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    Ajay.Gov
    @ajay-gov
    @Pasvaz thanks for pointing the issue with the flight tracker. traffic (https://github.com/swimos/traffic), transit (https://github.com/swimos/transit) work on safari and on android.
    https://traffic.swim.ai/ and https://transit.swim.ai/ are the hosted versions of those repos respectively
    Scott Clarke
    @scottswim
    flight tracker should be working better now in safari too.
    just pushed some quick fixes for safari to github and the live demo site.
    Pasquale Vazzana
    @Pasvaz
    Thanks @ajay-gov @scottswim
    Pasquale Vazzana
    @Pasvaz
    transit is quite cool and probably a better place to start
    Ajay.Gov
    @ajay-gov
    @Pasvaz thanks. Please do ping us if you have any questions.
    Peace Michaels
    @oexza

    Hi @ajay-gov

    I am a two day old swimer, so the workings of swim are not yet very clear to me. I'm exploring the possibility of using a webagent as single writer per stream in an eventstore.

    How does one co-ordinate planes in such a manner that only one instance of a webagent can exist in a "cluster" of servers, and ensure that requests are routed/re-routed to the node that has that instance running? this would be kind of like what you can achieve with Akka Cluster Sharding. Is this possible with swim?

    Ajay.Gov
    @ajay-gov
    @oexza great question and this feature is supported In swimos. The way swimos distributes webagents in a cluster is very similar to how data is distributed across a Cassandra cluster(https://docs.datastax.com/en/cassandra-oss/3.0/cassandra/architecture/archDataDistributeDistribute.html). swimos computes a hash token for each agent's uri and the hash token is configured to a certain partition which pins agents to specific servers in the fabric. You can then address that agent using a swim client (or a browser running a swim app) by pointing the client to any plane in the fabric. Swim will transparently demultiplex links opened by external clients, and route them to the appropriate server in the fabric.
    For a concrete example on how to do this please refer to the swimos transit repo- https://github.com/swimos/transit. Specifically look at the https://github.com/swimos/transit#run-as-a-fabric section which guides you through the steps of how to setup a two server fabric. The partitions are configured in the server-a.recon and in the server-b.recon. Here we have a partition with two servers with agents being evenly distributed across both servers. Agent Uris that hash to a token that lies between 0x00000000 and 0x7fffffff are pinned to server-a and agent uris that hash to a token that lies between 0x80000000 and 0xffffffff are pinned to server-b
    Peace Michaels
    @oexza
    thanks @ajay-gov thanks, I looked at it and it seems pretty solid, the next logical question is how would you run this in a cloud environment or in kubernates where Ip Addresses are not static?
    Ajay.Gov
    @ajay-gov
    @oexza, thanks so much for checking it out! The k8s question is the next logical step indeed. Since swimos applications are stateful they need to deployed using k8s statefulsets
    The pods need to communicate internally but they can use the POD DNS names to look each other up (instead of using static IP addresses).
    External access to the k8s cluster can be made using the DNS name provided by the k8s load balancer for this cluster, swimos will then route requests to the appropriate pod internally.

    Using the transit as a concrete example, say you have the following set up in your k8s yaml file

    Service (ns/name): swimos/transit
    StatefulSet (ns/name): default/transit

    then the DNS and Hostnames will be

    StatefulSet Domain: transit.swimos.svc.cluster.local
    Pod DNS: transit-{0..N-1}.transit.swimos.svc.cluster.local
    Pod Hostname: transit-{0..N-1}

    For the 2 pod example with server-a as index 0 and server-b as index 1

    POD DNS for server-a will be: transit-0.transit.swimos.svc.cluster.local
    POD DNS for server-b will be: transit-1.transit.swimos.svc.cluster.local
    Also when running in a k8s cluster it will be best to run the app on the same port in all the pods. In order to do that change the port in @web section of the recon file. If you'd like to
    run it on port 9002 change the @web section of the recon file to be: @web(port: 9002) {

    With the apps running on port 9002, the next thing to fix is the the mesh part for the server recon.
    For server-a.recon this will be:

      @mesh {
        @part {
          key: partA
          predicate: @hash(0x00000000, 0x7fffffff)
          @host {
            primary: true
          }
    
        }
        @part {
          key: partB
          predicate: @hash(0x80000000, 0xffffffff)
          @host {
            uri: "warp://transit-1.transit.swimos.svc.cluster.local:9002"
            primary: true
          }
        }
      }

    For server-b.recon this will be:

      @mesh {
        @part {
          key: partA
          predicate: @hash(0x00000000, 0x7fffffff)
          @host {
            uri: "warp://transit-0.transit.swimos.svc.cluster.local:9002"
            primary: true
          }
        }
        @part {
          key: partB
          predicate: @hash(0x80000000, 0xffffffff)
          @host {
            primary: true
          }
        }
      }
    Ajay.Gov
    @ajay-gov
    @oexza A lot to take in, so please do let us know if you have more questions. As you can see with the current setup you will need a recon configuration file for each pod in your k8s cluster which is a tedious manual process. We are planning to add a k8s setup feature in our enterprise product swim continuum that will simplify this setup.
    Peace Michaels
    @oexza
    thanks so much for the detailed answer @ajay-gov a very lot to take in. this truly is tedious and unsustainable for on demand scaling. One thing that would really ease the pain, is a way to programatically configure the mesh instead of using the server.recon file. this is so that some kind of service discovery mechanism can be used in code instead. this kind of configuration is used alot in Apache Ignite, where discovery is so flexible to the point that even a good ol' database table can be used a registration and discovery point for the cluster. this FLEXIBILITY is HIGLY important. Would there be a way to achieve something similar today in swim?
    Ajay.Gov
    @ajay-gov
    @oexza programmatically configuring the meshes is definitely the way to go about it. The mesh configurations in the recon file is for convenience (for non-prod or single node deployments) but everything in the recon configuration file can be done programmatically. In fact we did exactly what you are asking for one of our customers where we run a multi-node k8s cluster. We can share this code with you if you'd like. Please do let us know.
    @oexza also these programmatic APIs are going to be used by our swim continuum product which will provide a UI console from which you can set up the meshes for your k8s cluster. Hopefully we will have that soon.
    Peace Michaels
    @oexza
    @ajay-gov thanks!!!. yes I'd tremendously appreciate it if you share the code with me. Thanks!
    Ajay.Gov
    @ajay-gov
    @oexza sure no problem, will do. Need to clean that code up a bit. Will have it by end of day (we are in California) if that is okay with you.
    Peace Michaels
    @oexza
    Thanks @ajay-gov I'll be waiting.
    Ajay.Gov
    @ajay-gov
    @oexza Committed the code in a branch of the transit repo. It can be found here: https://github.com/swimos/transit/tree/feature/cluster-config
    The TransitPlane class has the code that programmatically loads the mesh configurations. Please do check out this section of the readme as well
    Ajay.Gov
    @ajay-gov
    @oexza you should run it using k8s stateful sets. k8s stateful set will start up node 0 to node 5 in that order. When the TransitPlane in node 0 starts up it will try to connect to nodes 1-5 and you will see some ConnectionExceptions since those nodes aren't up yet. As the nodes come up these ConnectionExceptions will go away as the swimos kernel will try to reconnect and will eventually connect to those nodes. Usually you will see no exceptions in node 5 since nodes 0-4 would have already started up. Do let us know if you have any questions.
    Peace Michaels
    @oexza
    Thanks!!! @ajay-gov i'll test it out and give feedback.
    Dimitris Kakanis
    @itsjimos
    Hello guys, I'd like to understand more about swimos and how I can benefit from it being a full stack javascript developer
    Ajay.Gov
    @ajay-gov
    @itsjimos Hi Dimitris, swimOS is a software platform for building real-time applications. It's a self-contained vertically integrated stack, so you don't need an app server or a database or a message broker. swimOS also has UI libraries for real-time visualizations. Please refer to the docs at https://www.swimos.org/.
    Scott Clarke
    @scottswim
    Our UI libraries are javascript and integrate nicely with existing JS frameworks as well.
    Dimitris Kakanis
    @itsjimos
    My only experience with real-time applications was through socket.io for a small side project. If I'm correct swimOS is destined to a wider variety of applications like IoT.
    I lean towards web development and I'm curious of the use cases that there might be. I also see it a chance to get into DevOps. Thank you for your replies!
    Scott Clarke
    @scottswim
    on the UI side of things our Swim Client uses websockets for communication but all that is handled by our client for you. We have a number of demos, many of which have web based UIs. You can find those on our github @ https://github.com/swimos
    many of those demos have a live version as well. Some of those are:
    http://traffic.swim.ai/
    http://transit.swim.ai/
    http://swim.flights/
    http://swim.farm/
    I am a web dev as well and often build fun things with swim. My latest uses satellite data and three.js to create whats basically a pretty screensaver :D http://satellites.swim.ai/neon.html
    Scott Clarke
    @scottswim
    Swim also can act as a web server and is very easy to setup. This way you can easy fire up a web server if you dont have one already.
    Dimitris Kakanis
    @itsjimos
    Yea, these demos look great. I remembered that a couple of years ago I had some time with InfluxDB a time series database. To my eyes its philosophy is close to real time application technologies and therefore Swim. I will look at the docs and experiment a bit the following weeks. Keep it up!
    Scott Clarke
    @scottswim
    Awesome. let us know if you have questions or get stuck. We are here to help!
    Abhishek Khuntia
    @abhishaked_twitter
    hi Swim team, any updates on adding auth to server.recon? I am testing out swim now, looks very interesting. I see the Authenticator module but there are no examples , so am not sure how exactly to use it. Also can you comment on RBAC implementation with swim. Can we also control actions and roles with annotation or we write it from scratch ? Thanks!
    Ajay.Gov
    @ajay-gov

    @abhishaked_twitter We support authentication using the server.recon file now. If you are using google authenticator it will look something like this:

    tutorial: @fabric {
      @plane(class: "swim.tutorial.TutorialPlane")
      myauth: @googleId {
        @audience("yourkey.apps.googleusercontent.com")
        @email("youremail@gmail.com")
      } 
    }

    There is a similar way to add OpenId Authenticator parameters as well.

    Ajay.Gov
    @ajay-gov
    @abhishaked_twitter We also support authorization as well. You may intercept the incoming requests at different levels i.e on connect, on link to the server, on link to an agent, on link to a lane etc. and perform RBAC style authorizations at any of these levels.
    You are right though, we haven't documented any of these cleanly yet. Our top priority right now is to revamp our developer site. We will definitely add sample code for authentication and authorization as part of this process.
    Neelam Jain
    @neeluuuuuu_twitter
    Hi, I am new to SwimOs can we make logic configurable instead of hard coded in code ? please suggest.
    Ajay.Gov
    @ajay-gov
    @neeluuuuuu_twitter thanks for your question, please do look at https://www.swimos.org/ for more information on how to use swimOS
    Anoukh Ashley
    @anoukh_ashley_twitter
    Hi, I was going through https://www.swim.ai/architecture/ and it says web agents do aggregate, transform, analyze. Is this for SwimOS or Swim Continuum?
    brohitbrose
    @brohitbrose

    @anoukh_ashley_twitter Those features are available in SwimOS, requiring only that you express them in terms of Web Agents, Lanes, and lifecycle callbacks.

    Please see the tutorials for examples: https://www.swimos.org/tutorials/ . Aggregation is outlined under Downlinks, Join Value Lanes, and Join Map Lanes. Transformation and analysis take various forms through all the tutorials, but notably bridging to and from external processes is explained in Ingress Bridges and Egress Bridges.

    kumarsen26
    @kumarsen26
    Hi,
    I am new to SwimOS, If Swim server restart happens, how the data persistence or data integrity is maintained? is there a way where my data is saved.. In tradiditonal applications, we will store in Database.. How in Swim it is maintained?
    brohitbrose
    @brohitbrose

    @kumarsen26 Being a vertically integrated stack, SwimOS comes with a built-in database that tracks the state of all lanes that are not explicitly declared transient, but only if you opt into persistence. The easiest way to do this is via the recon configuration file; see https://github.com/swimos/traffic/blob/master/server/src/main/resources/server.recon#L14-L16 for an example. Note that the directory to which the database files are written is configurable.

    Upon restart, Swim will load the same values into the lanes that they had immediately before the shutdown.

    gkaur2294
    @gkaur2294
    @brohitbrose When I specify the @store {
    path: "/tmp/swim-test/"
    } in recon file
    Only empty tmp folder is getting created. Nothing inside...
    I am just newly exploring swim. Kindly suggest.
    brohitbrose
    @brohitbrose
    @gkaur2294 Have you confirmed that at least one Web Agent was started (easiest to do with print statements on the didStart callback of the agent) and that at least one of its (non-transient) lanes had a non empty value (easiest to do with print statements on didSet or didUpdate)?
    kumarsen26
    @kumarsen26

    @brohitbrose yes WebAgent is started verified it by
    @Override
    public void didStart() {
    logMessage("Web Agent Started");
    }
    Also created one lane
    @SwimLane("hello")
    ValueLane<String> info = this.<String>valueLane()
    .didSet((newValue, oldValue) -> {
    logMessage("info set to " + newValue + " from " + oldValue);
    });

    Both are non empty. Also pushed some data into other lanes.
    But, Still no store generated and on restart other lanes products are empty

    brohitbrose
    @brohitbrose

    @kumarsen26 I think I've got it. You're likely missing a module dependency. Please make sure that you have the following (or something similar to it) in the dependencies { ... } section of build.gradle:
    api group: 'org.swimos', name: 'swim-store-db, version: '3.10.2'

    Furthermore, if you're using Java 9+ with modules, you'll need the following in your module-info.java:
    requires swim.store.db;

    kumarsen26
    @kumarsen26
    Thank you. Now the Database is getting created.
    Now I am trying to deploy Swim server in Heroku. I am able to build and deploy but But able to connect server from Client which is running in my local. Kindly suggest.
    Ajay.Gov
    @ajay-gov
    @kumarsen26 Swim applications bind to a port specified in the server.recon file. Unfortunately in Heroku you don't have control over which port is exposed on the server since the port is assigned dynamically. Heroku does expose this port as an environment variable, so you'll have to read this property and inject that into the server configuration.