Script to purge varnish cache by URL, by regexp or all of it (for Debian)

purge-cache.sh

#!/bin/sh

# purge-cache: Script to purge varnish cache. Defaults are defined in
# /etc/default/varnish.
#
# Cosimo <[email protected]>
# Based on reload-vcl, by Stig Sandbeck Mathisen <ssm at debian dot org>

# Settings
defaults=/etc/default/varnish

# Paths
varnishadm=/usr/bin/varnishadm
date=/bin/date 
tempfile=/bin/tempfile

# Messages
# msg_no_varnishadm: varnishadm
msg_no_varnishadm="Error: Cannot execute %s\n"
msg_no_management="Error: \$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_usage="Usage: $0 [-h][-q][-u <url>|-r <regex>|-a]\n\t-h\tdisplay help\n\t-q\tbe quiet\n\t-u\tpurge by exact (relative) url (ex.: /en/products/)\n\t-r\tpurge objects with URL matching a regex (ex.: ^/blogs/)\n\t-a\tpurge all objects from cache\n"
msg_purge_failed="Error: purge command failed\n"
# msg_purge_url: url
msg_purge_url="Purging objects by exact url: %s\n"
# msg_purge_regex: regex
msg_purge_regex="Purging objects with URL matching regex: %s\n"
msg_purge_all="Purging all cache\n"
msg_purge_ok="Purge command successful\n"

# Load defaults file
if [ -f "$defaults" ]
then
    if [ -r "$defaults" ]
    then
        . "$defaults"
    else
        printf >&2 "$msg_defaults_not_readable" $defaults
        exit 1 
    fi
else
    printf >&2 "$msg_defaults_not_there" $defaults
    exit 1
fi

# parse command line arguments
while getopts hqu:r:a flag
do
    case $flag in
        h)
            printf >&2 "$msg_usage"
            exit 0
            ;; 
        u)
            purge_method=url
        url="$OPTARG"
            ;; 
        r)
            purge_method=regex
        regex="$OPTARG"
            ;; 
        a)
            purge_method=all
            ;; 
        q)
            quiet=1
            ;; 
        *)
            printf >&2 "$msg_usage\n"
            exit 1
            ;; 
    esac
done

# Parse $DAEMON_OPTS (options must be kept in sync with varnishd).
# 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:dFf:g:h:l:n:P:p: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  
            ;;  
    esac
done

# Sanity checks 
if [ ! -x "$varnishadm" ]
then
    printf >&2 "$msg_no_varnishadm" $varnishadm
    exit 1
fi

if [ -z "$mgmt_interface" ]
then
    printf >&2 "$msg_no_management"
    exit 1
fi

logfile=$($tempfile)
purge_command="vcl.list"

# Now run the purge command against the admin interface
if [[ $purge_method = "url" ]]
then
        purge_command="purge req.url == $url"
        printf >&2 "$msg_purge_url" $url | grep -v "^$" > $logfile
else
    if [[ $purge_method = "regex" ]]
    then
        purge_command="purge.url $regex"
        printf >&2 "$msg_purge_regex" $regex | grep -v "^$" > $logfile
    else
        if [[ $purge_method = "all" ]]
        then
            purge_command="purge.url ."
            printf >&2 "$msg_purge_all" | grep -v "^$" > $logfile
        fi
    fi
fi

# For some reason, using:
#
#   fi | grep -v "^$" > $logfile
#
# results in purge_command assignment being wiped out
# at the end of the block??

if [ -z "$purge_command" ]
then
    printf >&2 "$msg_usage\n"
    exit 1
fi

# echo "cmd: $varnishadm -T $mgmt_interface $purge_command"

if $varnishadm -T $mgmt_interface $purge_command
then
    printf >&2 "$msg_purge_ok"
else
    printf >&2 "$msg_purge_failed"
    exitstatus=1
fi | grep -v "^$" > $logfile

# Blather
if [ -z "${quiet}" -o -n "$exitstatus" ]
then
    cat >&2 $logfile
fi

# Cleanup
rm -f $logfile  
exit $exitstatus