feat(error code when shutdown fails): set exit flag to non-zero when shutdown times out

src/app.rs

@@ -1,5 +1,7 @@
 #![allow(missing_docs)]
-use std::{collections::HashMap, num::NonZeroUsize, path::PathBuf, time::Duration};
+use std::{
+    collections::HashMap, num::NonZeroUsize, path::PathBuf, process::ExitStatus, time::Duration,
+};
 
 use exitcode::ExitCode;
 use futures::StreamExt;
@@ -32,6 +34,11 @@ use crate::{
     trace,
 };
 
+#[cfg(unix)]
+use std::os::unix::process::ExitStatusExt;
+#[cfg(windows)]
+use std::os::windows::process::ExitStatusExt;
+
 pub static WORKER_THREADS: OnceNonZeroUsize = OnceNonZeroUsize::new();
 
 use crate::internal_events::{VectorQuit, VectorStarted, VectorStopped};
@@ -145,10 +152,10 @@ impl ApplicationConfig {
 }
 
 impl Application {
-    pub fn run() {
+    pub fn run() -> ExitStatus {
         let (runtime, app) = Self::prepare_start().unwrap_or_else(|code| std::process::exit(code));
 
-        runtime.block_on(app.run());
+        runtime.block_on(app.run())
     }
 
     pub fn prepare_start() -> Result<(Runtime, StartedApplication), ExitCode> {
@@ -242,7 +249,7 @@ pub struct StartedApplication {
 }
 
 impl StartedApplication {
-    pub async fn run(self) {
+    pub async fn run(self) -> ExitStatus {
         self.main().await.shutdown().await
     }
 
@@ -317,7 +324,7 @@ pub struct FinishedApplication {
 }
 
 impl FinishedApplication {
-    pub async fn shutdown(self) {
+    pub async fn shutdown(self) -> ExitStatus {
         let FinishedApplication {
             signal,
             mut signal_rx,
@@ -335,18 +342,42 @@ impl FinishedApplication {
             SignalTo::Shutdown => {
                 emit!(VectorStopped);
                 tokio::select! {
-                    _ = topology_controller.stop() => (), // Graceful shutdown finished
+                    _ = topology_controller.stop() => ExitStatus::from_raw({
+                            #[cfg(windows)]
+                            {
+                                exitcode::OK as u32
+                            }
+                            #[cfg(unix)]
+                            exitcode::OK
+                    }), // Graceful shutdown finished
                     _ = signal_rx.recv() => {
                         // It is highly unlikely that this event will exit from topology.
                         emit!(VectorQuit);
                         // Dropping the shutdown future will immediately shut the server down
+                        ExitStatus::from_raw({
+                            #[cfg(windows)]
+                            {
+                                exitcode::UNAVAILABLE as u32
+                            }
+                            #[cfg(unix)]
+                            exitcode::OK
+                        })
                     }
+
                 }
             }
             SignalTo::Quit => {
                 // It is highly unlikely that this event will exit from topology.
                 emit!(VectorQuit);
                 drop(topology_controller);
+                ExitStatus::from_raw({
+                    #[cfg(windows)]
+                    {
+                        exitcode::UNAVAILABLE as u32
+                    }
+                    #[cfg(unix)]
+                    exitcode::OK
+                })
             }
             _ => unreachable!(),
         }

src/main.rs

@@ -3,8 +3,10 @@
 extern crate vector;
 use vector::app::Application;
 
+use std::process::ExitCode;
+
 #[cfg(unix)]
-fn main() {
+fn main() -> ExitCode {
     #[cfg(feature = "allocation-tracing")]
     {
         use crate::vector::internal_telemetry::allocations::{
@@ -35,14 +37,17 @@ fn main() {
         }
     }
 
-    Application::run();
+    let exit_code = Application::run().code().unwrap_or(exitcode::UNAVAILABLE) as u8;
+    ExitCode::from(exit_code)
 }
 
 #[cfg(windows)]
-pub fn main() {
+pub fn main() -> ExitCode {
     // We need to be able to run vector in User Interactive mode. We first try
     // to run vector as a service. If we fail, we consider that we are in
     // interactive mode and then fallback to console mode.  See
     // https://docs.microsoft.com/en-us/dotnet/api/system.environment.userinteractive?redirectedfrom=MSDN&view=netcore-3.1#System_Environment_UserInteractive
-    vector::vector_windows::run().unwrap_or_else(|_| Application::run());
+    let exit_code = vector::vector_windows::run()
+        .unwrap_or_else(|_| Application::run().code().unwrap_or(exitcode::UNAVAILABLE));
+    ExitCode::from(exit_code as u8)
 }

src/vector_windows.rs

@@ -17,6 +17,7 @@ const SERVICE_NAME: &str = "vector";
 const SERVICE_TYPE: ServiceType = ServiceType::OWN_PROCESS;
 
 const NO_ERROR: u32 = 0;
+const ERROR: u32 = 121;
 
 pub mod service_control {
     use std::{ffi::OsString, fmt, fmt::Formatter, time::Duration};
@@ -361,8 +362,9 @@ fn win_main(arguments: Vec<OsString>) {
     if let Err(_e) = run_service(arguments) {}
 }
 
-pub fn run() -> Result<()> {
-    service_dispatcher::start(SERVICE_NAME, ffi_service_main)
+pub fn run() -> Result<i32> {
+    service_dispatcher::start(SERVICE_NAME, ffi_service_main).map(|()| 0_i32)
+    // Always returns 0 exit code as errors are handled by the service dispatcher.
 }
 
 fn run_service(_arguments: Vec<OsString>) -> Result<()> {
@@ -398,14 +400,21 @@ fn run_service(_arguments: Vec<OsString>) -> Result<()> {
                 process_id: None,
             })?;
 
-            runtime.block_on(app.run());
+            let program_completion_status = runtime.block_on(app.run());
 
             // Tell the system that service has stopped.
             status_handle.set_service_status(ServiceStatus {
                 service_type: SERVICE_TYPE,
                 current_state: ServiceState::Stopped,
                 controls_accepted: ServiceControlAccept::empty(),
-                exit_code: ServiceExitCode::Win32(NO_ERROR),
+                exit_code: {
+                    if program_completion_status.success() {
+                        ServiceExitCode::Win32(NO_ERROR)
+                    } else {
+                        // we didn't gracefully shutdown within grace period.
+                        ServiceExitCode::Win32(ERROR)
+                    }
+                },
                 checkpoint: 0,
                 wait_hint: Duration::default(),
                 process_id: None,