From 5cb900bfad0c364bd25cede9d9bb8977e8f2ff90 Mon Sep 17 00:00:00 2001
From: nikitapogromsky <129324283+nikitapogromsky@users.noreply.github.com>
Date: Mon, 7 Sep 2026 12:03:39 +0300
Subject: [PATCH 1/2] logger: make AddSystemTarget idempotent
Subscribe re-registered the console target on every console-log subscription, producing duplicate minio_logger_webhook_* series on each /minio/metrics/v3 scrape. Fixes #150
Signed-off-by: nikitapogromsky <129324283+nikitapogromsky@users.noreply.github.com>
---
internal/logger/targets.go | 36 ++++++++++-
internal/logger/targets_test.go | 105 ++++++++++++++++++++++++++++++++
2 files changed, 138 insertions(+), 3 deletions(-)
create mode 100644 internal/logger/targets_test.go
diff --git a/internal/logger/targets.go b/internal/logger/targets.go
index 774237e1d..9fcca6b14 100644
--- a/internal/logger/targets.go
+++ b/internal/logger/targets.go
@@ -59,11 +59,35 @@ func (tl *targetsList) get() []Target {
return tl.list
}
-func (tl *targetsList) add(t Target) {
+// contains reports whether t is already registered.
+func (tl *targetsList) contains(t Target) bool {
+ tl.mu.RLock()
+ defer tl.mu.RUnlock()
+
+ return tl.indexOf(t) >= 0
+}
+
+// addIfAbsent appends t unless it is already registered.
+// Returns true if t was added.
+func (tl *targetsList) addIfAbsent(t Target) bool {
tl.mu.Lock()
defer tl.mu.Unlock()
+ if tl.indexOf(t) >= 0 {
+ return false
+ }
tl.list = append(tl.list, t)
+ return true
+}
+
+// indexOf must be called with tl.mu held.
+func (tl *targetsList) indexOf(t Target) int {
+ for i, existing := range tl.list {
+ if existing == t {
+ return i
+ }
+ }
+ return -1
}
func (tl *targetsList) set(tgts []Target) {
@@ -125,8 +149,14 @@ func CurrentStats() map[string]types.TargetStats {
}
// AddSystemTarget adds a new logger target to the
-// list of enabled loggers
+// list of enabled loggers. Adding a target that is already
+// registered is a no-op, so callers may safely re-register
+// long-lived targets such as the console logger.
func AddSystemTarget(ctx context.Context, t Target) error {
+ if systemTargets.contains(t) {
+ return nil
+ }
+
if err := t.Init(ctx); err != nil {
return err
}
@@ -137,7 +167,7 @@ func AddSystemTarget(ctx context.Context, t Target) error {
}
}
- systemTargets.add(t)
+ systemTargets.addIfAbsent(t)
return nil
}
diff --git a/internal/logger/targets_test.go b/internal/logger/targets_test.go
new file mode 100644
index 000000000..5552eb734
--- /dev/null
+++ b/internal/logger/targets_test.go
@@ -0,0 +1,105 @@
+// Copyright (c) 2015-2026 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program 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 Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program. If not, see .
+
+package logger
+
+import (
+ "context"
+ "sync"
+ "sync/atomic"
+ "testing"
+
+ types "github.com/minio/minio/internal/logger/target/loggertypes"
+)
+
+// fakeTarget is a minimal Target used to exercise the registry.
+type fakeTarget struct {
+ name string
+ kind types.TargetType
+ inits atomic.Int32
+}
+
+func (f *fakeTarget) String() string { return f.name }
+func (f *fakeTarget) Endpoint() string { return "" }
+func (f *fakeTarget) Stats() types.TargetStats { return types.TargetStats{} }
+func (f *fakeTarget) Init(context.Context) error { f.inits.Add(1); return nil }
+func (f *fakeTarget) IsOnline(context.Context) bool { return true }
+func (f *fakeTarget) Cancel() {}
+func (f *fakeTarget) Send(context.Context, any) error { return nil }
+func (f *fakeTarget) Type() types.TargetType { return f.kind }
+
+// swapSystemTargets isolates the package-level registry for a test.
+func swapSystemTargets(t *testing.T) {
+ t.Helper()
+ prevTargets, prevConsole := systemTargets, consoleTgt
+ systemTargets, consoleTgt = newTargetsList(), nil
+ t.Cleanup(func() {
+ systemTargets, consoleTgt = prevTargets, prevConsole
+ })
+}
+
+// AddSystemTarget must not register the same target twice: the console
+// logger is re-added on every console-log subscription, and duplicates
+// surface as identical series in the /logger/webhook metrics collector.
+func TestAddSystemTargetIdempotent(t *testing.T) {
+ swapSystemTargets(t)
+ ctx := context.Background()
+
+ console := &fakeTarget{name: "console+http", kind: types.TargetConsole}
+ for range 3 {
+ if err := AddSystemTarget(ctx, console); err != nil {
+ t.Fatalf("AddSystemTarget: %v", err)
+ }
+ }
+ if got := len(SystemTargets()); got != 1 {
+ t.Fatalf("expected 1 system target after repeated add, got %d", got)
+ }
+ if got := console.inits.Load(); got != 1 {
+ t.Fatalf("expected Init to run once, ran %d times", got)
+ }
+ if consoleTgt != console {
+ t.Fatalf("consoleTgt not set to the console target")
+ }
+
+ other := &fakeTarget{name: "other", kind: types.TargetHTTP}
+ if err := AddSystemTarget(ctx, other); err != nil {
+ t.Fatalf("AddSystemTarget: %v", err)
+ }
+ if got := len(SystemTargets()); got != 2 {
+ t.Fatalf("expected 2 distinct system targets, got %d", got)
+ }
+}
+
+func TestAddSystemTargetConcurrent(t *testing.T) {
+ swapSystemTargets(t)
+ ctx := context.Background()
+
+ console := &fakeTarget{name: "console+http", kind: types.TargetConsole}
+ var wg sync.WaitGroup
+ for range 32 {
+ wg.Add(1)
+ go func() {
+ defer wg.Done()
+ _ = AddSystemTarget(ctx, console)
+ }()
+ }
+ wg.Wait()
+
+ if got := len(SystemTargets()); got != 1 {
+ t.Fatalf("expected 1 system target after concurrent adds, got %d", got)
+ }
+}
From 079ebb19261d5649074e5b1d275a89f721d7cd37 Mon Sep 17 00:00:00 2001
From: Feng Ruohang
Date: Tue, 8 Sep 2026 12:58:21 +0800
Subject: [PATCH 2/2] fix: serialize logger initialization and publish the
console target safely
Signed-off-by: Feng Ruohang
---
internal/logger/logger.go | 8 ++---
internal/logger/targets.go | 15 +++++---
internal/logger/targets_test.go | 64 ++++++++++++++++++++++++++++-----
3 files changed, 69 insertions(+), 18 deletions(-)
diff --git a/internal/logger/logger.go b/internal/logger/logger.go
index 09573ab49..335ce88fd 100644
--- a/internal/logger/logger.go
+++ b/internal/logger/logger.go
@@ -395,9 +395,9 @@ func consoleLogIf(ctx context.Context, subsystem string, err error, errKind ...a
if err == nil {
return
}
- if consoleTgt != nil {
+ if console := consoleTgt.Load(); console != nil {
entry := errToEntry(ctx, subsystem, err, errKind...)
- consoleTgt.Send(ctx, entry)
+ (*console).Send(ctx, entry)
}
}
@@ -423,8 +423,8 @@ func sendLog(ctx context.Context, entry log.Entry) {
// Iterate over all logger targets to send the log entry
for _, t := range systemTgts {
if err := t.Send(ctx, entry); err != nil {
- if consoleTgt != nil { // Sending to the console never fails
- consoleTgt.Send(ctx, errToEntry(ctx, "logging", fmt.Errorf("unable to send log event to Logger target (%s): %v", t.String(), err), entry.Level))
+ if console := consoleTgt.Load(); console != nil { // Sending to the console never fails
+ (*console).Send(ctx, errToEntry(ctx, "logging", fmt.Errorf("unable to send log event to Logger target (%s): %v", t.String(), err), entry.Level))
}
}
}
diff --git a/internal/logger/targets.go b/internal/logger/targets.go
index 9fcca6b14..0b2d20525 100644
--- a/internal/logger/targets.go
+++ b/internal/logger/targets.go
@@ -22,6 +22,7 @@ import (
"fmt"
"strings"
"sync"
+ "sync/atomic"
"github.com/minio/minio/internal/logger/target/http"
"github.com/minio/minio/internal/logger/target/kafka"
@@ -106,7 +107,10 @@ var (
auditTargets = newTargetsList()
// This is always set represent /dev/console target
- consoleTgt Target
+ consoleTgt atomic.Pointer[Target]
+
+ // Init may emit logs, so serialize registration without holding the list lock.
+ systemTargetInitMu sync.Mutex
)
// SystemTargets returns active targets.
@@ -153,6 +157,9 @@ func CurrentStats() map[string]types.TargetStats {
// registered is a no-op, so callers may safely re-register
// long-lived targets such as the console logger.
func AddSystemTarget(ctx context.Context, t Target) error {
+ systemTargetInitMu.Lock()
+ defer systemTargetInitMu.Unlock()
+
if systemTargets.contains(t) {
return nil
}
@@ -161,10 +168,8 @@ func AddSystemTarget(ctx context.Context, t Target) error {
return err
}
- if consoleTgt == nil {
- if t.Type() == types.TargetConsole {
- consoleTgt = t
- }
+ if t.Type() == types.TargetConsole {
+ consoleTgt.CompareAndSwap(nil, &t)
}
systemTargets.addIfAbsent(t)
diff --git a/internal/logger/targets_test.go b/internal/logger/targets_test.go
index 5552eb734..e1075df86 100644
--- a/internal/logger/targets_test.go
+++ b/internal/logger/targets_test.go
@@ -19,6 +19,7 @@ package logger
import (
"context"
+ "errors"
"sync"
"sync/atomic"
"testing"
@@ -31,12 +32,19 @@ type fakeTarget struct {
name string
kind types.TargetType
inits atomic.Int32
+ init func() error
}
-func (f *fakeTarget) String() string { return f.name }
-func (f *fakeTarget) Endpoint() string { return "" }
-func (f *fakeTarget) Stats() types.TargetStats { return types.TargetStats{} }
-func (f *fakeTarget) Init(context.Context) error { f.inits.Add(1); return nil }
+func (f *fakeTarget) String() string { return f.name }
+func (f *fakeTarget) Endpoint() string { return "" }
+func (f *fakeTarget) Stats() types.TargetStats { return types.TargetStats{} }
+func (f *fakeTarget) Init(context.Context) error {
+ f.inits.Add(1)
+ if f.init != nil {
+ return f.init()
+ }
+ return nil
+}
func (f *fakeTarget) IsOnline(context.Context) bool { return true }
func (f *fakeTarget) Cancel() {}
func (f *fakeTarget) Send(context.Context, any) error { return nil }
@@ -45,10 +53,12 @@ func (f *fakeTarget) Type() types.TargetType { return f.kind }
// swapSystemTargets isolates the package-level registry for a test.
func swapSystemTargets(t *testing.T) {
t.Helper()
- prevTargets, prevConsole := systemTargets, consoleTgt
- systemTargets, consoleTgt = newTargetsList(), nil
+ prevTargets, prevConsole := systemTargets, consoleTgt.Load()
+ systemTargets = newTargetsList()
+ consoleTgt.Store(nil)
t.Cleanup(func() {
- systemTargets, consoleTgt = prevTargets, prevConsole
+ systemTargets = prevTargets
+ consoleTgt.Store(prevConsole)
})
}
@@ -71,7 +81,7 @@ func TestAddSystemTargetIdempotent(t *testing.T) {
if got := console.inits.Load(); got != 1 {
t.Fatalf("expected Init to run once, ran %d times", got)
}
- if consoleTgt != console {
+ if got := consoleTgt.Load(); got == nil || *got != console {
t.Fatalf("consoleTgt not set to the console target")
}
@@ -89,17 +99,53 @@ func TestAddSystemTargetConcurrent(t *testing.T) {
ctx := context.Background()
console := &fakeTarget{name: "console+http", kind: types.TargetConsole}
+ console.init = func() error {
+ // Initialization is allowed to inspect or write to the existing logger.
+ _ = SystemTargets()
+ consoleLogIf(ctx, "test", errors.New("initializing logger"))
+ return nil
+ }
var wg sync.WaitGroup
+ start := make(chan struct{})
for range 32 {
wg.Add(1)
go func() {
defer wg.Done()
- _ = AddSystemTarget(ctx, console)
+ <-start
+ if err := AddSystemTarget(ctx, console); err != nil {
+ t.Errorf("AddSystemTarget: %v", err)
+ }
+ consoleLogIf(ctx, "test", errors.New("concurrent logger"))
}()
}
+ close(start)
wg.Wait()
if got := len(SystemTargets()); got != 1 {
t.Fatalf("expected 1 system target after concurrent adds, got %d", got)
}
+ if got := console.inits.Load(); got != 1 {
+ t.Fatalf("expected one concurrent initialization, got %d", got)
+ }
+}
+
+func TestAddSystemTargetRetriesFailedInit(t *testing.T) {
+ swapSystemTargets(t)
+ ctx := context.Background()
+ initErr := errors.New("target unavailable")
+ target := &fakeTarget{name: "console", kind: types.TargetConsole}
+ target.init = func() error { return initErr }
+ if err := AddSystemTarget(ctx, target); !errors.Is(err, initErr) {
+ t.Fatalf("expected initialization error, got %v", err)
+ }
+ if len(SystemTargets()) != 0 || consoleTgt.Load() != nil {
+ t.Fatal("failed initialization published a target")
+ }
+ target.init = nil
+ if err := AddSystemTarget(ctx, target); err != nil {
+ t.Fatal(err)
+ }
+ if got := len(SystemTargets()); got != 1 || target.inits.Load() != 2 {
+ t.Fatalf("retry: targets=%d, initializations=%d", got, target.inits.Load())
+ }
}