Add per-webhook event retention reaper (closes #63)

internal/config/config.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"strconv"
 	"strings"
+	"time"
 
 	"go.uber.org/fx"
 	"sneak.berlin/go/webhooker/internal/globals"
@@ -26,6 +27,10 @@ const (
 
 	// defaultPort is the default HTTP listen port.
 	defaultPort = 8080
+
+	// defaultRetentionSweepInterval is how often the retention
+	// reaper deletes events older than each webhook's RetentionDays.
+	defaultRetentionSweepInterval = time.Hour
 )
 
 // ErrInvalidEnvironment is returned when WEBHOOKER_ENVIRONMENT
@@ -51,8 +56,12 @@ type Config struct {
 	MetricsUsername string
 	Port            int
 	SentryDSN       string
-	params          *ConfigParams
-	log             *slog.Logger
+
+	// RetentionSweepInterval is how often the retention reaper runs.
+	RetentionSweepInterval time.Duration
+
+	params *ConfigParams
+	log    *slog.Logger
 }
 
 // IsDev returns true if running in development environment.
@@ -95,6 +104,23 @@ func envInt(key string, defaultValue int) int {
 	return defaultValue
 }
 
+// envDuration returns the value of the named environment variable
+// parsed as a Go duration (e.g. "1h", "30m"). Returns defaultValue if
+// not set or unparseable.
+func envDuration(
+	key string,
+	defaultValue time.Duration,
+) time.Duration {
+	if v := os.Getenv(key); v != "" {
+		d, err := time.ParseDuration(v)
+		if err == nil {
+			return d
+		}
+	}
+
+	return defaultValue
+}
+
 // New creates a Config by reading environment variables.
 //
 //nolint:revive // lc parameter is required by fx even if unused.
@@ -128,8 +154,12 @@ func New(lc fx.Lifecycle, params ConfigParams) (*Config, error) {
 		MetricsPassword: envString("METRICS_PASSWORD"),
 		Port:            envInt("PORT", defaultPort),
 		SentryDSN:       envString("SENTRY_DSN"),
-		log:             log,
-		params:          &params,
+		RetentionSweepInterval: envDuration(
+			"RETENTION_SWEEP_INTERVAL",
+			defaultRetentionSweepInterval,
+		),
+		log:    log,
+		params: &params,
 	}
 
 	// Set default DataDir. All SQLite databases (main application
@@ -151,6 +181,7 @@ func New(lc fx.Lifecycle, params ConfigParams) (*Config, error) {
 		"debug", s.Debug,
 		"maintenanceMode", s.MaintenanceMode,
 		"dataDir", s.DataDir,
+		"retentionSweepInterval", s.RetentionSweepInterval.String(),
 		"hasSentryDSN", s.SentryDSN != "",
 		"hasMetricsAuth",
 		s.MetricsUsername != "" && s.MetricsPassword != "",