control: Add signal triggers with propertiesChanged signals
Add signal trigger support to the available triggers and include the
ability to subscribe and handle propertiesChanged signals.
Subscribing to a signal involves creating the signal's match string and
packaging the signal data for when the signal is received. Since a
single signal could be configured to be used across multiple dbus
objects and/or actions, the signal package is added in a way that each
event configured for the signal is processed from the signal received.
Handling the propertiesChanged signal involves filtering for the
configured dbus property, updating the cached value of the property, and
then allowing the actions for that signal to be run.
Change-Id: I04bc163b65115d9bac30315f690db5fefca5bde4
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
diff --git a/control/json/triggers/signal.hpp b/control/json/triggers/signal.hpp
new file mode 100644
index 0000000..1077144
--- /dev/null
+++ b/control/json/triggers/signal.hpp
@@ -0,0 +1,78 @@
+/**
+ * Copyright © 2021 IBM Corporation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#pragma once
+
+#include "../manager.hpp"
+#include "action.hpp"
+
+#include <nlohmann/json.hpp>
+#include <sdbusplus/message.hpp>
+
+#include <functional>
+#include <memory>
+#include <unordered_map>
+#include <vector>
+
+namespace phosphor::fan::control::json::trigger::signal
+{
+
+using json = nlohmann::json;
+
+/**
+ * @brief Subscribe to a signal
+ *
+ * @param[in] match - Signal match string to subscribe to
+ * @param[in] pkg - Data package to attach to signal
+ * @param[in] mgr - Pointer to manager of the trigger
+ */
+void subscribe(const std::string& match, SignalPkg&& pkg,
+ std::function<bool(SignalPkg&)> isSameSig, Manager* mgr);
+
+/**
+ * @brief Subscribes to a propertiesChanged signal
+ *
+ * @param[in] mgr - Pointer to manager of the trigger
+ * @param[in] eventName - Name of event associated to the signal
+ * @param[in] action - Action to be run when signal is received
+ */
+void propertiesChanged(Manager* mgr, const std::string& eventName,
+ std::unique_ptr<ActionBase>& action);
+
+// Match setup function for signals
+using SignalMatch = std::function<void(Manager*, const std::string&,
+ std::unique_ptr<ActionBase>& action)>;
+
+/* Supported signals to their corresponding match setup functions */
+static const std::unordered_map<std::string, SignalMatch> signals = {
+ {"properties_changed", propertiesChanged}};
+
+/**
+ * @brief Trigger to process an event after a signal is received
+ *
+ * @param[in] jsonObj - JSON object for the trigger
+ * @param[in] eventName - Name of event associated to the signal
+ * @param[in] mgr - Pointer to manager of the trigger
+ * @param[in] actions - Actions associated with the trigger
+ *
+ * When fan control starts (or restarts), all events with 'signal' triggers are
+ * subscribed to run its corresponding actions when a signal, per its
+ * configuration, is received.
+ */
+void triggerSignal(const json& jsonObj, const std::string& eventName,
+ Manager* mgr,
+ std::vector<std::unique_ptr<ActionBase>>& actions);
+
+} // namespace phosphor::fan::control::json::trigger::signal