Daily Metrics Aggregation Lambda

[saquibb8]

User Story

As a system, I want an EventBridge-scheduled Lambda function to aggregate platform metrics daily and store them in S3, so that an always up-to-date snapshot of key stats is available for the application to consume.

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Background

The Saayam homepage displays four key metrics — Total Requests, Requests Resolved, Total Volunteers, and Total Beneficiaries. Currently these show as 0. These numbers need to be computed from Aurora/Postgres and made available to the frontend in a performant, scalable way without direct database access from the client.

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Objective

Build a Python-based AWS Lambda function triggered daily by EventBridge that queries Aurora/Postgres, aggregates the four homepage metrics, and writes the result as a JSON file to a designated S3 bucket.

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Scope

• Create an EventBridge cron rule to trigger the Lambda once daily
• Lambda queries Aurora/Postgres for the four metric counts
• Lambda writes the result to s3://saayam-public-metrics/homepage/metrics.json
• JSON schema to be documented and shared with the web app team
• Error handling and logging via CloudWatch

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Acceptance Criteria

• EventBridge triggers the Lambda on schedule daily
• Lambda successfully connects to Aurora and returns correct counts
• metrics.json is written to the correct S3 path after each run
• JSON follows the agreed schema:

  {
    "totalRequests": 120,
    "requestsResolved": 80,
    "totalVolunteers": 45,
    "totalBeneficiaries": 60
  }

• CloudWatch logs confirm successful execution or capture errors
• Schema is documented and handed off to the web app team

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