reload-vcl patch for config discards and safe stop

reload-vcl.patch

--- reload-vcl	2011-10-29 13:24:10.000000000 +0000
+++ /usr/share/varnish/reload-vcl	2016-12-11 09:51:08.696300339 +0000
@@ -1,9 +1,13 @@
 #!/bin/sh
-
+#
 # reload-varnish: Script to reload varnishd from VCL defined in
 # /etc/default/varnish.
 #
 # Stig Sandbeck Mathisen <ssm@debian.org>
+# Josh Enders <jenders@pinterest.com>
+
+# Environment
+TMPDIR="${TMPDIR:-/tmp}"
 
 # Settings
 defaults=/etc/default/varnish
@@ -12,74 +16,75 @@
 # Paths
 varnishadm=/usr/bin/varnishadm
 date=/bin/date
-tempfile=/bin/tempfile
+mktemp=/bin/mktemp
 
 # Messages
 # msg_no_varnishadm: varnishadm
 msg_no_varnishadm="Error: Cannot execute %s\n"
 msg_no_management="Management port disabled. \$DAEMON_OPTS must contain '-T hostname:port'\n"
+
 # msg_defaults_not_readable: defaults
 msg_defaults_not_readable="Error: %s is not readable\n"
-# msg_defaults_not_there: defaults
-msg_defaults_not_there="Error: %s does not exist\n"
+
+# msg_defaults_not_exist: defaults
+msg_defaults_not_exist="Error: %s does not exist\n"
 msg_no_vcl="Error: No VCL file used, nothing to reload\n"
 msg_usage="Usage: $0 [-h][-c][-q]\n\t-h\tdisplay help\n\t-q\tquiet\n\t-c\tcompile only, do not reload\n"
+
+# msg_discard_failed: vcl_last_label
+msg_discard_failed="Error: vcl.discard %s failed\n"
+
+# msg_discard_ok vcl_last_label
+msg_discard_ok="VCL %s discarded\n"
+
 # msg_compile_only: varnishadm, mgmt_interface, vcl_label
 msg_compile_only="To activate, run:\n\t%s -T %s \\\\\n\tvcl.use %s\n"
+
 # msg_compile_failed: vcl_label, vcl_file
 msg_compile_failed="Error: vcl.load %s %s failed"
+
 # msg_use_ok: vcl_label
 msg_use_ok="VCL reloaded, active label is %s\n"
+
 # msg_use_failed: vcl_label
 msg_use_failed="Error: vcl.use %s failed\n"
+
 # msg_secret_not_readable: secret
 msg_secret_not_readable="Error: Secret file %s is not readable\n"
-# msg_secret_not_there: secret
-msg_secret_not_there="Error: Secret file %s does not exist\n"
 
-# Generate a label, prefixed with the caller's username, from the
-# kernel random uuid generator, fallback to timestamp
-if [ -f /proc/sys/kernel/random/uuid ]
-then
-    uuid=$(cat /proc/sys/kernel/random/uuid)
-    vcl_label="${LOGNAME}${LOGNAME:+:}${uuid}"
-else
-    vcl_label="$($date +${LOGNAME}${LOGNAME:+:}%s.%N)"
-fi
+# msg_secret_not_exist: secret
+msg_secret_not_exist="Error: Secret file %s does not exist\n"
 
 # Load defaults file
-if [ -f "$defaults" ]
-then
-    if [ -r "$defaults" ]
-    then
-	. "$defaults"
+if [ -f "$defaults" ]; then
+    if [ -r "$defaults" ]; then
+        . "$defaults"
     else
-	printf >&2 "$msg_defaults_not_readable" $defaults
-	exit 1
+        printf "$msg_defaults_not_readable" "$defaults" >&2
+        exit 1
     fi
 else
-    printf >&2 "$msg_defaults_not_there" $defaults
+    printf "$msg_defaults_not_exist" "$defaults" >&2
     exit 1
 fi
 
 # parse command line arguments
-while getopts hcq flag
-do
-    case $flag in
-	h)
-	    printf >&2 "$msg_usage"
-	    exit 0
-	    ;;
-	c)
-	    compile_only=1
-	    ;;
-	q)
-	    quiet=1
-	    ;;
-	*)
-	    printf >&2 "$msg_usage\n"
-	    exit 1
-	    ;;
+while getopts hcq flag; do
+    case "$flag" in
+        h)
+            printf "$msg_usage" >&2
+            exit 0
+            ;;
+        c)
+            compile_only=1
+            ;;
+        q)
+            quiet=1
+            ;;
+        *)
+            printf "$msg_usage\n" >&2
+            exit 1
+            ;;
     esac
 done
 
@@ -87,87 +92,99 @@
 # Extract the -f and the -T option, and (try to) ensure that the
 # management interface is on the form hostname:address.
 OPTIND=1
-while getopts a:b:CdFf:g:h:i:l:M:n:P:p:S:s:T:t:u:Vw: flag $DAEMON_OPTS
-do
-    case $flag in
-		f)
-			if [ -f "$OPTARG" ]; then
-				vcl_file="$OPTARG"
-			fi
-			;;
-		T)
-			if [ -n "$OPTARG" -a "$OPTARG" != "${OPTARG%%:*}" ]
-			then
-				mgmt_interface="$OPTARG"
-			fi
-			;;
-		S)
-			secret="$OPTARG"
-			;;
+
+while getopts a:b:CdFf:g:h:i:l:M:n:P:p:S:s:T:t:u:Vw: flag $DAEMON_OPTS; do
+    case "$flag" in
+        f)
+            if [ -f "$OPTARG" ]; then
+                vcl_file="$OPTARG"
+            fi
+            ;;
+        T)
+            if [ -n "$OPTARG" -a "$OPTARG" != "${OPTARG%%:*}" ]; then
+                mgmt_interface="$OPTARG"
+            fi
+            ;;
+        S)
+            secret="$OPTARG"
+            ;;
     esac
 done
 
 
 # Sanity checks
-if [ ! -x "$varnishadm" ]
-then
-    printf >&2 "$msg_no_varnishadm" $varnishadm
+if [ ! -x "$varnishadm" ]; then
+    printf "$msg_no_varnishadm" "$varnishadm" >&2
     exit 1
 fi
 
-if [ -z "$mgmt_interface" ]
-then
-    printf >&2 "$msg_no_management"
+if [ -z "$mgmt_interface" ]; then
+    printf "$msg_no_management" >&2
     exit 1
 fi
 
-if [ -z "$vcl_file" ]
-then
-    printf >&2 "$msg_no_vcl"
+if [ -z "$vcl_file" ]; then
+    printf "$msg_no_vcl" >&2
     exit 1
 fi
 
 # Check secret file
-if [ -f "$secret" ]
-	then
-	if [ ! -r "$secret" ]
-	then
-		printf >&2 "$msg_secret_not_readable" $secret
-		exit 1
-	fi
+if [ -f "$secret" ]; then
+    if [ ! -r "$secret" ]; then
+        printf "$msg_secret_not_readable" "$secret" >&2
+        exit 1
+    fi
 else
-	printf >&2 "$msg_secret_not_there" $secret
-	exit 1
+    printf "$msg_secret_not_exist" "$secret" >&2
+    exit 1
 fi
 
-logfile=$($tempfile -n /tmp/$vcl_label)
+# Generate a name for the config
+count=$("$varnishadm" -T "$mgmt_interface" -S "$secret" vcl.list | awk '{ print $3 }' | sort -n | tail -1)
+
+# The initial config is conveniently called, "boot"
+if [ "$count" = 'boot' ]; then
+    count=0
+fi
 
-# Compile and maybe reload
-if $varnishadm -T $mgmt_interface -S ${secret} vcl.load $vcl_label $vcl_file
-then
-    if [ -n "$compile_only" ]
-    then
-	printf "$msg_compile_only" $varnishadm $mgmt_interface $vcl_label
+vcl_label="$((${count}+1))"
+logfile=$("$mktemp" "$TMPDIR/${0##*/}-XXXXXXXXXX")
+
+# Compile and maybe reload and discard
+if "$varnishadm" -T "$mgmt_interface" -S "$secret" vcl.load "$vcl_label" "$vcl_file" >> "$logfile" 2>&1; then
+    if [ -n "$compile_only" ]; then
+        printf "$msg_compile_only" "$varnishadm" "$mgmt_interface" "$vcl_label" >> "$logfile" 2>&1
     else
-	if $varnishadm -T $mgmt_interface -S ${secret} vcl.use $vcl_label
-	then
-	    printf "$msg_use_ok" $vcl_label
-	else
-	    printf "$msg_use_failed" $vcl_label
-	    exitstatus=1
-	fi
+        if "$varnishadm" -T "$mgmt_interface" -S "$secret" vcl.use "$vcl_label" >> "$logfile" 2>&1; then
+            if [ $count -ge $HOLDCOUNT ]; then
+                vcl_last_label=$((${count}-${HOLDCOUNT}))
+
+                if [ "$vcl_last_label" = 0 ]; then
+                    vcl_last_label='boot'
+                fi
+
+                if "$varnishadm" -T "$mgmt_interface" -S "$secret" vcl.discard "$vcl_last_label" >> "$logfile" 2>&1; then
+                    printf "$msg_discard_ok" "$vcl_last_label" >> "$logfile"
+                else
+                    printf "$msg_discard_failed" "$vcl_last_label" >> "$logfile"
+                    exitstatus=1
+                fi
+            fi
+            printf "$msg_use_ok" "$vcl_label" >> "$logfile"
+        else
+            printf "$msg_use_failed" "$vcl_label" >> "$logfile"
+            exitstatus=1
+        fi
     fi
 else
-    printf "$msg_compile_failed" $vcl_label $vcl_file
+    printf "$msg_compile_failed" "$vcl_label" "$vcl_file" >> "$logfile"
     exitstatus=1
-fi | grep -v "^$" > $logfile
+fi
 
-# Blather
-if [ -z "${quiet}" -o -n "$exitstatus" ]
-then
-    cat >&2 $logfile
+if [ -z "${quiet}" -o -n "$exitstatus" ]; then
+    cat "$logfile" >&2
 fi
 
 # Cleanup
-rm -f $logfile
+rm -f "${logfile:?}"
 exit $exitstatus