Added ability to configure JVM Memory settings via Docker ENV variables

This closes #3321

Signed-off-by: Mike Thomsen <mikerthomsen@gmail.com>

nifi-docker/dockerhub/README.md

@@ -191,6 +191,9 @@ can be published to the host.
 
 The Variable Registry can be configured for the docker image using the `NIFI_VARIABLE_REGISTRY_PROPERTIES` environment variable.
 
+The JVM Memory initial and maximum heap size can be set using the `NIFI_JVM_HEAP_INIT` and `NIFI_JVM_HEAP_MAX` environment variables. These use values acceptable to the JVM `Xmx` and `Xms` parameters such as `1g` or `512m`.
+
+
 =======  
 **NOTE**: If NiFi is proxied at context paths other than the root path of the proxy, the paths need to be set in the 
 _nifi.web.proxy.context.path_ property, which can be assigned via the environment variable _NIFI\_WEB\_PROXY\_CONTEXT\_PATH_.

nifi-docker/dockerhub/sh/common.sh

@@ -24,6 +24,7 @@ prop_replace () {
 }
 
 # NIFI_HOME is defined by an ENV command in the backing Dockerfile
+export nifi_bootstrap_file=${NIFI_HOME}/conf/bootstrap.conf
 export nifi_props_file=${NIFI_HOME}/conf/nifi.properties
 export nifi_toolkit_props_file=${HOME}/.nifi-cli.nifi.properties
 export hostname=$(hostname)

nifi-docker/dockerhub/sh/start.sh

@@ -19,6 +19,15 @@ scripts_dir='/opt/nifi/scripts'
 
 [ -f "${scripts_dir}/common.sh" ] && . "${scripts_dir}/common.sh"
 
+# Override JVM memory settings
+if [ ! -z "${NIFI_JVM_HEAP_INIT}" ]; then
+    prop_replace 'java.arg.2'       "-Xms${NIFI_JVM_HEAP_INIT}" ${nifi_bootstrap_file}
+fi
+
+if [ ! -z "${NIFI_JVM_HEAP_MAX}" ]; then
+    prop_replace 'java.arg.3'       "-Xmx${NIFI_JVM_HEAP_MAX}" ${nifi_bootstrap_file}
+fi
+
 # Establish baseline properties
 prop_replace 'nifi.web.http.port'               "${NIFI_WEB_HTTP_PORT:-8080}"
 prop_replace 'nifi.web.http.host'               "${NIFI_WEB_HTTP_HOST:-$HOSTNAME}"

nifi-docker/dockermaven/sh/common.sh

@@ -24,6 +24,7 @@ prop_replace () {
 }
 
 # NIFI_HOME is defined by an ENV command in the backing Dockerfile
+export nifi_bootstrap_file=${NIFI_HOME}/conf/bootstrap.conf
 export nifi_props_file=${NIFI_HOME}/conf/nifi.properties
 export nifi_toolkit_props_file=${HOME}/.nifi-cli.nifi.properties
 export hostname=$(hostname)

nifi-docker/dockermaven/sh/start.sh

@@ -19,6 +19,15 @@ scripts_dir='/opt/nifi/scripts'
 
 [ -f "${scripts_dir}/common.sh" ] && . "${scripts_dir}/common.sh"
 
+# Override JVM memory settings
+if [ ! -z "${NIFI_JVM_HEAP_INIT}" ]; then
+    prop_replace 'java.arg.2'       "-Xms${NIFI_JVM_HEAP_INIT}" ${nifi_bootstrap_file}
+fi
+
+if [ ! -z "${NIFI_JVM_HEAP_MAX}" ]; then
+    prop_replace 'java.arg.3'       "-Xmx${NIFI_JVM_HEAP_MAX}" ${nifi_bootstrap_file}
+fi
+
 # Establish baseline properties
 prop_replace 'nifi.web.http.port'               "${NIFI_WEB_HTTP_PORT:-8080}"
 prop_replace 'nifi.web.http.host'               "${NIFI_WEB_HTTP_HOST:-$HOSTNAME}"