Cleanup

backend-go/internal/config/config.go

@@ -1,4 +1,4 @@
-// Package config loads environment-based configuration.
+//loads environment-based configuration.
 package config
 
 import (
@@ -9,17 +9,12 @@ import (
 )
 
 const (
-	// defaultPort is the default HTTP server port.
 	defaultPort = 3001
-	// defaultDBPort is the default PostgreSQL port.
 	defaultDBPort = 5432
-	// defaultPollIntervalMS is the default poller interval in milliseconds.
 	defaultPollIntervalMS = 60000
-	// minPollIntervalMS is the minimum allowed poller interval.
 	minPollIntervalMS = 1000
 )
 
-// Config holds application configuration.
 type Config struct {
 	Port              int
 	APIBasePath       string
@@ -59,10 +54,8 @@ func Load() (*Config, error) {
 	return cfg, nil
 }
 
-// DSN returns the PostgreSQL data source name for the configured database.
 func (c *Config) DSN() string {
 	if c.DatabaseURL != "" {
-		// pgx defaults to sslmode=prefer, which fails against local Postgres.
 		// Append sslmode=disable if not already specified.
 		if !strings.Contains(c.DatabaseURL, "sslmode=") {
 			sep := "?"

backend-go/internal/domain/types.go

@@ -15,6 +15,9 @@ type Address struct {
 // AlertType identifies the kind of alert rule.
 type AlertType string
 
+// String implements fmt.Stringer.
+func (a AlertType) String() string { return string(a) }
+
 // Alert type constants define the supported alert triggers.
 const (
 	AlertIncomingTx    AlertType = "incoming_tx"
@@ -24,7 +27,7 @@ const (
 )
 
 // ValidAlertTypes lists all alert types accepted by the API.
-var ValidAlertTypes = []AlertType{
+var ValidAlertTypes = []AlertType{ //nolint:gochecknoglobals
 	AlertIncomingTx,
 	AlertOutgoingTx,
 	AlertLargeTransfer,
@@ -32,7 +35,7 @@ var ValidAlertTypes = []AlertType{
 }
 
 // ThresholdRequiredTypes lists alert types that require a threshold value.
-var ThresholdRequiredTypes = []AlertType{
+var ThresholdRequiredTypes = []AlertType{ //nolint:gochecknoglobals
 	AlertLargeTransfer,
 	AlertBalanceBelow,
 }
@@ -120,6 +123,9 @@ type NormalizedTx struct {
 // Direction indicates whether a transaction is incoming or outgoing.
 type Direction string
 
+// String implements fmt.Stringer.
+func (d Direction) String() string { return string(d) }
+
 // Direction constants indicate the flow of a transaction relative to a watched address.
 const (
 	DirectionIncoming Direction = "incoming"

backend-go/internal/handlers/alert_rule.go

@@ -68,7 +68,7 @@ func (h *AlertRuleHandler) Create(w http.ResponseWriter, r *http.Request) {
 	if !domain.IsValidAlertType(body.Type) {
 		types := make([]string, len(domain.ValidAlertTypes))
 		for i, t := range domain.ValidAlertTypes {
-			types[i] = string(t)
+			types[i] = t.String()
 		}
 		writeError(w, http.StatusBadRequest, "VALIDATION_ERROR",
 			"Invalid alert type. Must be one of: "+strings.Join(types, ", "))

backend-go/internal/middleware/auth.go

@@ -1,3 +1,4 @@
+// Package middleware provides HTTP middleware for authentication and context injection.
 package middleware
 
 import (

backend-go/internal/models/address.go

@@ -2,7 +2,9 @@ package models
 
 import (
 	"context"
+	"errors"
 
+	"github.com/jackc/pgx/v5"
 	"github.com/jackc/pgx/v5/pgxpool"
 	"github.com/kjannette/koin-ping/backend-go/internal/domain"
 )
@@ -97,7 +99,7 @@ func (m *AddressModel) FindByID(ctx context.Context, id int, userID *string) (*d
 	}
 
 	if err != nil {
-		if err.Error() == "no rows in result set" {
+		if errors.Is(err, pgx.ErrNoRows) {
 			return nil, nil
 		}
 		return nil, err

backend-go/internal/models/alert_rule.go

@@ -2,7 +2,9 @@ package models
 
 import (
 	"context"
+	"errors"
 
+	"github.com/jackc/pgx/v5"
 	"github.com/jackc/pgx/v5/pgxpool"
 	"github.com/kjannette/koin-ping/backend-go/internal/domain"
 )
@@ -21,7 +23,7 @@ func (m *AlertRuleModel) Create(ctx context.Context, addressID int, alertType do
 		`INSERT INTO alert_rules (address_id, type, threshold, enabled)
 		 VALUES ($1, $2, $3, TRUE)
 		 RETURNING id, address_id, type, threshold, enabled, created_at`,
-		addressID, string(alertType), threshold,
+		addressID, alertType.String(), threshold,
 	).Scan(&r.ID, &r.AddressID, &r.Type, &r.Threshold, &r.Enabled, &r.CreatedAt)
 	if err != nil {
 		return nil, err
@@ -75,7 +77,7 @@ func (m *AlertRuleModel) FindByID(ctx context.Context, id int, userID *string) (
 	}
 
 	if err != nil {
-		if err.Error() == "no rows in result set" {
+		if errors.Is(err, pgx.ErrNoRows) {
 			return nil, nil
 		}
 		return nil, err
@@ -93,7 +95,7 @@ func (m *AlertRuleModel) UpdateEnabled(ctx context.Context, id int, enabled bool
 		id, enabled,
 	).Scan(&r.ID, &r.AddressID, &r.Type, &r.Threshold, &r.Enabled, &r.CreatedAt)
 	if err != nil {
-		if err.Error() == "no rows in result set" {
+		if errors.Is(err, pgx.ErrNoRows) {
 			return nil, nil
 		}
 		return nil, err

backend-go/internal/models/checkpoint.go

@@ -2,7 +2,9 @@ package models
 
 import (
 	"context"
+	"errors"
 
+	"github.com/jackc/pgx/v5"
 	"github.com/jackc/pgx/v5/pgxpool"
 	"github.com/kjannette/koin-ping/backend-go/internal/domain"
 )
@@ -23,7 +25,7 @@ func (m *CheckpointModel) GetLastCheckedBlock(ctx context.Context, addressID int
 		addressID,
 	).Scan(&block)
 	if err != nil {
-		if err.Error() == "no rows in result set" {
+		if errors.Is(err, pgx.ErrNoRows) {
 			return 0, false, nil
 		}
 		return 0, false, err

backend-go/internal/models/notification_config.go

@@ -2,7 +2,9 @@ package models
 
 import (
 	"context"
+	"errors"
 
+	"github.com/jackc/pgx/v5"
 	"github.com/jackc/pgx/v5/pgxpool"
 	"github.com/kjannette/koin-ping/backend-go/internal/domain"
 )
@@ -26,7 +28,7 @@ func (m *NotificationConfigModel) GetConfig(ctx context.Context, userID string)
 	).Scan(&c.UserID, &c.DiscordWebhookURL, &c.TelegramChatID, &c.TelegramBotToken,
 		&c.Email, &c.NotificationEnabled, &c.CreatedAt, &c.UpdatedAt)
 	if err != nil {
-		if err.Error() == "no rows in result set" {
+		if errors.Is(err, pgx.ErrNoRows) {
 			return nil, nil
 		}
 		return nil, err

backend-go/internal/notifications/discord.go

@@ -9,6 +9,22 @@ import (
 	"time"
 )
 
+const (
+	// discordHTTPTimeoutSeconds is the timeout for Discord webhook requests.
+	discordHTTPTimeoutSeconds = 10
+
+	// Alert color codes for Discord embeds.
+	colorGreen  = 0x00ff00
+	colorOrange = 0xff9900
+	colorRed    = 0xff0000
+	colorBlue   = 0x0099ff
+)
+
+// discordHTTPClient is a shared HTTP client with a timeout for Discord requests.
+var discordHTTPClient = &http.Client{ //nolint:gochecknoglobals
+	Timeout: discordHTTPTimeoutSeconds * time.Second,
+}
+
 type AlertMetadata struct {
 	TxHash       string
 	AddressLabel string
@@ -73,7 +89,9 @@ func SendDiscordNotification(webhookURL, message string, meta AlertMetadata) (bo
 		return false, fmt.Errorf("marshal discord payload: %w", err)
 	}
 
-	resp, err := http.Post(webhookURL, "application/json", bytes.NewReader(body))
+	resp, err := discordHTTPClient.Post(
+		webhookURL, "application/json", bytes.NewReader(body),
+	)
 	if err != nil {
 		log.Printf("Failed to send Discord notification: %v", err)
 		return false, err
@@ -98,7 +116,9 @@ func TestDiscordWebhook(webhookURL string) (bool, error) {
 		return false, err
 	}
 
-	resp, err := http.Post(webhookURL, "application/json", bytes.NewReader(body))
+	resp, err := discordHTTPClient.Post(
+		webhookURL, "application/json", bytes.NewReader(body),
+	)
 	if err != nil {
 		log.Printf("Discord webhook test failed: %v", err)
 		return false, err
@@ -111,14 +131,14 @@ func TestDiscordWebhook(webhookURL string) (bool, error) {
 func colorForAlertType(alertType string) int {
 	switch alertType {
 	case "incoming_tx":
-		return 0x00ff00 // Green
+		return colorGreen
 	case "outgoing_tx":
-		return 0xff9900 // Orange
+		return colorOrange
 	case "large_transfer":
-		return 0xff0000 // Red
+		return colorRed
 	case "balance_below":
-		return 0xff0000 // Red
+		return colorRed
 	default:
-		return 0x0099ff // Blue
+		return colorBlue
 	}
 }

backend-go/internal/services/evaluator.go

@@ -170,7 +170,11 @@ func (s *EvaluatorService) fireAlert(ctx context.Context, rule domain.AlertRule,
 
 	// Send Discord notification (non-fatal on failure)
 	if addr != nil {
-		go s.sendNotification(ctx, addr.UserID, message, obs, addressLabel, rule, addr.Address)
+		go func() {
+			s.sendNotification(
+				ctx, addr.UserID, message, obs, addressLabel, rule, addr.Address,
+			)
+		}()
 	}
 
 	return nil