From de959153a857ba9394cc5841a716da8abbe24a59 Mon Sep 17 00:00:00 2001
From: Ross Jones <ross@register-dynamics.co.uk>
Date: Wed, 3 May 2023 09:24:56 +0100
Subject: [PATCH] Allow disabling of violation logging

When some tasks take too long, a violation is logged using the default
logging package.  We don't want to add more dependencies to this
package, but we also don't want to log these violations in every
circumstance (e.g. when used in a CLI).

Allows the caller enabled a tracing mutex to specify they want to
Disable violation logging.
---
 lock.go    | 15 ++++++++-------
 lock_rw.go | 15 ++++++++-------
 opts.go    | 11 +++++++----
 tracers.go |  3 +++
 4 files changed, 26 insertions(+), 18 deletions(-)

diff --git a/lock.go b/lock.go
index 10493d7..f8b9546 100644
--- a/lock.go
+++ b/lock.go
@@ -9,11 +9,12 @@ type Mutex struct {
 	lock sync.Mutex
 
 	// internal trace fields
-	threshold        atomic.Uint64 // 0 when disabled, else threshold in nanoseconds
-	beginAwaitLock   atomic.Uint64 // start time in unix nanoseconds from start waiting for lock
-	beginAwaitUnlock atomic.Uint64 // start time in unix nanoseconds from start waiting for unlock
-	lockObtained     atomic.Uint64 // once we've entered the lock in unix nanoseconds
-	id               []byte        // if set this will be printed as string
+	threshold           atomic.Uint64 // 0 when disabled, else threshold in nanoseconds
+	beginAwaitLock      atomic.Uint64 // start time in unix nanoseconds from start waiting for lock
+	beginAwaitUnlock    atomic.Uint64 // start time in unix nanoseconds from start waiting for unlock
+	lockObtained        atomic.Uint64 // once we've entered the lock in unix nanoseconds
+	id                  []byte        // if set this will be printed as string
+	DisableViolationLog bool
 }
 
 func (m *Mutex) Lock() {
@@ -66,7 +67,7 @@ func (m *Mutex) traceEndAwaitLock(threshold Threshold) {
 		// check for no overflow
 		took = ts - start
 	}
-	if took >= uint64(threshold) {
+	if took >= uint64(threshold) && !m.DisableViolationLog {
 		logViolation(Id(m.id), threshold, Actual(took), Now(ts), ViolationLock)
 	}
 }
@@ -86,7 +87,7 @@ func (m *Mutex) traceEndAwaitUnlock(threshold Threshold) {
 		took = ts - lockObtained
 	}
 
-	if took >= uint64(threshold) && lockObtained > 0 {
+	if took >= uint64(threshold) && lockObtained > 0 && !m.DisableViolationLog {
 		// lockObtained = 0 when the tracer is enabled half way
 		logViolation(Id(m.id), threshold, Actual(took), Now(ts), ViolationCritical)
 	}
diff --git a/lock_rw.go b/lock_rw.go
index cfa32af..9c1d69b 100644
--- a/lock_rw.go
+++ b/lock_rw.go
@@ -9,11 +9,12 @@ type RWMutex struct {
 	lock sync.RWMutex
 
 	// internal trace fields
-	threshold        atomic.Uint64 // 0 when disabled, else threshold in nanoseconds
-	beginAwaitLock   atomic.Uint64 // start time in unix nanoseconds from start waiting for lock
-	beginAwaitUnlock atomic.Uint64 // start time in unix nanoseconds from start waiting for unlock
-	lockObtained     atomic.Uint64 // once we've entered the lock in unix nanoseconds
-	id               []byte        // if set this will be printed as string
+	threshold           atomic.Uint64 // 0 when disabled, else threshold in nanoseconds
+	beginAwaitLock      atomic.Uint64 // start time in unix nanoseconds from start waiting for lock
+	beginAwaitUnlock    atomic.Uint64 // start time in unix nanoseconds from start waiting for unlock
+	lockObtained        atomic.Uint64 // once we've entered the lock in unix nanoseconds
+	id                  []byte        // if set this will be printed as string
+	DisableViolationLog bool
 }
 
 func (m *RWMutex) Lock() {
@@ -94,7 +95,7 @@ func (m *RWMutex) traceEndAwaitLock(threshold Threshold) {
 		// check for no overflow
 		took = ts - start
 	}
-	if took >= uint64(threshold) {
+	if took >= uint64(threshold) && !m.DisableViolationLog {
 		logViolation(Id(m.id), threshold, Actual(took), Now(ts), ViolationLock)
 	}
 }
@@ -114,7 +115,7 @@ func (m *RWMutex) traceEndAwaitUnlock(threshold Threshold) {
 		took = ts - lockObtained
 	}
 
-	if took >= uint64(threshold) && lockObtained > 0 {
+	if took >= uint64(threshold) && lockObtained > 0 && !m.DisableViolationLog {
 		// lockObtained = 0 when the tracer is enabled half way
 		logViolation(Id(m.id), threshold, Actual(took), Now(ts), ViolationCritical)
 	}
diff --git a/opts.go b/opts.go
index 7ec2e08..905a025 100644
--- a/opts.go
+++ b/opts.go
@@ -1,9 +1,12 @@
 package muxtracer
 
-import "time"
+import (
+	"time"
+)
 
 type Opts struct {
-	Threshold time.Duration
-	Enabled   bool
-	Id        string // use with
+	Threshold           time.Duration
+	Enabled             bool
+	Id                  string // use with
+	DisableViolationLog bool
 }
diff --git a/tracers.go b/tracers.go
index 00e3230..0476a16 100644
--- a/tracers.go
+++ b/tracers.go
@@ -10,6 +10,7 @@ func logViolation(id Id, threshold Threshold, actual Actual, now Now, violationT
 	if id != nil {
 		idStr = string(id) + " "
 	}
+
 	log.Printf("%sviolation %s section took %s %d (threshold %s)", idStr, violationType.String(), time.Duration(actual).String(), actual, time.Duration(threshold).String())
 }
 
@@ -32,6 +33,7 @@ func (m *Mutex) EnableTracerWithOpts(o Opts) {
 		m.id = []byte(o.Id)
 	}
 	m.threshold.Store(uint64(o.Threshold.Nanoseconds()))
+	m.DisableViolationLog = o.DisableViolationLog
 }
 
 func (m *Mutex) DisableTracer() {
@@ -47,6 +49,7 @@ func (m *RWMutex) EnableTracerWithOpts(o Opts) {
 		m.id = []byte(o.Id)
 	}
 	m.threshold.Store(uint64(o.Threshold.Nanoseconds()))
+	m.DisableViolationLog = o.DisableViolationLog
 }
 
 func (m *RWMutex) DisableTracer() {