feat: refactor signing in order to more easily be able to dryrun (#547)

* feat: refactor signing in order to more easily be able to dryrun

Co-authored-by: Sander Bosma <sanderbosma@gmail.com>
Co-authored-by: Daniel Savu <savudani04@yahoo.ro>

* chore: move dry_run to rpc file

* fix: failing dryrun test

* fix: run cargo fmt

* chore(dryrun): Replace complex SubmittableExtrinsic type with bytes array

* cargo fmt

* feat: add dry_run method to signed submittable extrinsic

* fmt

Co-authored-by: Sander Bosma <sanderbosma@gmail.com>

integration-tests/src/client/mod.rs

@@ -17,14 +17,24 @@
 use crate::{
     test_node_process,
     test_node_process_with,
-    utils::node_runtime::system,
+    utils::{
+        node_runtime::system,
+        pair_signer,
+        test_context,
+    },
 };
 
-use sp_core::storage::{
-    well_known_keys,
-    StorageKey,
+use sp_core::{
+    sr25519::Pair,
+    storage::{
+        well_known_keys,
+        StorageKey,
+    },
+    Pair as _,
 };
 use sp_keyring::AccountKeyring;
+use sp_runtime::DispatchOutcome;
+use subxt::Error;
 
 #[tokio::test]
 async fn insert_key() {
@@ -131,3 +141,86 @@ async fn fetch_system_info() {
     assert_eq!(client.rpc().system_name().await.unwrap(), "Substrate Node");
     assert!(!client.rpc().system_version().await.unwrap().is_empty());
 }
+
+#[tokio::test]
+async fn dry_run_passes() {
+    let node_process = test_node_process().await;
+    let client = node_process.client();
+
+    let alice = pair_signer(AccountKeyring::Alice.pair());
+    let bob = pair_signer(AccountKeyring::Bob.pair());
+    let bob_address = bob.account_id().clone().into();
+    let cxt = test_context().await;
+    let api = &cxt.api;
+    let signed_extrinsic = api
+        .tx()
+        .balances()
+        .transfer(bob_address, 10_000)
+        .unwrap()
+        .create_signed(&alice, Default::default())
+        .await
+        .unwrap();
+
+    client
+        .rpc()
+        .dry_run(signed_extrinsic.encoded(), None)
+        .await
+        .expect("dryrunning failed")
+        .expect("expected dryrunning to be successful")
+        .unwrap();
+    signed_extrinsic
+        .submit_and_watch()
+        .await
+        .unwrap()
+        .wait_for_finalized_success()
+        .await
+        .unwrap();
+}
+
+#[tokio::test]
+async fn dry_run_fails() {
+    let node_process = test_node_process().await;
+    let client = node_process.client();
+
+    let alice = pair_signer(AccountKeyring::Alice.pair());
+    let hans = pair_signer(Pair::generate().0);
+    let hans_address = hans.account_id().clone().into();
+    let cxt = test_context().await;
+    let api = &cxt.api;
+    let signed_extrinsic = api
+        .tx()
+        .balances()
+        .transfer(
+            hans_address,
+            100_000_000_000_000_000_000_000_000_000_000_000,
+        )
+        .unwrap()
+        .create_signed(&alice, Default::default())
+        .await
+        .unwrap();
+
+    let dry_run_res: DispatchOutcome = client
+        .rpc()
+        .dry_run(signed_extrinsic.encoded(), None)
+        .await
+        .expect("dryrunning failed")
+        .expect("expected dryrun transaction to be valid");
+    if let Err(sp_runtime::DispatchError::Module(module_error)) = dry_run_res {
+        assert_eq!(module_error.index, 6);
+        assert_eq!(module_error.error, 2);
+    } else {
+        panic!("expected a module error when dryrunning");
+    }
+    let res = signed_extrinsic
+        .submit_and_watch()
+        .await
+        .unwrap()
+        .wait_for_finalized_success()
+        .await;
+    if let Err(Error::Module(err)) = res {
+        assert_eq!(err.pallet, "Balances");
+        assert_eq!(err.error, "InsufficientBalance");
+    } else {
+        panic!("expected a runtime module error");
+    }
+}

subxt/src/client.rs

@@ -15,8 +15,11 @@
 // along with subxt.  If not, see <http://www.gnu.org/licenses/>.
 
 use futures::future;
-use sp_runtime::traits::Hash;
 pub use sp_runtime::traits::SignedExtension;
+use sp_runtime::{
+    traits::Hash,
+    ApplyExtrinsicResult,
+};
 
 use crate::{
     error::{
@@ -287,7 +290,7 @@ where
     /// Returns a [`TransactionProgress`], which can be used to track the status of the transaction
     /// and obtain details about it, once it has made it into a block.
     pub async fn sign_and_submit_then_watch_default(
-        self,
+        &self,
         signer: &(dyn Signer<T> + Send + Sync),
     ) -> Result<TransactionProgress<'client, T, E, Evs>, BasicError>
     where
@@ -302,22 +305,14 @@ where
     /// Returns a [`TransactionProgress`], which can be used to track the status of the transaction
     /// and obtain details about it, once it has made it into a block.
     pub async fn sign_and_submit_then_watch(
-        self,
+        &self,
         signer: &(dyn Signer<T> + Send + Sync),
         other_params: X::OtherParams,
     ) -> Result<TransactionProgress<'client, T, E, Evs>, BasicError> {
-        // Sign the call data to create our extrinsic.
-        let extrinsic = self.create_signed(signer, other_params).await?;
-
-        // Get a hash of the extrinsic (we'll need this later).
-        let ext_hash = T::Hashing::hash_of(&extrinsic);
-
-        tracing::info!("xt hash: {}", hex::encode(ext_hash.encode()));
-
-        // Submit and watch for transaction progress.
-        let sub = self.client.rpc().watch_extrinsic(extrinsic).await?;
-
-        Ok(TransactionProgress::new(sub, self.client, ext_hash))
+        self.create_signed(signer, other_params)
+            .await?
+            .submit_and_watch()
+            .await
     }
 
     /// Creates and signs an extrinsic and submits to the chain for block inclusion. Passes
@@ -331,7 +326,7 @@ where
     /// Success does not mean the extrinsic has been included in the block, just that it is valid
     /// and has been included in the transaction pool.
     pub async fn sign_and_submit_default(
-        self,
+        &self,
         signer: &(dyn Signer<T> + Send + Sync),
     ) -> Result<T::Hash, BasicError>
     where
@@ -349,12 +344,14 @@ where
     /// Success does not mean the extrinsic has been included in the block, just that it is valid
     /// and has been included in the transaction pool.
     pub async fn sign_and_submit(
-        self,
+        &self,
         signer: &(dyn Signer<T> + Send + Sync),
         other_params: X::OtherParams,
     ) -> Result<T::Hash, BasicError> {
-        let extrinsic = self.create_signed(signer, other_params).await?;
-        self.client.rpc().submit_extrinsic(extrinsic).await
+        self.create_signed(signer, other_params)
+            .await?
+            .submit()
+            .await
     }
 
     /// Creates a returns a raw signed extrinsic, without submitting it.
@@ -362,7 +359,7 @@ where
         &self,
         signer: &(dyn Signer<T> + Send + Sync),
         other_params: X::OtherParams,
-    ) -> Result<Encoded, BasicError> {
+    ) -> Result<SignedSubmittableExtrinsic<'client, T, X, E, Evs>, BasicError> {
         // 1. Get nonce
         let account_nonce = if let Some(nonce) = signer.nonce() {
             nonce
@@ -449,6 +446,67 @@ where
 
         // Wrap in Encoded to ensure that any more "encode" calls leave it in the right state.
         // maybe we can just return the raw bytes..
-        Ok(Encoded(extrinsic))
+        Ok(SignedSubmittableExtrinsic {
+            client: self.client,
+            encoded: Encoded(extrinsic),
+            marker: self.marker,
+        })
+    }
+}
+
+pub struct SignedSubmittableExtrinsic<'client, T: Config, X, E: Decode, Evs: Decode> {
+    client: &'client Client<T>,
+    encoded: Encoded,
+    marker: std::marker::PhantomData<(X, E, Evs)>,
+}
+
+impl<'client, T, X, E, Evs> SignedSubmittableExtrinsic<'client, T, X, E, Evs>
+where
+    T: Config,
+    X: ExtrinsicParams<T>,
+    E: Decode + HasModuleError,
+    Evs: Decode,
+{
+    /// Submits the extrinsic to the chain.
+    ///
+    /// Returns a [`TransactionProgress`], which can be used to track the status of the transaction
+    /// and obtain details about it, once it has made it into a block.
+    pub async fn submit_and_watch(
+        &self,
+    ) -> Result<TransactionProgress<'client, T, E, Evs>, BasicError> {
+        // Get a hash of the extrinsic (we'll need this later).
+        let ext_hash = T::Hashing::hash_of(&self.encoded);
+
+        // Submit and watch for transaction progress.
+        let sub = self.client.rpc().watch_extrinsic(&self.encoded).await?;
+
+        Ok(TransactionProgress::new(sub, self.client, ext_hash))
+    }
+
+    /// Submits the extrinsic to the chain for block inclusion.
+    ///
+    /// Returns `Ok` with the extrinsic hash if it is valid extrinsic.
+    ///
+    /// # Note
+    ///
+    /// Success does not mean the extrinsic has been included in the block, just that it is valid
+    /// and has been included in the transaction pool.
+    pub async fn submit(&self) -> Result<T::Hash, BasicError> {
+        self.client.rpc().submit_extrinsic(&self.encoded).await
+    }
+
+    /// Submits the extrinsic to the dry_run RPC, to test if it would succeed.
+    ///
+    /// Returns `Ok` with an [`ApplyExtrinsicResult`], which is the result of applying of an extrinsic.
+    pub async fn dry_run(
+        &self,
+        at: Option<T::Hash>,
+    ) -> Result<ApplyExtrinsicResult, BasicError> {
+        self.client.rpc().dry_run(self.encoded(), at).await
+    }
+
+    /// Returns the SCALE encoded extrinsic bytes.
+    pub fn encoded(&self) -> &[u8] {
+        &self.encoded.0
     }
 }

subxt/src/rpc.rs

@@ -146,9 +146,12 @@ use sp_core::{
     Bytes,
     U256,
 };
-use sp_runtime::generic::{
-    Block,
-    SignedBlock,
+use sp_runtime::{
+    generic::{
+        Block,
+        SignedBlock,
+    },
+    ApplyExtrinsicResult,
 };
 
 /// A number type that can be serialized both as a number or a string that encodes a number in a
@@ -643,6 +646,21 @@ impl<T: Config> Rpc<T> {
         let params = rpc_params![public_key, key_type];
         Ok(self.client.request("author_hasKey", params).await?)
     }
+
+    /// Submits the extrinsic to the dry_run RPC, to test if it would succeed.
+    ///
+    /// Returns `Ok` with an [`ApplyExtrinsicResult`], which is the result of applying of an extrinsic.
+    pub async fn dry_run(
+        &self,
+        encoded_signed: &[u8],
+        at: Option<T::Hash>,
+    ) -> Result<ApplyExtrinsicResult, BasicError> {
+        let params = rpc_params![format!("0x{}", hex::encode(encoded_signed)), at];
+        let result_bytes: Bytes = self.client.request("system_dryRun", params).await?;
+        let data: ApplyExtrinsicResult =
+            codec::Decode::decode(&mut result_bytes.0.as_slice())?;
+        Ok(data)
+    }
 }
 
 /// Build WS RPC client from URL