Enable logging in the puppet worker (#3411)

This is useful for tests where something is failing :D

polkadot/Cargo.lock

@@ -6234,6 +6234,7 @@ dependencies = [
  "sp-externalities",
  "sp-io",
  "sp-maybe-compressed-blob",
+ "sp-tracing",
  "sp-wasm-interface",
  "tempfile",
  "test-parachain-adder",

polkadot/node/core/pvf/Cargo.toml

@@ -31,6 +31,7 @@ sp-io = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-wasm-interface = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-maybe-compressed-blob = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-tracing = { git = "https://github.com/paritytech/substrate", branch = "master" }
 
 [dev-dependencies]
 adder = { package = "test-parachain-adder", path = "../../../parachain/test-parachains/adder" }

polkadot/node/core/pvf/src/lib.rs

@@ -88,6 +88,9 @@ mod worker_common;
 #[doc(hidden)]
 pub mod testing;
 
+#[doc(hidden)]
+pub use sp_tracing;
+
 pub use error::{ValidationError, InvalidCandidate};
 pub use priority::Priority;
 pub use pvf::Pvf;

polkadot/node/core/pvf/src/testing.rs

@@ -50,6 +50,8 @@ pub fn validate_candidate(
 macro_rules! decl_puppet_worker_main {
 	() => {
 		fn main() {
+			$crate::sp_tracing::try_init_simple();
+
 			let args = std::env::args().collect::<Vec<_>>();
 			if args.len() < 2 {
 				panic!("wrong number of arguments");