DIGITALL / SAP – Site Reliability Engineer Technical Tasks

This repository contains my completed Site Reliability Engineer (SRE) technical assessment for DIGITALL / SAP, demonstrating both software automation and infrastructure-as-code capabilities.

The repo is structured into two self-contained tasks:

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🧩 Task 1 – SSL/TLS Certificate Expiry Checker

Tech: Python 3 | Docker
Folder: task1/

A containerized Python utility that:

• Checks SSL/TLS certificate expiration for multiple domains.
• Supports configurable warning/critical thresholds via config.json.
• Optionally sends Slack notifications for expiring certificates.
• Includes Docker packaging for local or CI execution.

Purpose: Demonstrates scripting, containerization, and lightweight monitoring logic.

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⚙️ Task 2 – AWS Infrastructure Automation (Gitea Stack)

Tech: Terraform | AWS | GitHub Actions | Bash
Folder: task2/gitea-aws/

Implements a fully automated deployment of a web-application stack on AWS:

Component	AWS Service	Purpose
Load Balancer	ALB	Public entry point + health checks
Web App Servers	EC2 (ASG)	Run Gitea web UI + API
Database	RDS (PostgreSQL 16.x)	Persistent backend storage
Shared Storage	EFS	Persist Gitea repos/data across instances
CI/CD	GitHub Actions	Lint → Validate → Plan → Apply
Failover	ALB + ASG + EFS	Self-healing + multi-AZ resilience

Includes:

• main.tf, variables.tf, outputs.tf, and .tflint.hcl (for validation and best-practice linting).
• Automated provisioning with setup.sh and cleanup.sh.
• Documentation: ARCHITECTURE.md, CI_CD.md, docs/failover.md.
• Root-level CI/CD workflow: .github/workflows/terraform-task2.yml.

Purpose: Demonstrates professional IaC patterns — idempotent Terraform code, secure AWS architecture, and CI/CD pipeline integration.

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📦 Repository Structure

sap_tasks/
├── task1/ssl_checker/
│   ├── cert_checker.py
│   ├── config.json
│   ├── Dockerfile
│   └── README.md
└── task2/gitea-aws/
    ├── main.tf
    ├── variables.tf
    ├── outputs.tf
    ├── user-data.sh
    ├── scripts/
    ├── docs/
    └── .tflint.hcl

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🧠 Highlights

• Declarative IaC using Terraform with AWS provider.
• GitHub OIDC authentication (no static keys).
• Automated formatting, validation, and linting (tflint).
• Scalable and self-healing EC2 Auto Scaling Group.
• Persistent EFS volume for application data.
• Clean project structure with documentation and CI/CD workflow.

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🧰 Usage Notes

1. Clone the repository.
2. For Task 1, build and run the Docker image locally or in CI.
3. For Task 2, run:

   cd task2/gitea-aws
   terraform init
   terraform plan
   terraform apply -auto-approve

4. View Terraform outputs for the ALB DNS and RDS endpoint.

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🪄 CI/CD Workflow

• Defined in .github/workflows/terraform-task2.yml.
• Runs on every PR or push affecting task2/gitea-aws/**.
• Steps: fmt → validate → tflint → plan (+ optional manual apply).
• Uses GitHub OIDC to assume an AWS IAM role securely.

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📜 License

Licensed under the MIT License © 2025 Boris Petrov.
See the LICENSE file for details.