Fix disk storage on termination (#151)

See #150 for more information

CHANGELOG.md

@@ -2,6 +2,12 @@
 
 All changes in this project will be noted in this file.
 
+## Version 0.5.3 [2021-05-13]
+
+> No breaking changes
+
+Fix persistence (see [#150](https://github.com/skytable/skytable/issues/150))
+
 ## Version 0.5.2 [2021-05-07]
 
 > No breaking changes

server/src/coredb/mod.rs

@@ -287,7 +287,7 @@ impl CoreDB {
         bgsave: BGSave,
         snapshot_cfg: SnapshotConfig,
         restore_file: Option<String>,
-    ) -> TResult<(Self, Option<flock::FileLock>, flock::FileLock)> {
+    ) -> TResult<(Self, Option<flock::FileLock>)> {
         let coretable = diskstore::get_saved(restore_file)?;
         let mut background_tasks: usize = 0;
         if !bgsave.is_disabled() {
@@ -325,13 +325,12 @@ impl CoreDB {
         ));
         let lock = flock::FileLock::lock(&*PERSIST_FILE)
             .map_err(|e| format!("Failed to acquire lock on data file with error '{}'", e))?;
-        let cloned_descriptor = lock.try_clone()?;
         if bgsave.is_disabled() {
-            Ok((db, Some(lock), cloned_descriptor))
+            Ok((db, Some(lock)))
         } else {
             // Spawn the BGSAVE service in a separate task
             tokio::spawn(diskstore::bgsave_scheduler(db.clone(), bgsave, lock));
-            Ok((db, None, cloned_descriptor))
+            Ok((db, None))
         }
     }
     /// Create an empty in-memory table

server/src/dbnet/mod.rs

@@ -44,8 +44,7 @@ use crate::config::PortConfig;
 use crate::config::SnapshotConfig;
 use crate::config::SslOpts;
 use crate::dbnet::tcp::Listener;
-use crate::diskstore::{self, snapshot::DIR_REMOTE_SNAPSHOT};
-use diskstore::flock;
+use crate::diskstore::snapshot::DIR_REMOTE_SNAPSHOT;
 mod tcp;
 use crate::CoreDB;
 use libsky::TResult;
@@ -315,7 +314,7 @@ pub async fn run(
     snapshot_cfg: SnapshotConfig,
     sig: impl Future,
     restore_filepath: Option<String>,
-) -> (CoreDB, flock::FileLock) {
+) -> CoreDB {
     let (signal, _) = broadcast::channel(1);
     let (terminate_tx, terminate_rx) = mpsc::channel(1);
     match fs::create_dir_all(&*DIR_REMOTE_SNAPSHOT) {
@@ -328,14 +327,13 @@ pub async fn run(
             }
         },
     }
-    let (db, lock, cloned_descriptor) =
-        match CoreDB::new(bgsave_cfg, snapshot_cfg, restore_filepath) {
-            Ok((db, lock, cloned_descriptor)) => (db, lock, cloned_descriptor),
-            Err(e) => {
-                log::error!("ERROR: {}", e);
-                process::exit(0x100);
-            }
-        };
+    let (db, lock) = match CoreDB::new(bgsave_cfg, snapshot_cfg, restore_filepath) {
+        Ok((db, lock)) => (db, lock),
+        Err(e) => {
+            log::error!("ERROR: {}", e);
+            process::exit(0x100);
+        }
+    };
     let climit = Arc::new(Semaphore::new(50000));
     let mut server = match ports {
         PortConfig::InsecureOnly { host, port } => {
@@ -392,5 +390,5 @@ pub async fn run(
         log::error!("Failed to release lock on data file with '{}'", e);
         process::exit(0x100);
     }
-    (db, cloned_descriptor)
+    db
 }

server/src/diskstore/flock.rs

@@ -98,18 +98,6 @@ impl FileLock {
         // Now write to the file
         self.file.write_all(bytes)
     }
-    pub fn try_clone(&self) -> Result<Self> {
-        Ok(Self {
-            file: self.file.try_clone()?,
-            unlocked: false,
-        })
-    }
-    /// Reacquire a lock
-    pub fn reacquire(&mut self) -> Result<()> {
-        Self::_lock(&self.file)?;
-        self.unlocked = false;
-        Ok(())
-    }
 }
 
 impl Drop for FileLock {

server/src/main.rs

@@ -33,6 +33,7 @@
 use crate::config::BGSave;
 use crate::config::PortConfig;
 use crate::config::SnapshotConfig;
+use crate::diskstore::PERSIST_FILE;
 use std::io::{self, prelude::*};
 mod config;
 use std::env;
@@ -77,10 +78,10 @@ fn main() {
         .enable_all()
         .build()
         .unwrap();
-    let (db, mut descriptor) = runtime.block_on(async {
+    let db = runtime.block_on(async {
         let (tcplistener, bgsave_config, snapshot_config, restore_filepath) =
             check_args_and_get_cfg().await;
-        let (db, descriptor) = run(
+        let db = run(
             tcplistener,
             bgsave_config,
             snapshot_config,
@@ -88,7 +89,7 @@ fn main() {
             restore_filepath,
         )
         .await;
-        (db, descriptor)
+        db
     });
     // Make sure all background workers terminate
     drop(runtime);
@@ -98,18 +99,21 @@ fn main() {
         "Maybe the compiler reordered the drop causing more than one instance of CoreDB to live at this point"
     );
     // Try to acquire lock almost immediately
-    if let Err(e) = descriptor.reacquire() {
-        log::error!("Failed to reacquire lock on data file with error: '{}'", e);
-        panic!("FATAL: data file relocking failure");
-    }
-    if let Err(e) = flush_db!(db, descriptor) {
+    let mut lock = match diskstore::flock::FileLock::lock(&*PERSIST_FILE) {
+        Ok(lck) => lck,
+        Err(e) => {
+            log::error!("Failed to reacquire lock on data file with '{}'", e);
+            std::process::exit(0x100);
+        }
+    };
+    if let Err(e) = flush_db!(db, lock) {
         log::error!("Failed to flush data to disk with '{}'", e);
         loop {
             // Keep looping until we successfully write the in-memory table to disk
             log::warn!("Press enter to try again...");
             io::stdout().flush().unwrap();
             io::stdin().read(&mut [0]).unwrap();
-            if let Ok(_) = flush_db!(db, descriptor) {
+            if let Ok(_) = flush_db!(db, lock) {
                 log::info!("Successfully saved data to disk");
                 break;
             } else {
@@ -124,12 +128,7 @@ fn main() {
 
 /// This function checks the command line arguments and either returns a config object
 /// or prints an error to `stderr` and terminates the server
-async fn check_args_and_get_cfg() -> (
-    PortConfig,
-    BGSave,
-    SnapshotConfig,
-    Option<String>,
-) {
+async fn check_args_and_get_cfg() -> (PortConfig, BGSave, SnapshotConfig, Option<String>) {
     let cfg = config::get_config_file_or_return_cfg();
     let binding_and_cfg = match cfg {
         Ok(config::ConfigType::Custom(cfg, file)) => {