contextual logger attributes (#2)

* init fixed attribute, currently having issues with the factory

* using the much simpler api already defined: no factory, just define the sinks yourself

* async logger fixed attribute support

* fixed missing fixed attributes in default log calls

* forgot some spots, all cases were found?

* potential fix for illegal vector iterators

* kept up to date with attributes branch

* cleaner fixed logger api

* less function overloads, just add and remove context when needed

* fixed example to use new api

* added append function for nested context

* pushing and popping contexts for nested loggers

* fixed error due to implicit conversion

* fixed sign conversion error

* better attribute example with optional json example

Co-authored-by: Bailey Chittle <baileyc@tessonics.com>

example/example.cpp

@@ -394,15 +394,33 @@ void replace_default_logger_example()
 }
 
 void attribute_example() {
-    spdlog::default_logger_raw()->warn("EXPERIMENTAL: log with attributes", {{"attribute_key", "attribute value"}});
-
-    // logfmt structured logging using attributes
-
-    // auto logfmt_logger = spdlog::basic_logger_mt("logfmt_logger", "logs/mylog.txt");
-    auto logfmt_logger = spdlog::stdout_color_mt("logfmt_logger");
-
-    std::string logfmt_pattern = "time=%Y-%m-%dT%H:%M:%S.%f%z name=%n level=%^%l%$ process=%P thread=%t message=\"%v\"%( %K=\"%V\"%)";
-    logfmt_logger->set_pattern(logfmt_pattern);
-
-    logfmt_logger->info("logfmt structured logging", spdlog::attribute_list{{"key\n1", "value\n1"}, {"key\r\n2", "value\r\n2"}});
+    auto custom_logger = spdlog::stdout_color_mt("custom_logger");
+
+    custom_logger->push_context(spdlog::attribute_list{{"attribute_key", "attribute value"}});
+    custom_logger->warn("EXPERIMENTAL: log with attributes");
+    custom_logger->clear_context();
+
+    // structured logging using attributes
+
+    // auto s_logger = spdlog::basic_logger_mt("structured logger", "logs/mylog.txt");
+    auto s_logger = spdlog::stdout_color_mt("structured logger");
+
+    #if 0
+    std::string json_pattern = "{\"time\":\"%Y-%m-%dT%H:%M:%S.%e%z\",\"name\":\"%n\",\"level\":\"%l\",\"message\":\"%v\"%(,\"%K\":\"%V\"%)}";
+    s_logger->set_pattern(std::move(json_pattern));
+    #endif
+    #if 1
+    std::string logfmt_pattern = "time=%Y-%m-%dT%H:%M:%S.%f%z name=\"%n\" level=%^%l%$ process=%P thread=%t message=\"%v\"%( %K=\"%V\"%)";
+    s_logger->set_pattern(std::move(logfmt_pattern));
+    #endif
+
+    s_logger->push_context(spdlog::attribute_list{{"key\n1", "value\n1"}});
+    s_logger->info("structured logging: test 1");
+    s_logger->push_context(spdlog::attribute_list{{"key\n2", "value\n2"}});
+    s_logger->info("structured logging: test 2");
+    s_logger->pop_context();
+    s_logger->info("structured logging: test 3");
+    s_logger->pop_context();
+    s_logger->info("structured logging: test 4");
+    s_logger->clear_context();
 }

include/spdlog/logger.h

@@ -77,6 +77,7 @@ public:
         : logger(std::move(name), sinks.begin(), sinks.end())
     {}
 
+
     virtual ~logger() = default;
 
     logger(const logger &other);
@@ -84,10 +85,25 @@ public:
     logger &operator=(logger other) SPDLOG_NOEXCEPT;
     void swap(spdlog::logger &other) SPDLOG_NOEXCEPT;
 
-    template <typename T>
-    void log(level::level_enum lvl, const T &msg, attribute_list attrs)
-    {
-        log(source_loc{}, lvl, msg, attrs);
+    void push_context(attribute_list attrs) {
+        attributes.insert(attributes.end(), attrs.begin(), attrs.end());
+        attr_stack.push_back(static_cast<long>(attributes.size()));
+    }
+
+    void pop_context() {
+        if (attr_stack.size() > 1) {
+            attributes.erase(attributes.begin() + attr_stack[attr_stack.size() - 2], attributes.begin() + attr_stack[attr_stack.size() - 1]);
+            attr_stack.pop_back();
+        } else {
+            // is first element in stack, or empty. Delete the whole thing.
+            clear_context();
+        }
+    }
+
+    // removes context on loggers by clearing the attribute list
+    void clear_context() {
+        attributes.clear();
+        attr_stack.clear();
     }
 
     template<typename... Args>
@@ -125,23 +141,10 @@ public:
         }
 
         details::log_msg log_msg(log_time, loc, name_, lvl, msg);
+        log_msg.attributes.insert(log_msg.attributes.end(), attributes.begin(), attributes.end());
         log_it_(log_msg, log_enabled, traceback_enabled);
     }
 
-    void log(source_loc loc, level::level_enum lvl, string_view_t msg, attribute_list attrs)
-    {
-        bool log_enabled = should_log(lvl);
-        bool traceback_enabled = tracer_.enabled();
-        if (!log_enabled && !traceback_enabled)
-        {
-            return;
-        }
-
-        details::log_msg log_msg(loc, name_, lvl, msg);
-        // log_msg.attributes.push_back(attrs);
-        log_msg.attributes.insert(log_msg.attributes.end(), attrs.begin(), attrs.end());
-        log_it_(log_msg, log_enabled, traceback_enabled);
-    }
     void log(source_loc loc, level::level_enum lvl, string_view_t msg)
     {
         bool log_enabled = should_log(lvl);
@@ -152,6 +155,7 @@ public:
         }
 
         details::log_msg log_msg(loc, name_, lvl, msg);
+        log_msg.attributes.insert(log_msg.attributes.end(), attributes.begin(), attributes.end());
         log_it_(log_msg, log_enabled, traceback_enabled);
     }
 
@@ -221,6 +225,7 @@ public:
         memory_buf_t buf;
         details::os::wstr_to_utf8buf(wstring_view_t(msg.data(), msg.size()), buf);
         details::log_msg log_msg(log_time, loc, name_, lvl, string_view_t(buf.data(), buf.size()));
+        log_msg.attributes.insert(log_msg.attributes.end(), attributes.begin(), attributes.end());
         log_it_(log_msg, log_enabled, traceback_enabled);
     }
 
@@ -236,6 +241,7 @@ public:
         memory_buf_t buf;
         details::os::wstr_to_utf8buf(wstring_view_t(msg.data(), msg.size()), buf);
         details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
+        log_msg.attributes.insert(log_msg.attributes.end(), attributes.begin(), attributes.end());
         log_it_(log_msg, log_enabled, traceback_enabled);
     }
 
@@ -281,43 +287,6 @@ public:
     }
 #endif
 
-    // attributes endpoint
-    template<typename T>
-    void trace(const T &msg, attribute_list attrs)
-    {
-        log(level::trace, msg, attrs);
-    }
-
-    template<typename T>
-    void debug(const T &msg, attribute_list attrs)
-    {
-        log(level::debug, msg, attrs);
-    }
-
-    template<typename T>
-    void info(const T &msg, attribute_list attrs)
-    {
-        log(level::info, msg, attrs);
-    }
-
-    template<typename T>
-    void warn(const T &msg, attribute_list attrs)
-    {
-        log(level::warn, msg, attrs);
-    }
-
-    template<typename T>
-    void error(const T &msg, attribute_list attrs)
-    {
-        log(level::err, msg, attrs);
-    }
-
-    template<typename T>
-    void critical(const T &msg, attribute_list attrs)
-    {
-        log(level::critical, msg, attrs);
-    }
-
     // default endpoint
     template<typename T>
     void trace(const T &msg)
@@ -413,6 +382,9 @@ protected:
     err_handler custom_err_handler_{nullptr};
     details::backtracer tracer_;
 
+    attribute_list attributes;
+    std::vector<long> attr_stack; // used to push/pop nested contexts
+
     // common implementation for after templated public api has been resolved
     template<typename... Args>
     void log_(source_loc loc, level::level_enum lvl, string_view_t fmt, Args &&... args)
@@ -433,6 +405,7 @@ protected:
 #endif
 
             details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
+            log_msg.attributes.insert(log_msg.attributes.end(), attributes.begin(), attributes.end());
             log_it_(log_msg, log_enabled, traceback_enabled);
         }
         SPDLOG_LOGGER_CATCH(loc)
@@ -458,7 +431,8 @@ protected:
             memory_buf_t buf;
             details::os::wstr_to_utf8buf(wstring_view_t(wbuf.data(), wbuf.size()), buf);
             details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
-            log_it_(log_msg, log_enabled, traceback_enabled);
+            log_msg.attributes.insert(log_msg.attributes.end(), attributes.begin(), attributes.end());
+            log_og_msg, log_enabled, traceback_enabled);
         }
         SPDLOG_LOGGER_CATCH(loc)
     }

include/spdlog/pattern_formatter-inl.h

@@ -1145,8 +1145,8 @@ SPDLOG_INLINE void pattern_formatter::format(const details::log_msg &msg, memory
                 f->format(msg, cached_tm_, dest);
         }
     } else {
-    // ugly formatter iterator, due to needing to go back to previous iterators to repeat kv pairs
     auto it_end = formatters_.begin();
+    // ugly formatter iterator, due to needing to go back to previous iterators to repeat kv pairs
     for (auto it = formatters_.begin(); it != formatters_.end(); ++it)
     {
         if ((*it)->flag_ == details::attr_flags::start) {