feat: time database queries

internal/observability/db.go

@@ -0,0 +1,51 @@
+package observability
+
+import (
+	"context"
+	"database/sql"
+	"time"
+)
+
+type instrumentedDB struct {
+	db interface {
+		ExecContext(context.Context, string, ...interface{}) (sql.Result, error)
+		PrepareContext(context.Context, string) (*sql.Stmt, error)
+		QueryContext(context.Context, string, ...interface{}) (*sql.Rows, error)
+		QueryRowContext(context.Context, string, ...interface{}) *sql.Row
+	}
+	metrics *Metrics
+}
+
+func InstrumentDB(db interface {
+	ExecContext(context.Context, string, ...interface{}) (sql.Result, error)
+	PrepareContext(context.Context, string) (*sql.Stmt, error)
+	QueryContext(context.Context, string, ...interface{}) (*sql.Rows, error)
+	QueryRowContext(context.Context, string, ...interface{}) *sql.Row
+}, metrics *Metrics) *instrumentedDB {
+	return &instrumentedDB{db: db, metrics: metrics}
+}
+
+func (db *instrumentedDB) ExecContext(ctx context.Context, query string, args ...interface{}) (sql.Result, error) {
+	start := time.Now()
+	result, err := db.db.ExecContext(ctx, query, args...)
+	db.metrics.ObserveDBQuery("exec", time.Since(start), err)
+	return result, err
+}
+
+func (db *instrumentedDB) PrepareContext(ctx context.Context, query string) (*sql.Stmt, error) {
+	return db.db.PrepareContext(ctx, query)
+}
+
+func (db *instrumentedDB) QueryContext(ctx context.Context, query string, args ...interface{}) (*sql.Rows, error) {
+	start := time.Now()
+	rows, err := db.db.QueryContext(ctx, query, args...)
+	db.metrics.ObserveDBQuery("query", time.Since(start), err)
+	return rows, err
+}
+
+func (db *instrumentedDB) QueryRowContext(ctx context.Context, query string, args ...interface{}) *sql.Row {
+	start := time.Now()
+	row := db.db.QueryRowContext(ctx, query, args...)
+	db.metrics.ObserveDBQuery("query_row", time.Since(start), nil)
+	return row
+}