Improve transaction submission (#6599)

* Improve transaction submission

Before this pr the transaction pool validated each transaction, even if
the transaction was already known to the pool. This pr changes the
behavior to first check if we are already aware of a transaction and
thus, to only validate them if we don't know them yet. However, there is
still the possibility that a given transaction is validated multiple
times. This can happen if the transaction is added the first time, but
is not yet validated and added to the validated pool.

Besides that, this pr fixes the wrong metrics of gossiped transactions
in the network. It also moves some metrics to the transaction pool api,
to better track when a transaction actually is scheduled for validation.

* Make sure we don't submit the same transaction twice from the network concurrently

* Remove added listener call

* Feedback

* Ignore banned on resubmit

substrate/client/transaction-pool/src/metrics.rs

@@ -45,8 +45,7 @@ impl MetricsLink {
 
 /// Transaction pool Prometheus metrics.
 pub struct Metrics {
-	pub validations_scheduled: Counter<U64>,
-	pub validations_finished: Counter<U64>,
+	pub submitted_transactions: Counter<U64>,
 	pub validations_invalid: Counter<U64>,
 	pub block_transactions_pruned: Counter<U64>,
 	pub block_transactions_resubmitted: Counter<U64>,
@@ -55,17 +54,10 @@ pub struct Metrics {
 impl Metrics {
 	pub fn register(registry: &Registry) -> Result<Self, PrometheusError> {
 		Ok(Self {
-			validations_scheduled: register(
+			submitted_transactions: register(
 				Counter::new(
-					"sub_txpool_validations_scheduled",
-					"Total number of transactions scheduled for validation",
-				)?,
-				registry,
-			)?,
-			validations_finished: register(
-				Counter::new(
-					"sub_txpool_validations_finished",
-					"Total number of transactions that finished validation",
+					"sub_txpool_submitted_transactions",
+					"Total number of transactions submitted",
 				)?,
 				registry,
 			)?,
@@ -93,3 +85,45 @@ impl Metrics {
 		})
 	}
 }
+
+/// Transaction pool api Prometheus metrics.
+pub struct ApiMetrics {
+	pub validations_scheduled: Counter<U64>,
+	pub validations_finished: Counter<U64>,
+}
+
+impl ApiMetrics {
+	/// Register the metrics at the given Prometheus registry.
+	pub fn register(registry: &Registry) -> Result<Self, PrometheusError> {
+		Ok(Self {
+			validations_scheduled: register(
+				Counter::new(
+					"sub_txpool_validations_scheduled",
+					"Total number of transactions scheduled for validation",
+				)?,
+				registry,
+			)?,
+			validations_finished: register(
+				Counter::new(
+					"sub_txpool_validations_finished",
+					"Total number of transactions that finished validation",
+				)?,
+				registry,
+			)?,
+		})
+	}
+}
+
+/// An extension trait for [`ApiMetrics`].
+pub trait ApiMetricsExt {
+	/// Report an event to the metrics.
+	fn report(&self, report: impl FnOnce(&ApiMetrics));
+}
+
+impl ApiMetricsExt for Option<Arc<ApiMetrics>> {
+	fn report(&self, report: impl FnOnce(&ApiMetrics)) {
+		if let Some(metrics) = self.as_ref() {
+			report(metrics)
+		}
+	}
+}