impl: instance pool based on global state

- `KvsBuilder` is initializing KVS for given set of params.
- Future instances must be requested with same set of params.

Author: arkjedrz

src/rust/rust_kvs/examples/basic.rs

@@ -19,7 +19,7 @@ fn main() -> Result<(), ErrorCode> {
         // Build KVS instance for given instance ID and temporary directory.
         // `kvs_load` is explicitly set to `KvsLoad::Optional`, but this is the default value.
         // KVS files are not required.
-        let builder = KvsBuilder::<Kvs>::new(instance_id.clone())
+        let builder = KvsBuilder::new(instance_id.clone())
             .dir(dir_string.clone())
             .kvs_load(KvsLoad::Optional);
         let kvs = builder.build()?;
@@ -64,7 +64,7 @@ fn main() -> Result<(), ErrorCode> {
     {
         // Build KVS instance for given instance ID and temporary directory.
         // `kvs_load` is set to `KvsLoad::Required` - KVS files must already exist from previous KVS instance.
-        let builder = KvsBuilder::<Kvs>::new(instance_id)
+        let builder = KvsBuilder::new(instance_id)
             .dir(dir_string)
             .kvs_load(KvsLoad::Required);
         let kvs = builder.build()?;

src/rust/rust_kvs/examples/defaults.rs

@@ -43,7 +43,7 @@ fn main() -> Result<(), ErrorCode> {
 
     // Build KVS instance for given instance ID and temporary directory.
     // `defaults` is set to `Defaults::Required` - defaults are required.
-    let builder = KvsBuilder::<Kvs>::new(instance_id)
+    let builder = KvsBuilder::new(instance_id)
         .dir(dir_string)
         .defaults(Defaults::Required);
     let kvs = builder.build()?;

src/rust/rust_kvs/examples/flush.rs

@@ -33,7 +33,7 @@ fn main() -> Result<(), ErrorCode> {
 
         {
             // Build KVS instance for given instance ID and temporary directory.
-            let builder = KvsBuilder::<Kvs>::new(instance_id.clone()).dir(dir_string.clone());
+            let builder = KvsBuilder::new(instance_id.clone()).dir(dir_string.clone());
             let mut kvs = builder.build()?;
 
             // Disable flush on exit.
@@ -54,7 +54,7 @@ fn main() -> Result<(), ErrorCode> {
 
         {
             // Build KVS instance for given instance ID and temporary directory.
-            let builder = KvsBuilder::<Kvs>::new(instance_id.clone()).dir(dir_string.clone());
+            let builder = KvsBuilder::new(instance_id.clone()).dir(dir_string.clone());
             let mut kvs = builder.build()?;
 
             // Explicitly enable flush on exit - this is the default.
@@ -75,7 +75,7 @@ fn main() -> Result<(), ErrorCode> {
 
         {
             // Build KVS instance for given instance ID and temporary directory.
-            let builder = KvsBuilder::<Kvs>::new(instance_id.clone()).dir(dir_string.clone());
+            let builder = KvsBuilder::new(instance_id.clone()).dir(dir_string.clone());
             let mut kvs = builder.build()?;
 
             // Disable flush on exit.
@@ -91,7 +91,7 @@ fn main() -> Result<(), ErrorCode> {
 
         {
             // Build KVS instance to check current state.
-            let builder = KvsBuilder::<Kvs>::new(instance_id.clone())
+            let builder = KvsBuilder::new(instance_id.clone())
                 .dir(dir_string)
                 .kvs_load(KvsLoad::Required);
             let mut kvs = builder.build()?;

src/rust/rust_kvs/examples/snapshots.rs

@@ -17,7 +17,7 @@ fn main() -> Result<(), ErrorCode> {
         println!("-> `snapshot_count` and `snapshot_max_count` usage");
 
         // Build KVS instance for given instance ID and temporary directory.
-        let builder = KvsBuilder::<Kvs>::new(instance_id.clone()).dir(dir_string.clone());
+        let builder = KvsBuilder::new(instance_id.clone()).dir(dir_string.clone());
         let mut kvs = builder.build()?;
         kvs.set_flush_on_exit(FlushOnExit::No);
 
@@ -39,7 +39,7 @@ fn main() -> Result<(), ErrorCode> {
         println!("-> `snapshot_restore` usage");
 
         // Build KVS instance for given instance ID and temporary directory.
-        let builder = KvsBuilder::<Kvs>::new(instance_id.clone()).dir(dir_string.clone());
+        let builder = KvsBuilder::new(instance_id.clone()).dir(dir_string.clone());
         let mut kvs = builder.build()?;
         kvs.set_flush_on_exit(FlushOnExit::No);
 
@@ -52,7 +52,7 @@ fn main() -> Result<(), ErrorCode> {
 
         // Print current counter value, then restore oldest snapshot.
         println!("{counter_key} = {:?}", kvs.get_value(counter_key)?);
-        kvs.snapshot_restore(SnapshotId(2))?;
+        kvs.snapshot_restore(&SnapshotId(2))?;
         println!("{counter_key} = {:?}", kvs.get_value(counter_key)?);
 
         println!();

src/rust/rust_kvs/src/error_code.rs

@@ -14,10 +14,6 @@ extern crate alloc;
 use alloc::string::FromUtf8Error;
 use core::array::TryFromSliceError;
 
-use crate::kvs_value::KvsValue;
-use std::collections::HashMap;
-use std::sync::{MutexGuard, PoisonError};
-
 /// Runtime Error Codes
 #[derive(Debug, PartialEq)]
 pub enum ErrorCode {
@@ -75,11 +71,17 @@ pub enum ErrorCode {
     /// Invalid snapshot ID
     InvalidSnapshotId,
 
+    /// Invalid instance ID
+    InvalidInstanceId,
+
     /// Conversion failed
     ConversionFailed,
 
     /// Mutex failed
     MutexLockFailed,
+
+    /// Instance parameters mismatch
+    InstanceParametersMismatch,
 }
 
 impl From<std::io::Error> for ErrorCode {
@@ -116,21 +118,10 @@ impl From<Vec<u8>> for ErrorCode {
     }
 }
 
-impl From<PoisonError<MutexGuard<'_, HashMap<std::string::String, KvsValue>>>> for ErrorCode {
-    fn from(cause: PoisonError<MutexGuard<'_, HashMap<std::string::String, KvsValue>>>) -> Self {
-        eprintln!("error: Mutex locking failed: {cause:#?}");
-        ErrorCode::MutexLockFailed
-    }
-}
-
 #[cfg(test)]
 mod error_code_tests {
     use crate::error_code::ErrorCode;
-    use crate::kvs_value::KvsValue;
-    use std::collections::HashMap;
     use std::io::{Error, ErrorKind};
-    use std::sync::{Arc, Mutex};
-    use std::thread;
 
     #[test]
     fn test_from_io_error_to_file_not_found() {
@@ -165,20 +156,4 @@ mod error_code_tests {
         let bytes: Vec<u8> = vec![];
         assert_eq!(ErrorCode::from(bytes), ErrorCode::ConversionFailed);
     }
-
-    #[test]
-    fn test_from_poison_error_mutex_lock_failed() {
-        let mutex: Arc<Mutex<HashMap<String, KvsValue>>> = Arc::default();
-
-        // test from: https://doc.rust-lang.org/std/sync/struct.PoisonError.html
-        let c_mutex = Arc::clone(&mutex);
-        let _ = thread::spawn(move || {
-            let _unused = c_mutex.lock().unwrap();
-            panic!();
-        })
-        .join();
-
-        let error = mutex.lock().unwrap_err();
-        assert_eq!(ErrorCode::from(error), ErrorCode::MutexLockFailed);
-    }
 }