fix: better serde bounds

chains

.cargo/config.toml

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

.gitignore

@@ -19,4 +19,4 @@ target/
 
 # testing files
 *.jar
-data/
+data*/

CHANGELOG.md

@@ -7,6 +7,24 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased](https://git.rustybever.be/Chewing_Bever/alex/src/branch/dev)
 
+### Added
+
+* `backup` CLI command
+* Incremental backups
+    * Chain length describes how many incremental backups to create from the
+      same full backup
+    * "backups to keep" has been replaced by "chains to keep"
+* Server type & version is now stored as metadata in the metadata file
+
+### Changed
+
+* Running the server now uses the `run` CLI subcommand
+* `server_type` and `server_version` arguments are now optional flags
+
+### Removed
+
+* `max_backups` setting
+
 ## [0.2.2](https://git.rustybever.be/Chewing_Bever/alex/src/tag/0.2.2)
 
 ### Fixed

Cargo.lock

@@ -15,6 +15,8 @@ dependencies = [
  "chrono",
  "clap",
  "flate2",
+ "serde",
+ "serde_json",
  "signal-hook",
  "tar",
 ]
@@ -123,6 +125,7 @@ dependencies = [
  "iana-time-zone",
  "js-sys",
  "num-traits",
+ "serde",
  "time",
  "wasm-bindgen",
  "winapi",
@@ -292,6 +295,12 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "itoa"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "453ad9f582a441959e5f0d088b02ce04cfe8d51a8eaf077f12ac6d3e94164ca6"
+
 [[package]]
 name = "js-sys"
 version = "0.3.63"
@@ -384,6 +393,43 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "ryu"
+version = "1.0.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f91339c0467de62360649f8d3e185ca8de4224ff281f66000de5eb2a77a79041"
+
+[[package]]
+name = "serde"
+version = "1.0.164"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9e8c8cf938e98f769bc164923b06dce91cea1751522f46f8466461af04c9027d"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.164"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d9735b638ccc51c28bf6914d90a2e9725b377144fc612c49a611fddd1b631d68"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "serde_json"
+version = "1.0.96"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "057d394a50403bcac12672b2b18fb387ab6d289d957dab67dd201875391e52f1"
+dependencies = [
+ "itoa",
+ "ryu",
+ "serde",
+]
+
 [[package]]
 name = "signal-hook"
 version = "0.3.15"

Cargo.toml

@@ -12,10 +12,11 @@ edition = "2021"
 tar = "0.4.38"
 # Used to compress said tarballs using gzip
 flate2 = "1.0.26"
-# Used for backup filenames
-chrono = "0.4.26"
+chrono = { version = "0.4.26", features = ["serde"] }
 clap = { version = "4.3.1", features = ["derive", "env"] }
 signal-hook = "0.3.15"
+serde = { version = "1.0.164", features = ["derive", "rc"] }
+serde_json = "1.0.96"
 
 [profile.release]
 lto = "fat"

src/backup/delta.rs

@@ -0,0 +1,76 @@
+use serde::{Deserialize, Serialize};
+use std::collections::{HashMap, HashSet};
+use std::path::PathBuf;
+
+/// Represents the changes relative to the previous backup
+#[derive(Debug, Serialize, Deserialize)]
+pub struct Delta {
+    /// What files were added/modified in each part of the tarball.
+    pub added: HashMap<PathBuf, HashSet<PathBuf>>,
+    /// What files were removed in this backup, in comparison to the previous backup. For full
+    /// backups, this will always be empty, as they do not consider previous backups.
+    /// The map stores a separate list for each top-level directory, as the contents of these
+    /// directories can come for different source directories.
+    pub removed: HashMap<PathBuf, HashSet<PathBuf>>,
+}
+
+impl Delta {
+    pub fn new() -> Self {
+        Self {
+            added: HashMap::new(),
+            removed: HashMap::new(),
+        }
+    }
+
+    /// Update the current state so that its result becomes the merge of itself and the other
+    /// state.
+    #[allow(dead_code)]
+    pub fn merge(&mut self, delta: &Self) {
+        for (dir, added) in delta.added.iter() {
+            // Files that were removed in the current state, but added in the new state, are no
+            // longer removed
+            if let Some(orig_removed) = self.removed.get_mut(dir) {
+                orig_removed.retain(|k| !added.contains(k));
+            }
+
+            // Newly added files are added to the state as well
+            if let Some(orig_added) = self.added.get_mut(dir) {
+                orig_added.extend(added.iter().cloned());
+            } else {
+                self.added.insert(dir.clone(), added.clone());
+            }
+        }
+
+        for (dir, removed) in delta.removed.iter() {
+            // Files that were originally added, but now deleted are removed from the added list
+            if let Some(orig_added) = self.added.get_mut(dir) {
+                orig_added.retain(|k| !removed.contains(k));
+            }
+
+            // Newly removed files are added to the state as well
+            if let Some(orig_removed) = self.removed.get_mut(dir) {
+                orig_removed.extend(removed.iter().cloned());
+            } else {
+                self.removed.insert(dir.clone(), removed.clone());
+            }
+        }
+    }
+
+    /// Modify the given state by applying this delta's changes to it
+    pub fn apply(&self, state: &mut HashMap<PathBuf, HashSet<PathBuf>>) {
+        // First we add new files, then we remove the old ones
+        for (dir, added) in self.added.iter() {
+            if let Some(current) = state.get_mut(dir) {
+                current.extend(added.iter().cloned());
+            } else {
+                state.insert(dir.clone(), added.clone());
+            }
+        }
+
+        for (dir, removed) in self.removed.iter() {
+            if let Some(current) = state.get_mut(dir) {
+                current.retain(|k| !removed.contains(k));
+            }
+        }
+    }
+}

src/backup/manager.rs

@@ -0,0 +1,140 @@
+use super::Backup;
+use serde::Deserialize;
+use serde::Serialize;
+use std::fs::File;
+use std::io;
+use std::path::PathBuf;
+
+pub struct Manager<T>
+where
+    T: Clone + Serialize + for<'de> Deserialize<'de>,
+{
+    backup_dir: PathBuf,
+    config_dir: PathBuf,
+    world_dir: PathBuf,
+    default_metadata: T,
+    chain_len: u64,
+    chains_to_keep: u64,
+    chains: Vec<Vec<Backup<T>>>,
+}
+
+impl<T> Manager<T>
+where
+    T: Clone + Serialize + for<'de> Deserialize<'de>,
+{
+    const METADATA_FILE: &str = "alex.json";
+
+    /// Initialize a new instance of a `BackupManager`.
+    pub fn new(
+        backup_dir: PathBuf,
+        config_dir: PathBuf,
+        world_dir: PathBuf,
+        metadata: T,
+        chain_len: u64,
+        chains_to_keep: u64,
+    ) -> Self {
+        Self {
+            backup_dir,
+            config_dir,
+            world_dir,
+            default_metadata: metadata,
+            chain_len,
+            chains_to_keep,
+            chains: Vec::new(),
+        }
+    }
+
+    /// Create a new backup with the expected type.
+    pub fn create_backup(&mut self) -> io::Result<()> {
+        let dirs = vec![
+            (PathBuf::from("config"), self.config_dir.clone()),
+            (PathBuf::from("worlds"), self.world_dir.clone()),
+        ];
+
+        // We start a new chain if the current chain is complete, or if there isn't a first chain
+        // yet
+        if let Some(current_chain) = self.chains.last() {
+            let current_chain_len: u64 = current_chain.len().try_into().unwrap();
+
+            if current_chain_len >= self.chain_len {
+                self.chains.push(Vec::new());
+            }
+        } else {
+            self.chains.push(Vec::new());
+        }
+
+        let current_chain = self.chains.last_mut().unwrap();
+
+        let mut backup = if !current_chain.is_empty() {
+            let previous_backup = current_chain.last().unwrap();
+            let state = Backup::state(current_chain);
+
+            Backup::create_from(state, previous_backup.start_time, &self.backup_dir, dirs)?
+        } else {
+            Backup::create(&self.backup_dir, dirs)?
+        };
+
+        backup.set_metadata(self.default_metadata.clone());
+
+        current_chain.push(backup);
+
+        self.save()?;
+
+        Ok(())
+    }
+
+    /// Delete all backups associated with outdated chains, and forget those chains.
+    pub fn remove_old_backups(&mut self) -> io::Result<()> {
+        let chains_to_store: usize = self.chains_to_keep.try_into().unwrap();
+
+        if chains_to_store < self.chains.len() {
+            let mut remove_count: usize = self.chains.len() - chains_to_store;
+
+            // We only count finished chains towards the list of stored chains
+            let chain_len: usize = self.chain_len.try_into().unwrap();
+            if self.chains.last().unwrap().len() < chain_len {
+                remove_count -= 1;
+            }
+
+            for chain in self.chains.drain(..remove_count) {
+                for backup in chain {
+                    let path = Backup::path(&self.backup_dir, backup.start_time);
+                    std::fs::remove_file(path)?;
+                }
+            }
+
+            self.save()?;
+        }
+
+        Ok(())
+    }
+
+    /// Write the in-memory state to disk.
+    pub fn save(&self) -> io::Result<()> {
+        let json_file = File::create(self.backup_dir.join(Self::METADATA_FILE))?;
+        serde_json::to_writer(json_file, &self.chains)?;
+
+        Ok(())
+    }
+
+    /// Overwrite the in-memory state with the on-disk state.
+    pub fn load(&mut self) -> io::Result<()> {
+        let json_file = match File::open(self.backup_dir.join(Self::METADATA_FILE)) {
+            Ok(f) => f,
+            Err(e) => {
+                // Don't error out if the file isn't there, it will be created when necessary
+                if e.kind() == io::ErrorKind::NotFound {
+                    self.chains = Vec::new();
+
+                    return Ok(());
+                } else {
+                    return Err(e);
+                }
+            }
+        };
+
+        self.chains = serde_json::from_reader(json_file)?;
+
+        Ok(())
+    }
+}

src/backup/mod.rs

@@ -0,0 +1,160 @@
+mod delta;
+mod manager;
+mod path;
+
+use delta::Delta;
+pub use manager::Manager;
+
+use chrono::Utc;
+use flate2::write::GzEncoder;
+use flate2::Compression;
+use path::PathExt;
+use serde::{Deserialize, Serialize};
+use std::collections::{HashMap, HashSet};
+use std::fs::File;
+use std::io;
+use std::path::{Path, PathBuf};
+
+#[derive(Debug, PartialEq, Serialize, Deserialize)]
+pub enum BackupType {
+    Full,
+    Incremental,
+}
+
+/// Represents a successful backup
+#[derive(Serialize, Deserialize)]
+pub struct Backup<T: Clone> {
+    /// When the backup was started (also corresponds to the name)
+    pub start_time: chrono::DateTime<Utc>,
+    /// Type of the backup
+    pub type_: BackupType,
+    pub delta: Delta,
+    /// Additional metadata that can be associated with a given backup
+    pub metadata: Option<T>,
+}
+
+impl Backup<()> {
+    /// Return the path to a backup file by properly formatting the data.
+    pub fn path<P: AsRef<Path>>(backup_dir: P, start_time: chrono::DateTime<Utc>) -> PathBuf {
+        let backup_dir = backup_dir.as_ref();
+
+        let filename = format!("{}", start_time.format(Self::FILENAME_FORMAT));
+        backup_dir.join(filename)
+    }
+}
+
+impl<T: Clone> Backup<T> {
+    const FILENAME_FORMAT: &str = "%Y-%m-%d_%H-%M-%S.tar.gz";
+
+    pub fn set_metadata(&mut self, metadata: T) {
+        self.metadata = Some(metadata);
+    }
+
+    /// Resolve the state of the list of backups by applying their deltas in-order to an initially
+    /// empty state.
+    pub fn state(backups: &Vec<Self>) -> HashMap<PathBuf, HashSet<PathBuf>> {
+        let mut state: HashMap<PathBuf, HashSet<PathBuf>> = HashMap::new();
+
+        for backup in backups {
+            backup.delta.apply(&mut state);
+        }
+
+        state
+    }
+
+    /// Create a new Full backup, populated with the given directories.
+    ///
+    /// # Arguments
+    ///
+    /// * `backup_dir` - Directory to store archive in
+    /// * `dirs` - list of tuples `(path_in_tar, src_dir)` with `path_in_tar` the directory name
+    ///     under which `src_dir`'s contents should be stored in the archive
+    ///
+    /// # Returns
+    ///
+    /// The `Backup` instance describing this new backup.
+    pub fn create<P: AsRef<Path>>(
+        backup_dir: P,
+        dirs: Vec<(PathBuf, PathBuf)>,
+    ) -> io::Result<Self> {
+        let start_time = chrono::offset::Utc::now();
+
+        let path = Backup::path(backup_dir, start_time);
+        let tar_gz = File::create(path)?;
+        let enc = GzEncoder::new(tar_gz, Compression::default());
+        let mut ar = tar::Builder::new(enc);
+
+        let mut delta = Delta::new();
+
+        for (dir_in_tar, src_dir) in dirs {
+            let mut added_files: HashSet<PathBuf> = HashSet::new();
+
+            for entry in src_dir.read_dir_recursive()?.ignored("cache").files() {
+                let path = entry?.path();
+                let stripped = path.strip_prefix(&src_dir).unwrap();
+
+                ar.append_path_with_name(&path, dir_in_tar.join(stripped))?;
+                added_files.insert(stripped.to_path_buf());
+            }
+
+            delta.added.insert(dir_in_tar, added_files);
+        }
+
+        Ok(Backup {
+            type_: BackupType::Full,
+            start_time,
+            delta,
+            metadata: None,
+        })
+    }
+
+    /// Create a new incremental backup from a given previous backup
+    pub fn create_from<P: AsRef<Path>>(
+        previous_state: HashMap<PathBuf, HashSet<PathBuf>>,
+        previous_start_time: chrono::DateTime<Utc>,
+        backup_dir: P,
+        dirs: Vec<(PathBuf, PathBuf)>,
+    ) -> io::Result<Self> {
+        let start_time = chrono::offset::Utc::now();
+
+        let path = Backup::path(backup_dir, start_time);
+        let tar_gz = File::create(path)?;
+        let enc = GzEncoder::new(tar_gz, Compression::default());
+        let mut ar = tar::Builder::new(enc);
+
+        let mut delta = Delta::new();
+
+        for (dir_in_tar, src_dir) in dirs {
+            let mut all_files: HashSet<PathBuf> = HashSet::new();
+            let mut added_files: HashSet<PathBuf> = HashSet::new();
+
+            for entry in src_dir.read_dir_recursive()?.ignored("cache").files() {
+                let path = entry?.path();
+                let stripped = path.strip_prefix(&src_dir).unwrap();
+
+                if !path.not_modified_since(previous_start_time) {
+                    ar.append_path_with_name(&path, dir_in_tar.join(stripped))?;
+                    added_files.insert(stripped.to_path_buf());
+                }
+
+                all_files.insert(stripped.to_path_buf());
+            }
+
+            delta.added.insert(dir_in_tar.clone(), added_files);
+
+            if let Some(previous_files) = previous_state.get(&dir_in_tar) {
+                delta.removed.insert(
+                    dir_in_tar,
+                    previous_files.difference(&all_files).cloned().collect(),
+                );
+            }
+        }
+
+        Ok(Backup {
+            type_: BackupType::Incremental,
+            start_time,
+            delta,
+            metadata: None,
+        })
+    }
+}

src/backup/path.rs

@@ -0,0 +1,147 @@
+use chrono::{Local, Utc};
+use std::collections::HashSet;
+use std::ffi::OsString;
+use std::fs::DirEntry;
+use std::path::{Path, PathBuf};
+use std::{fs, io};
+
+pub struct ReadDirRecursive {
+    ignored: HashSet<OsString>,
+    read_dir: fs::ReadDir,
+    dir_stack: Vec<PathBuf>,
+    files_only: bool,
+}
+
+impl ReadDirRecursive {
+    /// Start the iterator for a new directory
+    pub fn start<P: AsRef<Path>>(path: P) -> io::Result<Self> {
+        let path = path.as_ref();
+        let read_dir = path.read_dir()?;
+
+        Ok(ReadDirRecursive {
+            ignored: HashSet::new(),
+            read_dir,
+            dir_stack: Vec::new(),
+            files_only: false,
+        })
+    }
+
+    pub fn ignored<S: Into<OsString>>(mut self, s: S) -> Self {
+        self.ignored.insert(s.into());
+
+        self
+    }
+
+    pub fn files(mut self) -> Self {
+        self.files_only = true;
+
+        self
+    }
+
+    /// Tries to populate the `read_dir` field with a new `ReadDir` instance to consume.
+    fn next_read_dir(&mut self) -> io::Result<bool> {
+        if let Some(path) = self.dir_stack.pop() {
+            self.read_dir = path.read_dir()?;
+
+            Ok(true)
+        } else {
+            Ok(false)
+        }
+    }
+
+    /// Convenience method to add a new directory to the stack.
+    fn push_entry(&mut self, entry: &io::Result<DirEntry>) {
+        if let Ok(entry) = entry {
+            if entry.path().is_dir() {
+                self.dir_stack.push(entry.path());
+            }
+        }
+    }
+
+    /// Determine whether an entry should be returned by the iterator.
+    fn should_return(&self, entry: &io::Result<DirEntry>) -> bool {
+        if let Ok(entry) = entry {
+            let mut res = !self.ignored.contains(&entry.file_name());
+
+            // Please just let me combine these already
+            if self.files_only {
+                if let Ok(file_type) = entry.file_type() {
+                    res = res && file_type.is_file();
+                }
+                // We  couldn't determine if it's a file, so we don't return it
+                else {
+                    res = false;
+                }
+            }
+
+            res
+        } else {
+            true
+        }
+    }
+}
+
+impl Iterator for ReadDirRecursive {
+    type Item = io::Result<DirEntry>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        loop {
+            // First, we try to consume the current directory's items
+            while let Some(entry) = self.read_dir.next() {
+                self.push_entry(&entry);
+
+                if self.should_return(&entry) {
+                    return Some(entry);
+                }
+            }
+
+            // If we get an error while setting up a new directory, we return this, otherwise we
+            // keep trying to consume the directories
+            match self.next_read_dir() {
+                Ok(true) => (),
+                // There's no more directories to traverse, so the iterator is done
+                Ok(false) => return None,
+                Err(e) => return Some(Err(e)),
+            }
+        }
+    }
+}
+
+pub trait PathExt {
+    /// Confirm whether the file has not been modified since the given timestamp.
+    ///
+    /// This function will only return true if it can determine with certainty that the file hasn't
+    /// been modified.
+    ///
+    /// # Args
+    ///
+    /// * `timestamp` - Timestamp to compare modified time with
+    ///
+    /// # Returns
+    ///
+    /// True if the file has not been modified for sure, false otherwise.
+    fn not_modified_since(&self, timestamp: chrono::DateTime<Utc>) -> bool;
+
+    /// An extension of the `read_dir` command that runs through the entire underlying directory
+    /// structure using breadth-first search
+    fn read_dir_recursive(&self) -> io::Result<ReadDirRecursive>;
+}
+
+impl PathExt for Path {
+    fn not_modified_since(&self, timestamp: chrono::DateTime<Utc>) -> bool {
+        if let Ok(metadata) = self.metadata() {
+            if let Ok(last_modified) = metadata.modified() {
+                let t: chrono::DateTime<Utc> = last_modified.into();
+                let t = t.with_timezone(&Local);
+
+                return t < timestamp;
+            }
+        }
+
+        false
+    }
+
+    fn read_dir_recursive(&self) -> io::Result<ReadDirRecursive> {
+        ReadDirRecursive::start(self)
+    }
+}

src/cli.rs

@@ -0,0 +1,106 @@
+use crate::server::ServerType;
+use clap::{Args, Parser, Subcommand};
+use std::path::PathBuf;
+
+#[derive(Parser)]
+#[command(author, version, about, long_about = None)]
+pub struct Cli {
+    #[command(subcommand)]
+    pub command: Commands,
+    /// Directory where configs are stored, and where the server will run
+    #[arg(
+        long,
+        value_name = "CONFIG_DIR",
+        default_value = ".",
+        env = "ALEX_CONFIG_DIR",
+        global = true
+    )]
+    pub config: PathBuf,
+    /// Directory where world files will be saved
+    #[arg(
+        long,
+        value_name = "WORLD_DIR",
+        default_value = "../worlds",
+        env = "ALEX_WORLD_DIR",
+        global = true
+    )]
+    pub world: PathBuf,
+    /// Directory where backups will be stored
+    #[arg(
+        long,
+        value_name = "BACKUP_DIR",
+        default_value = "../backups",
+        env = "ALEX_BACKUP_DIR",
+        global = true
+    )]
+    pub backup: PathBuf,
+
+    /// Length of a backup chain
+    #[arg(
+        short = 'l',
+        long,
+        default_value_t = 4,
+        env = "ALEX_CHAIN_LEN",
+        global = true
+    )]
+    pub chain_len: u64,
+    /// How many backup chains to keep
+    #[arg(
+        short = 'n',
+        long,
+        default_value_t = 7,
+        env = "ALEX_CHAINS",
+        global = true
+    )]
+    pub chains: u64,
+    /// Type of server
+    #[arg(long, default_value = "unknown", env = "ALEX_SERVER")]
+    pub server: ServerType,
+    /// Version string for the server, e.g. 1.19.4-545
+    #[arg(long, default_value = "", env = "ALEX_SERVER_VERSION")]
+    pub server_version: String,
+}
+
+#[derive(Subcommand)]
+pub enum Commands {
+    /// Run the server
+    Run(RunArgs),
+    /// Create a new backup of the server. This command should only be used when the server is not
+    /// running.
+    Backup(BackupArgs),
+}
+
+#[derive(Args)]
+pub struct RunArgs {
+    /// Server jar to execute
+    #[arg(
+        long,
+        value_name = "JAR_PATH",
+        default_value = "server.jar",
+        env = "ALEX_JAR"
+    )]
+    pub jar: PathBuf,
+
+    /// Java command to run the server jar with
+    #[arg(long, value_name = "JAVA_CMD", default_value_t = String::from("java"), env = "ALEX_JAVA")]
+    pub java: String,
+
+    /// XMS value in megabytes for the server instance
+    #[arg(long, default_value_t = 1024, env = "ALEX_XMS")]
+    pub xms: u64,
+    /// XMX value in megabytes for the server instance
+    #[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)]
+    pub dry: bool,
+}
+
+#[derive(Args)]
+pub struct BackupArgs {}

src/main.rs

@@ -1,78 +1,14 @@
+mod backup;
+mod cli;
 mod server;
 mod signals;
 mod stdin;
 
 use clap::Parser;
-use server::ServerType;
+use cli::{BackupArgs, Cli, Commands, RunArgs};
 use std::io;
-use std::path::PathBuf;
 use std::sync::{Arc, Mutex};
 
-#[derive(Parser)]
-#[command(author, version, about, long_about = None)]
-struct Cli {
-    /// Type of server
-    type_: ServerType,
-    /// Version string for the server, e.g. 1.19.4-545
-    #[arg(env = "ALEX_SERVER_VERSION")]
-    server_version: String,
-
-    /// Server jar to execute
-    #[arg(
-        long,
-        value_name = "JAR_PATH",
-        default_value = "server.jar",
-        env = "ALEX_JAR"
-    )]
-    jar: PathBuf,
-    /// Directory where configs are stored, and where the server will run
-    #[arg(
-        long,
-        value_name = "CONFIG_DIR",
-        default_value = ".",
-        env = "ALEX_CONFIG_DIR"
-    )]
-    config: PathBuf,
-    /// Directory where world files will be saved
-    #[arg(
-        long,
-        value_name = "WORLD_DIR",
-        default_value = "../worlds",
-        env = "ALEX_WORLD_DIR"
-    )]
-    world: PathBuf,
-    /// Directory where backups will be stored
-    #[arg(
-        long,
-        value_name = "BACKUP_DIR",
-        default_value = "../backups",
-        env = "ALEX_BACKUP_DIR"
-    )]
-    backup: PathBuf,
-    /// Java command to run the server jar with
-    #[arg(long, value_name = "JAVA_CMD", default_value_t = String::from("java"), env = "ALEX_JAVA")]
-    java: String,
-
-    /// XMS value in megabytes for the server instance
-    #[arg(long, default_value_t = 1024, env = "ALEX_XMS")]
-    xms: u64,
-    /// XMX value in megabytes for the server instance
-    #[arg(long, default_value_t = 2048, env = "ALEX_XMX")]
-    xmx: u64,
-
-    /// How many backups to keep
-    #[arg(short = 'n', long, default_value_t = 7, env = "ALEX_MAX_BACKUPS")]
-    max_backups: u64,
-    /// How frequently to perform a backup, in minutes; 0 to disable.
-    #[arg(short = 't', long, default_value_t = 0, env = "ALEX_FREQUENCY")]
-    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)]
-    dry: bool,
-}
-
 fn backups_thread(counter: Arc<Mutex<server::ServerProcess>>, frequency: u64) {
     loop {
         std::thread::sleep(std::time::Duration::from_secs(frequency * 60));
@@ -86,22 +22,22 @@ fn backups_thread(counter: Arc<Mutex<server::ServerProcess>>, frequency: u64) {
     }
 }
 
-fn main() -> io::Result<()> {
+fn command_run(cli: &Cli, args: &RunArgs) -> io::Result<()> {
     let (_, mut signals) = signals::install_signal_handlers()?;
-    let cli = Cli::parse();
 
-    let mut cmd = server::ServerCommand::new(cli.type_, &cli.server_version)
-        .java(&cli.java)
-        .jar(cli.jar)
-        .config(cli.config)
-        .world(cli.world)
-        .backup(cli.backup)
-        .xms(cli.xms)
-        .xmx(cli.xmx)
-        .max_backups(cli.max_backups);
+    let mut cmd = server::ServerCommand::new(cli.server, &cli.server_version)
+        .java(&args.java)
+        .jar(args.jar.clone())
+        .config(cli.config.clone())
+        .world(cli.world.clone())
+        .backup(cli.backup.clone())
+        .xms(args.xms)
+        .xmx(args.xmx)
+        .chain_len(cli.chain_len)
+        .chains_to_keep(cli.chains);
     cmd.canonicalize()?;
 
-    if cli.dry {
+    if args.dry {
         print!("{}", cmd);
 
         return Ok(());
@@ -109,9 +45,10 @@ fn main() -> io::Result<()> {
 
     let counter = Arc::new(Mutex::new(cmd.spawn()?));
 
-    if cli.frequency > 0 {
+    if args.frequency > 0 {
         let clone = Arc::clone(&counter);
-        std::thread::spawn(move || backups_thread(clone, cli.frequency));
+        let frequency = args.frequency;
+        std::thread::spawn(move || backups_thread(clone, frequency));
     }
 
     // Spawn thread that handles the main stdin loop
@@ -121,3 +58,32 @@ fn main() -> io::Result<()> {
     // Signal handler loop exits the process when necessary
     signals::handle_signals(&mut signals, counter)
 }
+
+fn commands_backup(cli: &Cli, _args: &BackupArgs) -> io::Result<()> {
+    let metadata = server::Metadata {
+        server_type: cli.server,
+        server_version: cli.server_version.clone(),
+    };
+
+    let mut manager = backup::Manager::new(
+        cli.backup.clone(),
+        cli.config.clone(),
+        cli.world.clone(),
+        metadata,
+        cli.chain_len,
+        cli.chains,
+    );
+    manager.load()?;
+
+    manager.create_backup()?;
+    manager.remove_old_backups()
+}
+
+fn main() -> io::Result<()> {
+    let cli = Cli::parse();
+
+    match &cli.command {
+        Commands::Run(args) => command_run(&cli, args),
+        Commands::Backup(args) => commands_backup(&cli, args),
+    }
+}

src/server/command.rs

@@ -1,13 +1,16 @@
+use crate::backup::Manager as BackupManager;
 use crate::server::ServerProcess;
 use clap::ValueEnum;
+use serde::{Deserialize, Serialize};
 use std::fmt;
 use std::fs::File;
 use std::io::Write;
 use std::path::{Path, PathBuf};
 use std::process::{Command, Stdio};
 
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, ValueEnum)]
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, ValueEnum, Serialize, Deserialize)]
 pub enum ServerType {
+    Unknown,
     Paper,
     Forge,
     Vanilla,
@@ -16,6 +19,7 @@ pub enum ServerType {
 impl fmt::Display for ServerType {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let s = match self {
+            ServerType::Unknown => "Unknown",
             ServerType::Paper => "PaperMC",
             ServerType::Forge => "Forge",
             ServerType::Vanilla => "Vanilla",
@@ -25,6 +29,12 @@ impl fmt::Display for ServerType {
     }
 }
 
+#[derive(Clone, Serialize, Deserialize)]
+pub struct Metadata {
+    pub server_type: ServerType,
+    pub server_version: String,
+}
+
 pub struct ServerCommand {
     type_: ServerType,
     version: String,
@@ -35,7 +45,8 @@ pub struct ServerCommand {
     backup_dir: PathBuf,
     xms: u64,
     xmx: u64,
-    max_backups: u64,
+    chain_len: u64,
+    chains_to_keep: u64,
 }
 
 impl ServerCommand {
@@ -50,7 +61,8 @@ impl ServerCommand {
             backup_dir: PathBuf::from("backups"),
             xms: 1024,
             xmx: 2048,
-            max_backups: 7,
+            chain_len: 4,
+            chains_to_keep: 7,
         }
     }
 
@@ -91,8 +103,13 @@ impl ServerCommand {
         self
     }
 
-    pub fn max_backups(mut self, v: u64) -> Self {
-        self.max_backups = v;
+    pub fn chain_len(mut self, v: u64) -> Self {
+        self.chain_len = v;
+        self
+    }
+
+    pub fn chains_to_keep(mut self, v: u64) -> Self {
+        self.chains_to_keep = v;
         self
     }
 
@@ -179,19 +196,25 @@ impl ServerCommand {
     }
 
     pub fn spawn(&mut self) -> std::io::Result<ServerProcess> {
+        let metadata = Metadata {
+            server_type: self.type_,
+            server_version: self.version.clone(),
+        };
+        let mut manager = BackupManager::new(
+            self.backup_dir.clone(),
+            self.config_dir.clone(),
+            self.world_dir.clone(),
+            metadata,
+            self.chain_len,
+            self.chains_to_keep,
+        );
+        manager.load()?;
+
         let mut cmd = self.create_cmd();
         self.accept_eula()?;
         let child = cmd.spawn()?;
 
-        Ok(ServerProcess::new(
-            self.type_,
-            self.version.clone(),
-            self.config_dir.clone(),
-            self.world_dir.clone(),
-            self.backup_dir.clone(),
-            self.max_backups,
-            child,
-        ))
+        Ok(ServerProcess::new(manager, child))
     }
 }
 

src/server/mod.rs

@@ -1,5 +1,5 @@
 mod command;
 mod process;
 
-pub use command::{ServerCommand, ServerType};
+pub use command::{Metadata, ServerCommand, ServerType};
 pub use process::ServerProcess;

src/server/process.rs

@@ -1,44 +1,18 @@
-use crate::server::ServerType;
-use flate2::write::GzEncoder;
-use flate2::Compression;
+use crate::backup::Manager as BackupManager;
+use crate::server::Metadata;
 use std::io::Write;
-use std::path::{Path, PathBuf};
 use std::process::Child;
 
-#[link(name = "c")]
-extern "C" {
-    fn geteuid() -> u32;
-    fn getegid() -> u32;
-}
-
 pub struct ServerProcess {
-    type_: ServerType,
-    version: String,
-    config_dir: PathBuf,
-    world_dir: PathBuf,
-    backup_dir: PathBuf,
-    max_backups: u64,
     child: Child,
+    backups: BackupManager<Metadata>,
 }
 
 impl ServerProcess {
-    pub fn new(
-        type_: ServerType,
-        version: String,
-        config_dir: PathBuf,
-        world_dir: PathBuf,
-        backup_dir: PathBuf,
-        max_backups: u64,
-        child: Child,
-    ) -> ServerProcess {
+    pub fn new(manager: BackupManager<Metadata>, child: Child) -> ServerProcess {
         ServerProcess {
-            type_,
-            version,
-            config_dir,
-            world_dir,
-            backup_dir,
-            max_backups,
             child,
+            backups: manager,
         }
     }
 
@@ -84,94 +58,33 @@ impl ServerProcess {
         // We wait some time to (hopefully) ensure the save-all call has completed
         std::thread::sleep(std::time::Duration::from_secs(10));
 
-        let res = self.create_backup_archive();
-
-        if res.is_ok() {
-            self.remove_old_backups()?;
-        }
+        let start_time = chrono::offset::Utc::now();
+        let res = self.backups.create_backup();
 
         // The server's save feature needs to be enabled again even if the archive failed to create
         self.custom("save-on")?;
+        self.custom("save-all")?;
 
         if res.is_ok() {
-            self.custom("say server backed up successfully")?;
+            self.backups.remove_old_backups()?;
+        }
+
+        let duration = chrono::offset::Utc::now() - start_time;
+        let duration_str = format!(
+            "{}m{}s",
+            duration.num_seconds() / 60,
+            duration.num_seconds() % 60
+        );
+
+        if res.is_ok() {
+            self.custom(&format!("say server backed up in {}", duration_str))?;
         } else {
-            self.custom("an error occured while backing up the server")?;
+            self.custom(&format!(
+                "an error occured after {} while backing up the server",
+                duration_str
+            ))?;
         }
 
         res
     }
-
-    /// Create a new compressed backup archive of the server's data.
-    fn create_backup_archive(&mut self) -> std::io::Result<()> {
-        // Create a gzip-compressed tarball of the worlds folder
-        let filename = format!(
-            "{}",
-            chrono::offset::Local::now().format("%Y-%m-%d_%H-%M-%S.tar.gz")
-        );
-        let path = self.backup_dir.join(filename);
-        let tar_gz = std::fs::File::create(path)?;
-        let enc = GzEncoder::new(tar_gz, Compression::default());
-        let mut tar = tar::Builder::new(enc);
-
-        tar.append_dir_all("worlds", &self.world_dir)?;
-
-        // Add all files from the config directory that aren't the cache
-        for entry in self
-            .config_dir
-            .read_dir()?
-            .filter_map(|e| e.ok())
-            .filter(|e| e.file_name() != "cache")
-        {
-            let tar_path = Path::new("config").join(entry.file_name());
-
-            if entry.file_type()?.is_dir() {
-                tar.append_dir_all(tar_path, entry.path())?;
-            } else {
-                tar.append_path_with_name(entry.path(), tar_path)?;
-            }
-        }
-
-        // We add a file to the backup describing for what version it was made
-        let info = format!("{} {}", self.type_, self.version);
-        let info_bytes = info.as_bytes();
-
-        let mut header = tar::Header::new_gnu();
-        header.set_size(info_bytes.len().try_into().unwrap());
-        header.set_mode(0o100644);
-        unsafe {
-            header.set_gid(getegid().into());
-            header.set_uid(geteuid().into());
-        }
-
-        tar.append_data(&mut header, "info.txt", info_bytes)?;
-
-        // Backup file gets finalized in the drop
-
-        Ok(())
-    }
-
-    /// Remove the oldest backups
-    fn remove_old_backups(&mut self) -> std::io::Result<()> {
-        // The naming format used allows us to sort the backups by name and still get a sorting by
-        // creation time
-        let mut backups = self
-            .backup_dir
-            .read_dir()?
-            .filter_map(|res| res.map(|e| e.path()).ok())
-            .collect::<Vec<PathBuf>>();
-        backups.sort();
-
-        let max_backups: usize = self.max_backups.try_into().unwrap();
-
-        if backups.len() > max_backups {
-            let excess_backups = backups.len() - max_backups;
-
-            for backup in &backups[0..excess_backups] {
-                std::fs::remove_file(backup)?;
-            }
-        }
-
-        Ok(())
-    }
 }