I've developed an application which connects to Neo4j and creates a bunch of nodes. I've also developed a plugin for Neo4j using Graphaware. And both these are run in separate dockers (one for the code and one for the Neo4j with plugin).
Now, since I start these containers automatically and simultaneously, the code should wait for the Neo4j to completely start before it tries creating the nodes. For that, I'm testing the availability of the Neo4j by trying to connect to it using bolt protocol (Neo4j's driver).
The problem I've got is that it seems Neo4j starts accepting incoming connections before it completely loads the plugins. As the result, the connection is made before Neo4j is actually prepared and also something goes wrong (I don't know what) and the whole code halts (I don't think this issue is important) all because the connection is made before the plugins are loaded. I know that since if I delay the connection manually, everything goes forward smoothly.
So my question is how to make sure that Neo4j is warmed up (fully) before starting to connect to it? Right now I'm checking the availability of management (http://localhost:7474) but what if there's no management, to begin with?
At the moment you'll find that you can keep the management interface local, but you can't actually turn it off (unless you're working in embedded mode), so waiting for http://localhost:7474 is a good approach. If you want to be more fine-grained, you can check yourinstallation\logs\debug.log
2017-07-27 03:58:53.643+0000 INFO [o.n.k.AvailabilityGuard] Fulfilling of requirement makes database available: Database available
2017-07-27 03:58:53.644+0000 INFO [o.n.k.i.f.GraphDatabaseFacadeFactory] Database is now ready
Hope this helps.
Regards,
Tom
Related
I have a windows service running using Topshelf. This service makes a lot of SQL server queries. When the hosting computer is restarted it almost always causes errors in my service due to SQL Server stopping in the middle of my service making a query. I've been asked to solve this so the logs won't have so many errors as these computers are restarted frequently.
Topshelf has some built-in WhenShutdown logic that you can use to run when the computer is shutdown/restarted, but there is still no guarantee that my service will stop before SQL Server, and based on the error frequency it pretty much always happens that way. I have tried to also use Topshelfs WhenCustomCommandReceived to listen for windows PreShutdown event as shown here, but my tests when logging any custom command received and then rebooting my computer shows no logs. I also tried adding SQL Server as a dependency to my service, but this still doesn't guarantee mine will stop before SQL Server.
I have also tried adding in the logic from this solution, but again I never see any logs indicating this code is even being executed on a restart. Any tips on how I can better solve this issue?
tldr: how to ensure my topshelf service stops before SQL server on a computer restart/shutdown
Thanks!
I want to create and host a file on a remote server and allow cytoscape to poll it every time it starts up to see if there are any changes. I'm not sure where to even start with that. Was hoping I might get some information here.
Actually, it's pretty easy. As part of your app initialization in your CyActivator, you could easily poll your remote site. The CyActivator start method gets called when Cytoscape starts up (or you app changes). I would strongly suggest that you do your poll in a separate thread since Cytoscape won't actually start until your start method returns...
-- scooter
I've spent a fair amount of time researching and I've not found a solution to my problem that I'm comfortable with. My app is working in a dockerized environment:
one container for the database;
one or more containers for the APP itself. Each container holds a specific version of the APP.
It's a multi-tenant application, so each client (or tenant) may be related to only one version at a time (migration should be handle per client, but that's not relevant).
The problem is I would like to have another container to handle scheduling jobs, like sending e-mails, processing some data, etc. The scheduler would then execute commands in app's containers. Projects like Ofelia offer a great promise but I would have to know the container to execute the command ahead of time. That's not possible because I need to go to the database container to discover which version the client is in, to figure it out what container the command should be executed in.
Is there a tool to help me here? Should I change the structure somehow? Any tips would be welcome.
Thanks.
So your question is you want to get the APP's version info in the database container before scheduling jobs,right?
I think this is relate to the business， not the dockerized environment,you may have ways to slove the problem:
Check the network ,make sure the network of the container can connect to each other
I think the database should support RPC function,you can use it to get the version data
You can use some RPC supported tools,like SSH
I've been trying to set up a Redmine on google compute engine with the mysql 5.5 database hosted on google cloud sql (d1, 512mb of ram, always-on, europe, package-billed).
Unfortunately, Redmine stops responding (really stops, I set the timeout to 1hour and nothing happens) to requests after a few minutes. Using newrelic I found out that it's database-related - ActiveRecord seems to have some problems with the database ..
In order to find out if the problems are really related to the cloud sql database, I set up a new database on my own server and it's working fine since then. So there definitely is an issue with the cloud sql database and redmine/ruby.
Does anyone have an idea what I can try to solve the problem?
Best,
Jan
GCE idle connections are closed automatically after 10 minutes as explained in [1]. As you are connecting to CloudSQL from a GCE instance, this is most likely the cause for your issue.
Additionally, take into account Cloud SQL instances can go down and come back anytime due to maintenances and connections must be managed accordingly. Checking the CloudSQL instance operation list would confirm this. Hope this helps.
[1] https://cloud.google.com/sql/docs/gce-access
We have a MVC 3 application which has been deployed onto a newly built Windows 2008 R2 Web Edition server which is performing badly.
This application has been through development, quality assurance and user acceptance testing cycles on the same operating system (different boxes) with no performance issues.
The only difference we can see with the server is that it sits in the DMZ and as such has two network adapters configured, one for the internet, and one to punch through the firewall.
We have put all sorts of logging into the application and confirmed that up until the 'return ActionResult' everything is working correctly (ie ~500ms). It then takes 15 seconds to render the page.
We have tried turning on debug=false in the config file, i'm not sure what else to look for here, it seems like an environment issue.
Any suggestions please ? I am about to investigate if the thread pool size could be causing problems.
Also, if it helps the page is using multiple partial views, i have read others having problems with them.
Thanks,
Matt
Since the application performs ok in other environments I would suggest you investigate following:
Database - are you running against different database? How long the queries execute? If you have non-optimized database with million records on production, and only few records in test you want find performance problems soon enough.
Network - what is the latency between web box and database? If you loose 100ms for each database query just because of network than if your page triggers 50 queries you've lost 5secs. I've seen poorly configured routers / load balancers that were doing just that.
Try profiling each component of your system (db, network, web box) in order to find out where you're wasting all that time. Try http://code.google.com/p/mvc-mini-profiler/.
PS. You MUST have debug=false in your prod env.