1 files changed, 187 insertions, 0 deletions
diff --git a/extensions/openpower-pels/event_logger.hpp b/extensions/openpower-pels/event_logger.hpp
new file mode 100644
index 0000000..b4df0d4
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+++ b/extensions/openpower-pels/event_logger.hpp
@@ -0,0 +1,187 @@
+#pragma once
+
+#include "additional_data.hpp"
+#include "elog_entry.hpp"
+
+#include <phosphor-logging/log.hpp>
+#include <queue>
+#include <sdeventplus/event.hpp>
+#include <sdeventplus/source/event.hpp>
+#include <tuple>
+
+namespace openpower::pels
+{
+
+/**
+ * @class EventLogger
+ *
+ * This class handles creating OpenBMC event logs (and thus PELs) from
+ * within the PEL extension code.
+ *
+ * The function to actually create the event log is passed in via the
+ * constructor so that different functions can be used when testing.
+ *
+ * To create the event log, call log() with the appropriate arguments
+ * and the log will be created as soon as the flow gets back to the event
+ * loop.  If the queue isn't empty after a log is created, the next
+ * one will be scheduled to be created from the event loop again.
+ *
+ * This class does not allow new events to be added while inside the
+ * creation function, because if the code added an event log every time
+ * it tried to create one, it would do so infinitely.
+ */
+class EventLogger
+{
+  public:
+    using ADMap = std::map<std::string, std::string>;
+    using LogFunction = std::function<void(
+        const std::string&, phosphor::logging::Entry::Level, const ADMap&)>;
+
+    static constexpr size_t msgPos = 0;
+    static constexpr size_t levelPos = 1;
+    static constexpr size_t adPos = 2;
+    using EventEntry = std::tuple<std::string, phosphor::logging::Entry::Level,
+                                  AdditionalData>;
+
+    EventLogger() = delete;
+    ~EventLogger() = default;
+    EventLogger(const EventLogger&) = delete;
+    EventLogger& operator=(const EventLogger&) = delete;
+    EventLogger(EventLogger&&) = delete;
+    EventLogger& operator=(EventLogger&&) = delete;
+
+    /**
+     * @brief Constructor
+     *
+     * @param[in] event - The sd_event object
+     * @param[in] creator - The function to use to create the event log
+     */
+    EventLogger(sd_event* event, LogFunction creator) :
+        _event(event), _creator(creator)
+    {
+    }
+
+    /**
+     * @brief Adds an event to the queue so that it will be created
+     *        as soon as the code makes it back to the event loop.
+     *
+     * Won't add it to the queue if already inside the create()
+     * callback.
+     *
+     * @param[in] message - The message property of the event log
+     * @param[in] severity - The severity level of the event log
+     * @param[in] ad - The additional data property of the event log
+     */
+    void log(const std::string& message,
+             phosphor::logging::Entry::Level severity, const AdditionalData& ad)
+    {
+        if (!_inEventCreation)
+        {
+            _eventsToCreate.emplace(message, severity, ad);
+
+            if (!_eventSource)
+            {
+                scheduleCreate();
+            }
+        }
+        else
+        {
+            phosphor::logging::log<phosphor::logging::level::INFO>(
+                "Already in event create callback, skipping new create",
+                phosphor::logging::entry("ERROR_NAME=%s", message.c_str()));
+        }
+    }
+
+    /**
+     * @brief Returns the event log queue size.
+     *
+     * @return size_t - The queue size
+     */
+    size_t queueSize() const
+    {
+        return _eventsToCreate.size();
+    }
+
+    /**
+     * @brief Schedules the create() function to run using the
+     *        'defer' sd_event source.
+     */
+    void scheduleCreate()
+    {
+        _eventSource = std::make_unique<sdeventplus::source::Defer>(
+            _event, std::bind(std::mem_fn(&EventLogger::create), this,
+                              std::placeholders::_1));
+    }
+
+  private:
+    /**
+     * @brief Creates an event log and schedules the next one if
+     *        there is one.
+     *
+     * This gets called from the event loop by the sd_event code.
+     *
+     * @param[in] source - The event source object used
+     */
+    void create(sdeventplus::source::EventBase& source)
+    {
+        _eventSource.reset();
+
+        if (_eventsToCreate.empty())
+        {
+            return;
+        }
+
+        auto event = _eventsToCreate.front();
+        _eventsToCreate.pop();
+
+        _inEventCreation = true;
+
+        try
+        {
+            _creator(std::get<msgPos>(event), std::get<levelPos>(event),
+                     std::get<adPos>(event).getData());
+        }
+        catch (std::exception& e)
+        {
+            phosphor::logging::log<phosphor::logging::level::ERR>(
+                "EventLogger's create function threw an exception",
+                phosphor::logging::entry("ERROR=%s", e.what()));
+        }
+
+        _inEventCreation = false;
+
+        if (!_eventsToCreate.empty())
+        {
+            scheduleCreate();
+        }
+    }
+
+    /**
+     * @brief The sd_event object.
+     */
+    sdeventplus::Event _event;
+
+    /**
+     * @brief The user supplied function to create the event log.
+     */
+    LogFunction _creator;
+
+    /**
+     * @brief Keeps track of if an event is currently being created.
+     *
+     * Guards against creating new events while creating events.
+     */
+    bool _inEventCreation = false;
+
+    /**
+     * @brief The event source object used for scheduling.
+     */
+    std::unique_ptr<sdeventplus::source::Defer> _eventSource;
+
+    /**
+     * @brief The queue of event logs to create.
+     */
+    std::queue<EventEntry> _eventsToCreate;
+};
+
+} // namespace openpower::pels