From 6822c833be9c9a19cd6c2f43d3dc001bdf1f64cb Mon Sep 17 00:00:00 2001
From: df <fieldhouse@gmx.net>
Date: Sun, 18 Oct 2020 14:53:23 +0000
Subject: [PATCH 1/5] Retry access in case the settings database is locked

Create `settings::_safer_query` class proc to allow 5 tries with 1s delay; use it for `_nval_setting` and `_tval_setting` methods
---
 webif/lib/settings.class | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/webif/lib/settings.class b/webif/lib/settings.class
index 05361dd..4251fa6 100644
--- a/webif/lib/settings.class
+++ b/webif/lib/settings.class
@@ -54,6 +54,21 @@ class settings {
 	rtschedule	0
 }
 
+proc {settings _safer_query} { queryText args } {
+	global settingsdb
+	# allow 5 (too many?) tries with 1s (too long?) delay to get access
+	for {set lockCnt 5} {} {sleep 1} {
+		try {
+			$settingsdb query $queryText {*}$args
+		} on error {msg opts} {
+			if {[string first "database is locked" $msg] >= 0 && [incr lockCnt -1] > 0} {
+				continue
+			}
+			return {*}$opts $msg
+		}
+	}
+}
+
 settings method hostname {{name ""}} {
 	if {$name == ""} {
 		# Get
@@ -104,11 +119,10 @@ settings method smtp_server {{server ""}} {
 }
 
 settings method _nval_setting {name {val -1}} {
-	global settingsdb
 
 	if {$val == -1} {
 		# Get
-		set res [$settingsdb query "
+		set res [settings::_safer_query "
 			select nval from settings
 			where name = '$name'
 		"]
@@ -118,7 +132,7 @@ settings method _nval_setting {name {val -1}} {
 		return 0
 	} else {
 		# Set
-		$settingsdb query "
+		settings::_safer_query "
 			replace into settings(name,nval)
 			values('$name', $val)
 		"
@@ -127,11 +141,10 @@ settings method _nval_setting {name {val -1}} {
 }
 
 settings method _tval_setting {name {val -1} {def 0}} {
-	global settingsdb
 
 	if {$val eq "-1"} {
 		# Get
-		set res [$settingsdb query "
+		set res [settings::_safer_query "
 			select tval from settings
 			where name = '$name'
 		"]
@@ -141,7 +154,7 @@ settings method _tval_setting {name {val -1} {def 0}} {
 		return $def
 	} else {
 		# Set
-		$settingsdb query "
+		settings::_safer_query "
 			replace into settings(name,tval)
 			values('$name', '%s')
 		" $val

From 9b64128c92198764295344e8a48f50d8caf7bfca Mon Sep 17 00:00:00 2001
From: df <fieldhouse@gmx.net>
Date: Sun, 18 Oct 2020 15:48:07 +0000
Subject: [PATCH 2/5] Retry access in case the settings database is locked

---
 webif/lib/settings.class | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/webif/lib/settings.class b/webif/lib/settings.class
index 4251fa6..5b56185 100644
--- a/webif/lib/settings.class
+++ b/webif/lib/settings.class
@@ -56,10 +56,11 @@ class settings {
 
 proc {settings _safer_query} { queryText args } {
 	global settingsdb
+
 	# allow 5 (too many?) tries with 1s (too long?) delay to get access
-	for {set lockCnt 5} {} {sleep 1} {
+	for {set lockCnt 5} {true} {sleep 1} {
 		try {
-			$settingsdb query $queryText {*}$args
+			return [$settingsdb query $queryText {*}$arg]
 		} on error {msg opts} {
 			if {[string first "database is locked" $msg] >= 0 && [incr lockCnt -1] > 0} {
 				continue
@@ -122,7 +123,7 @@ settings method _nval_setting {name {val -1}} {
 
 	if {$val == -1} {
 		# Get
-		set res [settings::_safer_query "
+		set res [settings _safer_query "
 			select nval from settings
 			where name = '$name'
 		"]
@@ -132,7 +133,7 @@ settings method _nval_setting {name {val -1}} {
 		return 0
 	} else {
 		# Set
-		settings::_safer_query "
+		settings _safer_query "
 			replace into settings(name,nval)
 			values('$name', $val)
 		"
@@ -144,7 +145,7 @@ settings method _tval_setting {name {val -1} {def 0}} {
 
 	if {$val eq "-1"} {
 		# Get
-		set res [settings::_safer_query "
+		set res [settings _safer_query "
 			select tval from settings
 			where name = '$name'
 		"]
@@ -154,7 +155,7 @@ settings method _tval_setting {name {val -1} {def 0}} {
 		return $def
 	} else {
 		# Set
-		settings::_safer_query "
+		settings _safer_query "
 			replace into settings(name,tval)
 			values('$name', '%s')
 		" $val

From 7bb66de5f2b54fb17bbf1aaaee41e00fcef2bb42 Mon Sep 17 00:00:00 2001
From: df <fieldhouse@gmx.net>
Date: Sun, 18 Oct 2020 19:19:26 +0000
Subject: [PATCH 3/5] Raise the "database locked" error from caller context

---
 webif/lib/settings.class | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/webif/lib/settings.class b/webif/lib/settings.class
index 5b56185..fa74b11 100644
--- a/webif/lib/settings.class
+++ b/webif/lib/settings.class
@@ -62,8 +62,14 @@ proc {settings _safer_query} { queryText args } {
 		try {
 			return [$settingsdb query $queryText {*}$arg]
 		} on error {msg opts} {
-			if {[string first "database is locked" $msg] >= 0 && [incr lockCnt -1] > 0} {
-				continue
+			if {[string first "database is locked" $msg] >= 0} {
+				if {[incr lockCnt -1] > 0} {
+					continue
+				} else {
+					# raise error from caller
+					set msg "Persistently unable to access Settings: database locked"
+					incr opts(-level)
+				}
 			}
 			return {*}$opts $msg
 		}

From 3e9ecc8a7ceab41ce383114b9c3d856251391a98 Mon Sep 17 00:00:00 2001
From: df <fieldhouse@gmx.net>
Date: Mon, 19 Oct 2020 11:44:53 +0000
Subject: [PATCH 4/5] Change to 0.5s, doubling for 4 tries

---
 webif/lib/settings.class | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/webif/lib/settings.class b/webif/lib/settings.class
index fa74b11..ac7c6d5 100644
--- a/webif/lib/settings.class
+++ b/webif/lib/settings.class
@@ -57,8 +57,8 @@ class settings {
 proc {settings _safer_query} { queryText args } {
 	global settingsdb
 
-	# allow 5 (too many?) tries with 1s (too long?) delay to get access
-	for {set lockCnt 5} {true} {sleep 1} {
+	# allow 4 tries from 0.5s delay, doubling, to get access
+	for {set lockCnt 4; set delay 0.5} {true} {sleep $delay; set delay $(2*$delay)} {
 		try {
 			return [$settingsdb query $queryText {*}$arg]
 		} on error {msg opts} {

From 7c600be77e3aa04123cab25e1453c2eab980d496 Mon Sep 17 00:00:00 2001
From: df <fieldhouse@gmx.net>
Date: Tue, 20 Oct 2020 18:34:19 +0000
Subject: [PATCH 5/5] Retry access in case the settings database is locked

---
 webif/lib/settings.class | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/webif/lib/settings.class b/webif/lib/settings.class
index ac7c6d5..f5edda2 100644
--- a/webif/lib/settings.class
+++ b/webif/lib/settings.class
@@ -60,7 +60,7 @@ proc {settings _safer_query} { queryText args } {
 	# allow 4 tries from 0.5s delay, doubling, to get access
 	for {set lockCnt 4; set delay 0.5} {true} {sleep $delay; set delay $(2*$delay)} {
 		try {
-			return [$settingsdb query $queryText {*}$arg]
+			return [$settingsdb query $queryText {*}$args]
 		} on error {msg opts} {
 			if {[string first "database is locked" $msg] >= 0} {
 				if {[incr lockCnt -1] > 0} {