From 2239e4becf614ff9c2f88bc284a60d5df6c2cb72 Mon Sep 17 00:00:00 2001
From: Tobie Morgan Hitchcock <tobie@abcum.com>
Date: Fri, 6 May 2022 21:57:12 +0100
Subject: [PATCH] Improve Datastore and Transaction errors

---
 lib/src/err/mod.rs      | 48 +++++++++++++++++++++++------------------
 lib/src/kvs/file/mod.rs |  2 +-
 lib/src/kvs/ixdb/mod.rs | 11 ++++++----
 lib/src/kvs/mem/mod.rs  |  2 +-
 lib/src/kvs/tikv/mod.rs | 13 ++++++-----
 5 files changed, 44 insertions(+), 32 deletions(-)

diff --git a/lib/src/err/mod.rs b/lib/src/err/mod.rs
index c2521599..33d4fa0f 100644
--- a/lib/src/err/mod.rs
+++ b/lib/src/err/mod.rs
@@ -28,13 +28,13 @@ pub enum Error {
 	#[error("Conditional clause is not truthy")]
 	Ignore,
 
-	/// There was an error when connecting to the underlying datastore
-	#[error("Couldn't setup connection to underlying datastore")]
-	Ds,
+	/// There was a problem with the underlying datastore
+	#[error("There was a problem with the underlying datastore: {0}")]
+	Ds(String),
 
-	/// There was an error when starting a new transaction
-	#[error("Couldn't create a database transaction")]
-	Tx,
+	/// There was a problem with a datastore transaction
+	#[error("There was a problem with a datastore transaction: {0}")]
+	Tx(String),
 
 	/// The transaction was already cancelled or committed
 	#[error("Couldn't update a finished transaction")]
@@ -235,27 +235,33 @@ pub enum Error {
 	#[error("Key decoding error: {0}")]
 	Decode(#[from] DecodeError),
 
-	/// Represents an underlying error from the EchoDB instance
-	#[cfg(feature = "kv-echodb")]
-	#[error("Datastore error: {0}")]
-	EchoDB(#[from] EchoDBError),
-
-	/// Represents an underlying error from the IndxDB instance
-	#[cfg(feature = "kv-indxdb")]
-	#[error("Datastore error: {0}")]
-	IndxDB(#[from] IndxDBError),
-
-	/// Represents an underlying error from the TiKV instance
-	#[cfg(feature = "kv-tikv")]
-	#[error("Datastore error: {0}")]
-	TiKV(#[from] TiKVError),
-
 	/// Represents an underlying error with Tokio message channels
 	#[cfg(feature = "parallel")]
 	#[error("Tokio Error: {0}")]
 	Tokio(#[from] TokioError<(Option<Thing>, Value)>),
 }
 
+#[cfg(feature = "kv-echodb")]
+impl From<EchoDBError> for Error {
+	fn from(e: EchoDBError) -> Error {
+		Error::Tx(e.to_string())
+	}
+}
+
+#[cfg(feature = "kv-indxdb")]
+impl From<IndxDBError> for Error {
+	fn from(e: IndxDBError) -> Error {
+		Error::Tx(e.to_string())
+	}
+}
+
+#[cfg(feature = "kv-tikv")]
+impl From<TiKVError> for Error {
+	fn from(e: TiKVError) -> Error {
+		Error::Tx(e.to_string())
+	}
+}
+
 impl Serialize for Error {
 	fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
 	where
diff --git a/lib/src/kvs/file/mod.rs b/lib/src/kvs/file/mod.rs
index 31613f69..28e2a707 100644
--- a/lib/src/kvs/file/mod.rs
+++ b/lib/src/kvs/file/mod.rs
@@ -33,7 +33,7 @@ impl Datastore {
 				rw: write,
 				tx,
 			}),
-			Err(_) => Err(Error::Tx),
+			Err(e) => Err(Error::Tx(e.to_string())),
 		}
 	}
 }
diff --git a/lib/src/kvs/ixdb/mod.rs b/lib/src/kvs/ixdb/mod.rs
index 675b5805..ef55b8ea 100644
--- a/lib/src/kvs/ixdb/mod.rs
+++ b/lib/src/kvs/ixdb/mod.rs
@@ -21,9 +21,12 @@ pub struct Transaction {
 impl Datastore {
 	// Open a new database
 	pub async fn new(path: &str) -> Result<Datastore, Error> {
-		Ok(Datastore {
-			db: indxdb::db::new(path).await?,
-		})
+		match indxdb::db::new(path).await {
+			Ok(db) => Ok(Datastore {
+				db,
+			}),
+			Err(e) => Err(Error::Ds(e.to_string())),
+		}
 	}
 	// Start a new transaction
 	pub async fn transaction(&self, write: bool, _: bool) -> Result<Transaction, Error> {
@@ -33,7 +36,7 @@ impl Datastore {
 				rw: write,
 				tx,
 			}),
-			Err(_) => Err(Error::Tx),
+			Err(e) => Err(Error::Tx(e.to_string())),
 		}
 	}
 }
diff --git a/lib/src/kvs/mem/mod.rs b/lib/src/kvs/mem/mod.rs
index 0d5ca476..2f010f63 100644
--- a/lib/src/kvs/mem/mod.rs
+++ b/lib/src/kvs/mem/mod.rs
@@ -33,7 +33,7 @@ impl Datastore {
 				rw: write,
 				tx,
 			}),
-			Err(_) => Err(Error::Tx),
+			Err(e) => Err(Error::Tx(e.to_string())),
 		}
 	}
 }
diff --git a/lib/src/kvs/tikv/mod.rs b/lib/src/kvs/tikv/mod.rs
index d9721604..c887c0be 100644
--- a/lib/src/kvs/tikv/mod.rs
+++ b/lib/src/kvs/tikv/mod.rs
@@ -21,9 +21,12 @@ pub struct Transaction {
 impl Datastore {
 	// Open a new database
 	pub async fn new(path: &str) -> Result<Datastore, Error> {
-		Ok(Datastore {
-			db: tikv::TransactionClient::new(vec![path]).await?,
-		})
+		match tikv::TransactionClient::new(vec![path]).await {
+			Ok(db) => Ok(Datastore {
+				db,
+			}),
+			Err(e) => Err(Error::Ds(e.to_string())),
+		}
 	}
 	// Start a new transaction
 	pub async fn transaction(&self, write: bool, lock: bool) -> Result<Transaction, Error> {
@@ -34,7 +37,7 @@ impl Datastore {
 					rw: write,
 					tx,
 				}),
-				Err(_) => Err(Error::Tx),
+				Err(e) => Err(Error::Tx(e.to_string())),
 			},
 			false => match self.db.begin_pessimistic().await {
 				Ok(tx) => Ok(Transaction {
@@ -42,7 +45,7 @@ impl Datastore {
 					rw: write,
 					tx,
 				}),
-				Err(_) => Err(Error::Tx),
+				Err(e) => Err(Error::Tx(e.to_string())),
 			},
 		}
 	}