refactor: let backup manager calculate next backup time

.cargo/config.toml

@@ -1,3 +1,3 @@
 [alias]
-runs = "run -- run paper 1.19.4-550 --config data/config --backup data/backups --world data/worlds --jar paper-1.19.4-550.jar"
+runs = "run -- run --config data/config --backup data/backups --world data/worlds --jar paper-1.19.4-550.jar --frequency 2"
 runrs = "run --release -- paper 1.19.4-545 --config data/config --backup data/backups --world data/worlds --jar data/paper-1.19.4-525.jar"

src/backup/manager.rs

@@ -1,4 +1,5 @@
 use super::Backup;
+use chrono::Utc;
 use serde::Deserialize;
 use serde::Serialize;
 use std::fs::File;
@@ -15,6 +16,7 @@ where
     default_metadata: T,
     chain_len: u64,
     chains_to_keep: u64,
+    frequency: chrono::Duration,
     chains: Vec<Vec<Backup<T>>>,
 }
 
@@ -32,6 +34,7 @@ where
         metadata: T,
         chain_len: u64,
         chains_to_keep: u64,
+        frequency: chrono::Duration,
     ) -> Self {
         Self {
             backup_dir: backup_dir.into(),
@@ -40,6 +43,7 @@ where
             default_metadata: metadata,
             chain_len,
             chains_to_keep,
+            frequency,
             chains: Vec::new(),
         }
     }
@@ -137,4 +141,16 @@ where
 
         Ok(())
     }
+
+    /// Calculate the next time a backup should be created. If no backup has been created yet, it
+    /// will return now.
+    pub fn next_scheduled_time(&self) -> chrono::DateTime<Utc> {
+        if let Some(last_chain) = self.chains.last() {
+            if let Some(last_backup) = last_chain.last() {
+                return last_backup.start_time + self.frequency;
+            }
+        }
+
+        chrono::offset::Utc::now()
+    }
 }

src/cli.rs

@@ -53,11 +53,22 @@ pub struct Cli {
         global = true
     )]
     pub chains: u64,
+
+    /// How frequently to perform a backup, in minutes; 0 to disable.
+    #[arg(
+        short = 't',
+        long,
+        default_value_t = 0,
+        env = "ALEX_FREQUENCY",
+        global = true
+    )]
+    pub frequency: u32,
+
     /// Type of server
-    #[arg(long, default_value = "unknown", env = "ALEX_SERVER")]
+    #[arg(long, default_value = "unknown", env = "ALEX_SERVER", global = true)]
     pub server: ServerType,
     /// Version string for the server, e.g. 1.19.4-545
-    #[arg(long, default_value = "", env = "ALEX_SERVER_VERSION")]
+    #[arg(long, default_value = "", env = "ALEX_SERVER_VERSION", global = true)]
     pub server_version: String,
 }
 
@@ -92,10 +103,6 @@ pub struct RunArgs {
     #[arg(long, default_value_t = 2048, env = "ALEX_XMX")]
     pub xmx: u64,
 
-    /// How frequently to perform a backup, in minutes; 0 to disable.
-    #[arg(short = 't', long, default_value_t = 0, env = "ALEX_FREQUENCY")]
-    pub frequency: u64,
-
     /// Don't actually run the server, but simply output the server configuration that would have
     /// been ran
     #[arg(short, long, default_value_t = false)]

src/main.rs

@@ -9,9 +9,17 @@ use cli::{BackupArgs, Cli, Commands, RunArgs};
 use std::io;
 use std::sync::{Arc, Mutex};
 
-fn backups_thread(counter: Arc<Mutex<server::ServerProcess>>, frequency: u64) {
+fn backups_thread(counter: Arc<Mutex<server::ServerProcess>>) {
     loop {
-        std::thread::sleep(std::time::Duration::from_secs(frequency * 60));
+        let next_scheduled_time = {
+            let server = counter.lock().unwrap();
+            server.backups.next_scheduled_time()
+        };
+
+        let now = chrono::offset::Utc::now();
+        if next_scheduled_time > now {
+            std::thread::sleep((next_scheduled_time - now).to_std().unwrap());
+        }
 
         {
             let mut server = counter.lock().unwrap();
@@ -34,7 +42,8 @@ fn command_run(cli: &Cli, args: &RunArgs) -> io::Result<()> {
         .xms(args.xms)
         .xmx(args.xmx)
         .chain_len(cli.chain_len)
-        .chains_to_keep(cli.chains);
+        .chains_to_keep(cli.chains)
+        .frequency(cli.frequency);
     cmd.canonicalize()?;
 
     if args.dry {
@@ -45,10 +54,9 @@ fn command_run(cli: &Cli, args: &RunArgs) -> io::Result<()> {
 
     let counter = Arc::new(Mutex::new(cmd.spawn()?));
 
-    if args.frequency > 0 {
+    if cli.frequency > 0 {
         let clone = Arc::clone(&counter);
-        let frequency = args.frequency;
-        std::thread::spawn(move || backups_thread(clone, frequency));
+        std::thread::spawn(move || backups_thread(clone));
     }
 
     // Spawn thread that handles the main stdin loop
@@ -72,6 +80,7 @@ fn commands_backup(cli: &Cli, _args: &BackupArgs) -> io::Result<()> {
         metadata,
         cli.chain_len,
         cli.chains,
+        chrono::Duration::minutes(cli.frequency.into()),
     );
     manager.load()?;
 

src/server/command.rs

@@ -47,6 +47,7 @@ pub struct ServerCommand {
     xmx: u64,
     chain_len: u64,
     chains_to_keep: u64,
+    frequency: u32,
 }
 
 impl ServerCommand {
@@ -63,6 +64,7 @@ impl ServerCommand {
             xmx: 2048,
             chain_len: 4,
             chains_to_keep: 7,
+            frequency: 0,
         }
     }
 
@@ -113,6 +115,11 @@ impl ServerCommand {
         self
     }
 
+    pub fn frequency(mut self, v: u32) -> Self {
+        self.frequency = v;
+        self
+    }
+
     fn accept_eula(&self) -> std::io::Result<()> {
         let mut eula_path = self.config_dir.clone();
         eula_path.push("eula.txt");
@@ -207,6 +214,7 @@ impl ServerCommand {
             metadata,
             self.chain_len,
             self.chains_to_keep,
+            chrono::Duration::minutes(self.frequency.into()),
         );
         manager.load()?;
 

src/server/process.rs

@@ -5,7 +5,7 @@ use std::process::Child;
 
 pub struct ServerProcess {
     child: Child,
-    backups: BackupManager<Metadata>,
+    pub backups: BackupManager<Metadata>,
 }
 
 impl ServerProcess {