Subscriptions

EventStoreDB
1

Hello,

on application startup i’m subscribing with the C# client to all events i’m interested in with $et- using SubscribeToStreamFrom(…).

But in the early stage of the application lifetime not all events are in the event store (like e.g. CustomerDisabled). And i get a CatchUpError with an access denied exception. Not very helpful because i want to subscribe and handle them as soon as such an event is fired.

How can i subscribe to such events?

2

A catch up subscription will deliver them as they happen perhaps you can share your code? What user is the subscription being connected as?

3

If it’s subscribing to $et-whatever you will need to authenticate as ACL for system streams is admin only by default iirc. admin/changeit are the defaults.

However it seems you’re likely on a wrong course with subscribing like that, if you can share your code we can probably help.

James

4

Hello,

the EventStore is just running local and used without credentials for now.

The sample code for the dispatcher is available here: https://gist.github.com/dnauck/7231622

Each event handler (read model projections, etc) registers all events that it is handling in the dispatcher and then it add a subscription to $et-.

The SubscribeToAllFrom(…) was not working, as it also required admin permissions. And i don’t want to subscribe to all events, just the ones i need.

Thanks for your help.

Daniel

5

You are passing in the connection to this code. If I understand you properly you are not setting credentials on it. To read system streams such as $et or $all you need to have admin privs (or change the default acls to allow it). Try setting user credentials of user:changeit on your connection and things should work. Alternatively instead of using $et streams you could write your own projection that writes to user space streams and set privs on them how you see fit via stream metadata

https://github.com/eventstore/eventstore/wiki/Stream-Metadata-Parameters

https://github.com/eventstore/eventstore/wiki/Access-Control-Lists

Should be useful.

Cheers,

Greg

6

Hi Greg,

thank you. It works now.

I’m using the sample projection from your blog:

fromAll().

``when({

``$any : ``function``(s,e) { linkTo(``"EventType-" + e.type, e); }

``});

But is this the way to go in general or do you suggest any other way to go when subscribing to events?

Thanks.

7

If you want it in user space that’s correct. If you are running the $et system projection though you probably prefer to just use it’s streams as otherwise you do all the same work twice :slight_smile: just adding the credentials (or creating a different user and giving them admin rights) will allow you to subscribe to the system streams.

Cheers.

Greg