fix: set runfiles and workdir for py3_image

{{ .ProjectSnake }}/tools/oci/py3_image.bzl

@@ -4,9 +4,27 @@ load("@aspect_bazel_lib//lib:transitions.bzl", "platform_transition_filegroup")
 load("@aspect_rules_py//py:defs.bzl", "py_image_layer")
 load("@rules_oci//oci:defs.bzl", "oci_image", "oci_load")
 
-def py3_image(name, binary, root = "/", layer_groups = {}, base = "@python_base"):
+def py3_image(name, binary, root = "/", layer_groups = {}, env = {}, workdir = None, base = "@python_base"):
+    """Create a Python 3 image from a Python binary.
+
+    Args:
+        name: The name of the image.
+        binary: The Python binary to create the image from.
+        root: The root directory where everything will be put into
+        layer_groups: The layer groups to use for the image.
+        env: The environment variables to set in the image.
+        workdir: The working directory to set in the image.
+        base: The base image to use for the image.
+    """
     binary = native.package_relative_label(binary)
     binary_path = "{}{}/{}".format(root, binary.package, binary.name)
+    runfiles_dir = "{}.runfiles".format(binary_path)
+    repo_name = binary.repo_name or "_main"
+    env = dict({
+        "BAZEL_WORKSPACE": repo_name, 
+        "RUNFILES_DIR": runfiles_dir,
+    }, **env)
+
     oci_image(
         name = name + "_image",
         base = base,
@@ -17,6 +35,8 @@ def py3_image(name, binary, root = "/", layer_groups = {}, base = "@python_base"
             layer_groups = layer_groups,
         ),
         entrypoint = [binary_path],
+        env = env,
+        workdir = workdir or "{}/{}".format(runfiles_dir, repo_name),
     )
     platform_transition_filegroup(
         name = name,