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