Adding MAX_CACHE_SIZE

Author: cytopia

Dockerfiles/data/docker-entrypoint.sh

@@ -76,6 +76,7 @@ DEFAULT_REFRESH_TIME=1200
 DEFAULT_RETRY_TIME=180
 DEFAULT_EXPIRY_TIME=1209600
 DEFAULT_MAX_CACHE_TIME=10800
+DEFAULT_MAX_CACHE_SIZE="90%"
 
 
 
@@ -285,13 +286,15 @@ add_options() {
 	local allow_query="${4}"
 	local allow_recursion="${5}"
 	local response_policy="${6}"
+	local max_cache_size="${7}"
 
 	{
 		echo "options {"
 		echo "    directory \"/var/cache/bind\";"
 		echo "    dnssec-validation ${dnssec_validate};"
 		echo "    auth-nxdomain no;    # conform to RFC1035"
 		echo "    listen-on-v6 { any; };"
+		echo "    max-cache-size ${max_cache_size};"
 		if [ -n "${response_policy}" ]; then
 			echo "    response-policy { zone \"${response_policy}\"; };"
 		fi
@@ -650,6 +653,39 @@ else
 	MAX_CACHE_TIME="${DEFAULT_MAX_CACHE_TIME}"
 fi
 
+if printenv MAX_CACHE_SIZE >/dev/null 2>&1 && [ -n "$( printenv MAX_CACHE_SIZE )" ]; then
+	MAX_CACHE_SIZE="$( printenv MAX_CACHE_SIZE )"
+	if [ "${MAX_CACHE_SIZE}" = "unlimited" ]; then
+		log "info" "Changing DNS Max Cache size to: ${MAX_CACHE_SIZE}" "${DEBUG_ENTRYPOINT}"
+	elif [ "${MAX_CACHE_SIZE}" = "0" ]; then
+		log "info" "Changing DNS Max Cache size to: ${MAX_CACHE_SIZE}" "${DEBUG_ENTRYPOINT}"
+	# Extract value and unit
+	else
+		MAX_CACHE_SIZE_VALUE="$( echo "${MAX_CACHE_SIZE}" | grep -Eo '[0-9]+' )"
+		MAX_CACHE_SIZE_UNIT="$( echo "${MAX_CACHE_SIZE}"  | grep -Eo '[^0-9]+' )"  # Allowed: %, k, K, m, M, g, G or empty
+
+		if [ -z "${MAX_CACHE_SIZE_VALUE}" ]; then
+			log "warn" "Wrong value for \$MAX_CACHE_SIZE '${MAX_CACHE_SIZE}', defaultint to: ${DEFAULT_MAX_CACHE_SIZE}" "${DEBUG_ENTRYPOINT}"
+			MAX_CACHE_SIZE="${DEFAULT_MAX_CACHE_SIZE}"
+		elif [ -z "${MAX_CACHE_SIZE_UNIT}" ]; then
+			log "info" "Changing DNS Max Cache size to: ${MAX_CACHE_SIZE}" "${DEBUG_ENTRYPOINT}"
+			MAX_CACHE_SIZE="${MAX_CACHE_SIZE_VALUE}"
+		else
+			# Validate correct unit
+			if ! echo "${MAX_CACHE_SIZE_UNIT}" | grep -E '[%kKmMgG]' >/dev/null; then
+				log "warn" "Wrong unit for \$MAX_CACHE_SIZE '${MAX_CACHE_SIZE_UNIT}', defaultint to: ${DEFAULT_MAX_CACHE_SIZE}" "${DEBUG_ENTRYPOINT}"
+				MAX_CACHE_SIZE="${DEFAULT_MAX_CACHE_SIZE}"
+			else
+				log "info" "Changing DNS Max Cache size to: ${MAX_CACHE_SIZE}" "${DEBUG_ENTRYPOINT}"
+				MAX_CACHE_SIZE="${MAX_CACHE_SIZE_VALUE}${MAX_CACHE_SIZE_UNIT}"
+			fi
+		fi
+	fi
+else
+	log "info" "Using default DNS Max Cache size: ${DEFAULT_MAX_CACHE_SIZE}" "${DEBUG_ENTRYPOINT}"
+	MAX_CACHE_SIZE="${DEFAULT_MAX_CACHE_SIZE}"
+fi
+
 
 
 ####################################################################################################
@@ -872,7 +908,8 @@ if ! printenv DNS_FORWARDER >/dev/null 2>&1; then
 		"" \
 		"${_allow_query_block}" \
 		"${_allow_recursion_block}" \
-		"${FWD_ZONES}"
+		"${FWD_ZONES}" \
+		"${MAX_CACHE_SIZE}"
 else
 
 	# To be pupulated
@@ -908,7 +945,8 @@ else
 		"${_forwarders_block}" \
 		"${_allow_query_block}" \
 		"${_allow_recursion_block}" \
-		"${FWD_ZONES}"
+		"${FWD_ZONES}" \
+		"${MAX_CACHE_SIZE}"
 fi
 
 

README.md

@@ -54,13 +54,14 @@ Bind caching DNS server based on Debian slim with support for DNS forwarders, in
         5. [DNS_PTR](#dns_ptr)
         6. [DNSSEC_VALIDATE](#dnssec_validate)
         7. [DNS_FORWARDER](#dns_forwarder)
-        8. [TTL_TIME](#ttl_time)
-        9. [REFRESH_TIME](#refresh_time)
-        10. [RETRY_TIME](#retry_time)
-        11. [EXPIRY_TIME](#expiry_time)
-        12. [MAX_CACHE_TIME](#max_cache_time)
-        13. [ALLOW_QUERY](#allow_query)
-        14. [ALLOW_RECURSION](#allow_recursion)
+        8. [MAX_CACHE_SIZE](#max_cache_size)
+        9. [TTL_TIME](#ttl_time)
+        10. [REFRESH_TIME](#refresh_time)
+        11. [RETRY_TIME](#retry_time)
+        12. [EXPIRY_TIME](#expiry_time)
+        13. [MAX_CACHE_TIME](#max_cache_time)
+        14. [ALLOW_QUERY](#allow_query)
+        15. [ALLOW_RECURSION](#allow_recursion)
 2. [Default mountpoints](#default-mountpoints)
 3. [Default ports](#default-ports)
 4. [Examples](#examples)
@@ -96,7 +97,8 @@ Bind caching DNS server based on Debian slim with support for DNS forwarders, in
 | `DNS_PTR`          | string |           | Comma separated list of PTR records (reverse DNS). |
 | `DNSSEC_VALIDATE`  | string | `no`      | Control the behaviour of DNSSEC validation. The default is to not validate: `no`. Other possible values are: `yes` and `auto`. |
 | `DNS_FORWARDER`    | string |           | Specify a comma separated list of IP addresses as custom DNS resolver. This is useful if your LAN already has a DNS server which adds custom/internal domains and you still want to keep them in this DNS server<br/>Example: `DNS_FORWARDER=8.8.8.8,8.8.4.4` |
-| `TTL_TIME`         | int    | `3600`    | (Time in seconds) See [BIND TTL](http://www.zytrax.com/books/dns/apa/ttl.html) and [BIND SOA](http://www.zytrax.com/books/dns/ch8/soa.html)|
+| `MAX_CACHE_SIZE`   | size   | `90%`     | Amount of memory used by the server (cached results) |
+| `ttl_time`         | int    | `3600`    | (time in seconds) see [bind ttl](http://www.zytrax.com/books/dns/apa/ttl.html) and [bind soa](http://www.zytrax.com/books/dns/ch8/soa.html)|
 | `REFRESH_TIME`     | int    | `1200`    | (Time in seconds) See [BIND SOA](http://www.zytrax.com/books/dns/ch8/soa.html) |
 | `RETRY_TIME`       | int    | `180`     | (Time in seconds) See [BIND SOA](http://www.zytrax.com/books/dns/ch8/soa.html) |
 | `EXPIRY_TIME`      | int    | `1209600` | (Time in seconds) See [BIND SOA](http://www.zytrax.com/books/dns/ch8/soa.html) |
@@ -202,6 +204,12 @@ Some examples
 DNS_FORWARDER='8.8.8.8'
 DNS_FORWARDER='8.8.8.8,192.168.0.10'
 ```
+#### MAX_CACHE_SIZE
+The amount of RAM used by the server to store results. You can use relative (percent) or absolute (bytes) values.
+Examples:
+* `MAX_CACHE_SIZE=30%` (Use 30% of the systems memory)
+* `MAX_CACHE_SIZE=512M` (Use 512 Megabytes)
+* `MAX_CACHE_SIZE=2G` (Use 2 Gigabytes)
 
 #### TTL_TIME
 Specify time in seconds.