feat(core): prevent multiple daemon and worker instances

Cargo.lock

@@ -311,6 +311,7 @@ dependencies = [
  "espanso-path",
  "espanso-render",
  "espanso-ui",
+ "fs2",
  "html2text",
  "lazy_static",
  "log",
@@ -484,6 +485,16 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "69a039c3498dc930fe810151a34ba0c1c70b02b8625035592e74432f678591f2"
 
+[[package]]
+name = "fs2"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9564fc758e15025b46aa6643b1b77d047d1a56a1aea6e01002ac0c7026876213"
+dependencies = [
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "fuchsia-cprng"
 version = "0.1.1"

espanso/Cargo.toml

@@ -38,3 +38,4 @@ serde_json = "1.0.62"
 markdown = "0.3.0"
 html2text = "0.2.1"
 log-panics = "2.0.0"
+fs2 = "0.4.3"

espanso/src/cli/daemon/mod.rs

@@ -19,7 +19,9 @@
 
 use std::process::Command;
 
-use log::info;
+use log::{error, info};
+
+use crate::lock::acquire_daemon_lock;
 
 use super::{CliModule, CliModuleArgs};
 
@@ -41,16 +43,20 @@ const VERSION: &str = env!("CARGO_PKG_VERSION");
 fn daemon_main(args: CliModuleArgs) {
   let paths = args.paths.expect("missing paths in daemon main");
 
+  // Make sure only one instance of the daemon is running
+  let lock_file = acquire_daemon_lock(&paths.runtime);
+  if lock_file.is_none() {
+    error!("daemon is already running!");
+    std::process::exit(1);
+  }
+
   info!("espanso version: {}", VERSION);
   // TODO: print os system and version? (with os_info crate)
 
-  // TODO: check daemon lock file to avoid duplicates
 
   // TODO: check worker lock file, if taken stop the worker process through IPC
 
-  // TODO: start IPC server
+  // TODO: register signals to terminate the worker if the daemon terminates
-
-  // TODO: start file watcher thread
 
   let espanso_exe_path =
     std::env::current_exe().expect("unable to obtain espanso executable location");
@@ -71,4 +77,12 @@ fn daemon_main(args: CliModuleArgs) {
   }
 
   command.spawn().expect("unable to spawn worker process");
+
+  // TODO: start IPC server
+
+  // TODO: start file watcher thread
+
+  loop {
+    std::thread::sleep(std::time::Duration::from_millis(1000));
+  }
 }

espanso/src/cli/worker/mod.rs

@@ -17,6 +17,10 @@
  * along with espanso.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+use log::error;
+
+use crate::lock::acquire_worker_lock;
+
 use self::ui::util::convert_icon_paths_to_tray_vec;
 
 use super::{CliModule, CliModuleArgs};
@@ -39,6 +43,15 @@ pub fn new() -> CliModule {
 }
 
 fn worker_main(args: CliModuleArgs) {
+  let paths = args.paths.expect("missing paths in worker main");
+
+  // Avoid running multiple worker instances
+  let lock_file = acquire_worker_lock(&paths.runtime);
+  if lock_file.is_none() {
+    error!("worker is already running!");
+    std::process::exit(1);
+  }
+
   let config_store = args
     .config_store
     .expect("missing config store in worker main");
@@ -46,8 +59,6 @@ fn worker_main(args: CliModuleArgs) {
     .match_store
     .expect("missing match store in worker main");
 
-  let paths = args.paths.expect("missing paths in worker main");
-
   let icon_paths =
     self::ui::icon::load_icon_paths(&paths.runtime).expect("unable to initialize icons");
 

espanso/src/lock.rs

@@ -0,0 +1,72 @@
+/*
+ * This file is part of espanso.
+ *
+ * Copyright (C) 2019-2021 Federico Terzi
+ *
+ * espanso is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * espanso is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with espanso.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+use anyhow::Result;
+use fs2::FileExt;
+use std::{
+  fs::{File, OpenOptions},
+  path::Path,
+};
+
+pub struct Lock {
+  lock_file: File,
+}
+
+impl Lock {
+  pub fn release(self) -> Result<()> {
+    self.lock_file.unlock()?;
+    Ok(())
+  }
+
+  fn acquire(runtime_dir: &Path, name: &str) -> Option<Lock> {
+    let lock_file_path = runtime_dir.join(format!("{}.lock", name));
+    let lock_file = OpenOptions::new()
+      .read(true)
+      .write(true)
+      .create(true)
+      .open(&lock_file_path)
+      .expect(&format!(
+        "unable to create reference to lock file: {:?}",
+        lock_file_path
+      ));
+
+    if lock_file.try_lock_exclusive().is_ok() {
+      Some(Lock { lock_file })
+    } else {
+      None
+    }
+  }
+}
+
+impl Drop for Lock {
+  fn drop(&mut self) {
+    self
+      .lock_file
+      .unlock()
+      .expect(&format!("unable to unlock lock_file: {:?}", self.lock_file));
+  }
+}
+
+pub fn acquire_daemon_lock(runtime_dir: &Path) -> Option<Lock> {
+  Lock::acquire(runtime_dir, "espanso-daemon.lock")
+}
+
+pub fn acquire_worker_lock(runtime_dir: &Path) -> Option<Lock> {
+  Lock::acquire(runtime_dir, "espanso-worker.lock")
+}

espanso/src/main.rs

@@ -35,6 +35,7 @@ use crate::cli::LogMode;
 mod cli;
 mod engine;
 mod gui;
+mod lock;
 mod logging;
 mod util;
 
@@ -253,7 +254,7 @@ fn main() {
     if handler.enable_logs {
       let config = ConfigBuilder::new()
         .set_time_to_local(true)
-        .set_time_format(format!("%H:%M:%S [{}]", handler.subcommand))
+        .set_time_format(format!("%H:%M:%S [{}({})]", handler.subcommand, std::process::id()))
         .set_location_level(LevelFilter::Off)
         .add_filter_ignore_str("html5ever")
         .build();