Merge pull request #1 from mprasil/concurrency_fix

WAL journal mode and delete retry added

src/db/models/attachment.rs

@@ -64,14 +64,33 @@ impl Attachment {
 
     pub fn delete(self, conn: &DbConn) -> QueryResult<()> {
         use util;
+        use std::{thread, time};
+
+        let mut retries = 10;
+        
+        loop {
+            match diesel::delete(
+                attachments::table.filter(
+                    attachments::id.eq(&self.id)
+                )
+            ).execute(&**conn) {
+                Ok(_) => break,
+                Err(err) => {
+                    if retries < 1 {
+                        println!("ERROR: Failed with 10 retries");
+                        return Err(err)
+                    } else {
+                        retries = retries - 1;
+                        println!("Had to retry! Retries left: {}", retries);
+                        thread::sleep(time::Duration::from_millis(500));
+                        continue
+                    }
+                }
+            }
+        }
 
         util::delete_file(&self.get_file_path());
-
+        Ok(())
-        diesel::delete(
-            attachments::table.filter(
-                attachments::id.eq(self.id)
-            )
-        ).execute(&**conn).and(Ok(()))
     }
 
     pub fn delete_all_by_cipher(cipher_uuid: &str, conn: &DbConn) -> QueryResult<()> {

src/main.rs

@@ -83,6 +83,11 @@ fn check_db() {
             exit(1);
         }
     }
+
+    // Turn on WAL in SQLite
+    use diesel::RunQueryDsl;
+    let connection = db::get_connection().expect("Can't conect to DB");
+    diesel::sql_query("PRAGMA journal_mode=wal").execute(&connection).expect("Failed to turn on WAL");
 }
 
 fn check_rsa_keys() {