Event Director (ED)

Overview

This application fetches an active network map either from cache or from a database, filters it for relevant messages, deduplicates rules, and dispatches them for processing

Services

• ArangoDB: Database Management
• NATS: Message queue

You also need NodeJS to be installed in your system. The current LTS should be suitable. Please open an issue if the application fails to build on the current LTS version. Unix platforms, you should be able to find nodejs in your package manager's repositories.

Setting Up

git clone https://github.com/frmscoe/event-director
cd event-director

You then need to configure your environment: a sample configuration file has been provided and you may adapt that to your environment. Copy it to .env and modify as needed:

cp .env.template .env

A registry of environment variables is provided to provide more context for what each variable is used for.

Additional Variables

Variable	Purpose	Example
DATABASE_URL	URL where Arango is served	tcp://arango:8529
DATABASE_USER	Arango database username	root
DATABASE_PASSWORD	Arango database password	password
DATABASE_NAME	Arango database name	configuration

Build and Start

npm i
npm run build
npm run start

Inputs

const transactionRequest = {
  metaData: { traceParent: "00-4bf92f3577b34da6a3ce929d0e0e4736-00f067aa0ba902b7-01" }, // https://www.w3.org/TR/trace-context/#examples-of-http-traceparent-headers
  transaction: { TxTp: "pacs.002.001.12", "FIToFIPmtSts": { /* Pacs002 */ } },
  DataCache: { /* cached data relevant to the transaction */ }
};

A Pacs002 message is expected as an input as defined here

Internal Process Flow

Sequence Diagram

sequenceDiagram
    participant A as TMS API
    participant B as NATS<br>(event-director)
    participant C as EVENT<br>DIRECTOR
    participant D as NATS<br>(sub-rule-*)

    A->>B: Publish message
    B->>+C: Read message
    C->>C: handleTransaction()
    C->>-D: Publish message/s

Loading

Activity Diagram

flowchart TD
    start([Start]) --> postRequest[Accept NATS message from TMS]
    postRequest --> note1["Data expected: Pacs002 with DataCache"]
    note1 --> readCache[Read active network map from Redis Cache]
    readCache --> note2["Required Parameter: Cache key"]
    note2 --> checkMemory{Active Network map is found in memory}
    checkMemory -->|Yes| pruneMap[prune network map]
    checkMemory -->|No| readDB[Read active network map from Database]
    readDB --> checkDB{Network map is found}
    checkDB -->|Yes| saveCache[Save Active network map to cache]
    saveCache --> note3["Required Parameter: Cache key, Active Network Map in JSON format, Expiry time based on environment"]
    note3 --> pruneMap
    checkDB -->|No| logResult[Return No network map found in DB and Log the result]
    logResult --> note4["Results: rulesSentTo empty, failedToSend empty, networkMap empty, transaction req"]
    note4 --> stop1([Stop])
    pruneMap --> deduplicate[deduplicate all rules]
    deduplicate --> ruleLoop{foreach rule in the network sub-map}
    ruleLoop -->|More rules| sendData[Send Data]
    sendData --> note5["Data sent: transaction, network sub-map"]
    sendData --> ruleLoop
    ruleLoop -->|No more rules| sendResponse[send response back to Data Preparation]
    sendResponse --> note6["Response includes: Rules sent to, Rules not sent to, Transaction, Network sub-map"]
    note6 --> stop2([Stop])

Loading

Outputs

The output is the input with an added NetworkMap:

{
  metaData: { traceParent: "00-4bf92f3577b34da6a3ce929d0e0e4736-00f067aa0ba902b7-01" }, // https://www.w3.org/TR/trace-context/#examples-of-http-traceparent-headers
  transaction: { TxTp: "pacs.002.001.12", "FIToFIPmtSts": { /* Pacs002 */ } },
  networkMap: { /* Network Map */ },
  DataCache: { /* cached data relevant to the transaction */ }
};

Troubleshooting

npm install

Ensure generated token has read package rights

npm build

Ensure that you're on the current LTS version of Node.JS

Runtime issues

Network Map changes are not reflected on the application

For changes in the network map, you will have to restart the application