Skip to content

Latest commit

 

History

History
175 lines (121 loc) · 6.06 KB

README.md

File metadata and controls

175 lines (121 loc) · 6.06 KB
Raw

The samples provide a simple example of a publisher and subscriber interacting with the Pub Sub Service in a dynamic way.

Setting Up Samples Configuration

The configuration files for samples are located in .agemo-samples/config.

Simple Samples

The default configuration file is setup to run the simple samples without any further modification.

Chariott-enabled Samples

To be able to run the Chariott-enabled samples, follow the below setup steps:

  1. Copy the samples_settings.yaml template to .agemo-samples/config if the file does not already exist. From the enlistment root, run:

    cp ./.agemo-samples/config/template/samples_settings.yaml ./.agemo-samples/config/

  2. Uncomment and set the following values:

    #
# Samples Configuration
#

### Chariott Service Configuration

# The URI that the Chariott Service listens on for requests.
# Needed for any Chariott enabled examples.
# Example: "http://0.0.0.0:50000"
chariott_uri: "http://0.0.0.0:50000"

###

### Pub Sub Service Configuration

# The namespace the Pub Sub Service registers under in Chariott.
# Needed for any Chariott enabled examples.
# Example: "sdv.pubsub"
pub_sub_namespace: "sdv.pubsub"

###

### Publisher Service Configuration

# The service identifier for the publisher service used when registering
# with Chariott.
# Needed for any Chariott enabled examples.
publisher_identifier:

   # The namespace of the service.
   # Example: "sdv.publisher"
   namespace: "sdv.publisher"

   # The name of the service, which can be different from the namespace.
   # Example: "dynamic.publisher"
   name: "dynamic.publisher"

   # The version of the service.
   # Example: "0.1.0"
   version: "0.1.0"

###

    This will override the default configuration and tell the service to interact with Chariott. see config overrides for more information.

Running the simple samples

To run the simple samples, take the following steps.

  1. Start the pub-sub-service in a terminal window.

  2. Start the simple publisher in a new terminal window.

    cargo run -p simple-publisher

  3. Start one or more simple subscribers with a requested subject in a new terminal window.

    cargo run -p simple-subscriber gps

You should see simulated data flowing to the subscriber(s).

Running the Chariott-enabled samples

To run the Chariott samples, take the following steps.

  1. Follow the steps at Running the Pub Sub Service with Chariott before starting the service.

    cargo run -p pub-sub-service

  2. Start the Chariott publisher in a new terminal window under the root folder of the repo.

    cargo run -p chariott-publisher

  3. Start one or more Chariott subscribers with a requested subject in a new terminal window under the root folder of the repo.

    cargo run -p chariott-subscriber gps

  4. At this point all 3 services should be waiting for the Chariott Service to be started up. In a new terminal window either pointing to the Chariott repo, or under the 'external/chariott' folder, run:

    cargo run -p service_discovery

All services should then recognize that Chariott has been started:

  1. The Pub Sub Service will register with Chariott.
  2. The publisher will find the Pub Sub Service through Chariott service discovery and communicate with the Pub Sub Service and then register itself with Chariott.
  3. The subscriber(s) will find the publisher through Chariott service discovery and use the returned uri to communicate with the publisher and set up a subscription.

You should then see simulated data flowing to the subscriber(s).

Understanding the samples

For all samples

Once the samples are up and running, you can see the dynamic topic management in action several ways.

  1. If you stop the Subscriber with Ctrl+C a STOP message will be sent to the Publisher if there are no more subscribers on the topic. Eventually (~30 secs), the Publisher will send a DELETE command to the pub-sub-service to remove the dynamic topic.
  2. If you stop the Publisher with Ctrl+C while there is a Subscriber on a topic, the Subscriber will get a TOPIC DELETED notification on the topic and cleanly disconnect from the broker. Note that once the Publisher is stopped, an error will surface if the Chariott service is not stopped as this simple example does not unregister itself with Chariott.

In addition, you will see the subject requested (ie. gps) and the dynamically created topic in the data print outs on the subscriber window.

For Chariott-enabled samples

The sample subscriber(s) will attempt to find the sample publisher through Chariott service discovery. If the publisher service is not running yet, then the subscriber will retry discovery every 5 seconds until the publisher registers.

The sample publisher will attempt to find the Pub Sub Service through Chariott service discovery. If the Pub Sub Service is not running yet, then the publisher will retry discovery every 5 seconds until the Pub Sub Service registers.

All services will retry every 5 seconds when attempting connection to Chariott until the Chariott service is up and running.

Running the samples in a Container

Please refer to containers.md for instructions on how to build and run the sample applications. All the samples use the same Dockerfile so the build arg APP_NAME will need to be set when building the sample application image. For the Chariott-enabled samples, one may need to override the configuration. Please see Running in Docker with Overridden Configuration and Running in Podman with Overridden Configuration for more information.