out_mongo: add MongoDB as default output plugin

MongoDB output plugin as a default plugin to ease the process of
setting up the connection between such databases and Fluent-bit.

I've opended an issue for the missing feature:

  #8846

Signed-off-by: Barnabas Ifkovics <ifkovics.barnabas@gmail.com>

CMakeLists.txt

@@ -258,6 +258,7 @@ option(FLB_OUT_VIVO_EXPORTER           "Enabel Vivo exporter output plugin"
 option(FLB_OUT_WEBSOCKET               "Enable Websocket output plugin"               Yes)
 option(FLB_OUT_ORACLE_LOG_ANALYTICS    "Enable Oracle Cloud Infrastructure Logging analytics plugin"          Yes)
 option(FLB_OUT_CHRONICLE               "Enable Google Chronicle output plugin"        Yes)
+option(FLB_OUT_MONGO                   "Enable MongoDB output plugin"                 Yes)
 option(FLB_FILTER_ALTER_SIZE           "Enable alter_size filter"                     Yes)
 option(FLB_FILTER_AWS                  "Enable aws filter"                            Yes)
 option(FLB_FILTER_ECS                  "Enable AWS ECS filter"                        Yes)
@@ -1048,6 +1049,13 @@ if(FLB_OUT_PGSQL AND (NOT PostgreSQL_FOUND))
    FLB_OPTION(FLB_OUT_PGSQL OFF)
 endif()
 
+# MongoDB
+# =======
+if(FLB_OUT_MONGO)
+  set(ENABLE_MONGOC ON)
+  add_subdirectory(${FLB_PATH_LIB_MONGO} EXCLUDE_FROM_ALL)
+endif()
+
 # Arrow GLib
 # ==========
 find_package(PkgConfig)

cmake/headers.cmake

@@ -39,6 +39,11 @@ include_directories(
   ${FLB_PATH_ROOT_SOURCE}/${FLB_PATH_LIB_CARES}/include
   ${FLB_PATH_ROOT_SOURCE}/${FLB_PATH_LIB_RING_BUFFER}/lwrb/src/include
 
+  ${FLB_PATH_ROOT_SOURCE}/${FLB_PATH_LIB_MONGO}/src/libmongoc/src
+  ${CMAKE_CURRENT_BINARY_DIR}/${FLB_PATH_LIB_MONGO}/src/libmongoc/src/mongoc
+  ${FLB_PATH_ROOT_SOURCE}/${FLB_PATH_LIB_MONGO}/src/libbson/src
+  ${CMAKE_CURRENT_BINARY_DIR}/${FLB_PATH_LIB_MONGO}/src/libbson/src
+
   ${CMAKE_CURRENT_BINARY_DIR}/${FLB_PATH_LIB_CARES}
   ${CMAKE_CURRENT_BINARY_DIR}/${FLB_PATH_LIB_JANSSON}/include
   ${CMAKE_CURRENT_BINARY_DIR}/lib/cmetrics

cmake/libraries.cmake

@@ -24,3 +24,4 @@ set(FLB_PATH_LIB_SNAPPY      "lib/snappy-fef67ac")
 set(FLB_PATH_LIB_RDKAFKA     "lib/librdkafka-2.3.0")
 set(FLB_PATH_LIB_RING_BUFFER "lib/lwrb")
 set(FLB_PATH_LIB_WASM_MICRO_RUNTIME  "lib/wasm-micro-runtime-WAMR-1.3.0")
+set(FLB_PATH_LIB_MONGO       "lib/mongo-c-driver")

plugins/CMakeLists.txt

@@ -341,6 +341,7 @@ REGISTER_OUT_PLUGIN("out_prometheus_remote_write")
 REGISTER_OUT_PLUGIN("out_s3")
 REGISTER_OUT_PLUGIN("out_vivo_exporter")
 REGISTER_OUT_PLUGIN("out_chronicle")
+REGISTER_OUT_PLUGIN("out_mongo")
 
 # FILTERS
 # =======

plugins/out_mongo/CMakeLists.txt

@@ -0,0 +1 @@
+FLB_PLUGIN(out_mongo "mongo.c" "")

plugins/out_mongo/mongo.c

@@ -0,0 +1,41 @@
+#include <fluent-bit/flb_utils.h>
+
+// USE: #include "mongo.h"
+#include <mongoc/mongoc.h>
+#include <fluent-bit/flb_output.h>
+
+static int cb_mongodb_init(struct flb_output_instance *ins, struct flb_config *config, void *data)
+{
+  mongoc_init();
+  printf("Init ran\n");
+  return 0;
+}
+
+static void cb_mongodb_flush(struct flb_event_chunk *event_chunk,
+                             struct flb_output_flush *out_flush,
+                             struct flb_input_instance *i_ins,
+                             void *out_context,
+                             struct flb_config *config)
+{
+  printf("Flush ran\n");
+  FLB_OUTPUT_RETURN(FLB_OK);
+}
+
+static int cb_mongodb_exit(void *data, struct flb_config *config)
+{
+  printf("Exit ran\n");
+  return 0;
+}
+
+struct flb_output_plugin out_mongo_plugin = {
+    .name         = "mongo",
+    .description  = "MongoDB",
+    .cb_init      = cb_mongodb_init,
+    .cb_pre_run   = NULL,
+    .cb_flush     = cb_mongodb_flush,
+    .cb_exit      = cb_mongodb_exit,
+    .config_map   = NULL,
+    .flags        = FLB_OUTPUT_NET | FLB_IO_OPT_TLS,
+    .event_type   = FLB_OUTPUT_LOGS | FLB_OUTPUT_METRICS
+};
+

plugins/out_mongo/mongo.h

@@ -0,0 +1,10 @@
+#ifndef FLB_OUT_MONGO_H
+#define FLB_OUT_MONGO_H
+
+#define FLB_MONGODB_LOCALHOST "127.0.0.1"
+#define FLB_MONGODB_PORT 8988
+
+struct flb_mongodb {
+};
+
+#endif // FLB_OUT_MONGO_H

src/CMakeLists.txt

@@ -474,6 +474,10 @@ if(FLB_JEMALLOC)
   target_link_libraries(fluent-bit-static libjemalloc)
 endif()
 
+if(FLB_OUT_MONGO)
+  target_link_libraries(fluent-bit-static mongoc_static)
+endif()
+
 # Binary / Executable
 if(FLB_BINARY)
   find_package (Threads)