outlet/clickhouse: make grace period for flushing configurable

console/data/docs/02-configuration.md

@@ -613,6 +613,7 @@ are configurable:
 
 - `maximum-batch-size` defines how many flows to send to ClickHouse in a single batch at most
 - `minimum-wait-time` defines how long to wait before sending an incomplete batch
+- `grace-period` defines how long to wait when flushing data to ClickHouse on shutdown
 
 These numbers are per-worker (as defined in the Kafka component). A worker will
 send a batch of size at most `maximum-batch-size` at least every

outlet/clickhouse/config.go

@@ -9,6 +9,8 @@ import (
 
 // Configuration describes the configuration for the ClickHouse exporter.
 type Configuration struct {
+	// GracePeriod defines how long to wait for flushing a batch to ClickHouse on shutdown.
+	GracePeriod time.Duration `validate:"min=10s"`
 	// MaximumBatchSize is the maximum number of rows to send to ClickHouse in one batch.
 	MaximumBatchSize uint `validate:"min=1"`
 	// MaximumWaitTime is the maximum number of seconds to wait before sending the current batch.
@@ -22,6 +24,7 @@ const minimumBatchSizeDivider = 10
 // DefaultConfiguration represents the default configuration for the ClickHouse exporter.
 func DefaultConfiguration() Configuration {
 	return Configuration{
+		GracePeriod:      time.Minute,
 		MaximumBatchSize: 50_000,
 		MaximumWaitTime:  5 * time.Second,
 	}

outlet/clickhouse/worker.go

@@ -137,7 +137,7 @@ func (w *realWorker) Flush(ctx context.Context) {
 		}
 
 		// Don't use the parent context, it may be too short.
-		chCtx, cancel := context.WithTimeout(context.Background(), time.Minute)
+		chCtx, cancel := context.WithTimeout(context.Background(), w.c.config.GracePeriod)
 		defer cancel()
 
 		// Send to ClickHouse in flows_XXXXX_raw.