README.md

Key-Value Store Application

This is an example provider that offers the capability to read from and write to an in-memory key-value store. It also supports subscribing to changes in the key store where the events are delivered over an opened channel.

Testing

Start Chariott followed by this application:

cargo run -p chariott &
cargo run -p kv-app &

Once both are up and running successfully, use the following to write a key-value pair to the store via Chariott:

grpcurl -plaintext -d @ 0.0.0.0:4243 chariott.runtime.v1.ChariottService/Fulfill <<EOF
{
  "namespace": "sdv.kvs",
  "intent": {
    "write": {
      "key": "date-time",
      "value": {
        "string": "$(date)"
      }
    }
  }
}
EOF

To read the value of the key written in the above example, run:

grpcurl -plaintext -d @ 0.0.0.0:4243 chariott.runtime.v1.ChariottService/Fulfill <<EOF
{
  "namespace": "sdv.kvs",
  "intent": {
    "read": {
      "key": "date-time"
    }
  }
}
EOF

To discover the service end-points:

grpcurl -plaintext -d @ 0.0.0.0:4243 chariott.runtime.v1.ChariottService/Fulfill <<EOF
{
  "namespace": "sdv.kvs",
  "intent": {
    "discover": {
    }
  }
}
EOF

Open a channel for receiving events:

grpcurl -v -plaintext -import-path proto -proto \
    proto/chariott/streaming/v1/streaming.proto 0.0.0.0:50064 \
    chariott.streaming.v1.ChannelService/Open | tee events.log &

The above command will run in the background and write the events to the file events.log as well as to the standard output.

The channel identifier, which is returned as the response header named x-chariott-channel-id, can be extracted from the file into a variable:

export CHANNEL_ID=$(grep -E "^x-chariott-channel-id:" events.log \
    | sed -E s/^x-chariott-channel-id:\\s//g)

Next, subscribe to a key for events to be delivered to the open channel:

grpcurl -plaintext -d @ 0.0.0.0:4243 chariott.runtime.v1.ChariottService/Fulfill <<EOF
{
  "namespace": "sdv.kvs",
  "intent": {
    "subscribe": {
        "channel_id": "$CHANNEL_ID",
        "sources": [
            "date-time"
        ]
    }
  }
}
EOF

Finally, writing to the key:

grpcurl -plaintext -d @ 0.0.0.0:4243 chariott.runtime.v1.ChariottService/Fulfill <<EOF
{
  "namespace": "sdv.kvs",
  "intent": {
    "write": {
      "key": "date-time",
      "value": {
        "string": "$(date)"
      }
    }
  }
}
EOF

should generate a new event.

To clean-up from the above commands, run:

pkill kv-app
pkill chariott
pkill grpcurl
unset CHANNEL_ID