feat: restore backup chains using cli commands

src/backup/manager/meta.rs

@@ -9,7 +9,7 @@ use std::path::PathBuf;
 /// Manages a collection of backup layers, allowing them to be utilized as a single object.
 pub struct MetaManager<T>
 where
-    T: Clone + Serialize + for<'de> Deserialize<'de>,
+    T: Clone + Serialize + for<'de> Deserialize<'de> + std::fmt::Debug,
 {
     backup_dir: PathBuf,
     dirs: Vec<(PathBuf, PathBuf)>,
@@ -19,7 +19,7 @@ where
 
 impl<T> MetaManager<T>
 where
-    T: Clone + Serialize + for<'de> Deserialize<'de>,
+    T: Clone + Serialize + for<'de> Deserialize<'de> + std::fmt::Debug,
 {
     pub fn new<P: Into<PathBuf>>(
         backup_dir: P,
@@ -116,4 +116,15 @@ where
             None
         }
     }
+
+    /// Restore a backup for a specific layer
+    pub fn restore_backup(
+        &self,
+        layer: &str,
+        start_time: chrono::DateTime<Utc>,
+    ) -> Option<io::Result<()>> {
+        self.managers
+            .get(layer)
+            .map(|manager| manager.restore_backup(start_time))
+    }
 }

src/backup/manager/mod.rs

@@ -5,6 +5,8 @@ pub use config::ManagerConfig;
 pub use meta::MetaManager;
 
 use super::Backup;
+use crate::other;
+use chrono::SubsecRound;
 use chrono::Utc;
 use serde::Deserialize;
 use serde::Serialize;
@@ -15,7 +17,7 @@ use std::path::PathBuf;
 /// Manages a single backup layer consisting of one or more chains of backups.
 pub struct Manager<T>
 where
-    T: Clone + Serialize + for<'de> Deserialize<'de>,
+    T: Clone + Serialize + for<'de> Deserialize<'de> + std::fmt::Debug,
 {
     backup_dir: PathBuf,
     dirs: Vec<(PathBuf, PathBuf)>,
@@ -28,7 +30,7 @@ where
 
 impl<T> Manager<T>
 where
-    T: Clone + Serialize + for<'de> Deserialize<'de>,
+    T: Clone + Serialize + for<'de> Deserialize<'de> + std::fmt::Debug,
 {
     const METADATA_FILE: &str = "alex.json";
 
@@ -156,4 +158,27 @@ where
 
         chrono::offset::Utc::now()
     }
+
+    /// Restore the backup with the given start time by restoring its chain up to and including the
+    /// backup, in order.
+    pub fn restore_backup(&self, start_time: chrono::DateTime<Utc>) -> io::Result<()> {
+        // Iterate over each chain, skipping elements until the element with the given start time
+        // is possibly found.
+        for chain in &self.chains {
+            // If we find the element in the chain, restore the entire chain up to and including
+            // the element
+            if let Some(index) = chain
+                .iter()
+                .position(|b| b.start_time.trunc_subsecs(0) == start_time)
+            {
+                for backup in chain.iter().take(index + 1) {
+                    backup.restore(&self.backup_dir, &self.dirs)?;
+                }
+
+                return Ok(());
+            }
+        }
+
+        Err(other("Unknown backup."))
+    }
 }

src/backup/mod.rs

@@ -8,6 +8,7 @@ pub use manager::ManagerConfig;
 pub use manager::MetaManager;
 
 use chrono::Utc;
+use flate2::read::GzDecoder;
 use flate2::write::GzEncoder;
 use flate2::Compression;
 use path::PathExt;
@@ -24,7 +25,7 @@ pub enum BackupType {
 }
 
 /// Represents a successful backup
-#[derive(Serialize, Deserialize)]
+#[derive(Serialize, Deserialize, Debug)]
 pub struct Backup<T: Clone> {
     /// When the backup was started (also corresponds to the name)
     pub start_time: chrono::DateTime<Utc>,
@@ -36,6 +37,8 @@ pub struct Backup<T: Clone> {
 }
 
 impl Backup<()> {
+    pub const FILENAME_FORMAT: &str = "%Y-%m-%d_%H-%M-%S.tar.gz";
+
     /// 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();
@@ -46,8 +49,6 @@ impl Backup<()> {
 }
 
 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);
     }
@@ -159,4 +160,48 @@ impl<T: Clone> Backup<T> {
             metadata: None,
         })
     }
+
+    pub fn restore<P: AsRef<Path>>(
+        &self,
+        backup_dir: P,
+        dirs: &Vec<(PathBuf, PathBuf)>,
+    ) -> io::Result<()> {
+        let path = Backup::path(backup_dir, self.start_time);
+        let tar_gz = File::open(path)?;
+        let enc = GzDecoder::new(tar_gz);
+        let mut ar = tar::Archive::new(enc);
+
+        // Unpack each file by matching it with one of the destination directories and extracting
+        // it to the right path
+        for entry in ar.entries()? {
+            let mut entry = entry?;
+            let entry_path_in_tar = entry.path()?.to_path_buf();
+
+            for (path_in_tar, dst_dir) in dirs {
+                if entry_path_in_tar.starts_with(path_in_tar) {
+                    let dst_path =
+                        dst_dir.join(entry_path_in_tar.strip_prefix(path_in_tar).unwrap());
+
+                    // Ensure all parent directories are present
+                    std::fs::create_dir_all(dst_path.parent().unwrap())?;
+
+                    entry.unpack(dst_path)?;
+
+                    break;
+                }
+            }
+        }
+
+        // Remove any files
+        for (path_in_tar, dst_dir) in dirs {
+            if let Some(removed) = self.delta.removed.get(path_in_tar) {
+                for path in removed {
+                    let dst_path = dst_dir.join(path);
+                    std::fs::remove_file(dst_path)?;
+                }
+            }
+        }
+
+        Ok(())
+    }
 }

src/cli/backup.rs

@@ -1,11 +1,19 @@
+use crate::backup::Backup;
 use crate::cli::Cli;
+use crate::other;
+use chrono::{TimeZone, Utc};
 use clap::{Args, Subcommand};
 use std::io;
+use std::path::PathBuf;
 
 #[derive(Subcommand)]
 pub enum BackupCommands {
-    Create(BackupCreateArgs),
+    /// List all tracked backups
     List,
+    /// Manually create a new backup
+    Create(BackupCreateArgs),
+    /// Restore a backup
+    Restore(BackupRestoreArgs),
 }
 
 #[derive(Args)]
@@ -20,11 +28,21 @@ pub struct BackupCreateArgs {
     layer: String,
 }
 
+#[derive(Args)]
+pub struct BackupRestoreArgs {
+    /// Path to the backup inside the backup directory
+    path: PathBuf,
+    /// Whether to overwrite the contents of the existing directories
+    #[arg(short, long, default_value_t = false)]
+    force: bool,
+}
+
 impl BackupArgs {
     pub fn run(&self, cli: &Cli) -> io::Result<()> {
         match &self.command {
             BackupCommands::Create(args) => args.run(cli),
             BackupCommands::List => Ok(()),
+            BackupCommands::Restore(args) => args.run(cli),
         }
     }
 }
@@ -40,3 +58,65 @@ impl BackupCreateArgs {
         }
     }
 }
+
+impl BackupRestoreArgs {
+    pub fn run(&self, cli: &Cli) -> io::Result<()> {
+        let backup_dir = cli.backup.canonicalize()?;
+
+        // Parse input path
+        let path = self.path.canonicalize()?;
+
+        if !path.starts_with(&backup_dir) {
+            return Err(other("Provided file is not inside the backup directory."));
+        }
+
+        let layer = if let Some(parent) = path.parent() {
+            // Backup files should be stored nested inside a layer's folder
+            if parent != backup_dir {
+                parent.file_name().unwrap().to_string_lossy()
+            } else {
+                return Err(other("Invalid path."));
+            }
+        } else {
+            return Err(other("Invalid path."));
+        };
+
+        let timestamp = if let Some(filename) = path.file_name() {
+            Utc.datetime_from_str(&filename.to_string_lossy(), Backup::FILENAME_FORMAT)
+                .map_err(|_| other("Invalid filename."))?
+        } else {
+            return Err(other("Invalid filename."));
+        };
+
+        let meta = cli.meta()?;
+
+        // Clear previous contents of directories
+        let mut entries = cli
+            .config
+            .canonicalize()?
+            .read_dir()?
+            .chain(cli.world.canonicalize()?.read_dir()?)
+            .peekable();
+
+        if entries.peek().is_some() && !self.force {
+            return Err(other("Output directories are not empty. If you wish to overwrite these contents, use the force flag."));
+        }
+
+        for entry in entries {
+            let path = entry?.path();
+
+            if path.is_dir() {
+                std::fs::remove_dir_all(path)?;
+            } else {
+                std::fs::remove_file(path)?;
+            }
+        }
+
+        // Restore the backup
+        if let Some(res) = meta.restore_backup(&layer, timestamp) {
+            res
+        } else {
+            Err(other("Unknown layer"))
+        }
+    }
+}

src/cli/mod.rs

@@ -81,10 +81,10 @@ impl Cli {
             server_version: self.server_version.clone(),
         };
         let dirs = vec![
-            (PathBuf::from("config"), self.config.clone()),
-            (PathBuf::from("worlds"), self.world.clone()),
+            (PathBuf::from("config"), self.config.canonicalize()?),
+            (PathBuf::from("worlds"), self.world.canonicalize()?),
         ];
-        let mut meta = MetaManager::new(self.backup.clone(), dirs, metadata);
+        let mut meta = MetaManager::new(self.backup.canonicalize()?, dirs, metadata);
         meta.add_all(&self.layers)?;
 
         Ok(meta)

src/main.rs

@@ -8,6 +8,10 @@ use crate::cli::Cli;
 use clap::Parser;
 use std::io;
 
+pub fn other(msg: &str) -> io::Error {
+    io::Error::new(io::ErrorKind::Other, msg)
+}
+
 // fn commands_backup(cli: &Cli, args: &BackupArgs) -> io::Result<()> {
 //     let metadata = server::Metadata {
 //         server_type: cli.server,

src/server/mod.rs

@@ -8,7 +8,7 @@ use clap::ValueEnum;
 use serde::{Deserialize, Serialize};
 use std::fmt;
 
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, ValueEnum, Serialize, Deserialize)]
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, ValueEnum, Serialize, Deserialize, Debug)]
 pub enum ServerType {
     Unknown,
     Paper,
@@ -29,7 +29,7 @@ impl fmt::Display for ServerType {
     }
 }
 
-#[derive(Clone, Serialize, Deserialize)]
+#[derive(Clone, Serialize, Deserialize, Debug)]
 pub struct Metadata {
     pub server_type: ServerType,
     pub server_version: String,