C#•3y ago•

7 replies

Why Events Inserted Twice by EF Core?

Hi guys hope you're doing well,
I'm working on the following project : https://github.com/MbarkT3STO/ExpenovaApp
This project implemented using

Microservices Architecture

Microservices Architecture

I have a service called

Event-Sourcerer Service

Event-Sourcerer Service

, this service is responsible about applying

event-sourcing

event-sourcing

for others services databases records, of course this services communicate with others using

RabbitMQ

RabbitMQ

and

MassTransit

MassTransit

.
You can take a look on that service here : https://github.com/MbarkT3STO/ExpenovaApp/tree/main/Source/EventSourcererService

This service contains some

Message Consumers

Message Consumers

( classes where each one responsible to consume/handle a specific

Queue

Queue

's messages ).
This service uses

EF Core

EF Core

with

PostgreSQL

PostgreSQL

as data persistence.
After a

Servie X

Servie X

published an

Event

Event

that happened in it, and the

Event Handler

Event Handler

from that

Service X

Service X

will publish a copy of that event as a

Message

Message

RabbitMQ

RabbitMQ

then the

Consumers

Consumers

from the

Event-Sourcerer Service

Event-Sourcerer Service

will do their job by adding the message they are responsible for into the

Event-Sources

Event-Sources

database.

The issue: Is my consumers adding the event to database twice
To fix this issue I have created a service to handle the

Deduplication mechanism

Deduplication mechanism

as separated class called

DatabaseMessageDeduplicationService

DatabaseMessageDeduplicationService

you could take a look at it here : https://github.com/MbarkT3STO/ExpenovaApp/blob/main/Source/EventSourcererService/Services/DatabaseMessageDeduplicationService.cs

That class

DatabaseMessageDeduplicationService

DatabaseMessageDeduplicationService

is responsible about processing messages too.
So, for proccessing messages this class contains a method called

ProccessMessage

ProccessMessage

as following:

    public async Task ProcessMessage(Expression<Func<Task>> processMessageFunc)
    {
        await processMessageFunc.Compile().Invoke();
    }

    public async Task ProcessMessage(Expression<Func<Task>> processMessageFunc)
    {
        await processMessageFunc.Compile().Invoke();
    }

This method take a

func

func

/method from a

consumer

consumer

, that method consumer will contains the code to process the message and this

DatabaseMessageDeduplicationService

DatabaseMessageDeduplicationService

only invoking it.

Why Events Inserted Twice by EF Core?

Hi guys hope you're doing well,
I'm working on the following project : https://github.com/MbarkT3STO/ExpenovaApp
This project implemented using

Microservices Architecture

Microservices Architecture

I have a service called

Event-Sourcerer Service

Event-Sourcerer Service

, this service is responsible about applying

event-sourcing

event-sourcing

for others services databases records, of course this services communicate with others using

RabbitMQ

RabbitMQ

and

MassTransit

MassTransit

.
You can take a look on that service here : https://github.com/MbarkT3STO/ExpenovaApp/tree/main/Source/EventSourcererService

This service contains some

Message Consumers

Message Consumers

( classes where each one responsible to consume/handle a specific

Queue

Queue

's messages ).
This service uses

EF Core

EF Core

with

PostgreSQL

PostgreSQL

as data persistence.
After a

Servie X

Servie X

published an

Event

Event

that happened in it, and the

Event Handler

Event Handler

from that

Service X

Service X

will publish a copy of that event as a

Message

Message

RabbitMQ

RabbitMQ

then the

Consumers

Consumers

from the

Event-Sourcerer Service

Event-Sourcerer Service

will do their job by adding the message they are responsible for into the

Event-Sources

Event-Sources

database.

The issue: Is my consumers adding the event to database twice
To fix this issue I have created a service to handle the

Deduplication mechanism

Deduplication mechanism

as separated class called

DatabaseMessageDeduplicationService

DatabaseMessageDeduplicationService

you could take a look at it here : https://github.com/MbarkT3STO/ExpenovaApp/blob/main/Source/EventSourcererService/Services/DatabaseMessageDeduplicationService.cs

That class

DatabaseMessageDeduplicationService

DatabaseMessageDeduplicationService

is responsible about processing messages too.
So, for proccessing messages this class contains a method called

ProccessMessage

ProccessMessage

as following:

    public async Task ProcessMessage(Expression<Func<Task>> processMessageFunc)
    {
        await processMessageFunc.Compile().Invoke();
    }

    public async Task ProcessMessage(Expression<Func<Task>> processMessageFunc)
    {
        await processMessageFunc.Compile().Invoke();
    }

This method take a

func

func

/method from a

consumer

consumer

, that method consumer will contains the code to process the message and this

DatabaseMessageDeduplicationService

DatabaseMessageDeduplicationService

only invoking it.

Why Events Inserted Twice by EF Core?

Why Events Inserted Twice by EF Core?

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