sbt-native-packager scala play dockerfile not running with default config - scala

Question

I'm trying to use the sbt-native-packager to produce a Docker image of my Scala play app, I followed the steps described at http://www.scala-sbt.org/sbt-native-packager/formats/docker.html
This is my configuration:
on my plugins.sbt I added the dependency for sbt native packager:
// SBT Native
addSbtPlugin("com.typesafe.sbt" % "sbt-native-packager" % "1.2.1")
on my build.sbt I added the plugins for Universal and Docker:
.enablePlugins(PlayScala, JavaAppPackaging)
I also added some extra properties:
javaOptions in Universal ++= Seq(
// JVM memory tuning
"-J-Xmx1024m",
"-J-Xms512m",
// Since play uses separate pidfile we have to provide it with a proper path
// name of the pid file must be play.pid
s"-Dpidfile.path=/var/run/${packageName.value}/play.pid",
// Use separate configuration file for production environment
s"-Dconfig.file=/usr/share/${packageName.value}/conf/production.conf",
// Use separate logger configuration file for production environment
s"-Dlogger.file=/usr/share/${packageName.value}/conf/logback.xml"
)
// exposing the play ports
dockerExposedPorts in Docker := Seq(9000, 9443)
Then I generate the docker image using the plugin and SBT CLI:
docker:publishLocal
the dockerfile gets generated at ./target/docker/Dockerfile
when I inspect the file I see:
FROM openjdk:latest
WORKDIR /opt/docker
ADD opt /opt
RUN ["chown", "-R", "daemon:daemon", "."]
USER daemon
ENTRYPOINT ["bin/root"]
CMD []
which doesn't seem to contain all the necessary steps to run the app, when I use docker build . I get :
java.nio.file.NoSuchFileException: /var/run/root/play.pid
It seems like the Dockerfile is missing some steps where it should mkdir /var/run/{APP_NAME}/
(* creating folder inside docker container instance)
and chown that folder in order for play to create the PID file.
how to fix the above error ?

Answer 1

What's the error message when starting the docker image and how do you start it?
Then there are a couple of notable things.
play ships with native-packager
You shouldn't have to add any plugin, but only configure docker relevant stuff. You already linked the correct documentation for the package format ( docker ).
Archetypes Vs Formats
Your configuration won't work without the play plugin. Take a look at http://www.scala-sbt.org/sbt-native-packager/archetypes/java_app/index.html which explains how to configure a simple application build.
I'd also recommend to read the format and Archetypes section here:
http://www.scala-sbt.org/sbt-native-packager/introduction.html#archetype-plugins
Native docker build
Native-packager currently generates two docker files, which is confusing and not relevant. Sorry for that confusion. We plan to remove the redundant docker file.
Simply go one level deeper and run the docker build command.
Hope that helps,
Muki