allow to override builder parameters

src/main/groovy/de/gesellix/gradle/docker/tasks/DockerBuildTask.groovy

@@ -22,6 +22,9 @@ class DockerBuildTask extends DockerTask {
     @InputDirectory
     @Optional
     File buildContextDirectory
+    @Input
+    @Optional
+    def buildParams
 
     def tarOfBuildcontextTask
     def targetFile
@@ -62,8 +65,11 @@ class DockerBuildTask extends DockerTask {
     private def configureTarBuildContextTask() {
         if (tarOfBuildcontextTask == null) {
             targetFile = new File(getTemporaryDir(), "buildContext_${getNormalizedImageName()}.tar.gz")
-            tarOfBuildcontextTask = project.task([group: getGroup()], "tarBuildcontextFor${name.capitalize()}").doLast {
+            tarOfBuildcontextTask = project.task([group: getGroup()], "tarBuildcontextFor${name.capitalize()}")
+            tarOfBuildcontextTask.doFirst {
                 (targetFile as File).parentFile.mkdirs()
+            }
+            tarOfBuildcontextTask.doLast {
                 BuildContextBuilder.archiveTarFilesRecursively(getBuildContextDirectory(), targetFile)
             }
             tarOfBuildcontextTask.outputs.file(targetFile.absolutePath)
@@ -88,7 +94,11 @@ class DockerBuildTask extends DockerTask {
         // at this point we need the buildContext
         assert getBuildContext()
 
-        imageId = getDockerClient().build(getBuildContext())
+        if (getBuildParams()) {
+            imageId = getDockerClient().build(getBuildContext(), getBuildParams())
+        } else {
+            imageId = getDockerClient().build(getBuildContext())
+        }
         if (getImageName()) {
             logger.info "tag $imageId as '${getImageName()}'..."
             getDockerClient().tag(imageId, getImageName(), true)

src/test/groovy/de/gesellix/gradle/docker/PortFinder.groovy

@@ -0,0 +1,28 @@
+package de.gesellix.gradle.docker
+
+class PortFinder {
+
+    static int findFreePort() {
+        ServerSocket socket = null
+        try {
+            socket = new ServerSocket(0)
+            socket.setReuseAddress(true)
+            int port = socket.getLocalPort()
+            try {
+                socket.close()
+            } catch (IOException ignore) {
+                // Ignore IOException on close()
+            }
+            return port
+        } catch (IOException ignore) {
+        } finally {
+            if (socket != null) {
+                try {
+                    socket.close()
+                } catch (IOException ignore) {
+                }
+            }
+        }
+        throw new IllegalStateException("Could not find a free TCP/IP port")
+    }
+}

src/test/groovy/de/gesellix/gradle/docker/tasks/DockerBuildTaskSpec.groovy

@@ -115,6 +115,27 @@ class DockerBuildTaskSpec extends Specification {
         task.outputs.files.isEmpty()
     }
 
+    def "delegates to dockerClient with buildContext and buildParams"() {
+        def inputStream = new FileInputStream(File.createTempFile("docker", "test"))
+
+        given:
+        task.buildContext = inputStream
+        task.buildParams = [rm: true, dockerfile: './custom.Dockerfile']
+        task.imageName = "imageName"
+
+        when:
+        task.execute()
+
+        then:
+        1 * dockerClient.build(inputStream, [rm: true, dockerfile: './custom.Dockerfile']) >> "4711"
+
+        then:
+        1 * dockerClient.tag("4711", "imageName", true)
+
+        and:
+        task.outputs.files.isEmpty()
+    }
+
     // TODO this should become an integration test
     def "accepts only task configs with at least one of buildContext or buildContextDirectory"() {
         given:

src/test/groovy/de/gesellix/gradle/docker/tasks/DockerContainerTaskSpec.groovy

@@ -1,9 +1,9 @@
 package de.gesellix.gradle.docker.tasks
 
 import de.gesellix.docker.client.DockerClient
+import de.gesellix.gradle.docker.PortFinder
 import org.gradle.api.GradleException
 import org.gradle.testfixtures.ProjectBuilder
-import org.gradle.util.AvailablePortFinder
 import spock.lang.Specification
 
 class DockerContainerTaskSpec extends Specification {
@@ -465,7 +465,7 @@ class DockerContainerTaskSpec extends Specification {
 
     def "healthcheck on already running container - timeout"() {
         given:
-        int port = AvailablePortFinder.createPrivate().nextAvailable
+        int port = PortFinder.findFreePort()
 
         when:
         task.dockerHost = "tcp://127.0.0.1:999"
@@ -510,26 +510,26 @@ class DockerContainerTaskSpec extends Specification {
 
     def "healthcheck on already running container"() {
         given:
-        int port = 0
-
         Thread server = new Thread() {
             boolean initialized = false
             int serverPort = 0
+            boolean stopped = false
 
             public void run() {
-                ServerSocket ss;
+                ServerSocket ss
                 synchronized (this) {
-                    serverPort = AvailablePortFinder.createPrivate().nextAvailable
-                    ss = new ServerSocket(serverPort);
+                    serverPort = PortFinder.findFreePort()
+                    ss = new ServerSocket(serverPort)
                     initialized = true
                     notify()
                 }
-                while (true) {
-                    Socket client = ss.accept();
+                while (!stopped) {
+                    ss.accept()
                 }
             }
         }
 
+        def port
         server.start()
         synchronized (server) {
             if (!server.initialized) {
@@ -574,6 +574,7 @@ class DockerContainerTaskSpec extends Specification {
         task.changed == false
 
         cleanup:
-        server.stop();
+        server.stopped = true
+        server.stop()
     }
 }