Tesla Polyglot Scala

Who uses Maven? Who uses sbt? Who uses something else?

Who am I

Christopher Hunt

@huntchr

Developer for 30 years. Used many languages including COBOL! Committer on Play, author of Maven JavaScript Tools, JS Test Runner and other things.

typesafe.com

Build Reactive Apps on the JVM!

typesafe.com

Scala, Akka, Play Caretakers of Scala Martin Odersky Jonas Boner

Reactive

Event driven, scalable, resilient, interactive

- Resilient - recover and repair itself automatically for seamless business continuity - Interactive - rich & engaging, providing instant feedback based on user interactions - Scalable - predictably & elastically scalable; On-demand across cores, nodes and clusters - Event-Driven - processes messages in parallel, asynchronously without blocking, lock free

Tesla

Goal: next generation delivery
infrastructure for the JVM

- Jason Van Zyl - create Maven - Tesla is beyond just building - CI - build avoidance - CD - Provisioning & software delivery - Polyglot

Tesla Polyglot

Atom (Google Blaze)

Clojure

Groovy

Ruby

Scala

Yaml

- Maven's core is not, and never has been, tied to XML. - It's just a front-end format and really anything is possible - Think of the xml as the object code - translations available

- a stepping stone toward sbt - existing Maven/Scala experience poor - shouldn't *have* to use sbt - should want to - we still believe that sbt is the best tool for building Scala - embrace existing knowledge

Tesla Polyglot - XML

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>io.tesla.polyglot</groupId>
    <artifactId>tesla-polyglot</artifactId>
    <version>0.0.1-SNAPSHOT</version>
  </parent>
  <artifactId>tesla-polyglot-scala</artifactId>
  <name>Polyglot Tesla :: Scala</name>
  <contributors>
    <contributor>
      <name>Christopher Hunt</name>
      <organization>Typesafe</organization>
      <organizationUrl>http://typesafe.com</organizationUrl>
    </contributor>
  </contributors>
  <dependencies>
    <dependency>
      <groupId>io.tesla.polyglot</groupId>
      <artifactId>tesla-polyglot-common</artifactId>
      <version>0.0.1-SNAPSHOT</version>
    </dependency>
    <dependency>
      <groupId>com.twitter</groupId>
      <artifactId>util-eval</artifactId>
      <version>6.3.7</version>
    </dependency>
    <dependency>
      <groupId>com.googlecode.kiama</groupId>
      <artifactId>kiama_2.9.2</artifactId>
      <version>1.4.0</version>
    </dependency>
    <dependency>
      <groupId>org.scala-lang</groupId>
      <artifactId>scala-library</artifactId>
      <version>2.9.3</version>
    </dependency>
    <dependency>
      <groupId>org.specs2</groupId>
      <artifactId>specs2_2.9.3</artifactId>
      <version>1.12.4.1</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <scope>test</scope>
    </dependency>
  </dependencies>
		

Tesla Polyglot - Groovy

project {
  modelVersion '4.0.0'
  parent {
    groupId 'io.tesla.polyglot'
    artifactId 'tesla-polyglot'
    version '0.0.1-SNAPSHOT'
  }
  artifactId 'tesla-polyglot-scala'
  name 'Polyglot Tesla :: Scala'
  contributors {
    contributor {
      name 'Christopher Hunt'
      organization 'Typesafe'
      organizationUrl 'http://typesafe.com'
    }
  }
  dependencies {
    dependency {
      groupId 'io.tesla.polyglot'
      artifactId 'tesla-polyglot-common'
      version '0.0.1-SNAPSHOT'
    }
    dependency {
      groupId 'com.twitter'
      artifactId 'util-eval'
      version '6.3.7'
    }
    dependency {
      groupId 'com.googlecode.kiama'
      artifactId 'kiama_2.9.2'
      version '1.4.0'
    }
    dependency {
      groupId 'org.scala-lang'
      artifactId 'scala-library'
      version '2.9.3'
    }
    dependency {
      groupId 'org.specs2'
      artifactId 'specs2_2.9.3'
      version '1.12.4.1'
      scope 'test'
    }
    dependency {
      groupId 'junit'
      artifactId 'junit'
      scope 'test'
    }
  }
		

Tesla Polyglot
POM LOC Comparisons

Tesla Polyglot - Scala

import org.sonatype.maven.polyglot.scala.model._

Model(
  "" % "tesla-polyglot-scala",
  modelVersion = "4.0.0",
  parent = Parent("io.tesla.polyglot" % "tesla-polyglot" % "0.0.1-SNAPSHOT"),
  name = "Polyglot Tesla :: Scala",
  contributors = Seq(
    Contributor(
      name = "Christopher Hunt",
      organization = "Typesafe",
      organizationUrl = "http://typesafe.com"
    )
  ),
  dependencies = Seq(
    Dependency("io.tesla.polyglot" % "tesla-polyglot-common" % "0.0.1-SNAPSHOT"),
    Dependency("com.twitter" % "util-eval" % "6.3.7"),
    Dependency("com.googlecode.kiama" % "kiama_2.9.2" % "1.4.0"),
    Dependency("org.scala-lang" % "scala-library" % "2.9.3"),
    Dependency("org.specs2" % "specs2_2.9.3" % "1.12.4.1", scope = "test"),
    Dependency("junit" % "junit", scope = "test")
  ),
		

- named parameters - default args - functional - full Scala - not really a DSL - just a set of domain objects - scope for improvement - shorthand for dependencies

Under the Hood

- everything translates to a Maven Model - Java POJOs - pom.xml has precedence over pom.scala etc. - scala classes are cached in the target folder to minimise the need for compilation - similar to sbt in this regard

Soon... inlined Plugins

Model(
  "io.tesla.polyglot" % "tesla-polyglot" % "0.0.1-SNAPSHOT",
  Build(
    tasks = Seq(
      Task("hello", "validate") {
        p =>
          println("hello, I am Scala inside Maven.")
      }
    )
  )
)
		

- id, phase, block with project passed in - #1 complaint about Maven

Next Steps

- finish domain model (almost done) - release tesla-polyglot (waiting on me mainly) - may be use sbt eval - or externalise that - inline plugins