client_) {
+				if (config_.verbose() > 1)
+					std::cerr << "KuksaClient::subscribe::Reader done" << std::endl;
+				client_->handleSubscribeDone(request_, status_, done_cb_);
+			}
+
+			// gRPC engine is done with us, safe to self-delete
+			delete request_;
+			delete this;
+		}
+
+	private:
+		KuksaClient *client_;
+		KuksaConfig config_;
+		const SubscribeRequest *request_;
+		SubscribeResponseCallback cb_;
+		SubscribeDoneCallback done_cb_;
+
+		ClientContext context_;
+		SubscribeResponse response_;
+		std::mutex mutex_;
+		Status status_;
+	};
+	Reader *reader = new Reader(m_stub.get(), this, m_config, request, cb, done_cb);
+	if (!reader)
+		handleCriticalFailure("Could not create Subscribe reader");
+}
+
+// Private
+
+void KuksaClient::set(const std::string &path, const Datapoint &dp, SetResponseCallback cb, const bool actuator)
+{
+	ClientContext *context = new ClientContext();
+	if (!context) {
+		handleCriticalFailure("Could not create ClientContext");
+		return;
+	}
+	std::string token = m_config.authToken();
+	if (!token.empty()) {
+		token.insert(0, std::string("Bearer "));
+		context->AddMetadata(std::string("authorization"), token);
+	}
+
+	SetRequest request;
+	auto update = request.add_updates();
+	auto entry = update->mutable_entry();
+	entry->set_path(path);
+	if (actuator) {
+		auto target = entry->mutable_actuator_target();
+		*target = dp;
+		update->add_fields(Field::FIELD_ACTUATOR_TARGET);
+	} else {
+		auto value = entry->mutable_value();
+		*value = dp;
+		update->add_fields(Field::FIELD_VALUE);		
+	}
+
+	SetResponse *response = new SetResponse();
+	if (!response) {
+		handleCriticalFailure("Could not create SetResponse");
+		delete context;
+		return;
+	}
+
+	// NOTE: Using ClientUnaryReactor instead of the shortcut method
+	//       would allow getting detailed errors.
+	m_stub->async()->Set(context, &request, response,
+				       [this, cb, context, response](Status s) {
+					       if (s.ok())
+						       handleSetResponse(response, cb);
+					       delete response;
+					       delete context;
+				       });
+}
+
+void KuksaClient::handleGetResponse(const GetResponse *response, GetResponseCallback cb)
+{
+	if (!(response && response->entries_size() && cb))
+		return;
+
+	for (auto it = response->entries().begin(); it != response->entries().end(); ++it) {
+		// We expect paths in the response entries
+		if (!it->path().size())
+			continue;
+
+		Datapoint dp;
+		if (it->has_actuator_target())
+			dp = it->actuator_target();
+		else
+			dp = it->value();
+		cb(it->path(), dp);
+	}
+}
+
+void KuksaClient::handleSetResponse(const SetResponse *response, SetResponseCallback cb)
+{
+	if (!(response && response->errors_size() && cb))
+		return;
+
+	for (auto it = response->errors().begin(); it != response->errors().end(); ++it) {
+		cb(it->path(), it->error());
+	}
+
+}
+
+void KuksaClient::handleSubscribeResponse(const SubscribeResponse *response, SubscribeResponseCallback cb)
+{
+	if (!(response && response->updates_size() && cb))
+		return;
+
+	for (auto it = response->updates().begin(); it != response->updates().end(); ++it) {
+		// We expect entries that have paths in the response
+		if (!(it->has_entry() && it->entry().path().size()))
+			continue;
+
+		auto entry = it->entry();
+		if (m_config.verbose())
+			std::cout << "KuksaClient::handleSubscribeResponse: got value for " << entry.path() << std::endl;
+
+		Datapoint dp;
+		if (entry.has_actuator_target())
+			dp = entry.actuator_target();
+		else
+			dp = entry.value();
+
+		cb(entry.path(), dp);
+	}
+}
+
+void KuksaClient::handleSubscribeDone(const SubscribeRequest *request,
+				      const Status &status,
+				      SubscribeDoneCallback cb)
+{
+	if (cb)
+		cb(request, status);
+}
+
+void KuksaClient::handleCriticalFailure(const std::string &error)
+{
+	if (error.size())
+		std::cerr << error << std::endl;
+	exit(1);
+}
+
diff --git a/src/KuksaClient.h b/src/KuksaClient.h
new file mode 100644
index 0000000..fd9a9e0
--- /dev/null
+++ b/src/KuksaClient.h
@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2023 Konsulko Group
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef KUKSA_CLIENT_H
+#define KUKSA_CLIENT_H
+
+#include <string>
+#include <map>
+#include <grpcpp/grpcpp.h>
+#include "kuksa/val/v1/val.grpc.pb.h"
+
+// Just pull in the whole namespace since Datapoint contains a lot of
+// definitions that may potentially be needed.
+using namespace kuksa::val::v1;
+
+using grpc::Status;
+
+#include "KuksaConfig.h"
+
+// API response callback types
+typedef std::function<void(const std::string &path, const Datapoint &dp)> GetResponseCallback;
+typedef std::function<void(const std::string &path, const Error &error)> SetResponseCallback;
+typedef std::function<void(const std::string &path, const Datapoint &dp)> SubscribeResponseCallback;
+typedef std::function<void(const SubscribeRequest *request, const Status &status)> SubscribeDoneCallback;
+
+// KUKSA.val databroker "VAL" gRPC API client class
+
+class KuksaClient
+{
+public:
+	explicit KuksaClient(const std::shared_ptr< ::grpc::ChannelInterface>& channel, const KuksaConfig &config);
+
+	void get(const std::string &path, GetResponseCallback cb, const bool actuator = false);
+
+	void set(const std::string &path, const std::string &value, SetResponseCallback cb, const bool actuator = false);
+	void set(const std::string &path, const int8_t value, SetResponseCallback cb, const bool actuator = false);
+	void set(const std::string &path, const int16_t value, SetResponseCallback cb, const bool actuator = false);
+	void set(const std::string &path, const int32_t value, SetResponseCallback cb, const bool actuator = false);
+	void set(const std::string &path, const int64_t value, SetResponseCallback cb, const bool actuator = false);
+	void set(const std::string &path, const uint8_t value, SetResponseCallback cb, const bool actuator = false);
+	void set(const std::string &path, const uint16_t value, SetResponseCallback cb, const bool actuator = false);
+	void set(const std::string &path, const uint32_t value, SetResponseCallback cb, const bool actuator = false);
+	void set(const std::string &path, const uint64_t value, SetResponseCallback cb, const bool actuator = false);
+	void set(const std::string &path, const float value, SetResponseCallback cb, const bool actuator = false);
+	void set(const std::string &path, const double value, SetResponseCallback cb, const bool actuator = false);
+
+	void subscribe(const std::string &path,
+		       SubscribeResponseCallback cb,
+		       const bool actuator = false,
+		       SubscribeDoneCallback done_cb = nullptr);
+	void subscribe(const std::map<std::string, bool> signals,
+		       SubscribeResponseCallback cb,
+		       SubscribeDoneCallback done_cb = nullptr);
+	void subscribe(const SubscribeRequest *request,
+		       SubscribeResponseCallback cb,
+		       SubscribeDoneCallback done_cb = nullptr);
+
+private:
+	KuksaConfig m_config;
+	std::shared_ptr<VAL::Stub> m_stub;
+
+	void set(const std::string &path, const Datapoint &dp, SetResponseCallback cb, const bool actuator);
+
+	void handleGetResponse(const GetResponse *response, GetResponseCallback cb);
+
+	void handleSetResponse(const SetResponse *response, SetResponseCallback cb);
+
+	void handleSubscribeResponse(const SubscribeResponse *response, SubscribeResponseCallback cb);
+
+	void handleSubscribeDone(const SubscribeRequest *request, const Status &status, SubscribeDoneCallback cb);
+
+	void handleCriticalFailure(const std::string &error);
+	void handleCriticalFailure(const char *error) { handleCriticalFailure(std::string(error)); };
+};
+
+#endif // KUKSA_CLIENT_H
diff --git a/src/vis-config.cpp b/src/KuksaConfig.cpp
index a55e235..8fe09f6 100644
--- a/src/vis-config.cpp
+++ b/src/KuksaConfig.cpp
@@ -1,18 +1,21 @@
-// SPDX-License-Identifier: Apache-2.0
+/*
+ * Copyright (C) 2022,2023 Konsulko Group
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
-#include "vis-config.hpp"
 #include <iostream>
 #include <iomanip>
 #include <sstream>
+#include <exception>
 #include <boost/property_tree/ptree.hpp>
 #include <boost/property_tree/ini_parser.hpp>
 #include <boost/filesystem.hpp>
+#include "KuksaConfig.h"
 
 namespace property_tree = boost::property_tree;
 namespace filesystem = boost::filesystem;
 
-#define DEFAULT_CLIENT_KEY_FILE  "/etc/kuksa-val/Client.key"
-#define DEFAULT_CLIENT_CERT_FILE "/etc/kuksa-val/Client.pem"
 #define DEFAULT_CA_CERT_FILE     "/etc/kuksa-val/CA.pem"
 
 inline
@@ -21,32 +24,32 @@ void load_string_file(const filesystem::path& p, std::string& str)
 	std::ifstream file;
 	file.exceptions(std::ifstream::failbit | std::ifstream::badbit);
 	file.open(p, std::ios_base::binary);
-	std::size_t sz = static_cast<std::size_t>(filesystem::file_size(p));
-	str.resize(sz, '\0');
-	file.read(&str[0], sz);
+	if (file.good()) {
+		std::size_t sz = static_cast<std::size_t>(filesystem::file_size(p));
+		str.resize(sz, '\0');
+		file.read(&str[0], sz);
+	} else {
+		str.clear();
+	}
 }
 
-VisConfig::VisConfig(const std::string &hostname,
-		     const unsigned port,
-		     const std::string &clientKey,
-		     const std::string &clientCert,
-		     const std::string &caCert,
-		     const std::string &authToken,
-		     bool verifyPeer) :
+KuksaConfig::KuksaConfig(const std::string &hostname,
+			 const unsigned port,
+			 const std::string &caCert,
+			 const std::string &tlsServerName,
+			 const std::string &authToken) :
 	m_hostname(hostname),
 	m_port(port),
-	m_clientKey(clientKey),
-	m_clientCert(clientCert),
 	m_caCert(caCert),
+	m_tlsServerName(tlsServerName),
 	m_authToken(authToken),
-	m_verifyPeer(verifyPeer),
 	m_verbose(0),
 	m_valid(true)
 {
 	// Potentially could do some certificate validation here...
 }
 
-VisConfig::VisConfig(const std::string &appname) :
+KuksaConfig::KuksaConfig(const std::string &appname) :
 	m_valid(false)
 {
 	std::string config("/etc/xdg/AGL/");
@@ -70,7 +73,7 @@ VisConfig::VisConfig(const std::string &appname) :
 		return;
 	}
 	const property_tree::ptree &settings =
-		pt.get_child("vis-client", property_tree::ptree());
+		pt.get_child("kuksa-client", property_tree::ptree());
 
 	m_hostname = settings.get("server", "localhost");
 	std::stringstream ss;
@@ -81,48 +84,12 @@ VisConfig::VisConfig(const std::string &appname) :
 		return;
 	}
 
-	m_port = settings.get("port", 8090);
+	m_port = settings.get("port", 55555);
 	if (m_port == 0) {
 		std::cerr << "Invalid server port" << std::endl;
 		return;
 	}
 
-	// Default to disabling peer verification for now to be able
-        // to use the default upstream KUKSA.val certificates for
-	// testing.  Wrangling server and CA certificate generation
-	// and management to be able to verify will require further
-	// investigation.
-	m_verifyPeer = settings.get("verify-server", false);
-
-	std::string keyFileName = settings.get("key", DEFAULT_CLIENT_KEY_FILE);
-	std::stringstream().swap(ss);
-	ss << keyFileName;
-	ss >> std::quoted(keyFileName);
-	ss.str("");
-	if (keyFileName.empty()) {
-		std::cerr << "Invalid client key filename" << std::endl;
-		return;
-	}
-	load_string_file(keyFileName, m_clientKey);
-	if (m_clientKey.empty()) {
-		std::cerr << "Invalid client key file" << std::endl;
-		return;
-	}
-
-	std::string certFileName = settings.get("certificate", DEFAULT_CLIENT_CERT_FILE);
-	std::stringstream().swap(ss);
-	ss << certFileName;
-	ss >> std::quoted(certFileName);
-	if (certFileName.empty()) {
-		std::cerr << "Invalid client certificate filename" << std::endl;
-		return;
-	}
-	load_string_file(certFileName, m_clientCert);
-	if (m_clientCert.empty()) {
-		std::cerr << "Invalid client certificate file" << std::endl;
-		return;
-	}
-
 	std::string caCertFileName = settings.get("ca-certificate", DEFAULT_CA_CERT_FILE);
 	std::stringstream().swap(ss);
 	ss << caCertFileName;
@@ -131,12 +98,14 @@ VisConfig::VisConfig(const std::string &appname) :
 		std::cerr << "Invalid CA certificate filename" << std::endl;
 		return;
 	}
-	load_string_file(caCertFileName, m_caCert);
+	readFile(caCertFileName, m_caCert);
 	if (m_caCert.empty()) {
 		std::cerr << "Invalid CA certificate file" << std::endl;
 		return;
 	}
 
+	m_tlsServerName = settings.get("tls-server-name", "");
+
 	std::string authTokenFileName = settings.get("authorization", "");
 	std::stringstream().swap(ss);
 	ss << authTokenFileName;
@@ -145,7 +114,7 @@ VisConfig::VisConfig(const std::string &appname) :
 		std::cerr << "Invalid authorization token filename" << std::endl;
 		return;
 	}
-	load_string_file(authTokenFileName, m_authToken);
+	readFile(authTokenFileName, m_authToken);
 	if (m_authToken.empty()) {
 		std::cerr << "Invalid authorization token file" << std::endl;
 		return;
@@ -165,3 +134,14 @@ VisConfig::VisConfig(const std::string &appname) :
 
 	m_valid = true;
 }
+
+// Private
+
+void KuksaConfig::readFile(const std::string &filename, std::string &data)
+{
+	try {
+		load_string_file(filename, data);
+	} catch (const std::exception &e) {
+		data.clear();
+	}
+}
diff --git a/src/KuksaConfig.h b/src/KuksaConfig.h
new file mode 100644
index 0000000..e70385f
--- /dev/null
+++ b/src/KuksaConfig.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2022,2023 Konsulko Group
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef _KUKSA_CONFIG_H
+#define _KUKSA_CONFIG_H
+
+#include <string>
+
+class KuksaConfig
+{
+public:
+        explicit KuksaConfig(const std::string &hostname,
+			     const unsigned port,
+			     const std::string &caCert,
+			     const std::string &tlsServerName,
+			     const std::string &authToken);
+        explicit KuksaConfig(const std::string &appname);
+        ~KuksaConfig() {};
+
+	std::string hostname() { return m_hostname; };
+	unsigned port() { return m_port; };
+	std::string caCert() { return m_caCert; };
+	std::string tlsServerName() { return m_tlsServerName; };
+	std::string authToken() { return m_authToken; };
+	bool valid() { return m_valid; };
+	unsigned verbose() { return m_verbose; };
+
+private:
+	std::string m_hostname;
+	unsigned m_port;
+	std::string m_caCert;
+	std::string m_tlsServerName;
+	std::string m_authToken;
+	unsigned m_verbose;
+	bool m_valid;
+
+	void readFile(const std::string &filename, std::string &data);
+};
+
+#endif // _KUKSA_CONFIG_H
diff --git a/src/hvac-service.cpp b/src/hvac-service.cpp
deleted file mode 100644
index ee05806..0000000
--- a/src/hvac-service.cpp
+++ /dev/null
@@ -1,85 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0
-
-#include "hvac-service.hpp"
-#include <iostream>
-#include <algorithm>
-
-
-HvacService::HvacService(const VisConfig &config, net::io_context& ioc, ssl::context& ctx) :
-	VisSession(config, ioc, ctx),
-	m_can_helper(),
-	m_led_helper()
-{
-}
-
-void HvacService::handle_authorized_response(void)
-{
-	subscribe("Vehicle.Cabin.HVAC.Station.Row1.Left.Temperature");
-	subscribe("Vehicle.Cabin.HVAC.Station.Row1.Left.FanSpeed");
-	subscribe("Vehicle.Cabin.HVAC.Station.Row1.Right.Temperature");
-	subscribe("Vehicle.Cabin.HVAC.Station.Row1.Right.FanSpeed");
-}
-
-void HvacService::handle_get_response(std::string &path, std::string &value, std::string &timestamp)
-{
-	// Placeholder since no gets are performed ATM
-}
-
-void HvacService::handle_notification(std::string &path, std::string &value, std::string &timestamp)
-{
-	if (path == "Vehicle.Cabin.HVAC.Station.Row1.Left.Temperature") {
-		try {
-			int temp = std::stoi(value);
-			if (temp >= 0 && temp < 256)
-				set_left_temperature(temp);
-		}
-		catch (std::exception ex) {
-			// ignore bad value
-		}
-	} else if (path == "Vehicle.Cabin.HVAC.Station.Row1.Right.Temperature") {
-		try {
-			int temp = std::stoi(value);
-			if (temp >= 0 && temp < 256)
-				set_right_temperature(temp);
-		}
-		catch (std::exception ex) {
-			// ignore bad value
-		}
-	} else if (path == "Vehicle.Cabin.HVAC.Station.Row1.Left.FanSpeed") {
-		try {
-			int speed = std::stoi(value);
-			if (speed >= 0 && speed < 256)
-				set_fan_speed(speed);
-		}
-		catch (std::exception ex) {
-			// ignore bad value
-		}
-	} else if (path == "Vehicle.Cabin.HVAC.Station.Row1.Right.FanSpeed") {
-		try {
-			int speed = std::stoi(value);
-			if (speed >= 0 && speed < 256)
-				set_fan_speed(speed);
-		}
-		catch (std::exception ex) {
-			// ignore bad value
-		}
-	}
-	// else ignore
-}
-
-void HvacService::set_left_temperature(uint8_t temp)
-{
-	m_can_helper.set_left_temperature(temp);
-	m_led_helper.set_left_temperature(temp);
-}
-
-void HvacService::set_right_temperature(uint8_t temp)
-{
-	m_can_helper.set_right_temperature(temp);
-	m_led_helper.set_right_temperature(temp);
-}
-
-void HvacService::set_fan_speed(uint8_t speed)
-{
-	m_can_helper.set_fan_speed(speed);
-}
diff --git a/src/hvac-service.hpp b/src/hvac-service.hpp
deleted file mode 100644
index 27bfe1a..0000000
--- a/src/hvac-service.hpp
+++ /dev/null
@@ -1,33 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0
-
-#ifndef _HVAC_SERVICE_HPP
-#define _HVAC_SERVICE_HPP
-
-#include "vis-session.hpp"
-#include "hvac-can-helper.hpp"
-#include "hvac-led-helper.hpp"
-
-class HvacService : public VisSession
-{
-public:
-	HvacService(const VisConfig &config, net::io_context& ioc, ssl::context& ctx);
-
-protected:
-	virtual void handle_authorized_response(void) override;
-
-	virtual void handle_get_response(std::string &path, std::string &value, std::string &timestamp) override;
-
-	virtual void handle_notification(std::string &path, std::string &value, std::string &timestamp) override;
-
-private:
-	HvacCanHelper m_can_helper;
-	HvacLedHelper m_led_helper;
-
-	void set_left_temperature(uint8_t temp);
-
-	void set_right_temperature(uint8_t temp);
-
-	void set_fan_speed(uint8_t temp);
-};
-
-#endif // _HVAC_SERVICE_HPP
diff --git a/src/main.cpp b/src/main.cpp
index 6bb165f..2cce0e7 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,34 +1,52 @@
-// SPDX-License-Identifier: Apache-2.0
+/*
+ * Copyright (C) 2022,2023 Konsulko Group
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
-#include <iostream>
-#include <iomanip>
-#include <boost/asio/signal_set.hpp>
-#include <boost/bind.hpp>
-#include "hvac-service.hpp"
+#include <glib.h>
+#include <glib-unix.h>
+#include <systemd/sd-daemon.h>
 
-using work_guard_type = boost::asio::executor_work_guard<boost::asio::io_context::executor_type>;
+#include "HvacService.h"
+
+static gboolean quit_cb(gpointer user_data)
+{
+	GMainLoop *loop = (GMainLoop*) user_data;
+
+	g_info("Quitting...");
+
+	if (loop)
+		g_idle_add(G_SOURCE_FUNC(g_main_loop_quit), loop);
+	else
+		exit(0);
+
+	return G_SOURCE_REMOVE;
+}
 
 int main(int argc, char** argv)
 {
-	// The io_context is required for all I/O
-	net::io_context ioc;
+	GMainLoop *loop = NULL;
+
+	loop = g_main_loop_new(NULL, FALSE);
+	if (!loop) {
+		std::cerr << "Could not create GLib event loop" << std::endl;
+		exit(1);
+	}
+
+	KuksaConfig config("agl-service-hvac");
 
-	// Register to stop I/O context on SIGINT and SIGTERM
-	net::signal_set signals(ioc, SIGINT, SIGTERM);
-	signals.async_wait(boost::bind(&net::io_context::stop, &ioc));
+	g_unix_signal_add(SIGTERM, quit_cb, (gpointer) loop);
+	g_unix_signal_add(SIGINT, quit_cb, (gpointer) loop);
 
-	// The SSL context is required, and holds certificates
-	ssl::context ctx{ssl::context::tlsv12_client};
+	HvacService service(config, loop);
 
-	// Launch the asynchronous operation
-	VisConfig config("agl-service-hvac");
-	std::make_shared<HvacService>(config, ioc, ctx)->run();
+	sd_notify(0, "READY=1");
 
-	// Ensure I/O context continues running even if there's no work
-	work_guard_type work_guard(ioc.get_executor());
+	g_main_loop_run(loop);
 
-	// Run the I/O context
-	ioc.run();
+	// Clean up
+	g_main_loop_unref(loop);
 
 	return 0;
 }
diff --git a/src/meson.build b/src/meson.build
index 149ec99..40aaec8 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -1,19 +1,60 @@
 boost_dep = dependency('boost',
                        version : '>=1.72',
                        modules : [ 'thread', 'filesystem', 'program_options', 'log', 'system' ])
-openssl_dep = dependency('openssl')
-thread_dep = dependency('threads')
-cxx = meson.get_compiler('cpp')
 
-src =  [ 'vis-config.cpp',
-         'vis-session.cpp',
-         'hvac-service.cpp',
-         'hvac-can-helper.cpp',
-         'hvac-led-helper.cpp',
-         'main.cpp'
+cpp = meson.get_compiler('cpp')
+grpcpp_reflection_dep = cpp.find_library('grpc++_reflection')
+
+service_dep = [
+    boost_dep,
+    dependency('glib-2.0'),
+    dependency('openssl'),
+    dependency('threads'),
+    dependency('libsystemd'),
+    dependency('protobuf'),
+    dependency('grpc'),
+    dependency('grpc++'),
+    grpcpp_reflection_dep
 ]
+
+protoc = find_program('protoc')
+grpc_cpp = find_program('grpc_cpp_plugin')
+
+protos_base_dir = get_option('protos')
+protos_dir = protos_base_dir / 'kuksa/val/v1'
+protoc_gen = generator(protoc, \
+                       output : ['@BASENAME@.pb.cc', '@BASENAME@.pb.h'],
+                       arguments : ['-I=' + protos_base_dir,
+                         '--cpp_out=@BUILD_DIR@',
+                         '@INPUT@'])
+generated_protoc_sources = [ \
+    protoc_gen.process(protos_dir / 'types.proto', preserve_path_from : protos_base_dir),
+    protoc_gen.process(protos_dir / 'val.proto', preserve_path_from : protos_base_dir),
+]
+
+grpc_gen = generator(protoc, \
+                     output : ['@BASENAME@.grpc.pb.cc', '@BASENAME@.grpc.pb.h'],
+                     arguments : ['-I=' + protos_base_dir,
+                       '--grpc_out=@BUILD_DIR@',
+                       '--plugin=protoc-gen-grpc=' + grpc_cpp.path(),
+                       '@INPUT@'])
+generated_grpc_sources = [ \
+    grpc_gen.process(protos_dir / 'val.proto', preserve_path_from : protos_base_dir),
+]
+
+src =  [
+    'KuksaConfig.cpp',
+    'KuksaClient.cpp',
+    'HvacService.cpp',
+    'HvacCanHelper.cpp',
+    'HvacLedHelper.cpp',
+    'main.cpp',
+    generated_protoc_sources,
+    generated_grpc_sources,
+]
+
 executable('agl-service-hvac',
            src,
-           dependencies: [boost_dep, openssl_dep, thread_dep, systemd_dep],
+           dependencies: service_dep,
            install: true,
            install_dir : get_option('sbindir'))
diff --git a/src/vis-config.hpp b/src/vis-config.hpp
deleted file mode 100644
index b0f72f9..0000000
--- a/src/vis-config.hpp
+++ /dev/null
@@ -1,43 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0
-
-#ifndef _VIS_CONFIG_HPP
-#define _VIS_CONFIG_HPP
-
-#include <string>
-
-class VisConfig
-{
-public:
-        explicit VisConfig(const std::string &hostname,
-			   const unsigned port,
-			   const std::string &clientKey,
-			   const std::string &clientCert,
-			   const std::string &caCert,
-			   const std::string &authToken,
-			   bool verifyPeer = true);
-        explicit VisConfig(const std::string &appname);
-        ~VisConfig() {};
-
-	std::string hostname() { return m_hostname; };
-	unsigned port() { return m_port; };
-	std::string clientKey() { return m_clientKey; };
-	std::string clientCert() { return m_clientCert; };
-	std::string caCert() { return m_caCert; };
-	std::string authToken() { return m_authToken; };
-	bool verifyPeer() { return m_verifyPeer; };
-	bool valid() { return m_valid; };
-	unsigned verbose() { return m_verbose; };
-
-private:
-	std::string m_hostname;
-	unsigned m_port;
-	std::string m_clientKey;
-	std::string m_clientCert;
-	std::string m_caCert;
-	std::string m_authToken;
-	bool m_verifyPeer;
-	unsigned m_verbose;
-	bool m_valid;
-};
-
-#endif // _VIS_CONFIG_HPP
diff --git a/src/vis-session.cpp b/src/vis-session.cpp
deleted file mode 100644
index 53a554c..0000000
--- a/src/vis-session.cpp
+++ /dev/null
@@ -1,380 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0
-
-#include "vis-session.hpp"
-#include <iostream>
-#include <sstream>
-#include <thread>
-
-
-// Logging helper
-static void log_error(beast::error_code error, char const* what)
-{
-	std::cerr << what << " error: " << error.message() << std::endl;
-}
-
-
-// Resolver and socket require an io_context
-VisSession::VisSession(const VisConfig &config, net::io_context& ioc, ssl::context& ctx) :
-	m_config(config),
-	m_resolver(net::make_strand(ioc)),
-	m_ws(net::make_strand(ioc), ctx)
-{
-}
-
-// Start the asynchronous operation
-void VisSession::run()
-{
-	if (!m_config.valid()) {
-		return;
-	}
-
-	// Start by resolving hostname
-	m_resolver.async_resolve(m_config.hostname(),
-				 std::to_string(m_config.port()),
-				 beast::bind_front_handler(&VisSession::on_resolve,
-							   shared_from_this()));
-}
-
-void VisSession::on_resolve(beast::error_code error,
-			    tcp::resolver::results_type results)
-{
-	if(error) {
-		log_error(error, "resolve");
-		return;
-	}
-
-	// Set a timeout on the connect operation
-	beast::get_lowest_layer(m_ws).expires_after(std::chrono::seconds(30));
-
-	// Connect to resolved address
-	if (m_config.verbose())
-		std::cout << "Connecting" << std::endl;
-	m_results = results;
-	connect();
-}
-
-void VisSession::connect()
-{
-	beast::get_lowest_layer(m_ws).async_connect(m_results,
-						    beast::bind_front_handler(&VisSession::on_connect,
-									      shared_from_this()));
-}
-
-void VisSession::on_connect(beast::error_code error,
-			    tcp::resolver::results_type::endpoint_type endpoint)
-{
-	if(error) {
-		// The server can take a while to be ready to accept connections,
-		// so keep retrying until we hit the timeout.
-		if (error == net::error::timed_out) {
-			log_error(error, "connect");
-			return;
-		}
-
-		// Delay 500 ms before retrying
-		std::this_thread::sleep_for(std::chrono::milliseconds(500));
-
-		if (m_config.verbose())
-			std::cout << "Connecting" << std::endl;
-		
-		connect();
-		return;
-	}
-
-	if (m_config.verbose())
-		std::cout << "Connected" << std::endl;
-
-	// Set handshake timeout
-	beast::get_lowest_layer(m_ws).expires_after(std::chrono::seconds(30));
-
-	// Set SNI Hostname (many hosts need this to handshake successfully)
-	if(!SSL_set_tlsext_host_name(m_ws.next_layer().native_handle(),
-				     m_config.hostname().c_str()))
-	{
-		error = beast::error_code(static_cast<int>(::ERR_get_error()),
-					  net::error::get_ssl_category());
-		log_error(error, "connect");
-		return;
-	}
-
-	// Update the hostname. This will provide the value of the
-	// Host HTTP header during the WebSocket handshake.
-	// See https://tools.ietf.org/html/rfc7230#section-5.4
-	m_hostname = m_config.hostname() + ':' + std::to_string(endpoint.port());
-
-	if (m_config.verbose())
-		std::cout << "Negotiating SSL handshake" << std::endl;
-
-	// Perform the SSL handshake
-	m_ws.next_layer().async_handshake(ssl::stream_base::client,
-					  beast::bind_front_handler(&VisSession::on_ssl_handshake,
-								    shared_from_this()));
-}
-
-void VisSession::on_ssl_handshake(beast::error_code error)
-{
-	if(error) {
-		log_error(error, "SSL handshake");
-		return;
-	}
-
-	// Turn off the timeout on the tcp_stream, because
-	// the websocket stream has its own timeout system.
-	beast::get_lowest_layer(m_ws).expires_never();
-	
-	// NOTE: Explicitly not setting websocket stream timeout here,
-	//       as the client is long-running.
-
-	if (m_config.verbose())
-		std::cout << "Negotiating WSS handshake" << std::endl;
-
-	// Perform handshake
-	m_ws.async_handshake(m_hostname,
-			     "/",
-			     beast::bind_front_handler(&VisSession::on_handshake,
-						       shared_from_this()));
-}
-
-void VisSession::on_handshake(beast::error_code error)
-{
-	if(error) {
-		log_error(error, "WSS handshake");
-		return;
-	}
-
-	if (m_config.verbose())
-		std::cout << "Authorizing" << std::endl;
-
-	// Authorize
-	json req;
-	req["requestId"] = std::to_string(m_requestid++);
-	req["action"]= "authorize";
-	req["tokens"] = m_config.authToken();
-	
-	m_ws.async_write(net::buffer(req.dump(4)),
-			 beast::bind_front_handler(&VisSession::on_authorize,
-						   shared_from_this()));
-}
-
-void VisSession::on_authorize(beast::error_code error, std::size_t bytes_transferred)
-{
-	boost::ignore_unused(bytes_transferred);
-
-	if(error) {
-		log_error(error, "authorize");
-		return;
-	}
-
-	// Read response
-	m_ws.async_read(m_buffer,
-			beast::bind_front_handler(&VisSession::on_read,
-						  shared_from_this()));
-}
-
-// NOTE: Placeholder for now
-void VisSession::on_write(beast::error_code error, std::size_t bytes_transferred)
-{
-	boost::ignore_unused(bytes_transferred);
-
-	if(error) {
-		log_error(error, "write");
-		return;
-	}
-
-	// Do nothing...
-}
-
-void VisSession::on_read(beast::error_code error, std::size_t bytes_transferred)
-{
-	boost::ignore_unused(bytes_transferred);
-
-	if(error) {
-		log_error(error, "read");
-		return;
-	}
-
-	// Handle message
-	std::string s = beast::buffers_to_string(m_buffer.data());
-	json response = json::parse(s, nullptr, false);
-	if (!response.is_discarded()) {
-		handle_message(response);
-	} else {
-		std::cerr << "json::parse failed? got " << s << std::endl;
-	}
-	m_buffer.consume(m_buffer.size());
-
-	// Read next message
-	m_ws.async_read(m_buffer,
-			beast::bind_front_handler(&VisSession::on_read,
-						  shared_from_this()));
-}
-
-void VisSession::get(const std::string &path)
-{
-	if (!m_config.valid()) {
-		return;
-	}
-
-	json req;
-	req["requestId"] = std::to_string(m_requestid++);
-	req["action"] = "get";
-	req["path"] = path;
-	req["tokens"] = m_config.authToken();
-
-	m_ws.write(net::buffer(req.dump(4)));
-}
-
-void VisSession::set(const std::string &path, const std::string &value)
-{
-	if (!m_config.valid()) {
-		return;
-	}
-
-	json req;
-	req["requestId"] = std::to_string(m_requestid++);
-	req["action"] = "set";
-	req["path"] = path;
-	req["value"] = value;
-	req["tokens"] = m_config.authToken();
-	
-	m_ws.write(net::buffer(req.dump(4)));
-}
-
-void VisSession::subscribe(const std::string &path)
-{
-	if (!m_config.valid()) {
-		return;
-	}
-
-	json req;
-	req["requestId"] = std::to_string(m_requestid++);
-	req["action"] = "subscribe";
-	req["path"] = path;
-	req["tokens"] = m_config.authToken();
-	
-	m_ws.write(net::buffer(req.dump(4)));
-}
-
-bool VisSession::parseData(const json &message, std::string &path, std::string &value, std::string &timestamp)
-{
-	if (message.contains("error")) {
-		std::string error = message["error"];
-		return false;
-	}
-
-	if (!(message.contains("data") && message["data"].is_object())) {
-		std::cerr << "Malformed message (data missing)" << std::endl;
-		return false;
-	}
-	auto data = message["data"];
-	if (!(data.contains("path") && data["path"].is_string())) {
-		std::cerr << "Malformed message (path missing)" << std::endl;
-		return false;
-	}
-	path = data["path"];
-	// Convert '/' to '.' in paths to ensure consistency for clients
-	std::replace(path.begin(), path.end(), '/', '.');
-
-	if (!(data.contains("dp") && data["dp"].is_object())) {
-		std::cerr << "Malformed message (datapoint missing)" << std::endl;
-		return false;
-	}
-	auto dp = data["dp"];
-	if (!dp.contains("value")) {
-		std::cerr << "Malformed message (value missing)" << std::endl;
-		return false;
-	} else if (dp["value"].is_string()) {
-		value = dp["value"];
-	} else if (dp["value"].is_number_float()) {
-		double num = dp["value"];
-		value = std::to_string(num);
-	} else if (dp["value"].is_number_unsigned()) {
-		unsigned int num = dp["value"];
-		value = std::to_string(num);
-	} else if (dp["value"].is_number_integer()) {
-		int num = dp["value"];
-		value = std::to_string(num);
-	} else if (dp["value"].is_boolean()) {
-		value = dp["value"] ? "true" : "false";
-	} else {
-		std::cerr << "Malformed message (unsupported value type)" << std::endl;
-		return false;
-	}
-
-	if (!(dp.contains("ts") && dp["ts"].is_string())) {
-		std::cerr << "Malformed message (timestamp missing)" << std::endl;
-		return false;
-	}
-	timestamp = dp["ts"];
-
-	return true;
-}
-
-void VisSession::handle_message(const json &message)
-{
-	if (m_config.verbose() > 1)
-		std::cout << "VisSession::handle_message: enter, message = " << to_string(message) << std::endl;
-
-	if (!message.contains("action")) {
-		std::cerr << "Received unknown message (no action), discarding" << std::endl;
-		return;
-	}
-	
-	std::string action = message["action"];
-	if (action == "authorize") {
-		if (message.contains("error")) {
-			std::string error = "unknown";
-			if (message["error"].is_object() && message["error"].contains("message"))
-				error = message["error"]["message"];
-			std::cerr << "VIS authorization failed: " << error << std::endl;
-		} else {
-			if (m_config.verbose() > 1)
-				std::cout << "authorized" << std::endl;
-
-			handle_authorized_response();
-		}
-	} else if (action == "subscribe") {
-		if (message.contains("error")) {
-			std::string error = "unknown";
-			if (message["error"].is_object() && message["error"].contains("message"))
-				error = message["error"]["message"];
-			std::cerr << "VIS subscription failed: " << error << std::endl;
-		}
-	} else if (action == "get") {
-		if (message.contains("error")) {
-			std::string error = "unknown";
-			if (message["error"].is_object() && message["error"].contains("message"))
-				error = message["error"]["message"];
-			std::cerr << "VIS get failed: " << error << std::endl;
-		} else {
-			std::string path, value, ts;
-			if (parseData(message, path, value, ts)) {
-				if (m_config.verbose() > 1)
-					std::cout << "VisSession::handle_message: got response " << path << " = " << value << std::endl;
-
-				handle_get_response(path, value, ts);
-			}
-		}
-	} else if (action == "set") {
-		if (message.contains("error")) {
-			std::string error = "unknown";
-			if (message["error"].is_object() && message["error"].contains("message"))
-				error = message["error"]["message"];
-			std::cerr << "VIS set failed: " << error;
-		}
-	} else if (action == "subscription") {
-		std::string path, value, ts;
-		if (parseData(message, path, value, ts)) {
-			if (m_config.verbose() > 1)
-				std::cout << "VisSession::handle_message: got notification " << path << " = " << value << std::endl;
-
-			handle_notification(path, value, ts);
-		}
-	} else {
-		std::cerr << "unhandled VIS response of type: " << action;
-	}
-
-	if (m_config.verbose() > 1)
-		std::cout << "VisSession::handle_message: exit" << std::endl;
-}
-
diff --git a/src/vis-session.hpp b/src/vis-session.hpp
deleted file mode 100644
index 8c7b0d9..0000000
--- a/src/vis-session.hpp
+++ /dev/null
@@ -1,78 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0
-
-#ifndef _VIS_SESSION_HPP
-#define _VIS_SESSION_HPP
-
-#include "vis-config.hpp"
-#include <atomic>
-#include <string>
-#include <boost/beast/core.hpp>
-#include <boost/beast/ssl.hpp>
-#include <boost/beast/websocket.hpp>
-#include <boost/beast/websocket/ssl.hpp>
-#include <boost/asio/strand.hpp>
-#include <nlohmann/json.hpp>
-
-namespace beast = boost::beast;
-namespace websocket = beast::websocket;
-namespace net = boost::asio;
-namespace ssl = boost::asio::ssl;
-using tcp = boost::asio::ip::tcp;
-using json = nlohmann::json;
-
-
-class VisSession : public std::enable_shared_from_this<VisSession>
-{
-	//net::io_context m_ioc;
-	tcp::resolver m_resolver;
-	tcp::resolver::results_type m_results;
-	std::string m_hostname;
-	websocket::stream<beast::ssl_stream<beast::tcp_stream>> m_ws;
-	beast::flat_buffer m_buffer;
-
-public:
-	// Resolver and socket require an io_context
-	explicit VisSession(const VisConfig &config, net::io_context& ioc, ssl::context& ctx);
-
-	// Start the asynchronous operation
-	void run();
-
-protected:
-	VisConfig m_config;
-	std::atomic_uint m_requestid;
-
-	void on_resolve(beast::error_code error, tcp::resolver::results_type results);
-
-	void connect();
-
-	void on_connect(beast::error_code error, tcp::resolver::results_type::endpoint_type endpoint);
-
-	void on_ssl_handshake(beast::error_code error);
-
-	void on_handshake(beast::error_code error);
-
-	void on_authorize(beast::error_code error, std::size_t bytes_transferred);
-
-	void on_write(beast::error_code error, std::size_t bytes_transferred);
-
-	void on_read(beast::error_code error, std::size_t bytes_transferred);
-
-	void get(const std::string &path);
-
-	void set(const std::string &path, const std::string &value);
-
-	void subscribe(const std::string &path);
-
-	void handle_message(const json &message);
-
-	bool parseData(const json &message, std::string &path, std::string &value, std::string &timestamp);
-
-	virtual void handle_authorized_response(void) = 0;
-
-	virtual void handle_get_response(std::string &path, std::string &value, std::string &timestamp) = 0;
-
-	virtual void handle_notification(std::string &path, std::string &value, std::string &timestamp) = 0;
-
-};
-
-#endif // _VIS_SESSION_HPP