tamarin: add prepareEnvironment() method

vars/tamarin.groovy

@@ -89,6 +89,31 @@ def buildPackage(
     
 }
 
+def prepareEnvironment(
+    String packageProfile = "debian",
+    String baseImage = ""
+) {
+    def tamarinImage
+
+    stage("Create Tamarin environment") {
+        tamarinImage = buildDockerImage()
+    }   
+    
+    stage("Prepare Tamarin") {
+        def dockerArgs = """
+        -v /var/run/docker.sock:/var/run/docker.sock
+        ${baseImage ? '-e TAMARIN_BASE_IMAGE='+baseImage : ''}
+        ${packageProfile ? '-e TAMARIN_PROFILE='+packageProfile : ''}
+        -e TAMARIN_PREPARE_ONLY=true
+        -e TAMARIN_FORCE_REBUILD=true
+        """.stripIndent()
+
+        tamarinImage.inside(dockerArgs) {
+            sh 'run-tamarin'
+        }
+    }
+}
+
 def buildDockerImage() {
     dir ('.tamarin') {
         def dockerfile = libraryResource 'com/cadoles/tamarin/Dockerfile'