MongoDB Golang UpdateOne array - mongodb

Question

I made a method UpdateMessage to update the message, I can only update a few fields: message.body, message.update_at and message.modifications array
Below I attached a method that I wrote, I do NOT get an error, none at all, but the data are not updated, if I make a query to the database and check after calling this method, the data will not change.
What am I doing wrong when trying to update a database record?
Is there anything I can do to simplify the ChangeMessage method, namely to get rid of passing the old message to the new one by parameters? I need each message to keep the old version of the message in the message.modifications field if the data changes?
type Message struct {
ID string `json:"id" bson:"id"`
ChatID string `json:"chat_id" bson:"chat_id"`
FromID string `json:"from_id" bson:"from_id"`
CreateDate int64 `json:"create_date" bson:"create_date"`
Type string `json:"type" bson:"type"`
Media string `json:"media" bson:"media"`
Body string `json:"body" bson:"body"`
UpdateAt int64 `json:"update_at" bson:"update_at"`
Modifications []*Message `json:"modifications,omitempty" bson:"modifications"`
Viewed bool `json:"viewed" bson:"viewed"`
}
func (srv *Service) ChangeMessage(ctx context.Context, message *Message) error {
...
chat, err := srv.db.Chat.Find(ctx, &Chat{ID: message.ChatID})
msg, err := srv.db.Chat.FindMessage(ctx, &Message{
ID: message.ID,
ChatID: chat.ID,
FromID: uid,
})
....
message.Modifications = msg.Modifications
message.Modifications = append(message.Modifications, msg)
message.FromID = msg.FromID
message.CreateDate = msg.CreateDate
message.Type = msg.Type
message.Media = msg.Media
message.ChatID = msg.ChatID
message.Viewed = msg.Viewed
err = srv.db.Chat.UpdateMessage(ctx, message)
.......
}
func (m *Mongo) UpdateMessage(ctx context.Context, msg *Message) error {
...
update := bson.M{
"$set": bson.M{
"body": msg.Body,
"update_at": time.Now().UnixMilli(),
},
"$push": bson.M{
"modifications": msg.Modifications,
},
}
_, err := m.col.UpdateOne(ctx, bson.M{"id": msg.ID}, update, options.Update().SetUpsert(true))
....
}

Answer 1

Let me try to help here. I put together a small example to show you how to deal with your scenario (at least for the updating issue):
package main
import (
"context"
"fmt"
"strings"
"time"
"go.mongodb.org/mongo-driver/bson"
"go.mongodb.org/mongo-driver/mongo"
"go.mongodb.org/mongo-driver/mongo/options"
)
var (
ctx context.Context
cancel context.CancelFunc
)
type Message struct {
ID string `json:"id" bson:"id"`
Name string `json:"name" bson:"name"`
}
func main() {
ctx, cancel = context.WithTimeout(context.Background(), 20*time.Second)
defer cancel()
// set MongoDB connection
clientOptions := options.Client().ApplyURI("mongodb://root:root#localhost:27017")
mongoClient, err := mongo.Connect(ctx, clientOptions)
if err != nil {
panic(err)
}
defer mongoClient.Disconnect(ctx)
// select collection
collection := mongoClient.Database("demodb").Collection("myCollection")
defer collection.Drop(ctx)
fmt.Println("original documents")
// insert some random msg
if _, err := collection.InsertMany(ctx, []interface{}{
Message{"1", "John Doe"},
Message{"2", "Suzy Lee"},
}); err != nil {
panic(err)
}
// get records
var messagesTmp []bson.M
cursorTmp, err := collection.Find(ctx, bson.M{})
if err != nil {
panic(err)
}
if err := cursorTmp.All(ctx, &messagesTmp); err != nil {
panic(err)
}
for _, v := range messagesTmp {
fmt.Println(v)
}
fmt.Println(strings.Repeat("#", 100))
// update
var updateRes *mongo.UpdateResult
if updateRes, err = collection.UpdateOne(ctx,
bson.M{"name": "John Doe"},
bson.D{
bson.E{
Key: "$set",
Value: bson.D{
bson.E{
Key: "name",
Value: "John Doe - Edited",
},
},
},
},
); err != nil {
panic(err)
}
fmt.Println("num docs updated:", updateRes.ModifiedCount)
// list all
fmt.Println(strings.Repeat("#", 100))
fmt.Println("new documents")
var messages []Message
cursor, err := collection.Find(ctx, bson.M{})
if err != nil {
panic(err)
}
if err := cursor.All(ctx, &messages); err != nil {
panic(err)
}
for _, v := range messages {
fmt.Println(v)
}
}
With this code, you should be able to successfully update your documents in MongoDB. To give it a try, make sure to run MongoDB at the right address with the credentials expected in the code.
About the document versioning, I think that you're already following a kind of Document Versioning Pattern. You can find more about it at this link.
Let me know if this clarifies your doubts or if you need something else, thanks!