Lamda , eventbridge, sqs

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Step 1: System Created in organization_webapi

• When a system is created (e.g., via an API call), the service layer in organization_webapi handles the logic.
• After saving the system to the database, it publishes an event to EventBridge.

Relevant code:

// apps/organization_webapi/app/service/dispatchEvents/index.js

async function postSystem(_id) {
  const Model = await this.Model;
  const data = await Model.System.findOne({ _id }).populate('address');
  const evtObj = new EventBridge(this.expressReq);
  return evtObj.putEvents(getEventBridgeEvent('org.post.system', data));
}

• This function fetches the new system, creates an EventBridge event (org.post.system), and publishes it.

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Step 2: EventBridge Receives the Event

• EventBridge is an AWS service that acts as an event bus.
• The event (org.post.system) is sent to EventBridge.

Configuration for EventBridge is typically found in:

• apps/organization_webapi/yml/Resource/Events.yml
• apps/organization_webapi/serverless/OrganizationEvents.js

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Step 3: EventBridge Forwards Event to SQS

• There is a rule in EventBridge that matches the event (org.post.system) and forwards it to an SQS queue.
• SQS is a queue that temporarily stores the event.

Configuration for this is in:

• apps/organization_webapi/yml/Resource/Events.yml
• apps/organization_webapi/yml/Resource/Resource.yml

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Step 4: Lambda is Triggered by SQS

• A Lambda function is set up to listen to the SQS queue.
• When a new event arrives, Lambda is triggered and processes the event.

Lambda handler example (in user_webapi):

// apps/user_webapi/serverless/UserEvents.js

Router.source('org.post.system', async function (event, body) {
  const systemResult = await new SystemService(this.expressReq).insertSystem(body);
  return await new UserService(this.expressReq).attachedSystemToFirstUser(systemResult._id);
});
exports.handler = async event => {
  return Router.listen(event);
};

• This code listens for the org.post.system event and creates the system in the user service.

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Step 5: user_webapi Creates the System

• The Lambda function (above) calls the user service logic to create the system in the user database.

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Summary Table

Step	Service/Component	File/Folder Example	What Happens
1	organization_webapi	app/service/dispatchEvents/index.js	System is created, event is published to EventBridge
2	EventBridge	yml/Resource/Events.yml	EventBridge receives the event
3	SQS	yml/Resource/Resource.yml	EventBridge forwards event to SQS queue
4	Lambda	serverless/UserEvents.js	Lambda is triggered by SQS, processes event
5	user_webapi	app/service/system.js	System is created in user database

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In Simple Terms

1. organization_webapi creates a system and tells EventBridge.
2. EventBridge forwards the event to an SQS queue.
3. Lambda picks up the event from SQS and tells user_webapi to create the same system.
4. user_webapi creates the system for the user.

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If you want to see the actual YAML/serverless config or more code for any step, let me know!