add extract method to MetaflowCode (Netflix#2246)

* add extract method to MetaflowCode

* add script property to metaflow code

* add script property to metaflow code

* add script property to metaflow code

* changes

* Address comments

Author: savingoyal

metaflow/client/core.py

@@ -5,6 +5,7 @@
 import tarfile
 from collections import namedtuple
 from datetime import datetime
+from tempfile import TemporaryDirectory
 from io import BytesIO
 from itertools import chain
 from typing import (
@@ -878,6 +879,73 @@ def tarball(self) -> tarfile.TarFile:
         """
         return self._tar
 
+    def extract(self) -> TemporaryDirectory:
+        """
+        Extracts the code package to a temporary directory.
+
+        This creates a temporary directory containing all user code
+        files from the code package. The temporary directory is
+        automatically deleted when the returned TemporaryDirectory
+        object is garbage collected or when its cleanup() is called.
+
+        To preserve the contents to a permanent location, use
+        os.replace() which performs a zero-copy move on the same
+        filesystem:
+
+        ```python
+        with task.code.extract() as tmp_dir:
+            # Move contents to permanent location
+            for item in os.listdir(tmp_dir):
+                src = os.path.join(tmp_dir, item)
+                dst = os.path.join('/path/to/permanent/dir', item)
+                os.makedirs(os.path.dirname(dst), exist_ok=True)
+                os.replace(src, dst)  # Atomic move operation
+        ```
+        Returns
+        -------
+        TemporaryDirectory
+            A temporary directory containing the extracted code files.
+            The directory and its contents are automatically deleted when
+            this object is garbage collected.
+        """
+        exclusions = [
+            "metaflow/",
+            "metaflow_extensions/",
+            "INFO",
+            "CONFIG_PARAMETERS",
+            "conda.manifest",
+            # This file is created when using the conda/pypi features available in
+            # nflx-metaflow-extensions: https://github.com/Netflix/metaflow-nflx-extensions
+            "condav2-1.cnd",
+        ]
+        members = [
+            m
+            for m in self.tarball.getmembers()
+            if not any(
+                (x.endswith("/") and m.name.startswith(x)) or (m.name == x)
+                for x in exclusions
+            )
+        ]
+
+        tmp = TemporaryDirectory()
+        self.tarball.extractall(tmp.name, members)
+        return tmp
+
+    @property
+    def script_name(self) -> str:
+        """
+        Returns the filename of the Python script containing the FlowSpec.
+
+        This is the main Python file that was used to execute the flow. For example,
+        if your flow is defined in 'myflow.py', this property will return 'myflow.py'.
+
+        Returns
+        -------
+        str
+            Name of the Python file containing the FlowSpec
+        """
+        return self._info["script"]
+
     def __str__(self):
         return "<MetaflowCode: %s>" % self._info["script"]