Add KAFKA_CONFIGS variable to do additional configuration

README.md

@@ -76,6 +76,13 @@ If you wish to use multi-line YAML or some other delimiter between your topic de
 
 For example, `KAFKA_CREATE_TOPICS_SEPARATOR: "$$'\n"'` would use a newline to split the topic definitions. Syntax has to follow docker-compose escaping rules, and [ANSI-C](https://www.gnu.org/software/bash/manual/html_node/ANSI_002dC-Quoting.html) quoting.
 
+Another environment variable can be added to perform further configuration changes: ```KAFKA_CONFIGS```. For example:
+
+    environment:
+      - KAFKA_CONFIGS=topics:Topic1:add:retention.ms=604800000 cleanup.policy=delete segment.bytes=1024
+
+The format for this variable mirrors the ```kafka-configs.sh``` script. For multi-line YAML a separate delimiter variable ```KAFKA_CREATE_TOPICS_SEPARATOR``` is available.
+
 ## Advertised hostname
 
 You can configure the advertised hostname in different ways

create-topics.sh

@@ -1,9 +1,5 @@
 #!/bin/bash
 
-if [[ -z "$KAFKA_CREATE_TOPICS" ]]; then
-    exit 0
-fi
-
 if [[ -z "$START_TIMEOUT" ]]; then
     START_TIMEOUT=600
 fi
@@ -26,24 +22,45 @@ if $start_timeout_exceeded; then
     exit 1
 fi
 
-# Expected format:
-#   name:partitions:replicas:cleanup.policy
-IFS="${KAFKA_CREATE_TOPICS_SEPARATOR-,}"; for topicToCreate in $KAFKA_CREATE_TOPICS; do
-    echo "creating topics: $topicToCreate"
-    IFS=':' read -r -a topicConfig <<< "$topicToCreate"
-    config=
-    if [ -n "${topicConfig[3]}" ]; then
-        config="--config=cleanup.policy=${topicConfig[3]}"
-    fi
-    COMMAND="JMX_PORT='' ${KAFKA_HOME}/bin/kafka-topics.sh \\
-		--create \\
-		--zookeeper ${KAFKA_ZOOKEEPER_CONNECT} \\
-		--topic ${topicConfig[0]} \\
-		--partitions ${topicConfig[1]} \\
-		--replication-factor ${topicConfig[2]} \\
-		${config} \\
-		--if-not-exists &"
-    eval "${COMMAND}"
-done
+if [[ -n "$KAFKA_CREATE_TOPICS" ]]; then
+    # Expected format:
+    # name:partitions:replicas:cleanup.policy
+        IFS="${KAFKA_CREATE_TOPICS_SEPARATOR-,}"; for topicToCreate in $KAFKA_CREATE_TOPICS; do
+        echo "creating topics: $topicToCreate"
+        IFS=':' read -r -a topicConfig <<< "$topicToCreate"
+        config=
+        if [ -n "${topicConfig[3]}" ]; then
+            config="--config=cleanup.policy=${topicConfig[3]}"
+        fi
+        COMMAND="JMX_PORT='' ${KAFKA_HOME}/bin/kafka-topics.sh \\
+    		--create \\
+		    --zookeeper ${KAFKA_ZOOKEEPER_CONNECT} \\
+    		--topic ${topicConfig[0]} \\
+		    --partitions ${topicConfig[1]} \\
+    		--replication-factor ${topicConfig[2]} \\
+		    ${config} \\
+    		--if-not-exists &"
+        eval "${COMMAND}"
+    done
+fi
+
+wait
+
+if [[ -n "$KAFKA_CONFIGS" ]]; then
+    # Expected format:
+    # type:name:add|delete:a=b c=d
+        IFS="${KAFKA_CONFIG_SEPARATOR-,}"; for configToChange in $KAFKA_CONFIGS; do
+        echo "changing config: $configToChange"
+        IFS=':' read -r -a entityConfig <<< "$configToChange"
+        config="${entityConfig[3]}"
+        COMMAND="JMX_PORT='' ${KAFKA_HOME}/bin/kafka-configs.sh \\
+		    --zookeeper ${KAFKA_ZOOKEEPER_CONNECT} \\
+    		--entity-type ${entityConfig[0]} \\
+    		--entity-name ${entityConfig[1]} \\
+        --alter \\
+        --${entityConfig[2]}-config ${config// /,} &"
+        eval "${COMMAND}"
+    done
+fi
 
 wait

start-kafka.sh

@@ -21,6 +21,7 @@ fi
 
 create-topics.sh &
 unset KAFKA_CREATE_TOPICS
+unset KAFKA_CONFIGS
 
 # DEPRECATED: but maintained for compatibility with older brokers pre 0.9.0 (https://issues.apache.org/jira/browse/KAFKA-1809)
 if [[ -z "$KAFKA_ADVERTISED_PORT" && \