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authorScott Murray <scott.murray@konsulko.com>2022-06-17 20:24:27 -0400
committerScott Murray <scott.murray@konsulko.com>2022-07-04 22:29:37 +0000
commit509105d48cd1524cba1f20c4e0641d8c2d3a9cb4 (patch)
treec9739f3e7bc741efb8c2760bf0dc917e920f5824 /src/vis-session.cpp
parentdadd3d771d5b27a455afffed8437c0a2e6db26b2 (diff)
Repurpose repository for a spiritual successor of the previous binding. The replacement is a daemon that demonstrates servicing the volume actuator from the VSS schema via VIS signals from KUKSA.val. Currently the connection to KUKSA.val is websocket based using the boost::asio framework, but the plan is to migrate to gRPC as that becomes more robust in KUKSA.val. As well, this new code will serve as the base for implementing a gRPC API to expose the full set of WirePlumber controls as was done with the previous binding. Notable changes: - New code is completely C++, partly to leverage using Boost, but also to futureproof future work with gRPC. The WirePlumber interfacing code that has been kept from the old binding is still C for now, converting it to C++ is a planned future rework. - Switch from CMake to meson for ease of development and some degree of futureproofing. - Use with systemd is assumed; behavior follows the systemd daemon guidelines barring the use of journald logging prefixes, which may be addressed with future work. A systemd unit is also installed as part of the build. - SPDX license headers using SPDX "short identifiers" are used in source files rather than the full copyright headers used in the previous codebase. This follows the direction that projects such as the Linux kernel are going in. Bug-AGL: SPEC-4409 Signed-off-by: Scott Murray <scott.murray@konsulko.com> Change-Id: Ibb7091c4354432bb094147d1419ab475486a4abc (cherry picked from commit 298bbf445a731b85cb8d5d19a3b595e8870d8701)
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diff --git a/src/vis-session.cpp b/src/vis-session.cpp
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+// 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_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;
+}
+