Some movement of helper code and refactoring of error handling

17 files changed, 137 insertions, 66 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 40d2a29f..033d157f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -474,6 +474,7 @@ version = "0.6.0"
 dependencies = [
  "arc-swap",
  "async-trait",
+ "err-derive 0.3.0",
  "futures",
  "futures-util",
  "garage_model 0.5.1",
diff --git a/src/api/error.rs b/src/api/error.rs
index 828a2342..d6d4a1d7 100644
--- a/src/api/error.rs
+++ b/src/api/error.rs
@@ -4,6 +4,7 @@ use err_derive::Error;
 use hyper::header::HeaderValue;
 use hyper::{HeaderMap, StatusCode};
 
+use garage_model::helper::error::Error as HelperError;
 use garage_util::error::Error as GarageError;
 
 use crate::s3_xml;
@@ -83,6 +84,15 @@ impl From<quick_xml::de::DeError> for Error {
 	}
 }
 
+impl From<HelperError> for Error {
+	fn from(err: HelperError) -> Self {
+		match err {
+			HelperError::Internal(i) => Self::InternalError(i),
+			HelperError::BadRequest(b) => Self::BadRequest(b),
+		}
+	}
+}
+
 impl Error {
 	/// Get the HTTP status code that best represents the meaning of the error for the client
 	pub fn http_status_code(&self) -> StatusCode {
diff --git a/src/garage/admin.rs b/src/garage/admin.rs
index 49890189..740114c6 100644
--- a/src/garage/admin.rs
+++ b/src/garage/admin.rs
@@ -7,7 +7,7 @@ use serde::{Deserialize, Serialize};
 
 use garage_util::crdt::*;
 use garage_util::data::*;
-use garage_util::error::*;
+use garage_util::error::{Error as GarageError, OkOrMessage};
 use garage_util::time::*;
 
 use garage_table::replication::*;
@@ -18,6 +18,7 @@ use garage_rpc::*;
 use garage_model::bucket_alias_table::*;
 use garage_model::bucket_table::*;
 use garage_model::garage::Garage;
+use garage_model::helper::error::{Error, OkOrBadRequest};
 use garage_model::key_table::*;
 use garage_model::migrate::Migrate;
 use garage_model::permission::*;
@@ -91,7 +92,7 @@ impl AdminRpcHandler {
 			.bucket_helper()
 			.resolve_global_bucket_name(&query.name)
 			.await?
-			.ok_or_message("Bucket not found")?;
+			.ok_or_bad_request("Bucket not found")?;
 
 		let bucket = self
 			.garage
@@ -137,7 +138,7 @@ impl AdminRpcHandler {
 		let alias = match self.garage.bucket_alias_table.get(&EmptyKey, name).await? {
 			Some(mut alias) => {
 				if !alias.state.get().is_deleted() {
-					return Err(Error::BadRpc(format!("Bucket {} already exists", name)));
+					return Err(Error::BadRequest(format!("Bucket {} already exists", name)));
 				}
 				alias.state.update(Deletable::Present(AliasParams {
 					bucket_id: bucket.id,
@@ -145,7 +146,7 @@ impl AdminRpcHandler {
 				alias
 			}
 			None => BucketAlias::new(name.clone(), bucket.id)
-				.ok_or_message(format!(INVALID_BUCKET_NAME_MESSAGE!(), name))?,
+				.ok_or_bad_request(format!(INVALID_BUCKET_NAME_MESSAGE!(), name))?,
 		};
 		bucket.state.as_option_mut().unwrap().aliases.merge_raw(
 			name,
@@ -164,7 +165,7 @@ impl AdminRpcHandler {
 			.get(&EmptyKey, &query.name)
 			.await?
 			.filter(|a| !a.is_deleted())
-			.ok_or_message(format!("Bucket {} does not exist", query.name))?;
+			.ok_or_bad_request(format!("Bucket {} does not exist", query.name))?;
 
 		let bucket_id = bucket_alias.state.get().as_option().unwrap().bucket_id;
 
@@ -182,7 +183,7 @@ impl AdminRpcHandler {
 			.filter(|(_, _, active)| *active)
 			.any(|(name, _, _)| name != &query.name)
 		{
-			return Err(Error::Message(format!("Bucket {} still has other global aliases. Use `bucket unalias` to delete them one by one.", query.name)));
+			return Err(Error::BadRequest(format!("Bucket {} still has other global aliases. Use `bucket unalias` to delete them one by one.", query.name)));
 		}
 		if bucket_state
 			.local_aliases
@@ -190,7 +191,7 @@ impl AdminRpcHandler {
 			.iter()
 			.any(|(_, _, active)| *active)
 		{
-			return Err(Error::Message(format!("Bucket {} still has other local aliases. Use `bucket unalias` to delete them one by one.", query.name)));
+			return Err(Error::BadRequest(format!("Bucket {} still has other local aliases. Use `bucket unalias` to delete them one by one.", query.name)));
 		}
 
 		// Check bucket is empty
@@ -200,11 +201,14 @@ impl AdminRpcHandler {
 			.get_range(&bucket_id, None, Some(DeletedFilter::NotDeleted), 10)
 			.await?;
 		if !objects.is_empty() {
-			return Err(Error::BadRpc(format!("Bucket {} is not empty", query.name)));
+			return Err(Error::BadRequest(format!(
+				"Bucket {} is not empty",
+				query.name
+			)));
 		}
 
 		if !query.yes {
-			return Err(Error::BadRpc(
+			return Err(Error::BadRequest(
 				"Add --yes flag to really perform this operation".to_string(),
 			));
 		}
@@ -218,7 +222,7 @@ impl AdminRpcHandler {
 						.await?;
 				}
 			} else {
-				return Err(Error::Message(format!("Key not found: {}", key_id)));
+				return Err(Error::BadRequest(format!("Key not found: {}", key_id)));
 			}
 		}
 		// 2. delete bucket alias
@@ -237,7 +241,7 @@ impl AdminRpcHandler {
 			.bucket_helper()
 			.resolve_global_bucket_name(&query.existing_bucket)
 			.await?
-			.ok_or_message("Bucket not found")?;
+			.ok_or_bad_request("Bucket not found")?;
 		let mut bucket = self
 			.garage
 			.bucket_helper()
@@ -257,12 +261,12 @@ impl AdminRpcHandler {
 						query.new_name, bucket_id, key.key_id
 					)));
 				} else {
-					return Err(Error::Message(format!("Alias {} already exists and points to different bucket: {:?} in namespace of key {}", query.new_name, existing_alias, key.key_id)));
+					return Err(Error::BadRequest(format!("Alias {} already exists and points to different bucket: {:?} in namespace of key {}", query.new_name, existing_alias, key.key_id)));
 				}
 			}
 
 			if !is_valid_bucket_name(&query.new_name) {
-				return Err(Error::Message(format!(
+				return Err(Error::BadRequest(format!(
 					INVALID_BUCKET_NAME_MESSAGE!(),
 					query.new_name
 				)));
@@ -312,7 +316,7 @@ impl AdminRpcHandler {
 							query.new_name, bucket_id
 						)));
 					} else {
-						return Err(Error::Message(format!(
+						return Err(Error::BadRequest(format!(
 							"Alias {} already exists and points to different bucket: {:?}",
 							query.new_name, p.bucket_id
 						)));
@@ -330,7 +334,7 @@ impl AdminRpcHandler {
 
 			let alias = match alias {
 				None => BucketAlias::new(query.new_name.clone(), bucket_id)
-					.ok_or_message(format!(INVALID_BUCKET_NAME_MESSAGE!(), query.new_name))?,
+					.ok_or_bad_request(format!(INVALID_BUCKET_NAME_MESSAGE!(), query.new_name))?,
 				Some(mut a) => {
 					a.state = Lww::raw(alias_ts, Deletable::present(AliasParams { bucket_id }));
 					a
@@ -360,7 +364,7 @@ impl AdminRpcHandler {
 				.get(&query.name)
 				.map(|a| a.into_option())
 				.flatten()
-				.ok_or_message("Bucket not found")?;
+				.ok_or_bad_request("Bucket not found")?;
 			let mut bucket = self
 				.garage
 				.bucket_helper()
@@ -379,7 +383,7 @@ impl AdminRpcHandler {
 					.iter()
 					.any(|((k, n), _, active)| *k == key.key_id && *n == query.name && *active);
 			if !has_other_aliases {
-				return Err(Error::Message(format!("Bucket {} doesn't have other aliases, please delete it instead of just unaliasing.", query.name)));
+				return Err(Error::BadRequest(format!("Bucket {} doesn't have other aliases, please delete it instead of just unaliasing.", query.name)));
 			}
 
 			// Checks ok, remove alias
@@ -410,7 +414,7 @@ impl AdminRpcHandler {
 				.bucket_helper()
 				.resolve_global_bucket_name(&query.name)
 				.await?
-				.ok_or_message("Bucket not found")?;
+				.ok_or_bad_request("Bucket not found")?;
 			let mut bucket = self
 				.garage
 				.bucket_helper()
@@ -429,7 +433,7 @@ impl AdminRpcHandler {
 					.iter()
 					.any(|(_, _, active)| *active);
 			if !has_other_aliases {
-				return Err(Error::Message(format!("Bucket {} doesn't have other aliases, please delete it instead of just unaliasing.", query.name)));
+				return Err(Error::BadRequest(format!("Bucket {} doesn't have other aliases, please delete it instead of just unaliasing.", query.name)));
 			}
 
 			let mut alias = self
@@ -461,7 +465,7 @@ impl AdminRpcHandler {
 			.bucket_helper()
 			.resolve_global_bucket_name(&query.bucket)
 			.await?
-			.ok_or_message("Bucket not found")?;
+			.ok_or_bad_request("Bucket not found")?;
 		let bucket = self
 			.garage
 			.bucket_helper()
@@ -491,7 +495,7 @@ impl AdminRpcHandler {
 			.bucket_helper()
 			.resolve_global_bucket_name(&query.bucket)
 			.await?
-			.ok_or_message("Bucket not found")?;
+			.ok_or_bad_request("Bucket not found")?;
 		let bucket = self
 			.garage
 			.bucket_helper()
@@ -521,7 +525,7 @@ impl AdminRpcHandler {
 			.bucket_helper()
 			.resolve_global_bucket_name(&query.bucket)
 			.await?
-			.ok_or_message("Bucket not found")?;
+			.ok_or_bad_request("Bucket not found")?;
 
 		let mut bucket = self
 			.garage
@@ -531,7 +535,7 @@ impl AdminRpcHandler {
 		let bucket_state = bucket.state.as_option_mut().unwrap();
 
 		if !(query.allow ^ query.deny) {
-			return Err(Error::Message(
+			return Err(Error::BadRequest(
 				"You must specify exactly one flag, either --allow or --deny".to_string(),
 			));
 		}
@@ -606,7 +610,7 @@ impl AdminRpcHandler {
 	async fn handle_delete_key(&self, query: &KeyDeleteOpt) -> Result<AdminRpc, Error> {
 		let mut key = self.get_existing_key(&query.key_pattern).await?;
 		if !query.yes {
-			return Err(Error::BadRpc(
+			return Err(Error::BadRequest(
 				"Add --yes flag to really perform this operation".to_string(),
 			));
 		}
@@ -659,7 +663,7 @@ impl AdminRpcHandler {
 	async fn handle_import_key(&self, query: &KeyImportOpt) -> Result<AdminRpc, Error> {
 		let prev_key = self.garage.key_table.get(&EmptyKey, &query.key_id).await?;
 		if prev_key.is_some() {
-			return Err(Error::Message(format!("Key {} already exists in data store. Even if it is deleted, we can't let you create a new key with the same ID. Sorry.", query.key_id)));
+			return Err(Error::BadRequest(format!("Key {} already exists in data store. Even if it is deleted, we can't let you create a new key with the same ID. Sorry.", query.key_id)));
 		}
 		let imported_key = Key::import(&query.key_id, &query.secret_key, &query.name);
 		self.garage.key_table.insert(&imported_key).await?;
@@ -682,7 +686,7 @@ impl AdminRpcHandler {
 			.filter(|k| !k.state.is_deleted())
 			.collect::<Vec<_>>();
 		if candidates.len() != 1 {
-			Err(Error::Message(format!(
+			Err(Error::BadRequest(format!(
 				"{} matching keys",
 				candidates.len()
 			)))
@@ -760,7 +764,7 @@ impl AdminRpcHandler {
 
 	async fn handle_migrate(self: &Arc<Self>, opt: MigrateOpt) -> Result<AdminRpc, Error> {
 		if !opt.yes {
-			return Err(Error::BadRpc(
+			return Err(Error::BadRequest(
 				"Please provide the --yes flag to initiate migration operation.".to_string(),
 			));
 		}
@@ -776,7 +780,7 @@ impl AdminRpcHandler {
 
 	async fn handle_launch_repair(self: &Arc<Self>, opt: RepairOpt) -> Result<AdminRpc, Error> {
 		if !opt.yes {
-			return Err(Error::BadRpc(
+			return Err(Error::BadRequest(
 				"Please provide the --yes flag to initiate repair operations.".to_string(),
 			));
 		}
@@ -803,7 +807,7 @@ impl AdminRpcHandler {
 			if failures.is_empty() {
 				Ok(AdminRpc::Ok("Repair launched on all nodes".to_string()))
 			} else {
-				Err(Error::Message(format!(
+				Err(Error::BadRequest(format!(
 					"Could not launch repair on nodes: {:?} (launched successfully on other nodes)",
 					failures
 				)))
@@ -946,7 +950,7 @@ impl EndpointHandler<AdminRpc> for AdminRpcHandler {
 			AdminRpc::Migrate(opt) => self.handle_migrate(opt.clone()).await,
 			AdminRpc::LaunchRepair(opt) => self.handle_launch_repair(opt.clone()).await,
 			AdminRpc::Stats(opt) => self.handle_stats(opt.clone()).await,
-			_ => Err(Error::BadRpc("Invalid RPC".to_string())),
+			m => Err(GarageError::unexpected_rpc_message(m).into()),
 		}
 	}
 }
diff --git a/src/garage/cli/cmd.rs b/src/garage/cli/cmd.rs
index 834261e4..cca7c401 100644
--- a/src/garage/cli/cmd.rs
+++ b/src/garage/cli/cmd.rs
@@ -6,6 +6,8 @@ use garage_rpc::layout::*;
 use garage_rpc::system::*;
 use garage_rpc::*;
 
+use garage_model::helper::error::Error as HelperError;
+
 use crate::admin::*;
 use crate::cli::*;
 
@@ -14,14 +16,14 @@ pub async fn cli_command_dispatch(
 	system_rpc_endpoint: &Endpoint<SystemRpc, ()>,
 	admin_rpc_endpoint: &Endpoint<AdminRpc, ()>,
 	rpc_host: NodeID,
-) -> Result<(), Error> {
+) -> Result<(), HelperError> {
 	match cmd {
-		Command::Status => cmd_status(system_rpc_endpoint, rpc_host).await,
+		Command::Status => Ok(cmd_status(system_rpc_endpoint, rpc_host).await?),
 		Command::Node(NodeOperation::Connect(connect_opt)) => {
-			cmd_connect(system_rpc_endpoint, rpc_host, connect_opt).await
+			Ok(cmd_connect(system_rpc_endpoint, rpc_host, connect_opt).await?)
 		}
 		Command::Layout(layout_opt) => {
-			cli_layout_command_dispatch(layout_opt, system_rpc_endpoint, rpc_host).await
+			Ok(cli_layout_command_dispatch(layout_opt, system_rpc_endpoint, rpc_host).await?)
 		}
 		Command::Bucket(bo) => {
 			cmd_admin(admin_rpc_endpoint, rpc_host, AdminRpc::BucketOperation(bo)).await
@@ -149,7 +151,7 @@ pub async fn cmd_connect(
 			println!("Success.");
 			Ok(())
 		}
-		r => Err(Error::BadRpc(format!("Unexpected response: {:?}", r))),
+		m => Err(Error::unexpected_rpc_message(m)),
 	}
 }
 
@@ -157,7 +159,7 @@ pub async fn cmd_admin(
 	rpc_cli: &Endpoint<AdminRpc, ()>,
 	rpc_host: NodeID,
 	args: AdminRpc,
-) -> Result<(), Error> {
+) -> Result<(), HelperError> {
 	match rpc_cli.call(&rpc_host, &args, PRIO_NORMAL).await?? {
 		AdminRpc::Ok(msg) => {
 			println!("{}", msg);
diff --git a/src/garage/main.rs b/src/garage/main.rs
index 69cd16e7..60a13ac7 100644
--- a/src/garage/main.rs
+++ b/src/garage/main.rs
@@ -22,6 +22,8 @@ use garage_util::error::*;
 use garage_rpc::system::*;
 use garage_rpc::*;
 
+use garage_model::helper::error::Error as HelperError;
+
 use admin::*;
 use cli::*;
 
@@ -136,5 +138,9 @@ async fn cli_command(opt: Opt) -> Result<(), Error> {
 	let system_rpc_endpoint = netapp.endpoint::<SystemRpc, ()>(SYSTEM_RPC_PATH.into());
 	let admin_rpc_endpoint = netapp.endpoint::<AdminRpc, ()>(ADMIN_RPC_PATH.into());
 
-	cli_command_dispatch(opt.cmd, &system_rpc_endpoint, &admin_rpc_endpoint, id).await
+	match cli_command_dispatch(opt.cmd, &system_rpc_endpoint, &admin_rpc_endpoint, id).await {
+		Err(HelperError::Internal(i)) => Err(i),
+		Err(HelperError::BadRequest(b)) => Err(Error::Message(format!("bad request: {}", b))),
+		Ok(x) => Ok(x),
+	}
 }
diff --git a/src/model/Cargo.toml b/src/model/Cargo.toml
index 03881f5d..14e49557 100644
--- a/src/model/Cargo.toml
+++ b/src/model/Cargo.toml
@@ -21,6 +21,7 @@ garage_model_050 = { package = "garage_model", version = "0.5.1" }
 
 async-trait = "0.1.7"
 arc-swap = "1.0"
+err-derive = "0.3"
 hex = "0.4"
 log = "0.4"
 rand = "0.8"
diff --git a/src/model/block.rs b/src/model/block.rs
index 6df8e265..1173c7b3 100644
--- a/src/model/block.rs
+++ b/src/model/block.rs
@@ -594,10 +594,8 @@ impl BlockManager {
 							need_nodes.push(*node);
 						}
 					}
-					_ => {
-						return Err(Error::Message(
-							"Unexpected response to NeedBlockQuery RPC".to_string(),
-						));
+					m => {
+						return Err(Error::unexpected_rpc_message(m));
 					}
 				}
 			}
@@ -730,7 +728,7 @@ impl EndpointHandler<BlockRpc> for BlockManager {
 			BlockRpc::PutBlock { hash, data } => self.write_block(hash, data).await,
 			BlockRpc::GetBlock(h) => self.read_block(h).await,
 			BlockRpc::NeedBlockQuery(h) => self.need_block(h).await.map(BlockRpc::NeedBlockReply),
-			_ => Err(Error::BadRpc("Unexpected RPC message".to_string())),
+			m => Err(Error::unexpected_rpc_message(m)),
 		}
 	}
 }
diff --git a/src/model/garage.rs b/src/model/garage.rs
index 9db1843c..78b4433a 100644
--- a/src/model/garage.rs
+++ b/src/model/garage.rs
@@ -15,8 +15,8 @@ use garage_table::*;
 use crate::block::*;
 use crate::block_ref_table::*;
 use crate::bucket_alias_table::*;
-use crate::bucket_helper::*;
 use crate::bucket_table::*;
+use crate::helper;
 use crate::key_table::*;
 use crate::object_table::*;
 use crate::version_table::*;
@@ -162,7 +162,7 @@ impl Garage {
 		self.block_manager.garage.swap(None);
 	}
 
-	pub fn bucket_helper(&self) -> BucketHelper {
-		BucketHelper(self)
+	pub fn bucket_helper(&self) -> helper::bucket::BucketHelper {
+		helper::bucket::BucketHelper(self)
 	}
 }
diff --git a/src/model/bucket_helper.rs b/src/model/helper/bucket.rs
index b55ebc4b..e89a723d 100644
--- a/src/model/bucket_helper.rs
+++ b/src/model/helper/bucket.rs
@@ -1,10 +1,9 @@
-use garage_util::data::*;
-use garage_util::error::*;
-
 use garage_table::util::EmptyKey;
+use garage_util::data::*;
 
 use crate::bucket_table::Bucket;
 use crate::garage::Garage;
+use crate::helper::error::*;
 
 pub struct BucketHelper<'a>(pub(crate) &'a Garage);
 
@@ -52,12 +51,6 @@ impl<'a> BucketHelper<'a> {
 			.get(&bucket_id, &EmptyKey)
 			.await?
 			.filter(|b| !b.is_deleted())
-			.map(Ok)
-			.unwrap_or_else(|| {
-				Err(Error::BadRpc(format!(
-					"Bucket {:?} does not exist",
-					bucket_id
-				)))
-			})
+			.ok_or_bad_request(format!("Bucket {:?} does not exist", bucket_id))
 	}
 }
diff --git a/src/model/helper/error.rs b/src/model/helper/error.rs
new file mode 100644
index 00000000..b9b515f3
--- /dev/null
+++ b/src/model/helper/error.rs
@@ -0,0 +1,51 @@
+use err_derive::Error;
+use serde::{Deserialize, Serialize};
+
+use garage_util::error::Error as GarageError;
+
+#[derive(Debug, Error, Serialize, Deserialize)]
+pub enum Error {
+	#[error(display = "Internal error: {}", _0)]
+	Internal(#[error(source)] GarageError),
+
+	#[error(display = "Bad request: {}", _0)]
+	BadRequest(String),
+}
+
+impl From<netapp::error::Error> for Error {
+	fn from(e: netapp::error::Error) -> Self {
+		Error::Internal(GarageError::Netapp(e))
+	}
+}
+
+pub trait OkOrBadRequest {
+	type S;
+	fn ok_or_bad_request<M: AsRef<str>>(self, reason: M) -> Result<Self::S, Error>;
+}
+
+impl<T, E> OkOrBadRequest for Result<T, E>
+where
+	E: std::fmt::Display,
+{
+	type S = T;
+	fn ok_or_bad_request<M: AsRef<str>>(self, reason: M) -> Result<T, Error> {
+		match self {
+			Ok(x) => Ok(x),
+			Err(e) => Err(Error::BadRequest(format!(
+				"{}: {}",
+				reason.as_ref(),
+				e.to_string()
+			))),
+		}
+	}
+}
+
+impl<T> OkOrBadRequest for Option<T> {
+	type S = T;
+	fn ok_or_bad_request<M: AsRef<str>>(self, reason: M) -> Result<T, Error> {
+		match self {
+			Some(x) => Ok(x),
+			None => Err(Error::BadRequest(reason.as_ref().to_string())),
+		}
+	}
+}
diff --git a/src/model/helper/mod.rs b/src/model/helper/mod.rs
new file mode 100644
index 00000000..2f4e8898
--- /dev/null
+++ b/src/model/helper/mod.rs
@@ -0,0 +1,2 @@
+pub mod bucket;
+pub mod error;
diff --git a/src/model/lib.rs b/src/model/lib.rs
index e7d7e98b..9deaae9d 100644
--- a/src/model/lib.rs
+++ b/src/model/lib.rs
@@ -12,6 +12,6 @@ pub mod version_table;
 
 pub mod block;
 
-pub mod bucket_helper;
 pub mod garage;
+pub mod helper;
 pub mod migrate;
diff --git a/src/rpc/system.rs b/src/rpc/system.rs
index aa8947ea..6bca6e3e 100644
--- a/src/rpc/system.rs
+++ b/src/rpc/system.rs
@@ -576,7 +576,7 @@ impl EndpointHandler<SystemRpc> for System {
 				self.clone().handle_advertise_cluster_layout(adv).await
 			}
 			SystemRpc::GetKnownNodes => Ok(self.handle_get_known_nodes()),
-			_ => Err(Error::BadRpc("Unexpected RPC message".to_string())),
+			m => Err(Error::unexpected_rpc_message(m)),
 		}
 	}
 }
diff --git a/src/table/gc.rs b/src/table/gc.rs
index 5cb8cb9b..8d0a5bef 100644
--- a/src/table/gc.rs
+++ b/src/table/gc.rs
@@ -315,7 +315,7 @@ where
 				}
 				Ok(GcRpc::Ok)
 			}
-			_ => Err(Error::Message("Unexpected GC RPC".to_string())),
+			m => Err(Error::unexpected_rpc_message(m)),
 		}
 	}
 }
diff --git a/src/table/sync.rs b/src/table/sync.rs
index df9fb4d0..1df2b01d 100644
--- a/src/table/sync.rs
+++ b/src/table/sync.rs
@@ -514,10 +514,7 @@ where
 		if let SyncRpc::Ok = rpc_resp {
 			Ok(())
 		} else {
-			Err(Error::Message(format!(
-				"Unexpected response to RPC Update: {}",
-				debug_serialize(&rpc_resp)
-			)))
+			Err(Error::unexpected_rpc_message(rpc_resp))
 		}
 	}
 }
@@ -545,7 +542,7 @@ where
 				self.data.update_many(items)?;
 				Ok(SyncRpc::Ok)
 			}
-			_ => Err(Error::Message("Unexpected sync RPC".to_string())),
+			m => Err(Error::unexpected_rpc_message(m)),
 		}
 	}
 }
diff --git a/src/table/table.rs b/src/table/table.rs
index 396888c1..01789c11 100644
--- a/src/table/table.rs
+++ b/src/table/table.rs
@@ -311,7 +311,7 @@ where
 				self.data.update_many(pairs)?;
 				Ok(TableRpc::Ok)
 			}
-			_ => Err(Error::BadRpc("Unexpected table RPC".to_string())),
+			m => Err(Error::unexpected_rpc_message(m)),
 		}
 	}
 }
diff --git a/src/util/error.rs b/src/util/error.rs
index ef5a76f2..bdb3a69b 100644
--- a/src/util/error.rs
+++ b/src/util/error.rs
@@ -59,8 +59,8 @@ pub enum Error {
 	)]
 	Quorum(usize, usize, usize, Vec<String>),
 
-	#[error(display = "Bad RPC: {}", _0)]
-	BadRpc(String),
+	#[error(display = "Unexpected RPC message: {}", _0)]
+	UnexpectedRpcMessage(String),
 
 	#[error(display = "Corrupt data: does not match hash {:?}", _0)]
 	CorruptData(Hash),
@@ -69,6 +69,12 @@ pub enum Error {
 	Message(String),
 }
 
+impl Error {
+	pub fn unexpected_rpc_message<T: Serialize>(v: T) -> Self {
+		Self::UnexpectedRpcMessage(debug_serialize(&v))
+	}
+}
+
 impl From<sled::transaction::TransactionError<Error>> for Error {
 	fn from(e: sled::transaction::TransactionError<Error>) -> Error {
 		match e {