How can I create a custom sbt task from existing tasks - scala

Question

I want to create a custom sbt task that use publishLocal in Docker, login in ecr, and publishLocal in Docker.
Also note that I modified "publishLocal in Docker" settings only on custom task.
I tried writing the code bellow but it did not work.
val releaseDev = taskKey[Unit]("push docker image")
releaseDev := (push in ecr).value
releaseDev := releaseDev.dependsOn(publishLocal in Docker).value
releaseDev := (projectSettings ++ Seq(repositoryName in ecr := (packageName in Docker).value + "-stg" + ":" + (version in Docker).value))

Answer 1

Here is how to trigger existing tasks from your custom one. From your question, you want them to be triggered in some particular sequence, so here is what you need to do
lazy val releaseDev = taskKey[Unit]("push docker image")
releaseDev := Def.sequential(push in ecr, publishLocal in Docker).value
Now when you trigger releaseDev it will first turn push in ecr then publishLocal in Docker.
Note: don't forget to add the lazy in your taskKey definition since it may lead to some strange initialization issues.

Answer 2

Thank you marios.
I tried writing the code below and task dependencies were properly handled.
However repositoryName is used that one of project settings.
// docker publish settings
import com.amazonaws.regions.{Region, Regions}
region in ecr := Region.getRegion(Regions.AP_NORTHEAST_1)
repositoryName in ecr := (packageName in Docker).value + ":" + (version in Docker).value
localDockerImage in ecr := (packageName in Docker).value + ":" + (version in Docker).value
// Publisher Setting
//~~~~~~~~~~~~~~~~~~~
import ReleaseTransformations._
releaseProcess := Seq[ReleaseStep](
checkSnapshotDependencies,
inquireVersions,
runClean,
runTest,
setReleaseVersion,
commitReleaseVersion,
tagRelease,
ReleaseStep(state => Project.extract(state).runTask(publishLocal in Docker, state)._1),
ReleaseStep(state => Project.extract(state).runTask(login in ecr, state)._1),
ReleaseStep(state => Project.extract(state).runTask(push in ecr, state)._1),
setNextVersion,
commitNextVersion,
pushChanges
)
lazy val releaseDev = taskKey[Unit]("push docker image")
releaseDev := Def.sequential( publishLocal in Docker, login in ecr, push in ecr).value
(repositoryName in ecr) in releaseDev := (packageName in Docker).value + "-stg" + ":" + (version in Docker).value