logging: add a LoggerDB::getConfig() method

[folly.git] / folly / experimental / logging / LoggerDB.h

diff --git a/folly/experimental/logging/LoggerDB.h b/folly/experimental/logging/LoggerDB.h
index 9580b7434c2adc0f9ac403431faa6921f48243f4..d65324f7ce004bc5154f89fc169c2078e9dee92c 100644 (file)
--- a/folly/experimental/logging/LoggerDB.h
+++ b/folly/experimental/logging/LoggerDB.h
@@ -29,6 +29,9 @@
 namespace folly {
 
 class LogCategory;
+class LogConfig;
+class LogHandler;
+class LogHandlerFactory;
 enum class LogLevel : uint32_t;
 
 /**
@@ -41,6 +44,8 @@ class LoggerDB {
    */
   static LoggerDB* get();
 
+  ~LoggerDB();
+
   /**
    * Get the LogCategory for the specified name.
    *
@@ -72,6 +77,17 @@ class LoggerDB {
   void setLevel(folly::StringPiece name, LogLevel level, bool inherit = true);
   void setLevel(LogCategory* category, LogLevel level, bool inherit = true);
 
+  /**
+   * Get a LogConfig object describing the current state of the LoggerDB.
+   *
+   * Note that this may not 100% accurately describe the current configuration
+   * if callers have manually added LogHandlers to some categories without
+   * using the updateConfig() or resetConfig() functions.  In this case
+   * getConfig() will simply report these handlers as "unknown_handler" when
+   * returning handler names for the categories in question.
+   */
+  LogConfig getConfig() const;
+
   /**
    * Apply a configuration string specifying a series a log levels.
    *
@@ -94,8 +110,39 @@ class LoggerDB {
   /**
    * Call flush() on all LogHandler objects registered on any LogCategory in
    * this LoggerDB.
+   *
+   * Returns the number of registered LogHandlers.
    */
-  void flushAllHandlers();
+  size_t flushAllHandlers();
+
+  /**
+   * Register a LogHandlerFactory.
+   *
+   * The LogHandlerFactory will be used to create LogHandler objects from a
+   * LogConfig object during updateConfig() and resetConfig() calls.
+   *
+   * Only one factory can be registered for a given handler type name.
+   * LogHandlerFactory::getType() returns the handler type supported by this
+   * LogHandlerFactory.
+   *
+   * If an existing LogHandlerFactory is already registered with this type name
+   * and replaceExisting is false a std::range_error will be thrown.
+   * Otherwise, if replaceExisting is true, the new factory will replace the
+   * existing factory.
+   */
+  void registerHandlerFactory(
+      std::unique_ptr<LogHandlerFactory> factory,
+      bool replaceExisting = false);
+
+  /**
+   * Remove a registered LogHandlerFactory.
+   *
+   * The type parameter should be the name of the handler type, as returned by
+   * LogHandlerFactory::getType().
+   *
+   * Throws std::range_error if no handler factory with this type name exists.
+   */
+  void unregisterHandlerFactory(folly::StringPiece type);
 
   /**
    * Initialize the LogCategory* and std::atomic<LogLevel> used by an XLOG()
@@ -169,6 +216,14 @@ class LoggerDB {
       LogName::Hash,
       LogName::Equals>;
 
+  using HandlerFactoryMap =
+      std::unordered_map<std::string, std::unique_ptr<LogHandlerFactory>>;
+  using HandlerMap = std::unordered_map<std::string, std::weak_ptr<LogHandler>>;
+  struct HandlerInfo {
+    HandlerFactoryMap factories;
+    HandlerMap handlers;
+  };
+
   // Forbidden copy constructor and assignment operator
   LoggerDB(LoggerDB const&) = delete;
   LoggerDB& operator=(LoggerDB const&) = delete;
@@ -199,6 +254,11 @@ class LoggerDB {
    */
   folly::Synchronized<LoggerNameMap> loggersByName_;
 
+  /**
+   * The LogHandlers and LogHandlerFactories.
+   */
+  folly::Synchronized<HandlerInfo> handlerInfo_;
+
   static std::atomic<InternalWarningHandler> warningHandler_;
 };
-}
+} // namespace folly