Log error in case consumer destructor throws

Author: accelerated

Diff for: include/cppkafka/exceptions.h

@@ -38,6 +38,18 @@
 
 namespace cppkafka {
 
+// Based on syslog.h levels
+enum LogLevel {
+    LOG_EMERG   = 0,    /* system is unusable */
+    LOG_ALERT   = 1,    /* action must be taken immediately */
+    LOG_CRIT    = 2,    /* critical conditions */
+    LOG_ERR     = 3,    /* error conditions */
+    LOG_WARNING = 4,    /* warning conditions */
+    LOG_NOTICE  = 5,    /* normal but significant condition */
+    LOG_INFO    = 6,    /* informational */
+    LOG_DEBUG   = 7     /* debug-level messages */
+};
+
 /**
  * Base class for all cppkafka exceptions
  */

Diff for: src/consumer.cpp

@@ -26,7 +26,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  */
-
+#include <sstream>
 #include "consumer.h"
 #include "exceptions.h"
 #include "configuration.h"
@@ -73,9 +73,17 @@ Consumer::~Consumer() {
         rebalance_error_callback_ = nullptr;
         close();
     }
-    catch (const Exception&) {
-        // If close throws just silently ignore until there's some
-        // logging facility (if any)
+    catch (const Exception& ex) {
+        constexpr const char* library_name = "cppkafka";
+        std::ostringstream error_msg;
+        error_msg << "Failed to close consumer [" << get_name() << "]: " << ex.what();
+        const auto& callback = get_configuration().get_log_callback();
+        if (callback) {
+            callback(*this, LogLevel::LOG_ERR, library_name, error_msg.str());
+        }
+        else {
+            rd_kafka_log_print(get_handle(), LogLevel::LOG_ERR, library_name, error_msg.str().c_str());
+        }
     }
 }