implement Simulate and globalize BufferLimit

pkg/sender/sender.go

@@ -2,6 +2,7 @@ package sender
 
 import (
 	"context"
+	"fmt"
 	"log"
 	"time"
 
@@ -56,13 +57,7 @@ func (queue Queue) Sender(db *mongo.Collection, metricsFilename string, cancelOn
 
 		promShipperSynced.WithLabelValues(metricsFilename).Set(0)
 
-		var batchBson []interface{} // mongo does not like typing
-		for _, b := range batch {
-			batchBson = append(batchBson, b.ToBson())
-		}
-
-		tru := true
-		result, err := db.InsertMany(globals.MongoTimeout(context.Background()), batchBson, &options.InsertManyOptions{Ordered: &tru})
+		result, err := insertManyWithSimulate(db, batch)
 
 		var succeedCount int
 		if result != nil {
@@ -89,3 +84,24 @@ func (queue Queue) Sender(db *mongo.Collection, metricsFilename string, cancelOn
 		}
 	}
 }
+
+func insertManyWithSimulate(db *mongo.Collection, batch []m.Record) (*mongo.InsertManyResult, error) {
+	if !globals.Simulate {
+		var batchBson []interface{} // mongo does not like typing
+		for _, b := range batch {
+			batchBson = append(batchBson, b.ToBson())
+		}
+
+		tru := true
+		return db.InsertMany(globals.MongoTimeout(context.Background()), batchBson, &options.InsertManyOptions{Ordered: &tru})
+	}
+
+	fmt.Printf("simulating successful database bulk write: %v", batch)
+
+	var res mongo.InsertManyResult
+	for range batch {
+		res.InsertedIDs = append(res.InsertedIDs, nil)
+	}
+
+	return &res, nil
+}