.asc signing for Maven publication.

src/main/kotlin/com/beust/kobalt/maven/Gpg.kt

@@ -0,0 +1,57 @@
+package com.beust.kobalt.maven
+
+import com.beust.kobalt.misc.log
+import com.google.inject.Singleton
+import java.io.File
+
+@Singleton
+public class Gpg {
+    val COMMANDS = listOf("gpg", "gpg2")
+
+     fun findGpgCommand() : String? {
+        val path = System.getenv("PATH")
+        if (path != null) {
+            path.split(File.pathSeparator).forEach { dir ->
+                COMMANDS.map { File(dir, it) }.firstOrNull { it.exists() }?.let {
+                    return it.absolutePath
+                }
+            }
+        }
+        return null
+    }
+
+    /**
+     * @return the .asc files
+     */
+    fun runGpg(files: List<File>) : List<File> {
+        val result = arrayListOf<File>()
+        val gpg = findGpgCommand()
+        if (gpg != null) {
+            val directory = files.get(0).parentFile.absoluteFile
+            files.forEach { file ->
+                with(File(directory, file.absolutePath + ".asc")) {
+                    delete()
+                    result.add(this)
+                }
+                val allArgs = arrayListOf<String>()
+                allArgs.add(gpg)
+                allArgs.add("-ab")
+                allArgs.add(file.absolutePath)
+
+                val pb = ProcessBuilder(allArgs)
+                pb.directory(directory)
+                pb.inheritIO()
+                log(1, "Signing files: " + allArgs.join(" "))
+                val process = pb.start()
+                val errorCode = process.waitFor()
+                if (errorCode != 0) {
+                    throw KobaltException("Couldn't sign file $file")
+                }
+            }
+
+            return files.map { File(it.absolutePath + ".asc") }
+        } else {
+            throw KobaltException("Couldn't find the command, is it installed and in your PATH?")
+        }
+    }
+}

src/main/kotlin/com/beust/kobalt/plugin/publish/JCenterApi.kt

@@ -3,6 +3,7 @@ package com.beust.kobalt.plugin.publish
 import com.beust.klaxon.*
 import com.beust.kobalt.api.Project
 import com.beust.kobalt.internal.TaskResult
+import com.beust.kobalt.maven.Gpg
 import com.beust.kobalt.maven.Http
 import com.beust.kobalt.maven.KobaltException
 import com.beust.kobalt.maven.Md5
@@ -43,7 +44,7 @@ open public class UnauthenticatedJCenterApi @Inject constructor(open val http: H
 
 public class JCenterApi @Inject constructor (@Nullable @Assisted("username") val username: String?,
         @Nullable @Assisted("password") val password: String?,
-        override val http: Http) : UnauthenticatedJCenterApi(http) {
+        override val http: Http, val gpg: Gpg) : UnauthenticatedJCenterApi(http) {
 
     interface IFactory {
         fun create(@Nullable @Assisted("username") username: String?,
@@ -88,24 +89,29 @@ public class JCenterApi @Inject constructor (@Nullable @Assisted("username") val
                 .join("/")
         }
 
-        return upload(files, configuration, fileToPath, true)
+        return upload(files, configuration, fileToPath, generateMd5 = true, generateAsc = true)
     }
 
-    fun uploadFile(file: File, url: String, configuration: JCenterConfiguration, generateMd5: Boolean = false) =
+    fun uploadFile(file: File, url: String, configuration: JCenterConfiguration, generateMd5: Boolean = false,
+            generateAsc: Boolean = false) =
         upload(arrayListOf(file), configuration, {
-                f: File -> "${UnauthenticatedJCenterApi.BINTRAY_URL_API_CONTENT}/$username/generic/$url"
+                f: File -> "${UnauthenticatedJCenterApi.BINTRAY_URL_API_CONTENT}/$username/generic/$url"},
-            }, generateMd5)
+                generateMd5, generateAsc)
 
     private fun upload(files: List<File>, configuration : JCenterConfiguration?, fileToPath: (File) -> String,
-            generateMd5: Boolean = false) : TaskResult {
+            generateMd5: Boolean = false, generateAsc: Boolean) : TaskResult {
         val successes = arrayListOf<File>()
         val failures = hashMapOf<File, String>()
         val filesToUpload = arrayListOf<File>()
-        files.forEach {
 
-            // Create the md5 for this file
+        if (generateAsc) {
+            // Create the .asc files
+            filesToUpload.addAll(gpg.runGpg(files))
+        }
+        files.forEach {
             filesToUpload.add(it)
             if (generateMd5) {
+                // Create and upload the md5 for this file
                 with(File(it.absolutePath)) {
                     val md5: String = Md5.toMd5(this)
                     val md5File = File(absolutePath + ".md5")