fix: terminate pgbouncer on compute suspend (#12153)

## Problem

PgBouncer does not terminate connections on a suspend:
https://github.com/neondatabase/cloud/issues/16282

## Summary of changes

1. Adds a pid file to store the pid of PgBouncer
2. Terminates connections on a compute suspend

---------

Co-authored-by: Alexey Kondratov <kondratov.aleksey@gmail.com>

compute_tools/src/bin/compute_ctl.rs

@@ -124,6 +124,10 @@ struct Cli {
     /// Interval in seconds for collecting installed extensions statistics
     #[arg(long, default_value = "3600")]
     pub installed_extensions_collection_interval: u64,
+
+    /// Run in development mode, skipping VM-specific operations like process termination
+    #[arg(long, action = clap::ArgAction::SetTrue)]
+    pub dev: bool,
 }
 
 impl Cli {
@@ -159,7 +163,7 @@ fn main() -> Result<()> {
         .build()?;
     let _rt_guard = runtime.enter();
 
-    runtime.block_on(init())?;
+    runtime.block_on(init(cli.dev))?;
 
     // enable core dumping for all child processes
     setrlimit(Resource::CORE, rlimit::INFINITY, rlimit::INFINITY)?;
@@ -198,13 +202,13 @@ fn main() -> Result<()> {
     deinit_and_exit(exit_code);
 }
 
-async fn init() -> Result<()> {
+async fn init(dev_mode: bool) -> Result<()> {
     init_tracing_and_logging(DEFAULT_LOG_LEVEL).await?;
 
     let mut signals = Signals::new([SIGINT, SIGTERM, SIGQUIT])?;
     thread::spawn(move || {
         for sig in signals.forever() {
-            handle_exit_signal(sig);
+            handle_exit_signal(sig, dev_mode);
         }
     });
 
@@ -263,9 +267,9 @@ fn deinit_and_exit(exit_code: Option<i32>) -> ! {
 /// When compute_ctl is killed, send also termination signal to sync-safekeepers
 /// to prevent leakage. TODO: it is better to convert compute_ctl to async and
 /// wait for termination which would be easy then.
-fn handle_exit_signal(sig: i32) {
+fn handle_exit_signal(sig: i32, dev_mode: bool) {
     info!("received {sig} termination signal");
-    forward_termination_signal();
+    forward_termination_signal(dev_mode);
     exit(1);
 }
 

compute_tools/src/compute.rs

@@ -35,6 +35,7 @@ use url::Url;
 use utils::id::{TenantId, TimelineId};
 use utils::lsn::Lsn;
 use utils::measured_stream::MeasuredReader;
+use utils::pid_file;
 
 use crate::configurator::launch_configurator;
 use crate::disk_quota::set_disk_quota;
@@ -44,6 +45,7 @@ use crate::lsn_lease::launch_lsn_lease_bg_task_for_static;
 use crate::metrics::COMPUTE_CTL_UP;
 use crate::monitor::launch_monitor;
 use crate::pg_helpers::*;
+use crate::pgbouncer::*;
 use crate::rsyslog::{
     PostgresLogsRsyslogConfig, configure_audit_rsyslog, configure_postgres_logs_export,
     launch_pgaudit_gc,
@@ -2246,12 +2248,68 @@ pub async fn installed_extensions(conf: tokio_postgres::Config) -> Result<()> {
     Ok(())
 }
 
-pub fn forward_termination_signal() {
+pub fn forward_termination_signal(dev_mode: bool) {
     let ss_pid = SYNC_SAFEKEEPERS_PID.load(Ordering::SeqCst);
     if ss_pid != 0 {
         let ss_pid = nix::unistd::Pid::from_raw(ss_pid as i32);
         kill(ss_pid, Signal::SIGTERM).ok();
     }
+
+    if !dev_mode {
+        info!("not in dev mode, terminating pgbouncer");
+
+        //  Terminate pgbouncer with SIGKILL
+        match pid_file::read(PGBOUNCER_PIDFILE.into()) {
+            Ok(pid_file::PidFileRead::LockedByOtherProcess(pid)) => {
+                info!("sending SIGKILL to pgbouncer process pid: {}", pid);
+                if let Err(e) = kill(pid, Signal::SIGKILL) {
+                    error!("failed to terminate pgbouncer: {}", e);
+                }
+            }
+            // pgbouncer does not lock the pid file, so we read and kill the process directly
+            Ok(pid_file::PidFileRead::NotHeldByAnyProcess(_)) => {
+                if let Ok(pid_str) = std::fs::read_to_string(PGBOUNCER_PIDFILE) {
+                    if let Ok(pid) = pid_str.trim().parse::<i32>() {
+                        info!(
+                            "sending SIGKILL to pgbouncer process pid: {} (from unlocked pid file)",
+                            pid
+                        );
+                        if let Err(e) = kill(Pid::from_raw(pid), Signal::SIGKILL) {
+                            error!("failed to terminate pgbouncer: {}", e);
+                        }
+                    }
+                } else {
+                    info!("pgbouncer pid file exists but process not running");
+                }
+            }
+            Ok(pid_file::PidFileRead::NotExist) => {
+                info!("pgbouncer pid file not found, process may not be running");
+            }
+            Err(e) => {
+                error!("error reading pgbouncer pid file: {}", e);
+            }
+        }
+    }
+
+    // Terminate local_proxy
+    match pid_file::read("/etc/local_proxy/pid".into()) {
+        Ok(pid_file::PidFileRead::LockedByOtherProcess(pid)) => {
+            info!("sending SIGTERM to local_proxy process pid: {}", pid);
+            if let Err(e) = kill(pid, Signal::SIGTERM) {
+                error!("failed to terminate local_proxy: {}", e);
+            }
+        }
+        Ok(pid_file::PidFileRead::NotHeldByAnyProcess(_)) => {
+            info!("local_proxy PID file exists but process not running");
+        }
+        Ok(pid_file::PidFileRead::NotExist) => {
+            info!("local_proxy PID file not found, process may not be running");
+        }
+        Err(e) => {
+            error!("error reading local_proxy PID file: {}", e);
+        }
+    }
+
     let pg_pid = PG_PID.load(Ordering::SeqCst);
     if pg_pid != 0 {
         let pg_pid = nix::unistd::Pid::from_raw(pg_pid as i32);

compute_tools/src/http/routes/terminate.rs

@@ -26,7 +26,7 @@ pub(in crate::http) async fn terminate(State(compute): State<Arc<ComputeNode>>)
         drop(state);
     }
 
-    forward_termination_signal();
+    forward_termination_signal(false);
     info!("sent signal and notified waiters");
 
     // Spawn a blocking thread to wait for compute to become Terminated.

compute_tools/src/lib.rs

@@ -22,6 +22,7 @@ mod migration;
 pub mod monitor;
 pub mod params;
 pub mod pg_helpers;
+pub mod pgbouncer;
 pub mod rsyslog;
 pub mod spec;
 mod spec_apply;

compute_tools/src/pgbouncer.rs

@@ -0,0 +1 @@
+pub const PGBOUNCER_PIDFILE: &str = "/tmp/pgbouncer.pid";