Add a MongoDB connector to the exporting engine (#8416)

* Copy files from the MongoDB backend

* Update the documentation

* Rename functions in the MongoDB backend

* Add the connector to the Netdata build

* Add an initializer and a worker

* Add specific configuration options

* Initialize the connector

* Add a ring buffer for inserting data to a MongoDB database

* Add unit tests

1 files changed, 6 insertions, 0 deletions

diff --git a/exporting/exporting_engine.h b/exporting/exporting_engine.h
index 6a8296a19b..1a3a3ecd09 100644
--- a/exporting/exporting_engine.h
+++ b/exporting/exporting_engine.h
@@ -75,6 +75,11 @@ struct aws_kinesis_specific_config {
     char *secure_key;
 };
 
+struct mongodb_specific_config {
+    char *database;
+    char *collection;
+};
+
 struct engine_config {
     const char *prefix;
     const char *hostname;
@@ -140,6 +145,7 @@ struct engine {
     time_t now;
 
     int aws_sdk_initialized;
+    int mongoc_initialized;
 
     struct instance *instance_root;
 };