Initial commit

internal/database/database.go

@@ -0,0 +1,115 @@
+package database
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"time"
+
+	_ "github.com/jackc/pgx/v5/stdlib"
+	_ "github.com/joho/godotenv/autoload"
+)
+
+// Service represents a service that interacts with a database.
+type Service interface {
+	// Health returns a map of health status information.
+	// The keys and values in the map are service-specific.
+	Health() map[string]string
+
+	// Close terminates the database connection.
+	// It returns an error if the connection cannot be closed.
+	Close() error
+}
+
+type service struct {
+	db *sql.DB
+}
+
+var (
+	database   = os.Getenv("BLUEPRINT_DB_DATABASE")
+	password   = os.Getenv("BLUEPRINT_DB_PASSWORD")
+	username   = os.Getenv("BLUEPRINT_DB_USERNAME")
+	port       = os.Getenv("BLUEPRINT_DB_PORT")
+	host       = os.Getenv("BLUEPRINT_DB_HOST")
+	schema     = os.Getenv("BLUEPRINT_DB_SCHEMA")
+	dbInstance *service
+)
+
+func New() Service {
+	// Reuse Connection
+	if dbInstance != nil {
+		return dbInstance
+	}
+	connStr := fmt.Sprintf("postgres://%s:%s@%s:%s/%s?sslmode=disable&search_path=%s", username, password, host, port, database, schema)
+	db, err := sql.Open("pgx", connStr)
+	if err != nil {
+		log.Fatal(err)
+	}
+	dbInstance = &service{
+		db: db,
+	}
+	return dbInstance
+}
+
+// Health checks the health of the database connection by pinging the database.
+// It returns a map with keys indicating various health statistics.
+func (s *service) Health() map[string]string {
+	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
+	defer cancel()
+
+	stats := make(map[string]string)
+
+	// Ping the database
+	err := s.db.PingContext(ctx)
+	if err != nil {
+		stats["status"] = "down"
+		stats["error"] = fmt.Sprintf("db down: %v", err)
+		log.Fatalf(fmt.Sprintf("db down: %v", err)) // Log the error and terminate the program
+		return stats
+	}
+
+	// Database is up, add more statistics
+	stats["status"] = "up"
+	stats["message"] = "It's healthy"
+
+	// Get database stats (like open connections, in use, idle, etc.)
+	dbStats := s.db.Stats()
+	stats["open_connections"] = strconv.Itoa(dbStats.OpenConnections)
+	stats["in_use"] = strconv.Itoa(dbStats.InUse)
+	stats["idle"] = strconv.Itoa(dbStats.Idle)
+	stats["wait_count"] = strconv.FormatInt(dbStats.WaitCount, 10)
+	stats["wait_duration"] = dbStats.WaitDuration.String()
+	stats["max_idle_closed"] = strconv.FormatInt(dbStats.MaxIdleClosed, 10)
+	stats["max_lifetime_closed"] = strconv.FormatInt(dbStats.MaxLifetimeClosed, 10)
+
+	// Evaluate stats to provide a health message
+	if dbStats.OpenConnections > 40 { // Assuming 50 is the max for this example
+		stats["message"] = "The database is experiencing heavy load."
+	}
+
+	if dbStats.WaitCount > 1000 {
+		stats["message"] = "The database has a high number of wait events, indicating potential bottlenecks."
+	}
+
+	if dbStats.MaxIdleClosed > int64(dbStats.OpenConnections)/2 {
+		stats["message"] = "Many idle connections are being closed, consider revising the connection pool settings."
+	}
+
+	if dbStats.MaxLifetimeClosed > int64(dbStats.OpenConnections)/2 {
+		stats["message"] = "Many connections are being closed due to max lifetime, consider increasing max lifetime or revising the connection usage pattern."
+	}
+
+	return stats
+}
+
+// Close closes the database connection.
+// It logs a message indicating the disconnection from the specific database.
+// If the connection is successfully closed, it returns nil.
+// If an error occurs while closing the connection, it returns the error.
+func (s *service) Close() error {
+	log.Printf("Disconnected from database: %s", database)
+	return s.db.Close()
+}