12461: Avoid race bug in Rails file cache.

[arvados.git] / services / ws / event_source.go

diff --git a/services/ws/event_source.go b/services/ws/event_source.go
index fe1876cc2788e9ccaaaff2f1f21d3116b3974b38..9acfca50e4db639c04dda22a7040d2e91a1c1c4c 100644 (file)
--- a/services/ws/event_source.go
+++ b/services/ws/event_source.go
@@ -1,3 +1,7 @@
+// Copyright (C) The Arvados Authors. All rights reserved.
+//
+// SPDX-License-Identifier: AGPL-3.0
+
 package main
 
 import (
@@ -29,8 +33,9 @@ func (c pgConfig) ConnectionString() string {
 }
 
 type pgEventSource struct {
-       DataSource string
-       QueueSize  int
+       DataSource   string
+       MaxOpenConns int
+       QueueSize    int
 
        db         *sql.DB
        pqListener *pq.Listener
@@ -115,6 +120,10 @@ func (ps *pgEventSource) Run() {
                logger(nil).WithError(err).Error("sql.Open failed")
                return
        }
+       if ps.MaxOpenConns <= 0 {
+               logger(nil).Warn("no database connection limit configured -- consider setting PostgresPool>0 in arvados-ws configuration file")
+       }
+       db.SetMaxOpenConns(ps.MaxOpenConns)
        if err = db.Ping(); err != nil {
                logger(nil).WithError(err).Error("db.Ping failed")
                return
@@ -234,9 +243,17 @@ func (ps *pgEventSource) NewSink() eventSink {
 }
 
 func (ps *pgEventSource) DB() *sql.DB {
+       ps.WaitReady()
        return ps.db
 }
 
+func (ps *pgEventSource) DBHealth() error {
+       ctx, cancel := context.WithDeadline(context.Background(), time.Now().Add(time.Second))
+       defer cancel()
+       var i int
+       return ps.db.QueryRowContext(ctx, "SELECT 1").Scan(&i)
+}
+
 func (ps *pgEventSource) DebugStatus() interface{} {
        ps.mtx.Lock()
        defer ps.mtx.Unlock()
@@ -252,6 +269,7 @@ func (ps *pgEventSource) DebugStatus() interface{} {
                "QueueDelay":   stats.Duration(ps.lastQDelay),
                "Sinks":        len(ps.sinks),
                "SinksBlocked": blocked,
+               "DBStats":      ps.db.Stats(),
        }
 }
 
@@ -270,7 +288,7 @@ func (sink *pgEventSink) Stop() {
                // Ensure this sink cannot fill up and block the
                // server-side queue (which otherwise could in turn
                // block our mtx.Lock() here)
-               for _ = range sink.channel {
+               for range sink.channel {
                }
        }()
        sink.source.mtx.Lock()