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The A1 Mediator listens on the northbound interface of the RIC for policy guidance. The caller (e.g., non RT RIC, SMO, etc.) creates policy types and policy instances through A1, and subsequently A1 exchanges messages with xApps via RMR.

Please see here for the docs: https://docs.o-ran-sc.org/projects/o-ran-sc-ric-plt-a1/en/latest/index.html

This wiki page may be useful for discussion about the A1 Mediator, feel free to post comments here.

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19 Comments

  1. Hi Chris Lott, I was reading this part: https://docs.o-ran-sc.org/projects/o-ran-sc-ric-plt-a1/en/latest/installation-guide.html#local-docker .
    I realized that i need localrt file and ricmanifest. 
    I tried to find an example for those files.. but couldn't find one. can you please share examples for them?
    Thanks
    Dongho

  2. The "local.rt" argument is an RMR routing table.  For examples please see the RMR documentation: https://docs.o-ran-sc.org/projects/o-ran-sc-ric-plt-lib-rmr/en/latest/overview.html

    I don't understand the question about "ricmanifest"


  3. docker run -dt -p 10000:10000 -v /path/to/localrt:/opt/route/local.rt -v /path/to/ricmanifest:/opt/ricmanifest.json a1:X.Y.Z -v 

    above command is from the instruction about running a docker container. 
    here, is ricmanifest not needed to run container?  

  4. Thanks, I see it now.  Correct, ricmanifest is not needed to run the container. I will update the document.

  5. $ docker run -dt -p 10000:10000 -v /home/dk5913/a1_mediator/localrt:/opt/route/local.rt a1:2.1.7
    4be8c7a60dc81b97c61c9d9fb8a69511db6f204b12e867c5c27c92fad66b7729
    $ docker ps -a
    CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
    4be8c7a60dc8 a1:2.1.7 "/bin/sh -c run.py" 2 seconds ago Exited (1) 1 second ago dreamy_bassi
    $ docker logs -f 4be8c7a60dc8
    Traceback (most recent call last):
    File "/home/a1user/.local/bin/run.py", line 5, in <module>
    from a1.run import main
    ModuleNotFoundError: No module named 'a1'


    I got above error once i ran the container.. 
    Do you have any clue? i am using the version of code as below.

    ----  git log 

    Author: Lott, Christopher (cl778h) <cl778h@att.com>
    Date: Wed Apr 22 10:54:20 2020 -0400

    Upgrade xapp-frame-go module in integration tests

    ...

    Change-Id: I9df1dce576b083674290857f1c23d9b3a25ab5c6


  6. Hi Dongho - did you build a docker image? Do "docker images | ls a1" and see if you see any images...Otherwise, you need to build a docker locally:

    Go to a1/ric-plt/a1 and run command "docker build --no-cache -t a1:1.0.0 ."

    This should create a docker image a1:1.0.0 that you can run locally...Hope this helps...


  7. yes, here is output.. 

    $ docker image ls
    REPOSITORY TAG IMAGE ID CREATED SIZE
    a1 2.1.7 c3a7905c8568 4 days ago 154MB

  8. It's very difficult for me to guess what happened here, especially without details of the routing table that you used. I think the command-line arguments -d (detach) and -t (allocate tty) should not be used together.  Trying to reproduce your result, I built a docker image from the same commit and launched it, the result is below.

    % docker run 1757f
    {"ts": 1588031693328, "crit": "DEBUG", "id": "a1.run", "mdc": {}, "msg": "Initializing rmr thread. A1s webserver will not start until rmr initialization is complete."}
    {"ts": 1588031693328, "crit": "DEBUG", "id": "a1.a1rmr", "mdc": {}, "msg": "Waiting for rmr to initialize.."}
    1588031693 1/RMR [INFO] ric message routing library on SI95/g mv=3 flg=02 (43b7981 3.8.0 built: Apr 21 2020)
    1588031694 1/RMR [INFO] endpoint: no counts: empty table

    Instead of introducing the uncertainty of building, please try running the released image like this:

        docker run nexus3.o-ran-sc.org:10002/o-ran-sc/ric-plt-a1:2.1.6
  9. let me try to go with the released image and see.

    Thanks for help!!
    Dongho

  10. now release image seems to be up. 
    when I did healthcheck as an initial testing, I find follow error in log.

    Traceback (most recent call last):
      File "/home/a1user/.local/lib/python3.8/site-packages/redis/connection.py", line 1179, in get_connection
        connection = self._available_connections.pop()
    IndexError: pop from empty list
    During handling of the above exception, another exception occurred:
    Traceback (most recent call last):
      File "/home/a1user/.local/lib/python3.8/site-packages/flask/app.py", line 2447, in wsgi_app
        response = self.full_dispatch_request()
      File "/home/a1user/.local/lib/python3.8/site-packages/flask/app.py", line 1952, in full_dispatch_request
        rv = self.handle_user_exception(e)
      File "/home/a1user/.local/lib/python3.8/site-packages/flask/app.py", line 1821, in handle_user_exception
        reraise(exc_type, exc_value, tb)
      File "/home/a1user/.local/lib/python3.8/site-packages/flask/_compat.py", line 39, in reraise
        raise value
      File "/home/a1user/.local/lib/python3.8/site-packages/flask/app.py", line 1950, in full_dispatch_request
        rv = self.dispatch_request()
      File "/home/a1user/.local/lib/python3.8/site-packages/flask/app.py", line 1936, in dispatch_request
        return self.view_functions[rule.endpoint](**req.view_args)
      File "/home/a1user/.local/lib/python3.8/site-packages/connexion/decorators/decorator.py", line 48, in wrapper
        response = function(request)
      File "/home/a1user/.local/lib/python3.8/site-packages/connexion/decorators/uri_parsing.py", line 144, in wrapper
        response = function(request)
      File "/home/a1user/.local/lib/python3.8/site-packages/connexion/decorators/parameter.py", line 121, in wrapper
        return function(**kwargs)
      File "/home/a1user/.local/lib/python3.8/site-packages/a1/controller.py", line 68, in get_healthcheck
        if not data.SDL.healthcheck():
      File "/home/a1user/.local/lib/python3.8/site-packages/ricxappframe/xapp_sdl.py", line 149, in healthcheck
        return self._sdl.is_active()
      File "/home/a1user/.local/lib/python3.8/site-packages/ricsdl/syncstorage.py", line 137, in is_active
        return self.__dbbackend.is_connected()
      File "/home/a1user/.local/lib/python3.8/site-packages/ricsdl/backend/redis.py", line 95, in is_connected
        return self.__redis.ping()
      File "/home/a1user/.local/lib/python3.8/site-packages/redis/client.py", line 1351, in ping
        return self.execute_command('PING')
      File "/home/a1user/.local/lib/python3.8/site-packages/redis/client.py", line 875, in execute_command
        conn = self.connection or pool.get_connection(command_name, **options)
      File "/home/a1user/.local/lib/python3.8/site-packages/redis/connection.py", line 1181, in get_connection
        connection = self.make_connection()
      File "/home/a1user/.local/lib/python3.8/site-packages/redis/connection.py", line 1220, in make_connection
        return self.connection_class(**self.connection_kwargs)
      File "/home/a1user/.local/lib/python3.8/site-packages/redis/connection.py", line 502, in __init__
        self.port = int(port)
    TypeError: int() argument must be a string, a bytes-like object or a number, not 'NoneType'
    ::ffff:172.17.0.1 - - [2020-04-28 23:06:51] "GET /a1-p/healthcheck HTTP/1.1" 500 387 0.011661


    my localrt looks like this (I got this from Amber release's integration_test directory)

    newrt|start
       rte|20000|devarchwork:4560
       rte|20001|devarchwork:4563
       rte|21024|devarchwork:4562
    newrt|end


    should I install something else?


  11. Please explain how you performed the healthcheck - for example, did you run a curl or wget command? How did you start the A1 mediator docker container; most importantly, what environment variables are active?

    The A1 Mediator requires access to a running SDL (Redis) instance, which it uses as a persistent store.  Is it possible that maybe you started an A1 container only, without launching a Redis container also? Also see https://pypi.org/project/ricsdl/

    The tests mock the SDL (Redis) instance to avoid the need for running one, like this:

        data.SDL = SDLWrapper(use_fake_sdl=True)


  12. ok, I was running only A1 mediator container. I did not know I needed to run redis container. that might be the issue.  

    I'm wondering if i can find a comprehensive document which explains all required modules or containers. 

    anyhow, here is what i did. hoping you can know anything else i am missing.

    -----

    before this, i did not have anything relevant to a1mediator.. 
    $ cat localrt2
    newrt|start
       rte|20000|devarchwork:4560
       rte|20001|devarchwork:4563
       rte|21024|devarchwork:4562
    newrt|end
    $ docker run -dt -p 10000:10000 --name=a1med -v /home/dk5913/a1_mediator/localrt2:/opt/route/local.rt nexus3.o-ran-sc.org:10002/o-ran-sc/ric-plt-a1:2.1.6
    $ docker logs a1med
    {"ts": 1588118114047, "crit": "DEBUG", "id": "a1.run", "mdc": {}, "msg": "Initializing rmr thread. A1s webserver will not start until rmr initialization is complete."}
    {"ts": 1588118114047, "crit": "DEBUG", "id": "a1.a1rmr", "mdc": {}, "msg": "Waiting for rmr to initialize.."}
    1588118114 1/RMR [INFO] ric message routing library on SI95/g mv=3 flg=02 (338fe5e 3.6.3 built: Apr  4 2020)
    {"ts": 1588118114549, "crit": "DEBUG", "id": "a1.a1rmr", "mdc": {}, "msg": "Work loop starting"}{"ts": 1588118114549, "crit": "DEBUG", "id": "a1.run", "mdc": {}, "msg": "Starting gevent server"}
    1588118115 1/RMR [INFO] sends: ts=1588118115 src=e19786a5ee4e:4562 target=devarchwork:4563 open=0 succ=0 fail=0 (hard=0 soft=0)
    $ curl -X GET http://172.17.0.2:10000/a1-p/healthcheck -H 'Accept: application/json' -H 'Cache-Control: no-cache' -H 'Content-Type: application/json'
    {
      "detail": "The server encountered an internal error and was unable to complete your request. Either the server is overloaded or there is an error in the application.",
      "status": 500,
      "title": "Internal Server Error",
      "type": "about:blank"
    }

    ---
    for environment variables, I did not set anything extra..

  13. The A1 Mediator is just one component of a large deployment that constitutes the RIC.  The Redis server is deployed under the name "database as a service" (dbaas) using this image:

    registry: "nexus3.o-ran-sc.org:10002/o-ran-sc"
    name: ric-plt-dbaas
    tag: 0.2.2

    It would help if you explain a bit more about what you're trying to do.  I don't have documentation ready that explains how to pull the A1 Mediator out and use it outside the context of the RIC deployment environment.

  14. Thanks again Chris. 
    I want to have a1mediator get a A1 policy instance and return a response. 
    for A1 policy, whatever schema should be fine.
    I don't need to see interactions between a1mediator and xAPPs if it is not needed to get a response..   
    if a1mediator has a kind of simulation mode (just getting whatever a1policy and returning response), it is also fine for me. 

    Please let me know whether for this purpose dbaas is needed or anything else is needed..
    if dbaas or other modules are needed, I hope to get information on how to stitch together with a1mediator.. 

  15. I think being able to start A1 easily in "mock" mode, i.e., without requiring SDL, will probably help multiple people. Please open a Jira ticket as a new user story and I'll look into it.  The tests already do exactly this, I just have to figure out how to expose that feature in the main module, possibly via a different invocation sequence.

  16. ok, I created one.. but not sure if I can get such mock mode in near term (e.g. 2-3 wks)

  17. Thanks Chris.. I saw you already commit the code.. I tested your new code in my setup and found it worked fine for me now.. 

  18. Hi Dongho Kim , all,

    You might find the OSC A1 simulator useful:

    It's a lightweight stateful multi-version A1 test stub that maintains A1 policy types and instances - so provides a realistic test environment for functions that use A1.

    Note it is not intended to act as a near-rt-ric simulator - just a realistic A1 test stub. 

  19. Please explain how A1 Mediator will be able to POST Feedback Notification to Non-RT RIC as defined in specification.

    In current dawn release, I am not sure if there is any support for A1 mediator to act as HTTP Client.

    Also need some more clarity on the notifcationDestination that NON-RT RIC will send to which later on Feedback would be posted.