How to reference a local project in Scala - scala

Question

First of all, apologies if this question has been answered already, or if there's a complete documentation / tutorial about it, I'm a Scala newbie and I've surely missed something.
I have a C# background, and I'm trying to expand my knowledge learning Scala. I would like to include a Scala microservice in a microservices architecture that's actually built using .NET projects. To implement the shared architectural code in the .NET projects I've developed a series of base project, referenced by all the microservices projects, and this operation with VS was pretty straightforward, but I failed to grasp how to achieve the same functionality on Scala.
In particular, I would like to understand whether there's a way to reference a Project A located in a local folder in Project B, in a similar way of referencing a project from Maven like this, for example:
libraryDependencies ++= Seq(
"com.typesafe.akka" %% "akka-http-spray-json" % "10.1.1",
"com.typesafe.akka" %% "akka-http" % "10.1.1",
"com.typesafe.akka" %% "akka-stream" % "2.5.11"
)
and what's the best way of doing it (referencing the jars, for example).

Answer 1

Yes you can reference to another scala project in scala using the simple build tool.
Let's say your architecture has
1) ChatMicroserviceApi.jar (depends on two local jars 2 and 3)
2) ChatMicroserviceSchema.jar
3) ChatMicroserviceExternalDeps.jar
Then your sbt script would look like below. I use sbt-assembly to create fat jars for which you have to add addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.14.6") in project/plugins.sbt
//build.sbt
name := "ChatMicroserviceParent"
organization in ThisBuild := "com.microservice.chat"
scalaVersion in ThisBuild := "2.12.5"
version := "1.0-SNAPSHOT"
//define what parent consists of in aggregate section
lazy val ChatMicroserviceParent = project
.in(file("."))
.settings(settings)
.aggregate(ChatMicroserviceSchema,
ChatMicroserviceExternalDeps,
ChatMicroserviceApi)
//creates schema.jar
lazy val ChatMicroserviceSchema =
project.settings(name := "ChatMicroserviceSchema",
publishMavenStyle := true,
settings,
apiSchemaAssemblySettings)
//creates external-deps.jar
lazy val ChatMicroserviceExternalDeps =
project.settings(
name := "ChatMicroserviceExternalDeps",
publishMavenStyle := true,
settings,
apiSchemaAssemblySettings,
libraryDependencies ++= Seq(
"com.softwaremill.sttp" %% "core" % "1.1.12",
"com.softwaremill.sttp" %% "async-http-client-backend-future" % "1.1.12"
exclude ("org.asynchttpclient", "async-http-client"),
"org.asynchttpclient" % "async-http-client" % "2.4.4"
excludeAll( ExclusionRule(organization = "io.netty") ),
"com.fasterxml.jackson.module" %% "jackson-module-scala" % "2.9.5",
"com.fasterxml.jackson.module" % "jackson-modules-java8" % "2.9.5",
"com.fasterxml.jackson.datatype" % "jackson-datatype-jsr310" % "2.9.5",
"com.fasterxml.jackson.datatype" % "jackson-datatype-jdk8" % "2.9.5"
)
)
val NettyVersion = "4.1.16.Final"
//creates api.jar which depends on schema.jar and external-deps.jar
lazy val ChatMicroserverApi = project
.settings(
name := "ChatMicroserverApi",
settings,
apiAssemblySettings,
libraryDependencies ++= Seq(
"com.github.finagle" %% "finch-core" % "0.18.0"
excludeAll( ExclusionRule(organization = "io.netty") )
exclude ("com.fasterxml.jackson.core", "jackson-databind"),
"com.github.finagle" %% "finch-circe" % "0.18.0",
"io.netty" % "netty-codec" % NettyVersion,
"io.netty" % "netty-codec-http" % NettyVersion,
"io.netty" % "netty-codec-http2" % NettyVersion,
"io.netty" % "netty-transport" % NettyVersion,
"io.netty" % "netty-buffer" % NettyVersion,
"io.netty" % "netty-common" % NettyVersion,
"io.netty" % "netty-resolver" % NettyVersion,
"io.netty" % "netty-handler" % NettyVersion,
"io.netty" % "netty-handler-proxy" % NettyVersion,
"io.netty" % "netty-transport-native-unix-common" % NettyVersion,
"io.netty" % "netty-transport-native-epoll" % NettyVersion,
"io.netty" % "netty-tcnative-boringssl-static" % "2.0.6.Final",
"io.netty" % "netty-codec-socks" % NettyVersion,
"io.circe" %% "circe-generic" % "0.9.3",
"com.typesafe" % "config" % "1.3.3",
"ch.qos.logback" % "logback-classic" % "1.2.3",
"com.typesafe.akka" %% "akka-actor" % "2.5.12",
"com.typesafe.akka" %% "akka-stream" % "2.5.12",
"com.typesafe.akka" %% "akka-http" % "10.1.1",
"com.fasterxml.jackson.module" %% "jackson-module-scala" % "2.9.5",
"com.fasterxml.jackson.module" % "jackson-modules-java8" % "2.9.5",
"com.fasterxml.jackson.datatype" % "jackson-datatype-jsr310" % "2.9.5",
"com.fasterxml.jackson.datatype" % "jackson-datatype-jdk8" % "2.9.5",
"io.circe" %% "circe-java8" % "0.9.3",
"com.softwaremill.sttp" %% "core" % "1.1.12",
"org.asynchttpclient" % "async-http-client" % "2.4.4"
excludeAll( ExclusionRule(organization = "io.netty") ),
"com.softwaremill.sttp" %% "async-http-client-backend-future" % "1.1.12"
exclude ("org.asynchttpclient", "async-http-client"),
"joda-time" % "joda-time" % "2.9.9"
)
)
.dependsOn(ChatMicroserviceExternalDeps, ChatMicroserviceSchema)
lazy val commonDependencies = Seq()
lazy val settings =
commonSettings
lazy val compilerOptions = Seq(
"-unchecked",
"-feature",
"-language:existentials",
"-language:higherKinds",
"-language:implicitConversions",
"-language:postfixOps",
"-deprecation",
"-encoding",
"utf8"
)
lazy val commonSettings = Seq(
scalacOptions ++= compilerOptions,
resolvers ++= Seq(
Resolver.sonatypeRepo("releases"),
Resolver.sonatypeRepo("snapshots")
)
)
lazy val apiAssemblySettings = Seq(
assemblyJarName in assembly := name.value + "-" + version.value + ".jar",
mainClass in assembly := Some(
"com.microservice.MainServerClass"),
assemblyMergeStrategy in assembly := {
case PathList("reference.conf") => MergeStrategy.concat
case PathList("META-INF", xs # _*) => MergeStrategy.discard
case _ => MergeStrategy.first
}
)
lazy val apiSchemaAssemblySettings = Seq(
assemblyJarName in assembly := name.value + "-" + version.value + ".jar")
assemblyMergeStrategy in assembly := {
case PathList("META-INF", xs # _*) => MergeStrategy.discard
case _ => MergeStrategy.first
}
lazy val apiExternalDepsAssemblySettings = Seq(
assemblyJarName in assembly := name.value + "-" + version.value + ".jar")
assemblyMergeStrategy in assembly := {
case PathList("META-INF", xs # _*) => MergeStrategy.discard
case _ => MergeStrategy.first
}
Here's working example which might help - https://github.com/duwamish-os/chat-server