kdatalog | Kafka as a Datalog Engine | Pub Sub library

 by   rayokota Java Version: Current License: LGPL-2.1

kandi X-RAY | kdatalog Summary

kandi X-RAY | kdatalog Summary

kdatalog is a Java library typically used in Messaging, Pub Sub, Kafka applications. kdatalog has no bugs, it has no vulnerabilities, it has build file available, it has a Weak Copyleft License and it has low support. You can download it from GitHub.

KDatalog is a distributed Datalog engine using Apache Kafka. It is implemented as a Pregel algorithm in Kafka Graphs, and is adapted from the Apache Giraph implementation of Datalog on Pregel from the work "Parallel Datalog on Pregel" by Matthias Maiterth. For more information, see KDatalog: Kafka as a Datalog Engine.
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            kandi-support Support

              kdatalog has a low active ecosystem.
              It has 25 star(s) with 4 fork(s). There are 4 watchers for this library.
              OutlinedDot
              It had no major release in the last 6 months.
              kdatalog has no issues reported. There are 2 open pull requests and 0 closed requests.
              It has a neutral sentiment in the developer community.
              The latest version of kdatalog is current.

            kandi-Quality Quality

              kdatalog has no bugs reported.

            kandi-Security Security

              kdatalog has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.

            kandi-License License

              kdatalog is licensed under the LGPL-2.1 License. This license is Weak Copyleft.
              Weak Copyleft licenses have some restrictions, but you can use them in commercial projects.

            kandi-Reuse Reuse

              kdatalog releases are not available. You will need to build from source code and install.
              Build file is available. You can build the component from source.

            Top functions reviewed by kandi - BETA

            kandi has reviewed kdatalog and discovered the below as its top functions. This is intended to give you an instant insight into kdatalog implemented functionality, and help decide if they suit your requirements.
            • Evaluate a vertex
            • Filter a set of predicates from a map
            • Vote the given vertex to halt
            • Evaluate this rule and evaluate the result
            • Check a rule
            • Checks if a given atom is verifiable
            • Checks if predicate is built in
            • Gets the recipients from rule
            • Checks if the given segment is a valid recipient list
            • Add all elements in the given relation
            • Add a tuple to the table
            • Convert a rule to a new rule
            • Replaces the variables in the literals with the appropriate constants
            • Gets the super step
            • Register all aggregators
            • The master compute function
            • Adds a broadcast rule
            • Adds a partial rule
            • Returns true if the given tuple contains the given tuple
            • Returns the tuple at the specified index
            • The number of tuples
            • Returns a string representation of this dictionary
            Get all kandi verified functions for this library.

            kdatalog Key Features

            No Key Features are available at this moment for kdatalog.

            kdatalog Examples and Code Snippets

            No Code Snippets are available at this moment for kdatalog.

            Community Discussions

            QUESTION

            Build JSON content in R according Google Cloud Pub Sub message format
            Asked 2022-Apr-16 at 09:59

            In R, I want to build json content according this Google Cloud Pub Sub message format: https://cloud.google.com/pubsub/docs/reference/rest/v1/PubsubMessage

            It have to respect :

            ...

            ANSWER

            Answered 2022-Apr-16 at 09:59

            Not sure why, but replacing the dataframe by a list seems to work:

            Source https://stackoverflow.com/questions/71892778

            QUESTION

            BigQuery Table a Pub Sub Topic not working in Apache Beam Python SDK? Static source to Streaming Sink
            Asked 2022-Apr-02 at 19:41

            My basic requirement was to create a pipeline to read from BigQuery Table and then convert it into JSON and pass it onto a PubSub topic.

            At first I read from Big Query and tried to write it into Pub Sub Topic but got an exception error saying "Pub Sub" is not supported for batch pipelines. So I tried some workarounds and

            I was able to work around this in python by

            • Reading from BigQuery-> ConvertTo JSON string-> Save as text file in cloud storage (Beam pipeline)
            ...

            ANSWER

            Answered 2021-Oct-14 at 20:27

            Because your pipeline does not have any unbounded PCollections, it will be automatically run in batch mode. You can force a pipeline to run in streaming mode with the --streaming command line flag.

            Source https://stackoverflow.com/questions/69549649

            QUESTION

            Pub Sub Lite topics with Peak Capacity Throughput option
            Asked 2022-Feb-20 at 21:46

            We are using Pub Sub lite instances along with reservations, we want to deploy it via Terraform, on UI while creating a Pub Sub Lite we get an option to specify Peak Publish Throughput (MiB/s) and Peak Subscribe Throughput (MiB/s) which is not available in the resource "google_pubsub_lite_topic" as per this doc https://registry.terraform.io/providers/hashicorp/google/latest/docs/resources/pubsub_lite_topic.

            ...

            ANSWER

            Answered 2022-Feb-20 at 21:46

            If you check the bottom of your Google Cloud console screenshot, you can see it suggests to have 4 partitions with 4MiB/s publish and subscribe throughput.

            Therefore your Terraform partition_config should match this. Count should be 4 for the 4 partitions, with capacity of 4MiB/s publish and 4MiB/s subscribe for each partition.

            The "peak throughput" in web UI is just for convenience to help you choose some numbers here. The actual underlying PubSub Lite API doesn't actually have this field, which is why there is no Terraform setting either. You will notice the sample docs require a per-partiton setting just like Terraform.

            eg. https://cloud.google.com/pubsub/lite/docs/samples/pubsublite-create-topic

            I think the only other alternative would be to create a reservation attached to your topic with enough throughput units for desired capacity. And then completely omit capacity block in Terraform and let the reservation decide.

            Source https://stackoverflow.com/questions/70210745

            QUESTION

            How do I add permissions to a NATS User to allow the User to query & create Jestream keyvalue stores?
            Asked 2022-Feb-14 at 14:46

            I have a User that needs to be able to query and create Jetstream keyvalue stores. I attempted to add pub/sub access to $JS.API.STREAM.INFO.* in order to give the User the ability to query and create keyvalue stores:

            ...

            ANSWER

            Answered 2022-Jan-31 at 16:16

            Should be:

            nsc edit user RequestCacheService --allow-pubsub '$JS.API.STREAM.INFO.*'

            With single-quotes around the subject. I was under the impression that double & single quotes would escape the $ but apparently only single-quote will escape special characters in the subject.

            Source https://stackoverflow.com/questions/70901601

            QUESTION

            MSK vs SQS + SNS
            Asked 2022-Feb-09 at 17:58

            I am deciding if I should use MSK (managed kafka from AWS) or a combination of SQS + SNS to achieve a pub sub model?

            Background

            Currently, we have a micro service architecture but we don't use any messaging service and only use REST apis (dont ask why - related to some 3rd party vendors who designed the architecture). Now, I want to revamp it and start using messaging for communication between micro-services.

            Initially, the plan is to start publishing entity events for any other micro service to consume - these events will also be stored in data lake in S3 which will also serve as a base for starting data team.

            Later, I want to move certain features from REST to async communication.

            Anyway, the main question I have is - should I decide to go with MSK or should I use SQS + SNS for the same? ( I already understand the basic concepts but wanted to understand from fellow community if there are some other pros and cons)?

            Thanks in advance

            ...

            ANSWER

            Answered 2022-Feb-09 at 17:58

            MSK VS SQS+SNS is not really 1:1 comparison. The choice depends on various use cases. Please find out some of specific difference between two

            1. Scalability -> MSK has better scalability option because of inherent design of partitions that allow parallelism and ordering of message. SNS has limitation of 300 publish/Second, to achieve same performance as MSK, there need to have higher number of SNS topic for same purpose.

            Example : Topic: Order Service in MSK -> one topic+ 10 Partitions SNS -> 10 topics

            if client/message producer use 10 SNS topic for same purpose, then client needs to have information of all 10 SNS topic and distribution of message. In MSK, it's pretty straightforward, key needs to send in message and kafka will allocate the partition based on Key value.

            1. Administration/Operation -> SNS+SQS setup is much simpler compare to MSK. Operational challenge is much more with MSK( even this is managed service). MSK needs more in depth skills to use optimally.

            2. SNS +SQS VS SQS -> I believe you have multiple subscription(fanout) for same message thats why you have refer SNS +SQS. If you have One Subscription for one message, then only SQS is also sufficient.

            3. Replay of message -> MSK can be use for replaying the already processed message. It will be tricky for SQS, though can be achieve by having duplicate queue so that can be use for replay.

            Source https://stackoverflow.com/questions/70648467

            QUESTION

            Dataflow resource usage
            Asked 2022-Feb-03 at 21:43

            After following the dataflow tutorial, I used the pub/sub topic to big query template to parse a JSON record into a table. The Job has been streaming for 21 days. During that time I have ingested about 5000 JSON records, containing 4 fields (around 250 bytes).

            After the bill came this month I started to look into resource usage. I have used 2,017.52 vCPU hr, memory 7,565.825 GB hr, Total HDD 620,407.918 GB hr.

            This seems absurdly high for the tiny amount of data I have been ingesting. Is there a minimum amount of data I should have before using dataflow? It seems over powered for small cases. Is there another preferred method for ingesting data from a pub sub topic? Is there a different configuration when setting up a Dataflow Job that uses less resources?

            ...

            ANSWER

            Answered 2022-Feb-03 at 21:43

            It seems that the numbers you mentioned, correspond to not customizing the job resources. By default streaming jobs use a n1-standar-4 machine:

            3 Streaming worker defaults: 4 vCPU, 15 GB memory, 400 GB Persistent Disk.
            4 vCPU x 24 hrs x 21 days = 2,016
            15 GB x 24 hrs x 21 days = 7,560

            If you really need streaming in Dataflow, you will need to pay for resources allocated even if there is nothing to process.

            Options:

            Optimizing Dataflow

            • Considering that the number and size of the JSON string you need to process are really small, you can reduce the cost to aprox 1/4 of current charge. You just need to set the job to use a n1-standard-1 machine, which has 1vCPU and 3.75GB memory. Just be careful with max nodes, unless you are planning increase the load, one node may be enough.

            Your own way

            • If you don't really need streaming (not likely), you can just create a function that pulls using Synchronous Pull, and add the part that writes to BigQuery. You can schedule according to your needs.

            Cloud functions (my recommendation)

            "Cloud Functions provides a perpetual free tier for compute-time resources, which includes an allocation of both GB-seconds and GHz-seconds. In addition to the 2 million invocations, the free tier provides 400,000 GB-seconds, 200,000 GHz-seconds of compute time and 5GB of Internet egress traffic per month."[1]

            [1] https://cloud.google.com/functions/pricing

            Source https://stackoverflow.com/questions/70972652

            QUESTION

            Run code on Python Flask AppEngine startup in GCP
            Asked 2021-Dec-27 at 16:07

            I need to have a TCP client that listens to messages constantly (and publish pub sub events for each message)

            Since there is no Kafka in GCP, I'm trying to do it using my flask service (which runs using AppEngine in GCP).

            I'm planning on setting the app.yaml as:

            ...

            ANSWER

            Answered 2021-Dec-27 at 16:07

            I eventually went for implementing a Kafka connector myself and using Kafka.

            Source https://stackoverflow.com/questions/70365210

            QUESTION

            Is there a way to listen for updates on multiple Google Classroom Courses using Pub Sub?
            Asked 2021-Dec-22 at 08:48
            Goal

            Trigger a function which updates Cloud Firestore when a student completes assignments or assignments are added for any course.

            Problem

            The official docs state that a feed for CourseWorkChangesInfo requires a courseId, and I would like to avoid having a registration and subscription for each course, each running on its own thread.

            What I Have

            I have managed to get a registration to one course working:

            ...

            ANSWER

            Answered 2021-Dec-22 at 08:48
            Answer:

            This is not possible.

            You cannot have a single registration to track course work changes for multiple courses, as you can see here:

            Types of feeds

            The Classroom API currently offers three types of feed:

            • Each domain has a roster changes for domain feed, which exposes notifications when students and teachers join and leave courses in that domain.
            • Each course has a roster changes for course feed, which exposes notifications when students and teachers join and leave courses in that course.
            • Each course has a course work changes for course feed, which exposes notifications when any course work or student submission objects are created or modified in that course.
            File a feature request:

            If you think this feature could be useful, I'd suggest you to file a feature request in Issue Tracker using this template.

            Reference:

            Source https://stackoverflow.com/questions/70428658

            QUESTION

            Flow.take(ITEM_COUNT) returning all the elements rather then specified amount of elements
            Asked 2021-Dec-17 at 21:00

            I've a method X that's getting data from the server via pub sub. This method returns a flow. I've another method that subscribes to the flow by method X but only wants to take the first 3 values max from the flow if the data is distinct compared to previous data. I've written the following code

            ...

            ANSWER

            Answered 2021-Dec-17 at 19:13

            You have a Flow> here, which means every element of this flow is itself a list.

            The take operator is applied on the flow, so you will take the 3 first lists of the flow. Each individual list is not limited, unless you use take on the list itself.

            So the name transformedListOf3Elements is incorrect, because the list is of an unknown number of elements, unless you filter it somehow in the map.

            Source https://stackoverflow.com/questions/70397526

            QUESTION

            Wrapping Pub-Sub Java API in Akka Streams Custom Graph Stage
            Asked 2021-Oct-26 at 13:31

            I am working with a Java API from a data vendor providing real time streams. I would like to process this stream using Akka streams.

            The Java API has a pub sub design and roughly works like this:

            ...

            ANSWER

            Answered 2021-Oct-26 at 13:31

            To feed a Source, you don't necessarily need to use a custom graph stage. Source.queue will materialize as a buffered queue to which you can add elements which will then propagate through the stream.

            There are a couple of tricky things to be aware of. The first is that there's some subtlety around materializing the Source.queue so you can set up the subscription. Something like this:

            Source https://stackoverflow.com/questions/69368519

            Community Discussions, Code Snippets contain sources that include Stack Exchange Network

            Vulnerabilities

            No vulnerabilities reported

            Install kdatalog

            You can download it from GitHub.
            You can use kdatalog like any standard Java library. Please include the the jar files in your classpath. You can also use any IDE and you can run and debug the kdatalog component as you would do with any other Java program. Best practice is to use a build tool that supports dependency management such as Maven or Gradle. For Maven installation, please refer maven.apache.org. For Gradle installation, please refer gradle.org .

            Support

            For any new features, suggestions and bugs create an issue on GitHub. If you have any questions check and ask questions on community page Stack Overflow .
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