Environment/system variables in server.xml

Question

How can I use environment/system variables in tomcat server.xml, context.xml, etc configuration files?

I tried to use ${ENV_VAR_NAME} (both for environment and system variable), ${env.ENV_VAR_NAME} (for environment variables). And nothing seems to work.

Answer 1

How it's realized in my box.

Bash-script for startup:

#!/bin/sh

SMEMORY=1G
XMEMORY=1G

if [ $ENV == DEV ]; then
  port_shutdown="8005"
  port_http="8080"
  port_https="8443"
elif
  [ $ENV == SIT ]; then
  port_shutdown="8006"
  port_http="8081"
  port_https="8444"
elif
  [ $ENV == UAT ]; then
  port_shutdown="8007"
  port_http="8082"
  port_https="8445"
else
  echo "Unknown ENV"
  exit 1
fi

export CATALINA_OPTS=" ${SYSTEM_PROPS} -d64 -server -Xms$SMEMORY -Xmx$XMEMORY \
 -XX:+UseCodeCacheFlushing -XX:ReservedCodeCacheSize=64M \
 -XX:+HeapDumpOnOutOfMemoryError -XX:MaxPermSize=1024M \
 -Dport.http=${port_http} -Dport.https=${port_https} -Dport.shutdown=${port_shutdown}"

exec $CATALINA_HOME/bin/startup.sh

In server.xml:

<Connector
  port="${port.http}"
  protocol="HTTP/1.1"
  connectionTimeout="20000"
  redirectPort="${port.https}"
/>

Take a look at process:

$ ps ux | grep tomcat
... -Xms1G -Xmx1G ... -Denv=KIEV_DEV... -Dport.http=8084 -Dport.https=8446 -Dport.shutdown=8008...

Check ports:

$ netstat -anp | grep java
(Not all processes could be identified, non-owned process info
 will not be shown, you would have to be root to see it all.)
tcp        0      0 :::8084                     :::*                        LISTEN      23343/java
tcp        0      0 :::8446                     :::*                        LISTEN      23343/java

Answer 2

Environment variables can be referenced in the server.xml etc by setting the system property org.apache.tomcat.util.digester.PROPERTY_SOURCE to the value org.apache.tomcat.util.digester.Digester$EnvironmentPropertySource.

That system property has been available since 7.0, but EnvironmentPropertySource was not mentioned in the doc until 8.5.

https://tomcat.apache.org/tomcat-9.0-doc/config/systemprops.html

Update (April 2020):

The latest tomcat releases (9.0.34, 8.5.54) now support property replacement in most configuration files: https://tomcat.apache.org/tomcat-9.0-doc/changelog.html#Tomcat_9.0.34_(markt)