nix: use unwrapped program by default in module

- Add watchdog timeout support
- Add native journald logging support
- Add application state notifications
- Add verbosity flag

Cargo.lock

@@ -284,6 +284,16 @@ dependencies = [
  "clap_derive",
 ]
 
+[[package]]
+name = "clap-verbosity-flag"
+version = "2.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e099138e1807662ff75e2cebe4ae2287add879245574489f9b1588eb5e5564ed"
+dependencies = [
+ "clap",
+ "log",
+]
+
 [[package]]
 name = "clap_builder"
 version = "4.5.20"
@@ -496,11 +506,14 @@ dependencies = [
  "anyhow",
  "axum",
  "clap",
+ "clap-verbosity-flag",
  "env_logger",
  "log",
  "mpvipc-async",
+ "sd-notify",
  "serde",
  "serde_json",
+ "systemd-journal-logger",
  "tempfile",
  "tokio",
  "tower",
@@ -983,6 +996,12 @@ version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
 
+[[package]]
+name = "sd-notify"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1be20c5f7f393ee700f8b2f28ea35812e4e212f40774b550cd2a93ea91684451"
+
 [[package]]
 name = "serde"
 version = "1.0.210"
@@ -1100,6 +1119,16 @@ version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2047c6ded9c721764247e62cd3b03c09ffc529b2ba5b10ec482ae507a4a70160"
 
+[[package]]
+name = "systemd-journal-logger"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c18918ae65f3d828ec9ab7f4714b8c564149045f47407e319dd25cadfaf9d0cf"
+dependencies = [
+ "log",
+ "rustix",
+]
+
 [[package]]
 name = "tempfile"
 version = "3.13.0"

Cargo.toml

@@ -12,11 +12,14 @@ readme = "README.md"
 anyhow = "1.0.82"
 axum = { version = "0.6.20", features = ["macros"] }
 clap = { version = "4.4.1", features = ["derive"] }
+clap-verbosity-flag = "2.2.2"
 env_logger = "0.10.0"
 log = "0.4.20"
 mpvipc-async = { git = "https://git.pvv.ntnu.no/oysteikt/mpvipc-async.git", rev = "v0.1.0" }
+sd-notify = "0.4.3"
 serde = { version = "1.0.188", features = ["derive"] }
 serde_json = "1.0.105"
+systemd-journal-logger = "2.2.0"
 tempfile = "3.11.0"
 tokio = { version = "1.32.0", features = ["full"] }
 tower = { version = "0.4.13", features = ["full"] }

default.nix

@@ -4,6 +4,7 @@
 , rustPlatform
 , makeWrapper
 , mpv
+, wrapped ? false
 }:
 
 rustPlatform.buildRustPackage rec {
@@ -13,13 +14,20 @@ rustPlatform.buildRustPackage rec {
     baseName = baseNameOf (toString path);
   in !(lib.any (b: b) [
       (!(lib.cleanSourceFilter path type))
-      (baseName == "target" && type == "directory")
-      (baseName == "nix" && type == "directory")
-      (baseName == "flake.nix" && type == "regular")
-      (baseName == "flake.lock" && type == "regular")
+      (type == "directory" && lib.elem baseName [
+        ".direnv"
+        ".git"
+        "target"
+        "result"
+      ])
+      (type == "regular" && lib.elem baseName [
+        "flake.nix"
+        "default.nix"
+        "module.nix"
+        ".envrc"
+      ])
     ])) ./.;
 
-
   nativeBuildInputs = [ makeWrapper ];
 
   cargoLock = {
@@ -29,7 +37,7 @@ rustPlatform.buildRustPackage rec {
     };
   };
 
-  postInstall = ''
+  postInstall = lib.optionalString wrapped ''
     wrapProgram $out/bin/greg-ng \
       --prefix PATH : '${lib.makeBinPath [ mpv ]}'
   '';

flake.nix

@@ -35,7 +35,7 @@
     apps = forAllSystems (system: pkgs: _: {
       default = self.apps.${system}.greg-ng;
       greg-ng = let
-        package = self.packages.${system}.greg-ng;
+        package = self.packages.${system}.greg-ng-wrapped;
       in {
         type = "app";
         program = lib.getExe package;
@@ -63,6 +63,9 @@
     packages = forAllSystems (system: pkgs: _: {
       default = self.packages.${system}.greg-ng;
       greg-ng = pkgs.callPackage ./default.nix { };
+      greg-ng-wrapped = pkgs.callPackage ./default.nix {
+        wrapped = true;
+      };
     });
   } // {
     nixosModules.default = ./module.nix;

module.nix

@@ -14,7 +14,19 @@ in
 
     enablePipewire = lib.mkEnableOption "pipewire" // { default = true; };
 
-    enableDebug = lib.mkEnableOption "debug logs";
+    logLevel = lib.mkOption {
+      type = lib.types.enum [ "quiet" "error" "warn" "info" "debug" "trace" ];
+      default = "debug";
+      description = "Log level.";
+      apply = level: {
+        "quiet" = "-q";
+        "error" = "";
+        "warn" = "-v";
+        "info" = "-vv";
+        "debug" = "-vvv";
+        "trace" = "-vvvv";
+      }.${level};
+    };
 
     # TODO: create some better descriptions
     settings = {
@@ -87,12 +99,18 @@ in
         description = "greg-ng, an mpv based media player";
         wantedBy = [ "graphical-session.target" ];
         partOf = [ "graphical-session.target" ];
-        environment.RUST_LOG = lib.mkIf cfg.enableDebug "greg_ng=trace,mpvipc=trace";
         serviceConfig = {
-          Type = "simple";
-          ExecStart = "${lib.getExe cfg.package} ${lib.cli.toGNUCommandLineShell { } cfg.settings}";
+          Type = "notify";
+          ExecStart = let
+            args = lib.cli.toGNUCommandLineShell { } (cfg.settings // {
+              systemd = true;
+            });
+          in "${lib.getExe cfg.package} ${cfg.logLevel} ${args}";
+
           Restart = "always";
           RestartSec = 3;
+          WatchdogSec = lib.mkDefault 15;
+          TimeoutStartSec = lib.mkDefault 30;
 
           RestrictAddressFamilies = [ "AF_UNIX" "AF_INET" "AF_INET6" ];
           AmbientCapabilities = [ "" ];

src/main.rs

@@ -1,8 +1,11 @@
 use anyhow::Context;
 use axum::{Router, Server};
 use clap::Parser;
+use clap_verbosity_flag::Verbosity;
 use mpv_setup::{connect_to_mpv, create_mpv_config_file, show_grzegorz_image};
+use mpvipc_async::Mpv;
 use std::net::{IpAddr, SocketAddr};
+use systemd_journal_logger::JournalLog;
 use tempfile::NamedTempFile;
 
 mod api;
@@ -16,6 +19,12 @@ struct Args {
     #[clap(short, long, default_value = "8008")]
     port: u16,
 
+    #[command(flatten)]
+    verbose: Verbosity,
+
+    #[clap(long)]
+    systemd: bool,
+
     #[clap(long, value_name = "PATH", default_value = "/run/mpv/mpv.sock")]
     mpv_socket_path: String,
 
@@ -40,6 +49,8 @@ struct MpvConnectionArgs<'a> {
     force_auto_start: bool,
 }
 
+/// Helper function to resolve a hostname to an IP address.
+/// Why is this not in the standard library? >:(
 async fn resolve(host: &str) -> anyhow::Result<IpAddr> {
     let addr = format!("{}:0", host);
     let addresses = tokio::net::lookup_host(addr).await?;
@@ -50,11 +61,71 @@ async fn resolve(host: &str) -> anyhow::Result<IpAddr> {
         .ok_or_else(|| anyhow::anyhow!("Failed to resolve address"))
 }
 
+/// Helper function that spawns a tokio thread that
+/// continuously sends a ping to systemd watchdog, if enabled.
+async fn setup_systemd_watchdog_thread() -> anyhow::Result<()> {
+    let mut watchdog_microsecs: u64 = 0;
+    if sd_notify::watchdog_enabled(true, &mut watchdog_microsecs) {
+        watchdog_microsecs = watchdog_microsecs.div_ceil(2);
+        tokio::spawn(async move {
+            log::debug!(
+                "Starting systemd watchdog thread with {} millisecond interval",
+                watchdog_microsecs.div_ceil(1000)
+            );
+            loop {
+                tokio::time::sleep(tokio::time::Duration::from_micros(watchdog_microsecs)).await;
+                if let Err(err) = sd_notify::notify(false, &[sd_notify::NotifyState::Watchdog]) {
+                    log::warn!("Failed to notify systemd watchdog: {}", err);
+                } else {
+                    log::trace!("Ping sent to systemd watchdog");
+                }
+            }
+        });
+    } else {
+        log::info!("Watchdog not enabled, skipping");
+    }
+    Ok(())
+}
+
+async fn shutdown(mpv: Mpv, proc: Option<tokio::process::Child>) {
+    log::info!("Shutting down");
+    sd_notify::notify(false, &[sd_notify::NotifyState::Stopping])
+        .unwrap_or_else(|e| log::warn!("Failed to notify systemd that the service is stopping: {}", e));
+
+    mpv.disconnect()
+        .await
+        .unwrap_or_else(|e| log::warn!("Failed to disconnect from mpv: {}", e));
+    if let Some(mut proc) = proc {
+        proc.kill()
+            .await
+            .unwrap_or_else(|e| log::warn!("Failed to kill mpv process: {}", e));
+    }
+}
+
 #[tokio::main]
 async fn main() -> anyhow::Result<()> {
-    env_logger::init();
     let args = Args::parse();
 
+    let systemd_mode = args.systemd && sd_notify::booted().unwrap_or(false);
+    if systemd_mode {
+        JournalLog::new()
+            .context("Failed to initialize journald logging")?
+            .install()
+            .context("Failed to install journald logger")?;
+
+        log::set_max_level(args.verbose.log_level_filter());
+
+        log::debug!("Running with systemd integration");
+
+        setup_systemd_watchdog_thread().await?;
+    } else {
+        env_logger::Builder::new()
+            .filter_level(args.verbose.log_level_filter())
+            .init();
+
+        log::info!("Running without systemd integration");
+    }
+
     let mpv_config_file = create_mpv_config_file(args.mpv_config_file)?;
 
     let (mpv, proc) = connect_to_mpv(&MpvConnectionArgs {
@@ -64,37 +135,65 @@ async fn main() -> anyhow::Result<()> {
         auto_start: args.auto_start_mpv,
         force_auto_start: args.force_auto_start,
     })
-    .await?;
+    .await
+    .context("Failed to connect to mpv")?;
 
     if let Err(e) = show_grzegorz_image(mpv.clone()).await {
-      log::warn!("Could not show Grzegorz image: {}", e);
+        log::warn!("Could not show Grzegorz image: {}", e);
     }
 
-    let addr = SocketAddr::new(resolve(&args.host).await?, args.port);
-    log::info!("Starting API on {}", addr);
+    let addr = match resolve(&args.host)
+        .await
+        .context(format!("Failed to resolve address: {}", &args.host))
+    {
+        Ok(addr) => addr,
+        Err(e) => {
+            log::error!("{}", e);
+            shutdown(mpv, proc).await;
+            return Err(e);
+        }
+    };
+    let socket_addr = SocketAddr::new(addr, args.port);
+    log::info!("Starting API on {}", socket_addr);
 
     let app = Router::new().nest("/api", api::rest_api_routes(mpv.clone()));
+    let server = match Server::try_bind(&socket_addr.clone())
+        .context(format!("Failed to bind API server to '{}'", &socket_addr))
+    {
+        Ok(server) => server,
+        Err(e) => {
+            log::error!("{}", e);
+            shutdown(mpv, proc).await;
+            return Err(e);
+        }
+    };
+
+    if systemd_mode {
+        match sd_notify::notify(false, &[sd_notify::NotifyState::Ready])
+            .context("Failed to notify systemd that the service is ready")
+        {
+            Ok(_) => log::trace!("Notified systemd that the service is ready"),
+            Err(e) => {
+                log::error!("{}", e);
+                shutdown(mpv, proc).await;
+                return Err(e);
+            }
+        }
+    }
 
     if let Some(mut proc) = proc {
         tokio::select! {
             exit_status = proc.wait() => {
                 log::warn!("mpv process exited with status: {}", exit_status?);
-                mpv.disconnect().await?;
+                shutdown(mpv, Some(proc)).await;
             }
             _ = tokio::signal::ctrl_c() => {
                 log::info!("Received Ctrl-C, exiting");
-                mpv.disconnect().await?;
-                proc.kill().await?;
+                shutdown(mpv, Some(proc)).await;
             }
-            result = async {
-              match Server::try_bind(&addr.clone()).context("Failed to bind server") {
-                Ok(server) => server.serve(app.into_make_service()).await.context("Failed to serve app"),
-                Err(err) => Err(err),
-              }
-            } => {
+            result = server.serve(app.into_make_service()) => {
               log::info!("API server exited");
-              mpv.disconnect().await?;
-              proc.kill().await?;
+              shutdown(mpv, Some(proc)).await;
               result?;
             }
         }
@@ -102,11 +201,12 @@ async fn main() -> anyhow::Result<()> {
         tokio::select! {
             _ = tokio::signal::ctrl_c() => {
                 log::info!("Received Ctrl-C, exiting");
-                mpv.disconnect().await?;
+                shutdown(mpv.clone(), None).await;
             }
-            _ =  Server::bind(&addr.clone()).serve(app.into_make_service()) => {
-                log::info!("API server exited");
-                mpv.disconnect().await?;
+            result = server.serve(app.into_make_service()) => {
+              log::info!("API server exited");
+              shutdown(mpv.clone(), None).await;
+              result?;
             }
         }
     }