如何用sbt-assembly制作多项目fat jar

Question

我有一个使用spark的scala多项目，并尝试使用sbt插件sbt-assembly 0.14.3来制作一个胖jar。我的buils.sbt是这样的：

lazy val commonSettings = Seq(
  organization := "blabla",
  version := "0.1.0",
  scalaVersion := "2.11.8"
)


lazy val core = (project in file("."))
  .settings(commonSettings: _*)
  .settings(libraryDependencies ++= Seq(
"org.apache.spark" %% "spark-core" % "1.6.1" % "provided",
"org.apache.spark" %% "spark-sql" % "1.6.1" % "provided",
"org.apache.spark" %% "spark-mllib" % "1.6.1" % "provided",...)


lazy val sub_project = project
  .settings(commonSettings: _*)
  .aggregate(core)
  .dependsOn(core)

我想创建一个sub_project的fat jar，这样这个fat jar就包含了项目核心中的所有库和代码。我尝试了以下几种方法：

sbt
project sub_project
assembly

我得到了以下错误：

[error] missing or invalid dependency detected while loading class file 'blabla.class'.
[error] Could not access term spark in package org.apache,
[error] because it (or its dependencies) are missing. Check your build definition for
[error] missing or conflicting dependencies. (Re-run with `-Ylog-classpath` to see the problematic classpath.)
[error] A full rebuild may help if 'blabla.class' was compiled against an incompatible version of org.apache.
[error] one error found

然而，当我在核心项目上使用"assembly“时，我可以得到我的胖jar。

Answer 1

您的构建表明，sub_project的类路径中不存在对Spark的库依赖(与provided语句无关)，并且您得到的错误消息与此相匹配。您可能希望将此依赖项添加到通用设置中。