Database Load Balancer module for MarchProxy with support for multiple database protocols, connection pooling, rate limiting, and SQL injection detection.

• Multi-Protocol Support: MySQL, PostgreSQL, MongoDB, Redis, MSSQL
• Connection Pooling: Efficient connection reuse and management
• Rate Limiting: Per-route connection and query rate limiting
• SQL Injection Detection: Pattern-based security checking
• gRPC ModuleService: Full ModuleService interface implementation
• Health & Metrics: HTTP endpoints for monitoring and observability
• Production Ready: Containerized deployment with K8s support

go build -o proxy-dblb ./cmd/main.go

./proxy-dblb --config config.yaml

docker build -t marchproxy/dblb:latest .
docker run -p 3306:3306 -p 5432:5432 -p 7002:7002 marchproxy/dblb:latest

Example configuration (config.yaml):

grpc_addr: "0.0.0.0"
grpc_port: 50052
metrics_addr: ":7002"

manager_url: "http://api-server:8000"
cluster_api_key: "${CLUSTER_API_KEY}"

# Connection pooling
max_connections_per_route: 100
connection_idle_timeout: 5m
connection_max_lifetime: 30m

# Rate limiting
enable_rate_limiting: true
default_connection_rate: 100.0  # connections/sec
default_query_rate: 1000.0      # queries/sec

# Security
enable_sql_injection_detection: true
block_suspicious_queries: true

# Routes
routes:
  - name: "mysql-primary"
    protocol: "mysql"
    listen_port: 3306
    backend_host: "mysql-server"
    backend_port: 3306
    max_connections: 100
    connection_rate: 50.0
    query_rate: 500.0
    enable_auth: false

  - name: "postgres-main"
    protocol: "postgresql"
    listen_port: 5432
    backend_host: "postgres-server"
    backend_port: 5432
    max_connections: 200
    connection_rate: 100.0
    query_rate: 1000.0

• CLUSTER_API_KEY: API key for cluster authentication (required)
• MARCHPROXY_DBLB_*: Override any config value (e.g., MARCHPROXY_DBLB_GRPC_PORT)

GET http://localhost:7002/healthz

GET http://localhost:7002/metrics

GET http://localhost:7002/status

Returns JSON with handler and pool statistics.

DBLB implements the full ModuleService interface for NLB integration:

• GetStatus - Module health and status
• Reload - Graceful configuration reload
• Shutdown - Graceful shutdown
• GetMetrics - Real-time metrics
• HealthCheck - Deep health verification
• GetStats - Detailed statistics

Client -> DBLB (TCP Proxy) -> Backend Database
           |
           +-> Connection Pool
           +-> Rate Limiter
           +-> SQL Injection Checker
           +-> Metrics Collection

• Go 1.24.7 or later
• Docker (for containerized builds)

go test ./...

golangci-lint run

See k8s/unified/dblb/ for deployment manifests:

• deployment.yaml - DBLB deployment with 2 replicas
• service.yaml - Service exposure

kubectl apply -f k8s/unified/dblb/

DBLB exposes Prometheus metrics on :7002/metrics:

• dblb_connections_active - Active database connections
• dblb_connections_total - Total connections (lifetime)
• dblb_queries_blocked - Queries blocked by security
• dblb_pool_size - Connection pool sizes

DBLB includes pattern-based SQL injection detection:

• Common SQL injection patterns
• Comment injection detection
• Excessive SQL keyword heuristics
• Custom pattern support

Configure via:

enable_sql_injection_detection: true
block_suspicious_queries: true

Limited AGPL3 with Contributor Employer Exception

Copyright (c) 2024 PenguinTech.io

• Documentation: https://docs.marchproxy.io
• Issues: https://github.com/penguintech/marchproxy/issues
• Website: https://www.penguintech.io