Blockchain connector for corda
- FireFly Cordapp
- Connector springboot application
- Exposes REST endpoint to interact with firefly cordapp
- Exposes REST endpoints to manage eventstreams and subscriptions
- Exposes Websocket endpoint to consume events from corda ledger
PRE-REQS
- JDK 11 (such as from https://adoptopenjdk.net/)
- gradle (https://gradle.org/install/)
BUILD
./gradlew build
The outputs are in these folders:
- Cordapp jars
cordapp/firefly-contracts/build/libs/firefly-contracts.jarcordapp/firefly-flows/build/libs/firefly-flows.jar
- Connector springboot application
connector/build/libs/connector.jar
Running locally
Prerequisites
- Install above cordapps on corda nodes in your corda network
Running connector locally
- Run following command to run the connector springboot application
./gradlew bootRun --args='--rpc.host=<rpc host for corda node> --rpc.username=test --rpc.password=client123!'
- Open
http://localhost:8080/swagger-ui/index.htmlto view rest endpoints available. - Create an eventstream using
POST /eventstream, example request body
{
"data": {
"name": "eventstream-0",
"batchSize": 10,
"batchTimeoutMS": 5000,
"blockedRetryDelaySec": 20,
"errorHandling": "BLOCK",
"websocket": {
"topic": "eventstream-0-topic"
}
}
}
- Note the eventstream id from the response
{
"statusCode": 200,
"status": true,
"message": "SUCCESS",
"data": {
"id": "es-622a2ff8-b688-46b2-874b-de7c5cd4e8dc",
"name": "eventstream-0",
"batchSize": 10,
"batchTimeoutMs": 5000,
"batchRetryDelaySec": 20,
"errorHandling": "BLOCK",
"websocketTopic": "eventstream-0-topic",
"suspended": false,
"created": "2021-06-24T19:49:53.775Z",
"updated": null
}
}
- Create an subscription using
POST /subscriptions, example request body using id of eventstream created in previous step
{
"data": {
"fromTime": "2021-06-24T19:54:17.776Z",
"stream": "es-622a2ff8-b688-46b2-874b-de7c5cd4e8dc",
"filter": {
"stateType": "io.kaleido.firefly.cordapp.states.BroadcastBatch",
"stateStatus": "UNCONSUMED",
"relevancyStatus": "RELEVANT"
},
"name": "subscription-0"
}
}
- response
{
"statusCode": 200,
"status": true,
"message": "SUCCESS",
"data": {
"id": "sb-6dd6e475-b2ed-4109-9831-b259e9b08ef2",
"name": "subscription-0",
"stream": {
"id": "es-622a2ff8-b688-46b2-874b-de7c5cd4e8dc",
"name": "eventstream-0",
"batchSize": 10,
"batchTimeoutMs": 5000,
"batchRetryDelaySec": 20,
"errorHandling": "BLOCK",
"websocketTopic": "eventstream-0-topic",
"suspended": false,
"created": "2021-06-24T19:49:53.775Z",
"updated": null
},
"stateType": "io.kaleido.firefly.cordapp.states.BroadcastBatch",
"stateStatus": "UNCONSUMED",
"relevancyStatus": "RELEVANT",
"fromTime": "2021-06-24T19:54:17.776Z",
"lastCheckpoint": null,
"created": "2021-06-24T19:56:15.845Z",
"updated": null
}
}
- setup websocket client to listen to corda events, you can use following node sample
const WebSocket = require('ws')
const ws = new WebSocket(`ws://localhost:8080/ws`);
let lastAck = null;
let heartBeatTimeout = setTimeout(() => {
console.error('Event stream ping timeout');
ws.terminate();
}, 10000);
const heartBeat = () => {
ws.ping();
clearTimeout(heartBeatTimeout);
heartBeatTimeout = setTimeout(() => {
console.error('Event stream ping timeout');
ws.terminate();
}, 2000);
}
ws.on('open', () => {
ws.send(JSON.stringify({
type: 'listen',
topic: 'eventstream-0-topic'
}));
heartBeat();
}).on('close', () => {
console.error(`Event stream websocket disconnected`);
}).on('message', async (message) => {
const data = JSON.parse(message);
for(var i=0; i<data.length; i++) {
console.log(JSON.stringify(data[i]));
}
ws.send(JSON.stringify({
type: 'ack',
topic: 'eventstream-0-topic'
}));
}).on('pong', () => {
heartBeat();
}).on('error', err => {
console.error(`Event stream websocket error. ${err}`);
});
- send a firefly transaction using
POST /broadcastBatch, request body
{
"data": {
"batchId": "batch-id-0",
"payloadRef": "some-payload-ref-0",
"observers": [
"CN=Node of u0xrgv6atc for u0fifdgpl8, O=Kaleido, L=Raleigh, C=US"
],
"groupId": "3fa85f64-5717-4562-b3fc-2c963f66afa6"
}
}
- you would receive transaction hash as response
{
"statusCode": 200,
"status": true,
"message": "SUCCESS",
"data": "891F8893DB10130413C4D504F42395C9D8C788684074C325DCE115E8DBF915CE"
}
- On websocket client you would receive the event message from corda
{
"data":
{
"data":
{
"@class":"io.kaleido.firefly.cordapp.states.BroadcastBatch",
"author":"CN=Node of u0jh5fc7yc for u0fifdgpl8, O=Kaleido, L=Raleigh, C=US",
"batchId":"batch-id-0",
"payloadRef":"some-payload-ref-0",
"participants":["CN=Node of u0xrgv6atc for u0fifdgpl8, O=Kaleido, L=Raleigh, C=US","CN=Node of u0jh5fc7yc for u0fifdgpl8, O=Kaleido, L=Raleigh, C=US"]
},
"contract":"io.kaleido.firefly.cordapp.contracts.FireflyContract",
"notary":"CN=Node of u0congcs2l for u0fifdgpl8, O=Kaleido, L=Raleigh, C=US",
"encumbrance":null,
"constraint":
{
"@class":"net.corda.core.contracts.SignatureAttachmentConstraint",
"key":"3mviYCPz42wQCX8yUe3fdhFKHg7ZDA1dthqUQF946tgfUC43hosoa8Ef98JXufsSVMW8C6L3UEHhh4kdKr1xashDNWuacM5F43dL9Btzs534H2iEksEDX3aWWAMgXBMj88jiEmQi7orS2VSrpB29QNGYTKWZrcKrK4oJm3bYNKiv4Smrkd5zWoZQ8Tzz2HKamvSXqQ2s3MxTYXZrJ6zTz2rEMjXBF3s1d8tPqV3LBhvpDwG4MaVhg3UREzKkZGe58T8x1QJ4GEu6TGU43T3VJ295dyZSEguXj6v1g6HVqTPE8CnLvszy31E3xSBGU2sQFNeC"
}
},
"subId":"sb-6dd6e475-b2ed-4109-9831-b259e9b08ef2",
"signature":"io.kaleido.firefly.cordapp.states.BroadcastBatch",
"stateRef":
{
"txhash":"891F8893DB10130413C4D504F42395C9D8C788684074C325DCE115E8DBF915CE",
"index":0
},
"recordedTime":"2021-06-24T20:04:30.361398Z",
"consumedTime":null
}
TODOS
- Solve broadcast problem for corda
- All communication is corda is point to point, and there is no concept of global blockchain state in corda.
- We currently solve it by passing a list of observers (list of corda nodes)
- This solution has a late join problem
- add support for async requests
- add support for request retries similaer to ethconnect
- e2e integration with firefly
- Add unit/integration tests and coverage
- Add acceptance tests
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