FIX #82 adding the ability to specify jvm options via sbt

Author: muuki88

src/main/scala/com/typesafe/sbt/packager/archetypes/JavaServerApplication.scala

@@ -3,7 +3,7 @@ package packager
 package archetypes
 
 import sbt._
-import sbt.Keys.{ target, mainClass, sourceDirectory, streams }
+import sbt.Keys.{ target, mainClass, sourceDirectory, streams, javaOptions, run }
 import SbtNativePackager.{ Debian, Rpm, Universal }
 import packager.Keys.{ packageName }
 import linux.{ LinuxFileMetaData, LinuxPackageMapping, LinuxSymlink, LinuxPlugin }
@@ -46,6 +46,7 @@ object JavaServerAppPackaging extends AutoPlugin {
    * - config directory
    */
   def linuxSettings: Seq[Setting[_]] = Seq(
+    javaOptions in Linux := Nil,
     // === logging directory mapping ===
     linuxPackageMappings <+= (packageName in Linux, defaultLinuxLogsLocation, daemonUser in Linux, daemonGroup in Linux) map {
       (name, logsDir, user, group) => packageTemplateMapping(logsDir + "/" + name)() withUser user withGroup group withPerms "755"
@@ -60,7 +61,7 @@ object JavaServerAppPackaging extends AutoPlugin {
       if (overrideScript.exists) overrideScript.toURI.toURL
       else etcDefaultTemplateSource
     },
-    makeEtcDefault <<= (packageName in Linux, target in Universal, linuxEtcDefaultTemplate, linuxScriptReplacements)
+    makeEtcDefault <<= (packageName in Linux, target in Universal, linuxEtcDefaultTemplate, linuxScriptReplacements, javaOptions in Linux)
       map makeEtcDefaultScript,
     linuxPackageMappings <++= (makeEtcDefault, bashScriptConfigLocation) map { (conf, configLocation) =>
       configLocation.flatMap { path =>
@@ -259,10 +260,26 @@ object JavaServerAppPackaging extends AutoPlugin {
     Some(script)
   }
 
-  protected def makeEtcDefaultScript(name: String, tmpDir: File, source: java.net.URL, replacements: Seq[(String, String)]): Option[File] = {
+  /**
+   * Creates the etc-default file, which will contain the basic configuration
+   * for an app.
+   * 
+   * @param name of the etc-default config file
+   * @param tmpDir to store the resulting file in (e.g. target in Universal)
+   * @param source of etc-default script
+   * @param replacements for placeholders in etc-default script
+   * @param javaOptions that get appended to the etc-default script
+   * 
+   * @return Some(file: File)
+   */
+  protected def makeEtcDefaultScript(name: String, tmpDir: File, source: java.net.URL,
+    replacements: Seq[(String, String)], javaOptions: Seq[String]): Option[File] = {
     val scriptBits = TemplateWriter.generateScript(source, replacements)
     val script = tmpDir / "tmp" / "etc" / "default" / name
     IO.write(script, scriptBits)
+    if (javaOptions.nonEmpty) {
+      IO.writeLines(script, "# java options from build" +: javaOptions, append = true)
+    }
     Some(script)
   }
 

src/sbt-test/universal/jvmopts-makeEtcDefault/build.sbt

@@ -0,0 +1,18 @@
+enablePlugins(JavaServerAppPackaging)
+
+name := "simple-test"
+
+version := "0.1.0"
+
+javaOptions in Linux ++= Seq(
+  "-J-Xmx64m", "-J-Xms64m", "-Dproperty=true"
+)
+
+TaskKey[Unit]("check") := {
+  val etc = (target in Universal).value / "tmp" / "etc" / "default" / name.value
+  val content = IO.read(etc)
+  val options = (javaOptions in Linux).value
+  options.foreach { opt => 
+    assert(content.contains(opt), "Option [" + opt + "] is missing")
+  }
+}

src/sbt-test/universal/jvmopts-makeEtcDefault/project/plugins.sbt

@@ -0,0 +1 @@
+addSbtPlugin("com.typesafe.sbt" % "sbt-native-packager" % sys.props("project.version"))

src/sbt-test/universal/jvmopts-makeEtcDefault/src/main/scala/Main.scala

@@ -0,0 +1,3 @@
+object Main extends App {
+  println("Hello world")
+}

src/sbt-test/universal/jvmopts-makeEtcDefault/test

@@ -0,0 +1,4 @@
+# Run the zip packaging.
+> show makeEtcDefault
+$ exists target/universal/tmp/etc/default/simple-test
+> check

src/sphinx/archetypes/java_server/customize.rst

@@ -18,7 +18,18 @@ As this file is OS dependend, each OS gets section.
 Linux Configuration
 -------------------
 
-Create ``src/templates/etc-default`` with the following template
+You have two options. First, you can specify your options via the ``build.sbt``.
+
+.. code-block :: scala
+
+    javaOptions in Linux ++= Seq(
+        "-J-Xmx64m", "-J-Xms64m", "-Dproperty=true",  
+    )
+
+For the ``-X`` settings you need to add a suffix ``-J`` so the start script will
+recognize these as vm config parameters. 
+
+The other option is to create ``src/templates/etc-default`` with the following template
 
 .. code-block :: bash
 
@@ -59,7 +70,8 @@ Create ``src/templates/etc-default`` with the following template
     # -d -- -d
 
 The file will be installed to ``/etc/default/<normalizedName>`` and read from there
-by the startscript.
+by the startscript. You can use ``#`` for comments and new lines as you like. The
+available are listed in the template or you can display them via ``show linuxScriptReplacements``.
 
 Environment variables
 ~~~~~~~~~~~~~~~~~~~~~