Add a new exposed 'unpacking' phase to the build and make sure that the unzip/untar/etc always occurs under a try-except

workers/dockerfilebuild.py

@@ -521,16 +521,6 @@ class DockerfileBuildWorker(Worker):
     logger.info(filetype_msg)
     log_appender(filetype_msg)
 
-    if c_type not in self._mime_processors:
-      log_appender('error', build_logs.PHASE)
-      repository_build.phase = 'error'
-      repository_build.save()
-      message = 'Unknown mime-type: %s' % c_type
-      log_appender(message, build_logs.ERROR)
-      raise JobException(message)
-
-    build_dir = self._mime_processors[c_type](docker_resource)
-
     # Spawn a notification that the build has started.
     event_data = {
       'build_id': repository_build.uuid,
@@ -544,6 +534,7 @@ class DockerfileBuildWorker(Worker):
                        subpage='build?current=%s' % repository_build.uuid,
                        pathargs=['build', repository_build.uuid])
 
+
     # Setup a handler for spawning failure messages.
     def spawn_failure(message, event_data):
       event_data['error_message'] = message
@@ -551,6 +542,28 @@ class DockerfileBuildWorker(Worker):
                          subpage='build?current=%s' % repository_build.uuid,
                          pathargs=['build', repository_build.uuid])
 
+    if c_type not in self._mime_processors:
+      log_appender('error', build_logs.PHASE)
+      repository_build.phase = 'error'
+      repository_build.save()
+      message = 'Unknown mime-type: %s' % c_type
+      log_appender(message, build_logs.ERROR)
+      spawn_failure(message, event_data)
+      raise JobException(message)
+
+    # Try to build the build directory package from the buildpack.
+    log_appender('unpacking', build_logs.PHASE)
+    repository_build.phase = 'unpacking'
+    repository_build.save()
+
+    build_dir = None
+    try:
+      build_dir = self._mime_processors[c_type](docker_resource)
+    except Exception as ex:
+      log_appender(ex.message, build_logs.ERROR)
+      spawn_failure(ex.message, event_data)
+      raise JobException(ex.message)      
+
     # Start the build process.
     try:
       with DockerfileBuildContext(build_dir, build_subdir, repo, tag_names, access_token,