Full configuration of kafka by enviroment variables

kafka/scripts/start-kafka.sh

@@ -1,12 +1,13 @@
-#!/bin/sh
+#!/bin/bash
 
 # Optional ENV variables:
+#
+# Any variable prefixed with KAFKA will be transformed to name of parameter for example
+# KAFKA_AUTO_CREATE_TOPICS_ENABLE: 'false' will set auto.create.topic to false
+#
 # * ADVERTISED_HOST: the external ip for the container, e.g. `docker-machine ip \`docker-machine active\``
 # * ADVERTISED_PORT: the external port for Kafka, e.g. 9092
 # * ZK_CHROOT: the zookeeper chroot that's used by Kafka (without / prefix), e.g. "kafka"
-# * LOG_RETENTION_HOURS: the minimum age of a log file in hours to be eligible for deletion (default is 168, for 1 week)
-# * LOG_RETENTION_BYTES: configure the size at which segments are pruned from the log, (default is 1073741824, for 1GB)
-# * NUM_PARTITIONS: configure the default number of log partitions per topic
 
 # Configure advertised host/port if we run in helios
 if [ ! -z "$HELIOS_PORT_kafka" ]; then
@@ -41,27 +42,25 @@ if [ ! -z "$ZK_CHROOT" ]; then
     sed -r -i "s/(zookeeper.connect)=(.*)/\1=localhost:2181\/$ZK_CHROOT/g" $KAFKA_HOME/config/server.properties
 fi
 
-# Allow specification of log retention policies
-if [ ! -z "$LOG_RETENTION_HOURS" ]; then
-    echo "log retention hours: $LOG_RETENTION_HOURS"
-    sed -r -i "s/(log.retention.hours)=(.*)/\1=$LOG_RETENTION_HOURS/g" $KAFKA_HOME/config/server.properties
-fi
-if [ ! -z "$LOG_RETENTION_BYTES" ]; then
-    echo "log retention bytes: $LOG_RETENTION_BYTES"
-    sed -r -i "s/#(log.retention.bytes)=(.*)/\1=$LOG_RETENTION_BYTES/g" $KAFKA_HOME/config/server.properties
-fi
+### START LICENSED CODE ###
+# The following is copied from https://github.com/wurstmeister/kafka-docker/blob/master/start-kafka.sh
+# under ASL v2 license
 
-# Configure the default number of log partitions per topic
-if [ ! -z "$NUM_PARTITIONS" ]; then
-    echo "default number of partition: $NUM_PARTITIONS"
-    sed -r -i "s/(num.partitions)=(.*)/\1=$NUM_PARTITIONS/g" $KAFKA_HOME/config/server.properties
-fi
+for VAR in `env`
+do
+  if [[ $VAR =~ ^KAFKA_ && ! $VAR =~ ^KAFKA_HOME ]]; then
+    kafka_name=`echo "$VAR" | sed -r "s/KAFKA_(.*)=.*/\1/g" | tr '[:upper:]' '[:lower:]' | tr _ .`
+    env_var=`echo "$VAR" | sed -r "s/(.*)=.*/\1/g"`
+    if egrep -q "(^|^#)$kafka_name=" $KAFKA_HOME/config/server.properties; then
+        sed -r -i "s@(^|^#)($kafka_name)=(.*)@\2=${!env_var}@g" $KAFKA_HOME/config/server.properties #note that no config values may contain an '@' char
+    else
+        echo "$kafka_name=${!env_var}" >> $KAFKA_HOME/config/server.properties
+    fi
+    echo "$kafka_name=$env_var"
+  fi
+done
 
-# Enable/disable auto creation of topics
-if [ ! -z "$AUTO_CREATE_TOPICS" ]; then
-    echo "auto.create.topics.enable: $AUTO_CREATE_TOPICS"
-    echo "auto.create.topics.enable=$AUTO_CREATE_TOPICS" >> $KAFKA_HOME/config/server.properties
-fi
+### END LICENSED CODE ###
 
 # Run Kafka
 $KAFKA_HOME/bin/kafka-server-start.sh $KAFKA_HOME/config/server.properties