COAR PingPong with two DSpace8 servers

[Jens Witzel]

Hello everyone

 

Question: Who has ever successfully set up two DS8 instances and had them feed each other via LDN and COAR?

 

For a better understanding in the future (and to take a closer look at the killer feature ‘COAR Notify’ of DS8), we have set up two DS8 instances and are now working on the configs and the documentation on https://wiki.lyrasis.org/display/DSDOC8x/COAR+Notify. As we understand it, the local.cfg on both servers (I'll call them A and B) is extended by *ldn.enabled=true *and then administered via the ‘COAR Notify’ admin menu:

 

* Dashboard provides a nice overview of the ‘Number of

received LDN’ and ‘Number of generated LDN’, i.e. Inbox/Outbox

* LDN Services contains profiles about when, who and about what

is informed

 

This all looks very clear there - big praise to the makers 😊

 

Now we have set up the profiles on both A and B to the best of our knowledge and belief and classified them as mutually trustworthy. Everything according to the instructions https://wiki.lyrasis.org/display/DSDOC8x/COAR+Notify

 

If I now create a public item on one of the two servers, the LDN message should go out to the other ... but the dashboard and the logs remain empty.

 

What else needs to be activated or configured?

 

The database has tables with the names notifypatterns_to, and notifyservice_inbound_pattern.

 

Who has experience here? A hint as to what we are thinking wrong, which logs we should look at or what we should debug would be great.

 

Many thanks and greetings from Zurich

Jens & Martin

 

--
Jens Witzel
Universität Zürich
Zentrale Informatik
Pfingstweidstrasse 60B
CH-8005 Zürich

mail:  jens....@uzh.ch
phone: +41 44 63 56777
http://www.zi.uzh.ch

 

 

[DSpace Technical Support]

Hi Jens,

I know this is possible, but documentation is currently missing it seems.  This feature to allow two DSpace sites to communicate via Notify was added by the 4Science team.  

Here's the ticket where it was initially described (including a link to a video that shows the expected behavior): https://github.com/DSpace/DSpace/issues/9644    Here's the PRs where the behavior was added https://github.com/DSpace/DSpace/pull/9645 and https://github.com/DSpace/dspace-angular/pull/3113    (The first of those PRs has the basic steps listed for how to configure two DSpaces to talk to one another.)

If you manage to get it working, I'd very much appreciate better documentation in this area.  It seems to not yet be documented in any of the pages under https://wiki.lyrasis.org/display/DSDOC8x/COAR+Notify   So, if you (or anyone else reading this) are interested in helping to better document this, I'd appreciate it.

Tim

[Jens Witzel]

Thx Tim, once again

very interesting what Andrea Bollini from 4Science was presenting at  COAR Conference – that was exactly what I want to *see* playing with two DS8. What I want to *know* is how “Notifocations QA” and “COAR Notify / LDN Service” were configured, and what else is needed in local.cfg (I think I read the 4Science and Lyrasis documentation multiple times and tried out a lot).

 

I’ll ask Andrea or if anybody in this round has experience and screenshots or ideas to share - I would welcome that very much. => PM me. Once it is running – I swear – I’ll enrich the documentation! 😊

Kind regards
Jens

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[DSpace Technical Support]

Hi Jens (and all),

I've just noticed that Stefano Maffei from the 4Science team was busy adding this documentation to our DSpace Documentation over the last few days.  See https://wiki.lyrasis.org/display/DSDOC8x/Use+Cases+-+Getting+two+DSpace+application+to+communicate+with+each+other    Thanks to Stefano!

Tim

[Jens Witzel]

Dear Tim

 

Sounds good! I’ll have a look at it and try it out … coming back here with my experience

THX
Jens

 

--
Jens Witzel
Universität Zürich

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[Jens Witzel]

Hi Tim and all

 

So, as I understand there is nothing realized  but Announce Relationship belonging to COAR in DSpace8.x. This is a bit confusing, because I’ll find 4 supported pattern to choose from but only one should work… nevertheless: thx for development and documentation @4Science! 😊

 

Unfornunately the documentation is not practicable – yet: the global overview, the important entries in local.cfg, the ‘Quality Assurance’ registration and the ‘Notification / LDN Service’ eintries and the understanding of the scheduler … they are all not 1:1 copy/paste usable, but once I’ve got it working on my two DS instances I’ll add my experience in https://wiki.lyrasis.org/display/DSDOC8x/Use+Cases+-+Getting+two+DSpace+application+to+communicate+with+each+other. I will continue and am grateful for any help.

THX to all involved, 1^st of all to Stefano Maffei from the 4Science team
Jens

 

--
Jens Witzel
Universität Zürich
Zentrale Informatik
Pfingstweidstrasse 60B
CH-8005 Zürich

mail:  jens....@uzh.ch
phone: +41 44 63 56777
http://www.zi.uzh.ch

 

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[Jens Witzel]

Dear Tim

 

Unfortunately the docu from 4sience has a lot unsolved issues. E.g.

 

LDN Inbox URL: this is the url used to send the LDN Notifications. 

This url is also used when a notification is received to retrieve the registered LDN service it belongs to

This URL must is unique among the registered LDN Services

 

But config/modules/ldn.cfg says

#LDN message inbox endpoint

ldn.notify.inbox = ${dspace.server.url}/ldn/inbox

 

and

 

Service URL: the url of the remote Notify Service. This is mostly used as a descriptive URL when sending notification to an external system.

The service URL must not be confused with the inbox url. As said this url is descriptive so we expect the main application URL to be added here

 

So coming back to their documentation on https://wiki.lyrasis.org/display/DSDOC8x/Use+Cases+-+Getting+two+DSpace+application+to+communicate+with+each+other

 

• in the example screenshot, they’re both the same. That’s confusing me. I ask for screenshots of LDN Service from each server. In the wiki page both entries are pointing on https://dspace-coar.4sience.cloud
• and I asked for local.cfg or other modules where notification and ldn are specified

 

All in all we want to let it run and I’m happy to add this to the wiki if it runs 😉
THX
Jens

 

--
Jens Witzel
Universität Zürich
Zentrale Informatik
Pfingstweidstrasse 60B
CH-8005 Zürich

mail:  jens....@uzh.ch
phone: +41 44 63 56777
http://www.zi.uzh.ch

 

[Jens Witzel]

Dear Tim, dear group

 

After countless installation steps, tests, debugging with 4Science and grey hair, I managed to get the COAR / LDN messaging between 2 DSpace instances. Tons of rocks are falling from my chest #-). The thing is still so fragile in development, but we can prove that a decentralised network of repositories can exchange data via COAR.

Sender and receiver are running. I’ll put all together in a short “use case” documentation soon.

THX to everyone who helped, especially Stefano from 4Science ❤

Jens

 

--
Jens Witzel
Universität Zürich
Zentrale Informatik
Pfingstweidstrasse 60B
CH-8005 Zürich

mail:  jens....@uzh.ch
phone: +41 44 63 56777
http://www.zi.uzh.ch

 

To view this discussion visit https://groups.google.com/d/msgid/dspace-tech/GV0P278MB0163356800242A8A6CB3A0039DD92%40GV0P278MB0163.CHEP278.PROD.OUTLOOK.COM.