Clojurians Log v2

we haven’t had need for stopping the background stuff

an outage? what does it mean “cluster node goes down”?

If for some reason a machine needs to be replaced (an auto-scaling event, for example), it wont be.

Hello! We are getting timeouts in this step of codedeploy consistently

aws s3 cp <s3://datomic-code-92caa718-792a-4ced-9b36-16d4c09dabd4/datomic/libs/mvn> /home/datomic/.cognitect-s3-libs/.m2/repository --recursive --only-show-errors --exclude * --include crisptrutski/boot-cljs-test/0.2.2-20160402.204547-3.zip

What's you aproach to doing analytics? Is the out-of-the-box support good enough in your experience or do you use any other ETL tools? Mainly I'm looking for a way to work with datomic data on python

@cuaucortes (assuming Cloud) have you looked at https://docs.datomic.com/cloud/analytics/analytics-jupyter.html ? (there is a similar entry for on-prem)

FWIW, it looks like AWS pushed the https://docs.aws.amazon.com/lambda/latest/dg/runtime-support-policy.html from the end of March.

@lanejo01 Do you have any best practices / solutions in this topic?

What actual problem are you trying to solve @furkan3ayraktar? • "Having background threads do work" isn't a problem, it's a capability. • "I have to process a lot of data and I need to apply back-pressure to ensure I don't overwhelm my system" is closer to a problem. I could tell you all sorts of things about lambdas, coordination, orchestration of stateful things in a distributed system, but I'd rather have the concrete scenario.

Thanks! I’m trying to figure out the best way to implement this and it would be very helpful if you can direct me to the right direction. Here is a concrete scenario. Let’s say I have a SQS queue and have a query group that is named worker-query-group. The each node in the worker-query-group is tasked to have a background thread which will poll from SQS continuously and process the messages received. I have this setup: 1. Ion Deploy worker-query-group 2. A new deployment is created in CodeDeploy 3. CodeDeploy deployment is successful 4. An EventBridge event is triggered after successful deployment 5. EventBridge event triggers a Lambda Ion, named sqs-poll-controller 6. sqs-poll-controller Lambda Ion is executed in one of the nodes within the worker-query-group 7. Polling from SQS is started I can also call sqs-poll-controller Lambda Ion manually to start/stop the background thread for polling from SQS. I have a problem when I have more than one nodes in the worker-query-group. The Lambda Ion (sqs-poll-controller) executes only on one of the instances and I’m in the search of figuring out how I can control all of the nodes within the query group with a Lambda Ion or any other way that is recommended. I got this idea of controlling background threads via a Lambda Ion from a Datomic team member’s https://forum.datomic.com/t/message-listeners-in-ions/860/2 and other linked https://forum.datomic.com/t/kafka-consumer-as-an-ion/823/4 of him on the forum.

Update. This issue is resolved inhttps://docs.datomic.com/cloud/releases.html#ion-dev-282 > Improvement: Limit how long to wait for a cluster node to gracefully shutdown.

Is this actually your use-case? Do you actually have an SQS queue of work?

> I have a problem when I have more than one nodes in the worker-query-group. This is a problem with one of many possible SOLUTIONS to problem X. What is problem X?

Yes, I’m not creating a non-existing issue. I have an SQS queue and a query-group dedicated for consuming messages from that SQS queue. Since there are many messages pushed to the queue, in order to increase the capacity, we wanted to add more nodes by increasing the number of instances in the auto-scaling group for the query-group. I agree, there might be different solutions to this problem. What I’m trying to learn is what is the best practice. I’m open to the ideas how to overcome the problem where there is one queue full of messages that needs to be read and processed.

And, the problem you quoted above comes from the fact that I’m trying to control (start/stop) background threads in the nodes via a Lambda Ion. I got that idea from the forum, but you can direct me a totally different approach to the root problem I’m trying to solve, which is, having a queue full of messages and needing nodes to read those messages and process.

Instead of using a pull based integration (workers polling) you should assess a push based model combining https://docs.aws.amazon.com/lambda/latest/dg/with-sqs.html . You would need to enhance one of the roles we create for an ion with an additional policy (documented in the link above) to allow SQS to invoke the lambda. Technically this isn't something we officially support, but I've seen it done successfully. A downside with this approach is that you run the risk of overwhelming the primary group with transactions from your autoscaling query group if you're not careful. The upside is that you don't have any state to manage in a distributed system.

Using Step Functions with Ions is another approach, depending on the needs of the business problem. (e.g., it is a long running process that requires human approval steps)

Are the docs (https://docs.datomic.com/cloud/index.html) down for anyone else?

I get the following when I visit that

@futuro Thanks for the heads up, we'll check it out.

👍:skin-tone-2:

@futuro Fixed

Fantastic, thank you 🙂

Hi there. Can anyone confirm if Datomic will run on Azure and/or any docs/blogs. I've done some googling but didn't find much.

I’ve implemented polling SQS via Lambda in another project in the past, however, Lambda polling SQS has some issues. You can see a glimpse of it here in this https://zaccharles.medium.com/lambda-concurrency-limits-and-sqs-triggers-dont-mix-well-sometimes-eb23d90122e0. For that reason, I prefer polling from the query-group rather than relying on a Lambda. I’m having hard time imagining a solution with Step Functions to this problem. Also, both cases will incur additional costs and complexity.  Anyway, my understanding is that there is no best practice around communicating to all of the nodes within the Datomic query groups. Something like a special kind of Lambda Ion which could trigger a Clojure function in all of the nodes of a query-group would be a very nice to have in order to communicate with the running nodes easily.