1 files changed, 116 insertions, 0 deletions
diff --git a/src/elog.hpp b/src/elog.hpp
index c3b0d02..3f8ae3b 100644
--- a/src/elog.hpp
+++ b/src/elog.hpp
@@ -12,6 +12,25 @@ namespace dbus
 namespace monitoring
 {
 
+/** @struct ToString
+ * @brief Convert numbers to strings
+ */
+template <typename T> struct ToString
+{
+    static auto op(T&& value)
+    {
+        return std::to_string(std::forward<T>(value));
+    }
+};
+
+template <> struct ToString<std::string>
+{
+    static auto op(const std::string& value)
+    {
+        return value;
+    }
+};
+
 /** @class ElogBase
  *  @brief Elog callback implementation.
  *
@@ -89,6 +108,103 @@ class Elog : public ElogBase
 
 };
 
+
+/**
+ * @class ElogWithMetadataCapture
+ *
+ * @brief A callback class that will save the paths, names, and
+ *       current values of certain properties in the metadata of the
+ *       error log it creates.
+ *
+ * The intended use case of this class is to create an error log with
+ * metadata that includes the property names and values that caused
+ * the condition to issue this callback.  When the condition ran, it had
+ * set the pass/fail field on each property it checked in the properties'
+ * entries in the Storage array.  This class then looks at those pass/fail
+ * fields to see which properties to log.
+ *
+ * Note that it's OK if different conditions and callbacks share the same
+ * properties because everything runs serially, so another condition can't
+ * touch those pass/fail fields until all of the first condition's callbacks
+ * are done.
+ *
+ * This class requires that the error log created only have 1 metadata field,
+ * and it must take a string.
+ *
+ * @tparam errorType - Error log type
+ * @tparam metadataType - The metadata to use
+ * @tparam propertyType - The data type of the captured properties
+ */
+template<typename errorType,
+         typename metadataType,
+         typename propertyType>
+class ElogWithMetadataCapture : public IndexedCallback
+{
+    public:
+        ElogWithMetadataCapture() = delete;
+        ElogWithMetadataCapture(const ElogWithMetadataCapture&) = delete;
+        ElogWithMetadataCapture(ElogWithMetadataCapture&&) = default;
+        ElogWithMetadataCapture& operator=(
+                const ElogWithMetadataCapture&) = delete;
+        ElogWithMetadataCapture& operator=(
+                ElogWithMetadataCapture&&) = default;
+        virtual ~ElogWithMetadataCapture() = default;
+        explicit ElogWithMetadataCapture(
+                const PropertyIndex& index) :
+            IndexedCallback(index) {}
+
+        /**
+         * @brief Callback interface implementation that
+         *        creates an error log
+         */
+        void operator()(Context ctx) override
+        {
+            auto data = captureMetadata();
+
+            phosphor::logging::report<errorType>(
+                    metadataType(data.c_str()));
+        }
+
+    private:
+
+        /**
+         * @brief Builds a metadata string with property information
+         *
+         * Finds all of the properties in the index that have
+         * their condition pass/fail fields (get<1>(storage))
+         * set to true, and then packs those paths, names, and values
+         * into a metadata string that looks like:
+         *
+         * |path1:name1=value1|path2:name2=value2|...
+         *
+         * @return The metadata string
+         */
+        std::string captureMetadata()
+        {
+            std::string metadata{'|'};
+
+            for (const auto& n : index)
+            {
+                const auto& storage = std::get<2>(n.second).get();
+                const auto& result = std::get<1>(storage);
+
+                if (!result.empty() && any_ns::any_cast<bool>(result))
+                {
+                    const auto& path = std::get<0>(n.first).get();
+                    const auto& propertyName = std::get<2>(n.first).get();
+                    auto value = ToString<propertyType>::op(
+                            any_ns::any_cast<propertyType>(
+                                    std::get<0>(storage)));
+
+                    metadata += path + ":" + propertyName +
+                            '=' + value + '|';
+                }
+            }
+
+            return metadata;
+        };
+};
+
 /** @brief Argument type deduction for constructing Elog instances.
  *
  *  @tparam T - Error log type