feat: add optional fs-uuid parameter for database initialization (#14)

Author: iamjoemccormick

mgmtd/src/config.rs

@@ -11,6 +11,7 @@ use std::fmt::Debug;
 use std::ops::RangeInclusive;
 use std::path::PathBuf;
 use std::time::Duration;
+use uuid::Uuid;
 
 /// Generates `Config` to be filled by the functions below and exported to be used by the program.
 ///
@@ -107,6 +108,16 @@ generate_structs! {
     #[serde(skip)]
     init: bool = false,
 
+    /// Optionally specifies the FsUuid when initializing the database.
+    ///
+    /// If not provided, a new FsUuid will be generated.
+    #[arg(long)]
+    #[arg(num_args = 1)]
+    #[arg(hide = true)]
+    #[arg(value_name = "UUID")]
+    #[serde(skip)]
+    fs_uuid: Option<Uuid> = None,
+
     /// Upgrades an outdated management database to the current version, then exits.
     ///
     /// Automatically creates a backup of the existing database file in the same directory.
@@ -393,6 +404,12 @@ generate_structs! {
 
 impl Config {
     pub fn check_validity(&self) -> Result<()> {
+        if let Some(ref uuid) = self.fs_uuid {
+            if uuid.get_version_num() != 4 {
+                bail!("Provided file system UUID is not a valid v4 UUID");
+            }
+        }
+
         if self.quota_enforce && !self.quota_enable {
             bail!("Quota enforcement requires quota being enabled");
         }

mgmtd/src/db.rs

@@ -37,8 +37,10 @@ pub const MIGRATIONS: &[sqlite::Migration] = include!(concat!(env!("OUT_DIR"), "
 
 /// Inserts initial entries into a new database. Remember to commit the transaction after calling
 /// this function.
-pub fn initial_entries(tx: &Transaction) -> Result<()> {
-    config::set(tx, Config::FsUuid, Uuid::new_v4().to_string())?;
+///
+/// If `fs_uuid` is provided, it will be used. Otherwise, a new FsUUID will be generated.
+pub fn initial_entries(tx: &Transaction, fs_uuid: Option<Uuid>) -> Result<()> {
+    config::set(tx, Config::FsUuid, fs_uuid.unwrap_or_else(Uuid::new_v4))?;
     config::set(
         tx,
         Config::FsInitDateSecs,

mgmtd/src/main.rs

@@ -11,6 +11,7 @@ use std::fmt::Write;
 use std::path::Path;
 use std::{fs, panic};
 use tokio::signal::ctrl_c;
+use uuid::Uuid;
 
 fn main() -> Result<(), i32> {
     inner_main().map_err(|err| {
@@ -62,7 +63,11 @@ fn inner_main() -> Result<()> {
     }
 
     if user_config.init || user_config.import_from_v7.is_some() {
-        init_db(&user_config.db_file, user_config.import_from_v7.as_deref())?;
+        init_db(
+            &user_config.db_file,
+            user_config.import_from_v7.as_deref(),
+            user_config.fs_uuid,
+        )?;
         return Ok(());
     }
 
@@ -149,10 +154,11 @@ doc.beegfs.io.",
     })
 }
 
-/// Create and initialize a new database. Optionally import v7 data from the given path.
+/// Create and initialize a new database.
 ///
-/// The database file is only written to disk if the initialization succeeds.
-fn init_db(db_file: &Path, v7_path: Option<&Path>) -> Result<()> {
+/// Optionally import v7 data from the given path. Optionally the FsUUID can be specified otherwise
+/// it will be autogenerated. The database file is only written to disk if initialization succeeds.
+fn init_db(db_file: &Path, v7_path: Option<&Path>, fs_uuid: Option<Uuid>) -> Result<()> {
     if db_file.try_exists()? {
         bail!("Database file {db_file:?} already exists");
     }
@@ -165,7 +171,7 @@ fn init_db(db_file: &Path, v7_path: Option<&Path>) -> Result<()> {
 
         let version =
             sqlite::migrate_schema(&tx, db::MIGRATIONS).context("Creating schema failed")?;
-        db::initial_entries(&tx).context("Creating initial entries failed")?;
+        db::initial_entries(&tx, fs_uuid).context("Creating initial entries failed")?;
 
         if let Some(v7_path) = v7_path {
             db::import_v7(&tx, v7_path).context("v7 management data import failed")?;