[execution][docker] Add support for custom mount points

Support giving a custom mount point to use for volume setup.

This will replace the cache path when creating the volumes.

beat/core/execution/docker.py

@@ -279,7 +279,9 @@ class DockerExecutor(RemoteExecutor):
         )
         return retval
 
-    def __setup_io_volumes(self, algorithm_container, configuration):
+    def __setup_io_volumes(
+        self, algorithm_container, docker_cache_mount_point, configuration
+    ):
         """Setup all the volumes for input and output files.
 
         Parameters:
@@ -293,25 +295,35 @@ class DockerExecutor(RemoteExecutor):
             file_path = item["path"]
             source_path = os.path.join(self.cache, file_path)
 
-            if os.path.isfile(source_path):
-                algorithm_container.add_volume(
-                    source_path, os.path.join(self.CONTAINER_CACHE_PATH, file_path)
-                )
+            if docker_cache_mount_point is None:
+                if os.path.isfile(source_path):
+                    algorithm_container.add_volume(
+                        source_path, os.path.join(self.CONTAINER_CACHE_PATH, file_path)
+                    )
+                else:
+                    all_files = getAllFilenames(source_path)
+                    for file_list in all_files:
+                        for file_ in file_list:
+                            target_path = file_[len(self.cache) + 1 :]
+                            cache_path = os.path.join(
+                                self.CONTAINER_CACHE_PATH, target_path
+                            )
+                            algorithm_container.add_volume(file_, cache_path)
             else:
-                all_files = getAllFilenames(source_path)
-                for file_list in all_files:
-                    for file_ in file_list:
-                        target_path = file_[len(self.cache) + 1 :]
-                        cache_path = os.path.join(
-                            self.CONTAINER_CACHE_PATH, target_path
-                        )
-                        algorithm_container.add_volume(file_, cache_path)
+                input_folder = file_path[: file_path.rfind("/")]
+                source_folder = os.path.join(docker_cache_mount_point, input_folder)
+                target_folder = os.path.join(self.CONTAINER_CACHE_PATH, input_folder)
+                algorithm_container.add_volume(source_folder, target_folder)
 
         def __add_writable_volume(file_path):
             output_folder = file_path[: file_path.rfind("/")]
             source_folder = os.path.join(self.cache, output_folder)
             if not os.path.exists(source_folder):
                 os.makedirs(source_folder)
+
+            if docker_cache_mount_point is not None:
+                source_folder = os.path.join(docker_cache_mount_point, output_folder)
+
             algorithm_container.add_volume(
                 source_folder,
                 os.path.join(self.CONTAINER_CACHE_PATH, output_folder),
@@ -405,6 +417,8 @@ class DockerExecutor(RemoteExecutor):
             port = utils.find_free_port_in_range(int(min_port), int(max_port))
             address += ":{}".format(port)
 
+        volume_cache_mount_point = self.data.pop("cache_mount_point", None)
+
         self.message_handler = MessageHandler(address, kill_callback=_kill)
 
         # ----- (If necessary) Instantiate the docker container that provide the databases
@@ -463,7 +477,9 @@ class DockerExecutor(RemoteExecutor):
             loop_algorithm_container.add_volume(
                 configuration_path, self.CONTAINER_PREFIX_PATH
             )
-            self.__setup_io_volumes(loop_algorithm_container, self.data["loop"])
+            self.__setup_io_volumes(
+                loop_algorithm_container, volume_cache_mount_point, self.data["loop"]
+            )
 
             # Start the container
             self.host.start(
@@ -505,7 +521,9 @@ class DockerExecutor(RemoteExecutor):
 
         # Volumes
         algorithm_container.add_volume(configuration_path, self.CONTAINER_PREFIX_PATH)
-        self.__setup_io_volumes(algorithm_container, self.data)
+        self.__setup_io_volumes(
+            algorithm_container, volume_cache_mount_point, self.data
+        )
 
         # Start the container
         self.host.start(