Blog post from a specific blog not displayed

[kamil-mrzyglod]

Hi,

is there any possibility to get some idea why blog posts from my blog are not displayed on the website? :) I've checked this locally and RSS feed returns correctly formatted output - all blogs are displayed correctly.

Maybe there's some issue in MongoDB? I saw this issue on other blogs also, but it disappeared after a day or two. In this particular case it lasts a month at least.

What is more initially it worked flawlessly.

Best regards, Kamil

[pawlos]

It looks like it's working ok now - closing.

[kamil-mrzyglod]

@pawlos It appeared again yesterday after update - no idea what's wrong :)

[pawlos]

@kamil-mrzyglod yeah, I can see that. What update are we talking about? The update on your page or this one?

[kamil-mrzyglod]

I believe two things happened since yesterday(correct me if I'm wrong):

• the page was updated with a new pull request
• blogs were fetched by a job

Personally I think that something happens when a background job regarding blogs runs, but I can't point an issue.

[meaboutsoftware]

It is happening from time to time. Personally, I think that it might be caused by temporary unavailability of RSS channel while the background job is running. Then no data will be fetched.

Of course, right now this is a guessing from my side. As I did the original version of RSS fetching for blogs, I will try to take a look at this problem at weekend.

[kamil-mrzyglod]

@jedmac It's perfectly fine. If you find something related to this problem please let me know, I'm willing to help here.

[pawelklimczyk]

how about adding a unit test and check how system behaves when RSS is not available ?

[meaboutsoftware]

@pawelklimczyk unit tests are a good idea in this area for documenting but not for checking how the system behaves - this is clear, when RSS is not available or there was a problem it returns an empty enumerable. But we can add some logging there within a try/catch. As I said before, I will take a look on it during the weekend.

[pawlos]

@jedmac what's the state of this one?

[Lazys]

I've added my blog yesterday (poznajprogramowanie.pl) and the same problem occured.

On localhost everything works correctly:

Is there any possibility to check out logs from production? I've looked to config files and it seems like Nlog logs everything to console. Am I wrong?

[pawlos]

@Lazys I can see posts there. I think there's a short delay between check-in and when the posts appear on the page. I would close this one if no-one is working on it

[Lazys]

@pawlos ok, I see them too right now.

[pawelklimczyk]

@Lazyr @pawlos the blogs are updated periodically

There is a background job BlogsUpdateJob that is executed every 8 hours. That's why new blog entries appear with delay

[meaboutsoftware]

As mentioned before - when job runs and there is a probem with reading RSS or unavailability of blog, then no posts will be shown. We can think about scheduling this job each 2 hours or caching - when there is empty enumerable returned, check if there is old content available and show it instead of nothing. @pawelklimczyk what do you think about it?

[pawlos]

Well it's kind of tricky thing. If the blog/rss is unavailable does it make sense to display old posts? Links will be broken anyway. I would rather hide those that are empty so that they are no blank spots.

[meaboutsoftware]

Not exactly. Current problem is that if during the update job, blog/rss iss unavailable, then it shows empty content. But for sure there is a situation when after 1h blog is working again and then the content needs to wait another 7h to be updated. Old links will not work only if blog is unavailable while clicking on the link. In all other cases we could show then old, cached version as links will not change.

But hiding would also be an option and I also like it.

[pawlos]

Well my understanding is this. If RSS is offline then blog is offline too. Maybe it will be back in one minute, maybe not. Maybe it will be offline for two weeks.

I think the issue here is that the scheduler is set to 8h - don't know why @pawelklimczyk chose such big interval. 1-2h should be ok so that we do not request too often but also give the nice refresh rate of the content.

I would go with this:

• put the interval to 2h
• when reading the RSS fails, try 2 more times before giving up
• hide entries that doesn't have any links present

In the future (when user accounts are present) give admin the ability to re-run the job.

[pawelklimczyk]

I've changed interval to 2h and added retry for blog retrieval.

So now if blog rss is not accessible several times empty list is returned (as it was)