in_kafka: add support to switch to auto-commit

Polling every 1ms and committing each message individually
results in rather pure performance in high volume Kafka
clusters.

Commiting in batches (relay on auto-commit of kafka)
drastically improves performance.

Signed-off-by: CoreidCC <[email protected]>

Author: coreidcc

plugins/in_kafka/in_kafka.c

@@ -180,8 +180,11 @@ static int in_kafka_collect(struct flb_input_instance *ins,
 
         rd_kafka_message_destroy(rkm);
 
-        /* TO-DO: commit the record based on `ret` */
-        rd_kafka_commit(ctx->kafka.rk, NULL, 0);
+        
+        if(!ctx->enable_auto_commit) {
+            /* TO-DO: commit the record based on `ret` */
+            rd_kafka_commit(ctx->kafka.rk, NULL, 0);
+        }
 
         /* Break from the loop when reaching the limit of polling if available */
         if (ctx->polling_threshold != FLB_IN_KAFKA_UNLIMITED &&
@@ -428,6 +431,11 @@ static struct flb_config_map config_map[] = {
     0, FLB_TRUE, offsetof(struct flb_in_kafka_config, buffer_max_size),
     "Set the maximum size of chunk"
    },
+   {
+    FLB_CONFIG_MAP_BOOL, "enable_auto_commit", FLB_IN_KAFKA_ENABLE_AUTO_COMMIT,
+    0, FLB_TRUE, offsetof(struct flb_in_kafka_config, enable_auto_commit),
+    "Rely on kafka auto-commit and commit messages in batches"
+   },
    /* EOF */
    {0}
 };

plugins/in_kafka/in_kafka.h

@@ -32,6 +32,7 @@
 #define FLB_IN_KAFKA_DEFAULT_FORMAT        "none"
 #define FLB_IN_KAFKA_UNLIMITED             (size_t)-1
 #define FLB_IN_KAFKA_BUFFER_MAX_SIZE       "4M"
+#define FLB_IN_KAFKA_ENABLE_AUTO_COMMIT    "false"
 
 enum {
     FLB_IN_KAFKA_FORMAT_NONE,
@@ -48,6 +49,7 @@ struct flb_in_kafka_config {
     int coll_fd;
     size_t buffer_max_size;          /* Maximum size of chunk allocation */
     size_t polling_threshold;
+    bool enable_auto_commit;
 };
 
 #endif