SBT Native Packager Not Including Entrypoint - docker

Question

I have a multi module SBT project that I'm using to build a Docker image out of. There is one module that depends on all the other modules and I'm actually trying to build the Docker image for this module. Here is a snippet from my build.sbt
lazy val impute = (project in file(MODULE_NAME_IMPUTE)).dependsOn(core% "compile->compile;test->test", config)
.settings(
commonSettings,
enablingCoverageSettings,
name := MODULE_NAME_IMPUTE,
description := "Impute the training data"
)
.enablePlugins(JavaAppPackaging, DockerPlugin)
lazy val split = (project in file(MODULE_NAME_SPLIT)).dependsOn(core% "compile->compile;test->test", config)
.settings(
commonSettings,
enablingCoverageSettings,
dockerSettings("split"),
name := MODULE_NAME_SPLIT,
description := "Split the dataset into train and test"
)
.enablePlugins(JavaAppPackaging, DockerPlugin)
lazy val run = (project in file(MODULE_NAME_RUN)).dependsOn(core % "compile->compile;test->test", config, cleanse, encode, feature, impute, split)
.settings(
commonSettings,
dockerSettings("run"),
enablingCoverageSettings,
name := MODULE_NAME_RUN,
description := "To run the whole setup as a pipeline locally"
)
.enablePlugins(JavaAppPackaging, DockerPlugin)
As you can see, the run module depends on all the other modules and I'm actually trying to build the Docker image for the run module for which I used the following command:
sbt run/docker:publishLocal
This works fine and the Docker image is also built, but when I inspect my Docker image, especially on the ENTRYPOINT, I get to see the following:
"Entrypoint": [
"/opt/docker/bin/run"
],
But instead, I would have expected to see something like this:
"Entrypoint": [
"java",
"-cp",
"com.mypackage.housingml.run.Main"
],
Is there anything else that I'm missing? Here is my dockerSettings() function from my build.sbt:
def dockerSettings(name: String) = {
Seq(
// Always use latest tag
dockerUpdateLatest := true,
maintainer := s"$projectMaintainer",
// https://hub.docker.com/r/adoptopenjdk/openjdk13
// Remember to use AshScriptPlugin if you are using an alpine based image
dockerBaseImage := "adoptopenjdk/openjdk13:alpine-slim",
// If you want to publish to a remote docker repository, uncomment the following:
//dockerRepository := Some("remote-docker-hostname"),
Docker / packageName := s"joesan/$projectName-$name",
// If we're running in a docker container, then export logging volume.
Docker / defaultLinuxLogsLocation := "/opt/docker/logs",
dockerExposedVolumes := Seq((Docker / defaultLinuxLogsLocation).value),
dockerEnvVars := Map(
"LOG_DIR" -> (Docker / defaultLinuxLogsLocation).value,
)
)
}

Answer 1

The sbt-native-packager creates a executable bash script to run your code and Docker ENTRYPOINT is by default set to that executable script as you can see.
This is customisable, see the docs for reference.
Also, the bash script is customisable - docs.