Stub out change watcher and simplify it.

controller/Cargo.toml

@@ -17,6 +17,7 @@ serde = { version = "^1", features = ["derive"], default-features = false }
 serde_json = { version = "^1", features = ["std"], default-features = false }
 serde_yaml = "^0"
 clap = { version = "^3", features = ["std", "suggestions"], default-features = false }
+notify = { version = "^5", features = ["macos_fsevent"], default-features = false }
 
 [target."cfg(not(windows))".dependencies]
 signal-hook = "^0"

controller/src/database.rs

@@ -7,14 +7,12 @@ use zerotier_utils::tokio::sync::broadcast::Receiver;
 
 use crate::model::*;
 
+/// Database change relevant to the controller and that was NOT initiated by the controller.
 #[derive(Clone)]
 pub enum Change {
-    NetworkCreated(Network),
-    NetworkDeleted(Network),
-    NetworkChanged(Network, Network),
-    MemberCreated(Member),
-    MemberDeleted(Member),
-    MemberChanged(Member, Member),
+    NetworkDeleted(NetworkId),
+    MemberAuthorized(NetworkId, Address),
+    MemberDeauthorized(NetworkId, Address),
 }
 
 #[async_trait]

controller/src/filedatabase.rs

@@ -3,16 +3,20 @@ use std::fmt::Display;
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
 use std::sync::atomic::{AtomicU64, Ordering};
+use std::sync::{Arc, Mutex};
 
 use async_trait::async_trait;
+use notify::{RecursiveMode, Watcher};
 
 use zerotier_network_hypervisor::vl1::{Address, Identity, NodeStorage};
 use zerotier_network_hypervisor::vl2::NetworkId;
 
 use zerotier_utils::io::{fs_restrict_permissions, read_limit};
-use zerotier_utils::tokio::fs;
 
-use crate::database::Database;
+use zerotier_utils::tokio::fs;
+use zerotier_utils::tokio::sync::broadcast::{channel, Receiver, Sender};
+
+use crate::database::{Change, Database};
 use crate::model::*;
 
 const IDENTITY_SECRET_FILENAME: &'static str = "identity.secret";
@@ -54,15 +58,42 @@ impl From<zerotier_utils::tokio::io::Error> for FileDatabaseError {
 pub struct FileDatabase {
     base_path: PathBuf,
     controller_address: AtomicU64,
+    change_sender: Arc<Sender<Change>>,
+    watcher: Mutex<Box<dyn Watcher + Send>>,
 }
 
 // TODO: should cache at least hashes and detect changes in the filesystem live.
 
 impl FileDatabase {
     pub async fn new<P: AsRef<Path>>(base_path: P) -> Result<Self, Box<dyn Error>> {
-        let base: PathBuf = base_path.as_ref().into();
-        let _ = fs::create_dir_all(&base).await?;
-        Ok(Self { base_path: base, controller_address: AtomicU64::new(0) })
+        let base_path: PathBuf = base_path.as_ref().into();
+        let _ = fs::create_dir_all(&base_path).await?;
+
+        let (change_sender, _) = channel(256);
+        let change_sender = Arc::new(change_sender);
+
+        let sender = Arc::downgrade(&change_sender);
+        let mut watcher: Box<dyn Watcher + Send> =
+            Box::new(notify::recommended_watcher(move |event: notify::Result<notify::event::Event>| {
+                if let Ok(event) = event {
+                    if let Some(_sender) = sender.upgrade() {
+                        // TODO
+                        match event.kind {
+                            notify::EventKind::Modify(_) => {}
+                            notify::EventKind::Remove(_) => {}
+                            _ => {}
+                        }
+                    }
+                }
+            })?);
+        watcher.watch(&base_path, RecursiveMode::Recursive)?;
+
+        Ok(Self {
+            base_path: base_path.clone(),
+            controller_address: AtomicU64::new(0),
+            change_sender,
+            watcher: Mutex::new(watcher),
+        })
     }
 
     fn get_controller_address(&self) -> Option<Address> {
@@ -90,6 +121,12 @@ impl FileDatabase {
     }
 }
 
+impl Drop for FileDatabase {
+    fn drop(&mut self) {
+        let _ = self.watcher.lock().unwrap().unwatch(&self.base_path);
+    }
+}
+
 impl NodeStorage for FileDatabase {
     fn load_node_identity(&self) -> Option<Identity> {
         let id_data = read_limit(self.base_path.join(IDENTITY_SECRET_FILENAME), 16384);
@@ -178,6 +215,10 @@ impl Database for FileDatabase {
         Ok(())
     }
 
+    async fn changes(&self) -> Option<Receiver<Change>> {
+        Some(self.change_sender.subscribe())
+    }
+
     async fn log_request(&self, obj: RequestLogItem) -> Result<(), Self::Error> {
         println!("{}", obj.to_string());
         Ok(())

controller/src/handler.rs

@@ -295,12 +295,11 @@ impl<DatabaseImpl: Database> Inner<DatabaseImpl> {
                     Ok(())
                 },
             );
+            // TODO: log errors
         }
     }
 
-    async fn handle_change_notification(self: Arc<Self>, _change: Change) {
-        todo!()
-    }
+    async fn handle_change_notification(self: Arc<Self>, change: Change) {}
 
     async fn handle_network_config_request<HostSystemImpl: HostSystem + ?Sized>(
         self: &Arc<Self>,

controller/src/model/network.rs

@@ -1,7 +1,6 @@
 // (c) 2020-2022 ZeroTier, Inc. -- currently propritery pending actual release and licensing. See LICENSE.md.
 
 use std::collections::{HashMap, HashSet};
-use std::error::Error;
 use std::hash::Hash;
 
 use serde::{Deserialize, Serialize};