Configure environment variable with Neo4j and docker-compose - docker

Question

I am packing my application into jar and run it with Docker using bash script (which executes jar). I would like to change neo4j database url configuration as environment variable in docker-compose file, however, I still get this error:
Exception in thread "main" com.typesafe.config.ConfigException$NotResolved: neo4j.url has not been resolved, you need to call Config#resolve(), see API docs for Config#resolve()
How can I solve this problem and where should I add some configurations for that?
I have only set up url variable in configurations file:
neo4j{
url= "bolt://localhost:7687"
url = ${?HOSTNAME}
user = "user"
password = "password"
}
Also, I use this variable in configurations method:
def getNeo4jConfig(configName: String) = {
val neo4jLocalConfig = ConfigFactory.parseFile(new File("configs/local_neo4j.conf"))
neo4jLocalConfig.resolve()
val driver = configName match {
case "neo4j_local" => GraphDatabase.driver(neo4jLocalConfig.getString("neo4j.url"),
AuthTokens.basic(neo4jLocalConfig.getString("neo4j.user"), neo4jLocalConfig.getString("neo4j.password")))
case _ => GraphDatabase.driver("url", AuthTokens.basic("user", "password"))
}
driver.session
}
In docker-compose.yml I defined the value of the hostname:
version: '3.3'
services:
neo4j_db:
image: neo4j:latest
ports:
- "7474:7474"
- "7473:7473"
- "7687:7687"
volumes:
- $HOME/neo4j/import:/var/lib/neo4j/import
- $HOME/neo4j/data:/neo4j/data
- $HOME/neo4j/conf:/neo4j/conf
- $HOME/neo4j/logs:/neo4j/logs
environment:
- NEO4J_dbms_active__database=graphImport.db
benchmarks:
image: "container"
volumes:
- ./:/workdir1
working_dir: /workdir1
links:
- neo4j_db
environment:
- HOSTNAME=myhoat
Also, bash script looks like this:
#!/usr/bin/env bash
for run in {1..2}
do
java -cp "target/scala-2.11/benchmarking.jar" benchmarks/Main $1 $2
done

Answer 1

Set these env in a .env file in the same location than your
docker-compose.yml file:
.env
VAR1=value
VAR2=2.0
VAR3=`awk -F ':' '{if ($3 == 1000) {print $1}}' /etc/passwd` <-- any bash command, for example
...
And for example, use them in your compose file sections:
docker-compose.yml
...
build:
dockerfile: Dockerfile_${VAR2}
...

Answer 2

I defined hostname as arg in Dockerfile and then defined it in docker-compose file for the application build. That solved the problem!
Docker-compose file:
version: '3.3'
services:
benchmarks-app:
build:
context: .
dockerfile: Dockerfile
args:
- HOST=neo4jdb
volumes:
- ./:/workdir
working_dir: /workdir
Dockerfile args definition:
FROM java:8
ARG HOST
ENV SCALA_VERSION 2.11.8
ENV SBT_VERSION 1.1.1
ENV SPARK_VERSION 2.2.0
ENV SPARK_DIST spark-$SPARK_VERSION-bin-hadoop2.6
ENV SPARK_ARCH $SPARK_DIST.tgz
ENV NEO4J_CONFIG $DB_CONFIG
ENV BENCHMARK $BENCHMARK_NAME
ENV HOSTNAME bolt://$HOST:7687
...