add convenience constructor

README.md

@@ -135,29 +135,26 @@ import sbtsparksubmit.SparkSubmitPlugin.autoImport._
 
 object SparkSubmit {
   lazy val settings =
-    SparkSubmitSetting("sparkPi").
-      setting(
-        sparkSubmitSparkArgs,
-        "--class", "SparkPi"
-      )
+    SparkSubmitSetting("sparkPi",
+      Seq("--class", "SparkPi")
+    )
 }
 ```
 Here we created a single `SparkSubmitSetting` object and fuses it with additional settings.
 
 To create multiple tasks, you can wrap them with `SparkSubmitSetting` again like this:
 ```scala
-lazy val settings = SparkSubmitSetting(
-    SparkSubmitSetting("spark2").
-      setting(sparkSubmitSparkArgs,
-        "--class", "Main2"
-      ),
-    SparkSubmitSetting("spark2Other").
-      setting(sparkSubmitSparkArgs,
-        "--class", "Main2"
-      ).
-      setting(sparkSubmitAppArgs,
-        "hello.txt"
-      )
+  lazy val settings = SparkSubmitSetting(
+    SparkSubmitSetting("spark1",
+      Seq("--class", "Main1")
+    ),
+    SparkSubmitSetting("spark2",
+      Seq("--class", "Main2")
+    ),
+    SparkSubmitSetting("spark2Other",
+      Seq("--class", "Main2"),
+      Seq("hello.txt")
+    )
   )
 ```
 
@@ -170,7 +167,23 @@ sbt spark2Other
 ```
 would be equivalent.
 
+`SparkSubmitSetting` has three `apply` functions:
+```scala
+def apply(name: String): SparkSubmitSetting
+def apply(name: String, sparkArgs: Seq[String] = Seq(), appArgs: Seq[String] = Seq()): SparkSubmitSetting
+def apply(sparkSubmitSettings: SparkSubmitSetting*): Seq[Def.Setting[_]]
+```
+The first creates a simple `SparkSubmitSetting` object with a custom task name. The object itself has `setting` function
+that allows you to blend in additional settings that is specific to this task.
+
+Because the most common use case of custom task is to provide custom default Spark and Application arguments,
+the second variant allow you provide those directly.
 
+There is already an implicit conversion from `SparkSubmitSetting` to `Seq[Def.Setting[_]]` which allows you to
+append itself to your project. When there are multiple settings, the third variant allows you to aggregate all
+of them without additional type hinting for implicit to work.
+
+See `src/sbt-test/sbt-spark-submit/multi-main` for examples.
 
 ## Multi-project builds
 
@@ -186,6 +199,8 @@ select any specific project.
 
 Of course, `sparkB` task won't even trigger a build on `A` unless `B` depends on `A` thanks to the magic of sbt.
 
+See `src/sbt-test/sbt-spark-submit/multi-project` for examples.
+
 ## Resources
 
 For more information and working examples, see projects under `examples` and `src/sbt-test`.

examples/sbt-assembly-on-yarn/project/SparkSubmit.scala

@@ -2,10 +2,10 @@ import sbtsparksubmit.SparkSubmitPlugin.autoImport._
 
 object SparkSubmit {
   lazy val settings: Seq[sbt.Def.Setting[_]] =
-    SparkSubmitSetting("sparkPi").
-      setting(
-        sparkSubmitSparkArgs,
-        "--class", "SparkPi",
-        "--num-executors", "1000"
+    SparkSubmitSetting("sparkPi",
+        Seq(
+          "--class", "SparkPi",
+          "--num-executors", "1000"
+        )
       )
 }

examples/spark-submit-plugin-test/project/SparkSubmit.scala

@@ -2,9 +2,5 @@ import sbtsparksubmit.SparkSubmitPlugin.autoImport._
 
 object SparkSubmit {
   lazy val settings =
-    SparkSubmitSetting("sparkPi").
-      setting(
-        sparkSubmitSparkArgs,
-        "--class", "SparkPi"
-      )
+    SparkSubmitSetting("sparkPi", Seq("--class", "SparkPi"))
 }

src/main/scala/sbtsparksubmit/SparkSubmitPlugin.scala

@@ -41,18 +41,10 @@ object SparkSubmitPlugin extends AutoPlugin {
         this.settings +:= (taskKey in this := value)
         this
       }
-      def setting[T](taskKey: TaskKey[Seq[T]], value: T*): this.type = {
-        this.settings +:= (taskKey in this := value)
-        this
-      }
       def setting[T](settingKey: SettingKey[T], value: T): this.type = {
         this.settings +:= (settingKey in this := value)
         this
       }
-      def setting[T](settingKey: SettingKey[Seq[T]], value: T*): this.type = {
-        this.settings +:= (settingKey in this := value)
-        this
-      }
 
 
       lazy val defaultSettings = Seq(
@@ -100,6 +92,11 @@ object SparkSubmitPlugin extends AutoPlugin {
 
     object SparkSubmitSetting {
       def apply(name: String): SparkSubmitSetting = new SparkSubmitSetting(name)
+      def apply(name: String, sparkArgs: Seq[String] = Seq(), appArgs: Seq[String] = Seq()): SparkSubmitSetting = {
+        new SparkSubmitSetting(name).
+          setting(sparkSubmitSparkArgs, sparkArgs).
+          setting(sparkSubmitAppArgs, appArgs)
+      }
       def apply(sparkSubmitSettings: SparkSubmitSetting*): Seq[Def.Setting[_]] = {
         sparkSubmitSettings.map(_.toSettings).reduce(_ ++ _)
       }

src/sbt-test/sbt-spark-submit/multi-main/project/SparkSubmit.scala

@@ -3,20 +3,15 @@ import sbt._
 
 object SparkSubmit {
   lazy val settings = SparkSubmitSetting(
-    SparkSubmitSetting("spark1").
-      setting(sparkSubmitSparkArgs,
-        "--class", "Main1"
-      ),
-    SparkSubmitSetting("spark2").
-      setting(sparkSubmitSparkArgs,
-        "--class", "Main2"
-      ),
-    SparkSubmitSetting("spark2Other").
-      setting(sparkSubmitSparkArgs,
-        "--class", "Main2"
-      ).
-      setting(sparkSubmitAppArgs,
-        "hello.txt"
-      )
+    SparkSubmitSetting("spark1",
+      Seq("--class", "Main1")
+    ),
+    SparkSubmitSetting("spark2",
+      Seq("--class", "Main2")
+    ),
+    SparkSubmitSetting("spark2Other",
+      Seq("--class", "Main2"),
+      Seq("hello.txt")
+    )
   )
-}
+}

src/sbt-test/sbt-spark-submit/multi-project/project/SparkSubmit.scala

@@ -3,15 +3,9 @@ import sbt._
 
 object SparkSubmit {
   lazy val settingsFoo = SparkSubmitSetting(
-    SparkSubmitSetting("sparkFoo").
-      setting(sparkSubmitSparkArgs,
-        "--class", "Main"
-      )
+    SparkSubmitSetting("sparkFoo", Seq("--class", "Main"))
   )
   lazy val settingsBar = SparkSubmitSetting(
-    SparkSubmitSetting("sparkBar").
-      setting(sparkSubmitSparkArgs,
-        "--class", "Main"
-      )
+    SparkSubmitSetting("sparkBar", Seq("--class", "Main"))
   )
-}
+}

src/sbt-test/sbt-spark-submit/sparkpi/project/SparkSubmit.scala

@@ -1,10 +1,5 @@
 import sbtsparksubmit.SparkSubmitPlugin.autoImport._
 
 object SparkSubmit {
-  lazy val settings =
-    SparkSubmitSetting("sparkPi").
-      setting(
-        sparkSubmitSparkArgs,
-        "--class", "SparkPi"
-      )
-}
+  lazy val settings = SparkSubmitSetting("sparkPi", Seq("--class", "SparkPi"))
+}