malus - mockable overseer mvp (#3224)

polkadot/node/malus/src/variant-a.rs

@@ -0,0 +1,110 @@
+// Copyright 2017-2020 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+//! A malicious overseer.
+//!
+//! An example on how to use the `OverseerGen` pattern to
+//! instantiate a modified subsystem implementation
+//! for usage with simnet/gurke.
+
+#![allow(missing_docs)]
+
+use color_eyre::eyre;
+use polkadot_cli::{
+	create_default_subsystems,
+	service::{
+		AuthorityDiscoveryApi, AuxStore, BabeApi, Block, Error, HeaderBackend, Overseer,
+		OverseerGen, OverseerGenArgs, OverseerHandler, ParachainHost, ProvideRuntimeApi,
+		SpawnNamed,
+	},
+	Cli,
+};
+
+// Import extra types relevant to the particular
+// subsystem.
+use polkadot_node_core_candidate_validation::{CandidateValidationSubsystem, Metrics};
+use polkadot_node_subsystem::messages::CandidateValidationMessage;
+use polkadot_node_subsystem_util::metrics::Metrics as _;
+
+// Filter wrapping related types.
+use malus::*;
+
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::sync::Arc;
+
+use structopt::StructOpt;
+
+/// Silly example, just drop every second outgoing message.
+#[derive(Clone, Default, Debug)]
+struct Skippy(Arc<AtomicUsize>);
+
+impl MsgFilter for Skippy {
+	type Message = CandidateValidationMessage;
+
+	fn filter_in(&self, msg: FromOverseer<Self::Message>) -> Option<FromOverseer<Self::Message>> {
+		if self.0.fetch_add(1, Ordering::Relaxed) % 2 == 0 {
+			Some(msg)
+		} else {
+			None
+		}
+	}
+	fn filter_out(&self, msg: AllMessages) -> Option<AllMessages> {
+		Some(msg)
+	}
+}
+
+/// Generates an overseer that exposes bad behavior.
+struct BehaveMaleficient;
+
+impl OverseerGen for BehaveMaleficient {
+	fn generate<'a, Spawner, RuntimeClient>(
+		&self,
+		args: OverseerGenArgs<'a, Spawner, RuntimeClient>,
+	) -> Result<(Overseer<Spawner, Arc<RuntimeClient>>, OverseerHandler), Error>
+	where
+		RuntimeClient: 'static + ProvideRuntimeApi<Block> + HeaderBackend<Block> + AuxStore,
+		RuntimeClient::Api: ParachainHost<Block> + BabeApi<Block> + AuthorityDiscoveryApi<Block>,
+		Spawner: 'static + SpawnNamed + Clone + Unpin,
+	{
+		let spawner = args.spawner.clone();
+		let leaves = args.leaves.clone();
+		let runtime_client = args.runtime_client.clone();
+		let registry = args.registry.clone();
+		let candidate_validation_config = args.candidate_validation_config.clone();
+		// modify the subsystem(s) as needed:
+		let all_subsystems = create_default_subsystems(args)?.replace_candidate_validation(
+			// create the filtered subsystem
+			FilteredSubsystem::new(
+				CandidateValidationSubsystem::with_config(
+					candidate_validation_config,
+					Metrics::register(registry)?,
+				),
+				Skippy::default(),
+			),
+		);
+
+		Overseer::new(leaves, all_subsystems, registry, runtime_client, spawner)
+			.map_err(|e| e.into())
+	}
+}
+
+fn main() -> eyre::Result<()> {
+	color_eyre::install()?;
+	let cli = Cli::from_args();
+	assert_matches::assert_matches!(cli.subcommand, None);
+	polkadot_cli::run_node(cli, BehaveMaleficient)?;
+	Ok(())
+}