Add dockerfile and entrypoint

Author: David Lorite

Dockerfile

@@ -0,0 +1,7 @@
+FROM openjdk:11-jre-slim-buster
+ARG EXPORTER_VERSION=0.9.10
+RUN mkdir -p /opt/cassandra_exporter
+ADD https://github.com/instaclustr/cassandra-exporter/releases/download/v${EXPORTER_VERSION}/cassandra-exporter-standalone-${EXPORTER_VERSION}.jar /opt/cassandra_exporter/cassandra_exporter.jar
+COPY ./entrypoint.sh /opt/cassandra_exporter/entrypoint.sh
+RUN chmod g+wrX,o+rX -R /opt/cassandra_exporter
+CMD sh /opt/cassandra_exporter/entrypoint.sh

entrypoint.sh

@@ -0,0 +1,6 @@
+#/bin/sh
+if [ -z ${CASSANDRA_EXPORTER_USER} ] && [ -z ${CASSANDRA_EXPORTER_PASSWORD} ]; then
+    java -jar /opt/cassandra_exporter/cassandra_exporter.jar
+else
+    java -jar /opt/cassandra_exporter/cassandra_exporter.jar --jmx-user=CASSANDRA_EXPORTER_USER  --jmx-password=CASSANDRA_EXPORTER_PASSWORD --table-labels=TABLE_TYPE --global-labels=CLUSTER,NODE
+fi