runtime-sdk: Add support for incoming messages

client-sdk/go/modules/core/types.go

@@ -25,6 +25,11 @@ type GasCosts struct {
 	AuthSignature            uint64 `json:"auth_signature"`
 	AuthMultisigSigner       uint64 `json:"auth_multisig_signer"`
 	CallformatX25519Deoxysii uint64 `json:"callformat_x25519_deoxysii"`
+
+	// Fields below have omitempty set for backwards compatibility. Once there are no deployed
+	// runtimes using an old version of the SDK, this should be removed.
+
+	InMsgBase uint64 `json:"inmsg_base,omitempty"`
 }
 
 // Parameters are the parameters for the consensus accounts module.
@@ -38,7 +43,8 @@ type Parameters struct {
 	// Fields below have omitempty set for backwards compatibility. Once there are no deployed
 	// runtimes using an old version of the SDK, this should be removed.
 
-	MaxTxSize uint32 `json:"max_tx_size,omitempty"`
+	MaxTxSize   uint32 `json:"max_tx_size,omitempty"`
+	MaxInMsgGas uint32 `json:"max_inmsg_gas,omitempty"`
 }
 
 // ModuleName is the core module name.

runtime-sdk/src/dispatcher.rs

@@ -31,7 +31,7 @@ use crate::{
     error::{Error as _, RuntimeError},
     event::IntoTags,
     keymanager::{KeyManagerClient, KeyManagerError},
-    module::{self, BlockHandler, MethodHandler, TransactionHandler},
+    module::{self, BlockHandler, InMsgHandler, InMsgResult, MethodHandler, TransactionHandler},
     modules,
     modules::core::API as _,
     runtime::Runtime,
@@ -582,7 +582,7 @@ impl<R: Runtime> Dispatcher<R> {
                 messages,
                 block_tags,
                 tx_reject_hashes: vec![],
-                in_msgs_count: 0, // TODO: Support processing incoming messages.
+                in_msgs_count: 0,
             })
         })
     }
@@ -593,17 +593,63 @@ impl<R: Runtime + Send + Sync> transaction::dispatcher::Dispatcher for Dispatche
         &self,
         rt_ctx: transaction::Context<'_>,
         batch: &TxnBatch,
-        _in_msgs: &[roothash::IncomingMessage],
+        in_msgs: &[roothash::IncomingMessage],
     ) -> Result<ExecuteBatchResult, RuntimeError> {
-        self.execute_batch_common(
+        let mut in_msgs_count = 0;
+
+        let mut result = self.execute_batch_common(
             rt_ctx,
             |ctx| -> Result<Vec<ExecuteTxResult>, RuntimeError> {
                 // If prefetch limit is set enable prefetch.
                 let prefetch_enabled = R::PREFETCH_LIMIT > 0;
+                let mut results = Vec::with_capacity(batch.len());
+
+                // Process incoming messages first.
+                let mut batch_it = batch.iter();
+                'inmsg: for in_msg in in_msgs {
+                    match R::IncomingMessagesHandler::process_in_msg(ctx, &in_msg) {
+                        InMsgResult::Skip => {
+                            // Skip, but treat as processed.
+                            in_msgs_count += 1;
+                        }
+                        InMsgResult::Execute(raw_tx, tx) => {
+                            // Verify that the transaction has been included in the batch.
+                            match batch_it.next() {
+                                None => {
+                                    // Nothing in the batch when there should be an incoming message.
+                                    return Err(Error::MalformedTransactionInBatch(anyhow!(
+                                        "missing incoming message"
+                                    ))
+                                    .into());
+                                }
+                                Some(batch_tx) if batch_tx != raw_tx => {
+                                    // Incoming message does not match what is in the batch.
+                                    return Err(Error::MalformedTransactionInBatch(anyhow!(
+                                        "mismatched incoming message"
+                                    ))
+                                    .into());
+                                }
+                                _ => {
+                                    // Everything is ok.
+                                }
+                            }
+
+                            // Further execute the inner transaction. The transaction has already
+                            // passed checks so it is ok to include in a block.
+                            let tx_size = raw_tx.len().try_into().unwrap();
+                            let index = results.len();
+                            results.push(Self::execute_tx(ctx, tx_size, tx, index)?);
+
+                            in_msgs_count += 1;
+                        }
+                        InMsgResult::Stop => break 'inmsg,
+                    }
+                }
 
+                let inmsg_txs = results.len();
                 let mut txs = Vec::with_capacity(batch.len());
                 let mut prefixes: BTreeSet<Prefix> = BTreeSet::new();
-                for tx in batch.iter() {
+                for tx in batch.iter().skip(inmsg_txs) {
                     let tx_size = tx.len().try_into().map_err(|_| {
                         Error::MalformedTransactionInBatch(anyhow!("transaction too large"))
                     })?;
@@ -629,23 +675,29 @@ impl<R: Runtime + Send + Sync> transaction::dispatcher::Dispatcher for Dispatche
 
                 // Execute the batch.
                 let mut results = Vec::with_capacity(batch.len());
-                for (index, (tx_size, tx_hash, tx)) in txs.into_iter().enumerate() {
+                for (index, (tx_size, tx_hash, tx)) in txs.into_iter().skip(inmsg_txs).enumerate() {
                     results.push(Self::execute_tx(ctx, tx_size, tx_hash, tx, index)?);
                 }
 
                 Ok(results)
             },
-        )
+        )?;
+
+        // Include number of processed incoming messages in the final result.
+        result.in_msgs_count = in_msgs_count;
+
+        Ok(result)
     }
 
     fn schedule_and_execute_batch(
         &self,
         rt_ctx: transaction::Context<'_>,
         batch: &mut TxnBatch,
-        _in_msgs: &[roothash::IncomingMessage],
+        in_msgs: &[roothash::IncomingMessage],
     ) -> Result<ExecuteBatchResult, RuntimeError> {
         let cfg = R::SCHEDULE_CONTROL;
         let mut tx_reject_hashes = Vec::new();
+        let mut in_msgs_count = 0;
 
         let mut result = self.execute_batch_common(
             rt_ctx,
@@ -655,13 +707,35 @@ impl<R: Runtime + Send + Sync> transaction::dispatcher::Dispatcher for Dispatche
                 // The idea is to keep scheduling transactions as long as we have some space
                 // available in the block as determined by gas use.
                 let mut new_batch = Vec::new();
-                let mut results = Vec::with_capacity(batch.len());
+                let mut results = Vec::with_capacity(in_msgs.len() + batch.len());
                 let mut requested_batch_len = cfg.initial_batch_size;
+
+                // Process incoming messages first.
+                'inmsg: for in_msg in in_msgs {
+                    match R::IncomingMessagesHandler::process_in_msg(ctx, &in_msg) {
+                        InMsgResult::Skip => {
+                            // Skip, but treat as processed.
+                            in_msgs_count += 1;
+                        }
+                        InMsgResult::Execute(raw_tx, tx) => {
+                            // Further execute the inner transaction. The transaction has already
+                            // passed checks so it is ok to include in a block.
+                            let tx_size = raw_tx.len().try_into().unwrap();
+                            let index = new_batch.len();
+                            new_batch.push(raw_tx.to_owned());
+                            results.push(Self::execute_tx(ctx, tx_size, tx, index)?);
+
+                            in_msgs_count += 1;
+                        }
+                        InMsgResult::Stop => break 'inmsg,
+                    }
+                }
+
+                // Process regular transactions.
                 'batch: loop {
                     // Remember length of last batch.
                     let last_batch_len = batch.len();
                     let last_batch_tx_hash = batch.last().map(|raw_tx| Hash::digest_bytes(raw_tx));
-
                     for raw_tx in batch.drain(..) {
                         // If we don't have enough gas for processing even the cheapest transaction
                         // we are done. Same if we reached the runtime-imposed maximum tx count.
@@ -774,8 +848,10 @@ impl<R: Runtime + Send + Sync> transaction::dispatcher::Dispatcher for Dispatche
             },
         )?;
 
-        // Include rejected transaction hashes in the final result.
+        // Include rejected transaction hashes and number of processed incoming messages in the
+        // final result.
         result.tx_reject_hashes = tx_reject_hashes;
+        result.in_msgs_count = in_msgs_count;
 
         Ok(result)
     }
@@ -1000,6 +1076,7 @@ mod test {
                 core::Genesis {
                     parameters: core::Parameters {
                         max_batch_gas: u64::MAX,
+                        max_inmsg_gas: 0,
                         max_tx_size: 32 * 1024,
                         max_tx_signers: 1,
                         max_multisig_signers: 8,

runtime-sdk/src/error.rs

@@ -1,4 +1,6 @@
 //! Error types for runtimes.
+use std::fmt::Display;
+
 pub use oasis_core_runtime::types::Error as RuntimeError;
 
 use crate::{dispatcher, module::CallResult};
@@ -56,6 +58,18 @@ pub trait Error: std::error::Error {
     {
         Err(self)
     }
+
+    /// Converts the error into a serializable error.
+    fn into_serializable(self) -> SerializableError
+    where
+        Self: Sized,
+    {
+        SerializableError {
+            module: self.module_name().to_owned(),
+            code: self.code(),
+            message: self.to_string(),
+        }
+    }
 }
 
 impl Error for std::convert::Infallible {
@@ -68,6 +82,47 @@ impl Error for std::convert::Infallible {
     }
 }
 
+/// A standardized serialized implementation for an error.
+#[derive(Debug, Default, Clone, thiserror::Error, cbor::Encode, cbor::Decode)]
+pub struct SerializableError {
+    pub module: String,
+    pub code: u32,
+    pub message: String,
+}
+
+impl Display for SerializableError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.message)
+    }
+}
+
+impl Error for SerializableError {
+    fn module_name(&self) -> &str {
+        &self.module
+    }
+
+    fn code(&self) -> u32 {
+        self.code
+    }
+}
+
+impl From<CallResult> for SerializableError {
+    fn from(result: CallResult) -> Self {
+        match result {
+            CallResult::Failed {
+                module,
+                code,
+                message,
+            } => Self {
+                module,
+                code,
+                message,
+            },
+            _ => Default::default(),
+        }
+    }
+}
+
 #[cfg(test)]
 mod test {
     use super::*;

runtime-sdk/src/module.rs

@@ -9,6 +9,7 @@ use impl_trait_for_tuples::impl_for_tuples;
 
 use crate::{
     context::Context,
+    core::consensus::roothash,
     dispatcher, error,
     error::Error as _,
     event, modules,
@@ -562,6 +563,39 @@ impl ModuleInfoHandler for Tuple {
     }
 }
 
+/// Incoming message handler.
+pub trait InMsgHandler {
+    /// Process an incoming message.
+    fn process_in_msg<'a, C: Context>(
+        ctx: &mut C,
+        in_msg: &'a roothash::IncomingMessage,
+    ) -> InMsgResult<'a>;
+}
+
+/// Result of processing an incoming message.
+#[derive(Debug)]
+pub enum InMsgResult<'a> {
+    /// Skip to next incoming message, but count as processed.
+    Skip,
+    /// Add to batch/verify inclusion and execute.
+    Execute(&'a [u8], Transaction),
+    /// Stop processing incoming messages.
+    Stop,
+}
+
+/// An incoming message handler which discards all incoming messages.
+pub struct InMsgDiscard;
+
+impl InMsgHandler for InMsgDiscard {
+    fn process_in_msg<'a, C: Context>(
+        _ctx: &mut C,
+        _in_msg: &'a roothash::IncomingMessage,
+    ) -> InMsgResult<'a> {
+        // Just skip all messages without doing anything.
+        InMsgResult::Skip
+    }
+}
+
 /// A runtime module.
 pub trait Module {
     /// Module name.
@@ -590,6 +624,11 @@ pub trait Module {
 
     /// Set the module's parameters.
     fn set_params(params: Self::Parameters) {
+        params
+            .validate_basic()
+            .map_err(|_| ())
+            .expect("module parameters are invalid");
+
         CurrentState::with_store(|store| {
             let store = storage::PrefixStore::new(store, &Self::NAME);
             let mut store = storage::TypedStore::new(store);

runtime-sdk/src/modules/consensus/mod.rs

@@ -74,7 +74,7 @@ impl Default for Parameters {
     fn default() -> Self {
         Self {
             gas_costs: Default::default(),
-            consensus_denomination: token::Denomination::from_str("TEST").unwrap(),
+            consensus_denomination: "TEST".parse().unwrap(),
             consensus_scaling_factor: 1,
             min_delegate_amount: 0,
         }

runtime-sdk/src/modules/consensus_inmsg/config.rs

@@ -0,0 +1,15 @@
+use crate::modules;
+
+/// Incoming message handler configuration.
+pub trait Config: 'static {
+    /// The accounts module to use.
+    type Accounts: modules::accounts::API;
+    /// The consensus module to use.
+    type Consensus: modules::consensus::API;
+
+    /// Maximum number of outgoing consensus message slots that an incoming message can claim.
+    ///
+    /// When this is configured to be greater than zero it allows incoming messages to also emit
+    /// consensus messages as a result of executing a transaction.
+    const MAX_CONSENSUS_MSG_SLOTS_PER_TX: u32 = 1;
+}

runtime-sdk/src/modules/consensus_inmsg/events.rs

@@ -0,0 +1,16 @@
+use super::MODULE_NAME;
+use crate::error;
+
+/// Events emitted by the consensus incoming message handler module.
+#[derive(Debug, cbor::Encode, oasis_runtime_sdk_macros::Event)]
+#[cbor(untagged)]
+pub enum Event {
+    #[sdk_event(code = 1)]
+    Processed {
+        id: u64,
+        #[cbor(optional)]
+        tag: u64,
+        #[cbor(optional)]
+        error: Option<error::SerializableError>,
+    },
+}