esp_log: Implemented esp_log_level_get(TAG)

Closes https://github.com/espressif/esp-idf/pull/6573

components/log/include/esp_log.h

@@ -71,6 +71,16 @@ extern esp_log_level_t esp_log_default_level;
  */
 void esp_log_level_set(const char* tag, esp_log_level_t level);
 
+/**
+ * @brief Get log level for given tag, can be used to avoid expensive log statements
+ *
+ * @param tag Tag of the log to query current level. Must be a non-NULL zero terminated
+ *            string.
+ *
+ * @return The current log level for the given tag
+ */
+esp_log_level_t esp_log_level_get(const char* tag);
+
 /**
  * @brief Set function used to output log entries
  *

components/log/log.c

@@ -141,6 +141,25 @@ void esp_log_level_set(const char *tag, esp_log_level_t level)
     esp_log_impl_unlock();
 }
 
+esp_log_level_t esp_log_level_get(const char* tag)
+{
+    esp_log_impl_lock();
+    esp_log_level_t level_for_tag;
+    // Look for the tag in cache first, then in the linked list of all tags
+    if (!get_cached_log_level(tag, &level_for_tag)) {
+        if (!get_uncached_log_level(tag, &level_for_tag)) {
+            level_for_tag = esp_log_default_level;
+        }
+        add_to_cache(tag, level_for_tag);
+#ifdef LOG_BUILTIN_CHECKS
+        ++s_log_cache_misses;
+#endif
+    }
+    esp_log_impl_unlock();
+
+    return level_for_tag;
+}
+
 void clear_log_level_list(void)
 {
     uncached_tag_entry_t *it;