This document provides detailed cost analysis and resource estimates for the Tash Slack PR Thread Bot based on the following usage patterns:
- 10 Slack users in 1 workspace
- 6 GitHub repositories being tracked
- 20 pull requests per day across all repos
- 2-3 approvals per PR (40-60 approval events/day)
- 5-10 comments per PR (100-200 comment events/day)
- 20 merges per day
- 4 active Slack channels
- 100+ Slack messages per day from the bot
| Metric | Daily Volume | Monthly Volume |
|---|---|---|
| Pull Requests | 20 | 600 |
| Webhook Events | 160-280 | 4,800-8,400 |
| Slack Messages | 160-280 | 4,800-8,400 |
| Database Records | 260-380 | 7,800-11,400 |
| Bandwidth | 4.8-5.5 MB | 145-165 MB |
Daily Data Growth:
- PR Tracking Records: 20 PRs × 4 channels = 80 records/day
- Message Deliveries: 160-280 delivery records/day
- User Connections: Minimal (10 users, mostly static)
- Health Checks: ~1,440 records/day (every minute)
Storage per Record:
- PR Tracking: ~500 bytes
- Message Delivery: ~400 bytes
- User Connection: ~1KB
- Health Check: ~200 bytes
Storage Calculations:
- Monthly Storage: ~12.2 MB
- Annual Storage: ~150 MB
- 10-Year Projection: ~1.5 GB
Recommendation: AWS RDS PostgreSQL (db.t3.micro) with 20GB storage
Redis Memory Requirements:
- Queue Jobs: ~320-560 KB/day
- Cached PR Tracking: ~80 KB
- User Mappings: ~20 KB
- Rate Limiting Data: ~4 KB
- Delivery Locks: ~1 KB
- Total Redis Memory: ~425-665 KB
Application Memory:
- Node.js Base: ~50-100 MB
- Dependencies: ~30-50 MB
- Queue Processing: ~20-30 MB
- Total Application Memory: ~100-180 MB
Recommendation: AWS ElastiCache Redis (cache.t3.micro) with 0.5GB memory
Incoming Traffic (GitHub Webhooks):
- Webhook Payloads: 160-280 events × 5KB = ~800KB-1.4MB/day
- Monthly Incoming: ~25-45 MB
Outgoing Traffic (Slack API + Database):
- Slack Messages: 160-280 messages × 2KB = ~320KB-560KB/day
- Database Queries: ~1,000 queries/day × 1KB = ~1MB/day
- Redis Operations: ~5,000 operations/day × 0.5KB = ~2.5MB/day
- Monthly Outgoing: ~115-125 MB
Total Bandwidth: ~140-170 MB/month
| Service | Instance Type | Monthly Cost |
|---|---|---|
| Application Server | ||
| EC2 t3.micro (1 vCPU, 1GB RAM) | On-Demand | $8.47 |
| Application Load Balancer | Standard | $16.20 |
| Auto Scaling Group | Min: 1, Max: 2 | $0 |
| Database | ||
| RDS PostgreSQL db.t3.micro | Multi-AZ | $24.82 |
| Storage (20GB) | gp2 | $2.30 |
| Cache | ||
| ElastiCache Redis cache.t3.micro | 0.5GB | $12.41 |
| Networking | ||
| VPC | Standard | $0 |
| NAT Gateway | Standard | $32.40 |
| Data Transfer | ~150MB/month | $0.50 |
| Monitoring | ||
| CloudWatch | Basic | $5.00 |
| CloudTrail | Basic | $2.00 |
| Total | $102.10 |
| Service | Instance Type | Monthly Cost |
|---|---|---|
| Application Server | ||
| ECS Fargate (0.25 vCPU, 0.5GB) | On-Demand | $6.00 |
| Application Load Balancer | Standard | $16.20 |
| Database | ||
| RDS PostgreSQL db.t3.micro | Single-AZ | $12.41 |
| Storage (20GB) | gp2 | $2.30 |
| Cache | ||
| ElastiCache Redis cache.t3.micro | 0.5GB | $12.41 |
| Networking | ||
| VPC | Standard | $0 |
| NAT Gateway | Standard | $32.40 |
| Data Transfer | ~150MB/month | $0.50 |
| Monitoring | ||
| CloudWatch | Basic | $5.00 |
| CloudTrail | Basic | $2.00 |
| Total | $87.22 |
| Service | Instance Type | Monthly Cost |
|---|---|---|
| Application Server | ||
| EC2 t3.micro | On-Demand | $8.47 |
| Database | ||
| RDS PostgreSQL db.t3.micro | Single-AZ | $12.41 |
| Storage (20GB) | gp2 | $2.30 |
| Cache | ||
| ElastiCache Redis cache.t3.micro | 0.5GB | $12.41 |
| Networking | ||
| VPC | Standard | $0 |
| Monitoring | ||
| CloudWatch | Basic | $5.00 |
| Total | $40.59 |
- Webhook Reception: ~10-20ms
- Queue Processing: ~5-10ms
- Database Operations: ~20-50ms
- Slack API Call: ~100-200ms
- Total Expected Latency: ~135-280ms
✅ Performance Target Met: Well under the 500ms requirement
- Current Load: 20 PRs/day, 160-280 webhook events/day
- 10x Growth Capacity: 200 PRs/day, 1,600-2,800 webhook events/day
- Infrastructure Changes Required: None (current setup can handle 10x growth)
- Start with Minimal Setup: Use Option 3 for initial deployment
- Monitor Usage: Track actual vs. projected usage for 1-2 months
- Upgrade as Needed: Move to Option 2 if high availability is required
- Reserved Instances: Save 30-50% with 1-year commitments
- Spot Instances: Use for non-critical workloads (development)
- Auto Scaling: Scale down during low-usage periods
- Data Archiving: Archive old delivery logs to S3 (cheaper storage)
- EC2 t3.micro: $6.10/month (28% savings)
- RDS db.t3.micro: $8.90/month (28% savings)
- ElastiCache cache.t3.micro: $8.90/month (28% savings)
- Budget: $50/month
- Setup: Option 3 (Minimal)
- Purpose: Validate functionality and measure actual usage
- Budget: $100/month
- Setup: Option 2 (Cost-Effective)
- Purpose: Reliable production deployment
- Budget: $150/month
- Setup: Option 1 (High Availability)
- Purpose: Handle increased load and ensure 99.9%+ uptime
- Webhook Processing Time: Should stay under 500ms
- Queue Depth: Alert if > 100 pending jobs
- Database Connections: Alert if > 80% of max connections
- Memory Usage: Alert if > 80% of allocated memory
- Error Rate: Alert if > 5% of webhook processing fails
- Daily Cost Tracking: Set up AWS Cost Explorer
- Budget Alerts: Set $50, $100, $150 thresholds
- Resource Utilization: Monitor actual vs. projected usage
The Tash Slack PR Thread Bot has very modest resource requirements due to its efficient architecture and relatively low usage volume. The application can be deployed cost-effectively while meeting all performance and reliability requirements.
Recommended Starting Point: Option 3 (Minimal Setup) at $41/month, with the ability to scale up to Option 2 ($87/month) or Option 1 (~$102/month) as needed.
Key Benefits:
- ✅ Meets 500ms latency requirement
- ✅ Supports high availability when needed
- ✅ Scales to 10x current load without changes
- ✅ Cost-effective for the provided value
- ✅ Future-proof architecture
Last Updated: $(date) Analysis Based On: 10 users, 20 PRs/day, 4 channels, 6 repositories