diff --git a/BUILD b/BUILD
index 3ae07ae..db34e8d 100644
--- a/BUILD
+++ b/BUILD
@@ -2,7 +2,7 @@ exports_files([
     "._dummy_.py",
     "pywrapper.sh",
     "coverage_report.sh",
-])
+] + glob(["external/*.BUILD"]))
 
 sh_library(
     name = "pywrapper",
diff --git a/bazel_pybind11.bzl b/bazel_pybind11.bzl
new file mode 100644
index 0000000..17c8e39
--- /dev/null
+++ b/bazel_pybind11.bzl
@@ -0,0 +1,138 @@
+
+def bazel_pybind11(
+    name = "pybind11",
+    build_file = "@pybind11_bazel//:pybind11.BUILD",
+    sha256 = "c9375b7453bef1ba0106849c83881e6b6882d892c9fae5b2572a2192100ffb8a",
+    strip_prefix = "pybind11-a54eab92d265337996b8e4b4149d9176c2d428a6",
+    urls = ["https://github.com/pybind/pybind11/archive/a54eab92d265337996b8e4b4149d9176c2d428a6.tar.gz"],
+):
+    native.http_archive(
+        name = name,
+        build_file = build_file,
+        sha256 = sha256,
+        strip_prefix = strip_prefix,
+        urls = urls,
+    )
+
+# https://github.com/pybind/pybind11_bazel/blob/master/build_defs.bzl
+# Copyright (c) 2019 The Pybind Development Team. All rights reserved.
+#
+# All rights reserved. Use of this source code is governed by a
+# BSD-style license that can be found in the LICENSE file.
+
+"""Build rules for pybind11."""
+
+def register_extension_info(**kwargs):
+    pass
+
+PYBIND_COPTS = select({
+    "@pybind11//:msvc_compiler": [],
+    "//conditions:default": [
+        "-fexceptions",
+    ],
+})
+
+PYBIND_FEATURES = [
+    "-use_header_modules",  # Required for pybind11.
+    "-parse_headers",
+]
+
+PYBIND_DEPS = [
+    "@pybind11",
+    # "@local_config_python//:python_headers",
+    # "@python//:python",
+    "@python",
+]
+
+# Builds a Python extension module using pybind11.
+# This can be directly used in python with the import statement.
+# This adds rules for a .so binary file.
+def pybind_extension(
+        name,
+        copts = [],
+        features = [],
+        linkopts = [],
+        tags = [],
+        deps = [],
+        **kwargs):
+    # Mark common dependencies as required for build_cleaner.
+    tags = tags + ["req_dep=%s" % dep for dep in PYBIND_DEPS]
+
+    native.cc_binary(
+        name = name + ".so",
+        copts = copts + PYBIND_COPTS + select({
+            "@pybind11//:msvc_compiler": [],
+            "//conditions:default": [
+                "-fvisibility=hidden",
+            ],
+        }),
+        features = features + PYBIND_FEATURES,
+        linkopts = linkopts + select({
+            "@pybind11//:msvc_compiler": [],
+            "@pybind11//:osx": [],
+            "//conditions:default": ["-Wl,-Bsymbolic"],
+        }),
+        linkshared = 1,
+        tags = tags,
+        deps = deps + PYBIND_DEPS,
+        **kwargs
+    )
+
+# Builds a pybind11 compatible library. This can be linked to a pybind_extension.
+def pybind_library(
+        name,
+        copts = [],
+        features = [],
+        tags = [],
+        deps = [],
+        **kwargs):
+    # Mark common dependencies as required for build_cleaner.
+    tags = tags + ["req_dep=%s" % dep for dep in PYBIND_DEPS]
+
+    native.cc_library(
+        name = name,
+        copts = copts + PYBIND_COPTS,
+        features = features + PYBIND_FEATURES,
+        tags = tags,
+        deps = deps + PYBIND_DEPS,
+        **kwargs
+    )
+
+# # Builds a C++ test for a pybind_library.
+# def pybind_library_test(
+#         name,
+#         copts = [],
+#         features = [],
+#         tags = [],
+#         deps = [],
+#         **kwargs):
+#     # Mark common dependencies as required for build_cleaner.
+#     tags = tags + ["req_dep=%s" % dep for dep in PYBIND_DEPS]
+
+#     native.cc_test(
+#         name = name,
+#         copts = copts + PYBIND_COPTS,
+#         features = features + PYBIND_FEATURES,
+#         tags = tags,
+#         deps = deps + PYBIND_DEPS + [
+#             "//util/python:python_impl",
+#             "//util/python:test_main",
+#         ],
+#         **kwargs
+#     )
+
+# Register extension with build_cleaner.
+register_extension_info(
+    extension = pybind_extension,
+    label_regex_for_dep = "{extension_name}",
+)
+
+register_extension_info(
+    extension = pybind_library,
+    label_regex_for_dep = "{extension_name}",
+)
+
+# register_extension_info(
+#     extension = pybind_library_test,
+#     label_regex_for_dep = "{extension_name}",
+# )
diff --git a/bazel_python.bzl b/bazel_python.bzl
index ccde609..1a634c8 100644
--- a/bazel_python.bzl
+++ b/bazel_python.bzl
@@ -1,17 +1,119 @@
 load("@bazel_tools//tools/python:toolchain.bzl", "py_runtime_pair")
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive", "http_file")
 
-def bazel_python(venv_name = "bazel_python_venv"):
+""" Using a local pre-installed Python. """
+
+_LOCAL_PYTHON_REPO_BUILD="""
+cc_library(
+    name = "python",
+    srcs = glob(["lib/*.a"]),
+    hdrs = glob([
+        "include/**/*.h",
+        "include/**/**/*.h",
+    ]),
+    includes = ["include/python3.9"],
+    visibility = ["//visibility:public"],
+)
+
+exports_files(glob(["bin/**"]))
+"""
+
+def _setup_local_python_repository_impl(repository_ctx):
+    BAZEL_PYTHON_DIR = repository_ctx.attr.dir \
+                    or repository_ctx.os.environ.get("BAZEL_PYTHON_DIR", None)
+    if BAZEL_PYTHON_DIR == None:
+        fail("Environment variable `BAZEL_PYTHON_DIR` is missing.")
+
+    path = "{}/{}".format(BAZEL_PYTHON_DIR, repository_ctx.attr.python_version)
+    repository_ctx.symlink(path, "")
+    repository_ctx.file("BUILD",
+        content = _LOCAL_PYTHON_REPO_BUILD,
+        executable = False,
+        legacy_utf8 = True
+    )
+    return BAZEL_PYTHON_DIR
+
+setup_local_python_repository = repository_rule(
+    implementation = _setup_local_python_repository_impl,
+    attrs = {
+        "python_version": attr.string(),
+        "dir": attr.string()
+    },
+    local = True,
+)
+
+def bazel_local_python(
+    python_version = "3.9.7",
+    name = "python",
+    venv_name = "bazel_python_venv"
+):
+    """Workspace rule setting up bazel_python for a repository from a
+       local Python installation.
+
+    Arguments
+    =========
+    @python_version should be a Python version number in `major.minor.patch`.
+    @name is the repository name.
+    @venv_name should match the 'name' argument given to the
+        bazel_python_interpreter call in the BUILD file.
+    """
+    native.register_toolchains("//:" + venv_name + "_toolchain")
+    setup_local_python_repository(
+        name=name,
+        python_version=python_version
+    )
+
+
+""" Build a hermetic Python. """
+
+_known_python_archives_sha256 = {
+    3: {
+        9: {
+            7: "a838d3f9360d157040142b715db34f0218e535333696a5569dc6f854604eb9d1"
+        }
+    }
+}
+
+def bazel_hermetic_python(
+    python_version = "3.9.7",
+    name = "python",
+    venv_name = "bazel_python_venv"
+):
     """Workspace rule setting up bazel_python for a repository.
 
     Arguments
     =========
+    @python_version should be a Python version number in `major.minor.patch`.
+    @name is the repository name.
     @venv_name should match the 'name' argument given to the
         bazel_python_interpreter call in the BUILD file.
     """
     native.register_toolchains("//:" + venv_name + "_toolchain")
 
+    print("""
+    =========================================================================================
+    Warning: build a hermetic Python is experimental.
+
+    Known issues:
+    1. "[33/43] test_pprint -- test_pickle failed (6 errors)" during PGO.
+    2. (Optional) `libsqlite3-dev` is required for Jupyter Notebook.
+
+    TODOs:
+    1. Build with tcmalloc.
+    =========================================================================================
+    """)
+    py_major, py_minor, py_patch = [int(num) for num in python_version.split(".")]
+    http_archive(
+        name = name,
+        build_file = "@bazel_python//:external/python{major}.{minor}.BUILD".format(
+            major=py_major, minor=py_minor),
+        sha256 = _known_python_archives_sha256[py_major][py_minor][py_patch],
+        strip_prefix = "Python-{}".format(python_version),
+        urls = ["https://www.python.org/ftp/python/{0}/Python-{0}.tgz".format(
+            python_version)],
+    )
+
 def bazel_python_interpreter(
-        python_version,
         name = "bazel_python_venv",
         requirements_file = None,
         **kwargs):
@@ -19,7 +121,7 @@ def bazel_python_interpreter(
 
     Arguments
     =========
-    @python_version should be the Python version string to use (e.g. 3.7.4 is
+    @python_version (deprecated) should be the Python version string to use (e.g. 3.7.4 is
         the standard for DARG projects). You must run the setup_python.sh
         script with this version number.
     @name is your preferred Bazel name for referencing this. The default should
@@ -30,7 +132,6 @@ def bazel_python_interpreter(
     """
     bazel_python_venv(
         name = name,
-        python_version = python_version,
         requirements_file = requirements_file,
         **kwargs
     )
@@ -68,71 +169,151 @@ def bazel_python_interpreter(
         toolchain_type = "@bazel_tools//tools/python:toolchain_type",
     )
 
+# def _bazel_python_install_external(ctx, srcs):
+#     outs = []
+#     for src in srcs:
+#         for file in src.files.to_list():
+#             out = ctx.actions.declare_file("{dir}/{name}".format(dir=bazel_python_external_bin, name=file.basename))
+#             outs.append(out)
+#             print(out.path)
+#             ctx.actions.symlink(output=out, target_file=file)
+
+#     return outs
+
+def _resolve_external_index(ctx, index_file_path, srcs):
+
+    files = [f for src in srcs for f in src.files.to_list()]
+
+    index = ctx.actions.declare_file(index_file_path)
+    ctx.actions.write(
+        output=index,
+        content="\n".join([f.path for f in files])
+    )
+
+    return index, files
+
 def _bazel_python_venv_impl(ctx):
     """A Bazel rule to set up a Python virtual environment.
 
     Also installs requirements specified by @ctx.attr.requirements_file.
     """
-    python_version = ctx.attr.python_version
-    use_system = False
-    only_warn = ctx.var.get("BAZEL_PYTHON_ONLY_WARN", "false").lower() == "true"
-    if "BAZEL_PYTHON_DIR" not in ctx.var:
-        if only_warn:
-            print("A bazel-python installation was not found. Falling back to the system python. For reproducibility, please run setup_python.sh for " + python_version)
-            use_system = True
-        else:
-            fail("You must run setup_python.sh for " + python_version)
-    if use_system:
-        python_dir = ""
-    else:
-        python_parent_dir = ctx.var.get("BAZEL_PYTHON_DIR")
-        python_dir = python_parent_dir + "/" + python_version
-
-    # TODO: Fail if python_dir does not exist.
+    tool_inputs, tool_input_mfs = ctx.resolve_tools(tools = [ctx.attr.python])
     venv_dir = ctx.actions.declare_directory("bazel_python_venv_installed")
+
     inputs = []
-    if use_system:
-        command = ""
-    else:
-        command = """
-            export PATH={py_dir}/bin:$PATH
-            export PATH={py_dir}/include:$PATH
-            export PATH={py_dir}/lib:$PATH
-            export PATH={py_dir}/share:$PATH
-            export PYTHON_PATH={py_dir}:{py_dir}/bin:{py_dir}/include:{py_dir}/lib:{py_dir}/share
-        """
-    command += """
-        python3 -m venv {out_dir} || exit 1
-        source {out_dir}/bin/activate || exit 1
+
+    inputs_setup = [ f for s in ctx.attr.setups for f in s.files.to_list() ]
+    index_setup = ctx.actions.declare_file("_external_setup_to_install")
+    ctx.actions.write(
+        output=index_setup,
+        content="\n".join([ s.label.workspace_root for s in ctx.attr.setups ])
+    )
+
+    inputs.append(index_setup)
+    inputs.extend(inputs_setup)
+
+    index_bin, inputs_bin = _resolve_external_index(ctx, "_external_bin_to_install", ctx.attr.bins)
+
+    inputs.append(index_bin)
+    inputs.extend(inputs_bin)
+
+    index_lib, inputs_lib = _resolve_external_index(ctx, "_external_lib_to_install", ctx.attr.libs)
+
+    inputs.append(index_lib)
+    inputs.extend(inputs_lib)
+
+    """ Setup venv. """
+    command = """
+        set -e
+
+        $(readlink -f {py_executable}) -m venv {venv_dir} || exit 1
+        source {venv_dir}/bin/activate || exit 1
+        export venv_path={venv_dir}
+        export bazel_bin_path={bazel_bin_dir}
+        export PATH=$PWD/{venv_dir}/bin:$PWD/{venv_dir}/include:$PWD/{venv_dir}/lib:$PWD/{venv_dir}/share:$PATH
+        export LD_LIBRARY_PATH=$PWD/{venv_dir}/lib:$LD_LIBRARY_PATH
+        export PYTHONPATH=$PWD/{venv_dir}:$PWD/{venv_dir}/bin:$PWD/{venv_dir}/include:$PWD/{venv_dir}/lib:$PWD/{venv_dir}/share
+
+        python3 -m pip install --upgrade pip
+
+        for _external_bin_src in $(cat {index_bin})
+        do
+            echo $_external_bin_src
+            ln -sfn $(readlink $_external_bin_src) $PWD/{venv_dir}/bin
+        done
+        rm {index_bin}
+
+        for _external_lib_src in $(cat {index_lib})
+        do
+            echo $_external_lib_src
+            ln -sfn $(readlink $_external_lib_src) $PWD/{venv_dir}/lib
+        done
+        rm {index_lib}
+
+        for _external_setup_prefix in $(cat {index_setup})
+        do
+            _external_setup_file=$(find . -path "*/$_external_setup_prefix/*/setup.py" | head -n 1)
+            pushd $(dirname $_external_setup_file)
+            python3 ./setup.py install || exit 1
+            popd
+        done
+        rm {index_setup}
+
     """
+
+    """ Install requirements.txt. """
     if ctx.attr.requirements_file:
         command += "pip3 install -r " + ctx.file.requirements_file.path + " || exit 1"
         inputs.append(ctx.file.requirements_file)
-    for src in ctx.attr.run_after_pip_srcs:
+
+    """ Include resources. """
+    for src in ctx.attr.data:
         inputs.extend(src.files.to_list())
+
+    """ Append post-pip scripts. """
     command += ctx.attr.run_after_pip
+
     command += """
-        REPLACEME=$PWD/'{out_dir}'
+        REPLACEME=$PWD/'{venv_dir}'
         REPLACEWITH='$PWD/bazel_python_venv_installed'
         # This prevents sed from trying to modify the directory. We may want to
         # do a more targeted sed in the future.
-        rm -rf {out_dir}/bin/__pycache__ || exit 1
-        sed -i'' -e s:$REPLACEME:$REPLACEWITH:g {out_dir}/bin/* || exit 1
+        rm -rf {venv_dir}/bin/__pycache__ || exit 1
+        sed -i'' -e s:$REPLACEME:$REPLACEWITH:g {venv_dir}/bin/* || exit 1
     """
+    command = command.format(
+        py_executable = ctx.executable.python.path,
+        venv_dir = venv_dir.path,
+        bazel_bin_dir = ctx.bin_dir.path,
+        index_bin = index_bin.path,
+        index_lib = index_lib.path,
+        index_setup = index_setup.path,
+    )
+
     ctx.actions.run_shell(
-        command = command.format(py_dir = python_dir, out_dir = venv_dir.path),
         inputs = inputs,
         outputs = [venv_dir],
+        tools = tool_inputs,
+        command = command
     )
+
     return [DefaultInfo(files = depset([venv_dir]))]
 
 bazel_python_venv = rule(
     implementation = _bazel_python_venv_impl,
     attrs = {
-        "python_version": attr.string(),
         "requirements_file": attr.label(allow_single_file = True),
+        "bins": attr.label_list(allow_files = True),
+        "libs": attr.label_list(allow_files = True),
+        "setups": attr.label_list(allow_files = True),
+        "data": attr.label_list(allow_files = True),
         "run_after_pip": attr.string(),
-        "run_after_pip_srcs": attr.label_list(allow_files = True),
+        "python": attr.label(
+            executable = True,
+            allow_single_file = True,
+            cfg = 'exec',
+            default = Label("@python//:bin/python3"),
+        ),
     },
 )
 
diff --git a/external/pybind11.BUILD b/external/pybind11.BUILD
new file mode 100644
index 0000000..65fe8a2
--- /dev/null
+++ b/external/pybind11.BUILD
@@ -0,0 +1,62 @@
+# pybind11 - Seamless operability between C++11 and Python.
+load("@rules_cc//cc:defs.bzl", "cc_library")
+
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])
+
+exports_files(["LICENSE"])
+
+OPTIONS = select({
+    ":msvc_compiler": [],
+    "//conditions:default": [
+        "-fexceptions",
+        # Useless warnings
+        "-Xclang-only=-Wno-undefined-inline",
+        "-Xclang-only=-Wno-pragma-once-outside-header",
+        "-Xgcc-only=-Wno-error",  # no way to just disable the pragma-once warning in gcc
+    ],
+})
+
+INCLUDES = [
+    "include/pybind11/**/*.h",
+]
+
+EXCLUDES = [
+    # Deprecated file that just emits a warning
+    "include/pybind11/common.h",
+]
+
+cc_library(
+    name = "pybind11",
+    hdrs = glob(
+        INCLUDES,
+        exclude = EXCLUDES,
+    ),
+    copts = OPTIONS,
+    includes = ["include"],
+    # deps = ["@local_config_python//:python_headers"],
+    deps = ["@python"],
+)
+
+cc_library(
+    name = "pybind11_embed",
+    hdrs = glob(
+        INCLUDES,
+        exclude = EXCLUDES,
+    ),
+    copts = OPTIONS,
+    includes = ["include"],
+    # deps = ["@local_config_python//:python_embed"],
+    deps = ["@python"],
+)
+
+config_setting(
+    name = "msvc_compiler",
+    flag_values = {"@bazel_tools//tools/cpp:compiler": "msvc-cl"},
+)
+
+config_setting(
+    name = "osx",
+    constraint_values = ["@platforms//os:osx"],
+)
diff --git a/external/python3.9.BUILD b/external/python3.9.BUILD
new file mode 100644
index 0000000..974ce6c
--- /dev/null
+++ b/external/python3.9.BUILD
@@ -0,0 +1,222 @@
+genrule(
+    name = "build_python",
+    srcs = glob(["**/**"]) + [
+        "@local_config_cc//:toolchain",
+    ],
+    outs = [
+        "bin/2to3",
+        "bin/2to3-3.9",
+        "bin/idle3",
+        "bin/idle3.9",
+        "bin/pip3",
+        "bin/pip3.9",
+        "bin/pydoc3",
+        "bin/pydoc3.9",
+        "bin/python3",
+        "bin/python3-config",
+        "bin/python3.9",
+        "bin/python3.9-config",
+        #
+        "lib/libpython3.9.a",
+        "lib/pkgconfig",
+        "lib/python3.9",
+        #
+        "include/python3.9/abstract.h",
+        "include/python3.9/asdl.h",
+        "include/python3.9/ast.h",
+        "include/python3.9/bitset.h",
+        "include/python3.9/bltinmodule.h",
+        "include/python3.9/boolobject.h",
+        "include/python3.9/bytearrayobject.h",
+        "include/python3.9/bytesobject.h",
+        "include/python3.9/cellobject.h",
+        "include/python3.9/ceval.h",
+        "include/python3.9/classobject.h",
+        "include/python3.9/code.h",
+        "include/python3.9/codecs.h",
+        "include/python3.9/compile.h",
+        "include/python3.9/complexobject.h",
+        "include/python3.9/context.h",
+        "include/python3.9/datetime.h",
+        "include/python3.9/descrobject.h",
+        "include/python3.9/dictobject.h",
+        "include/python3.9/dynamic_annotations.h",
+        "include/python3.9/enumobject.h",
+        "include/python3.9/errcode.h",
+        "include/python3.9/eval.h",
+        "include/python3.9/exports.h",
+        "include/python3.9/fileobject.h",
+        "include/python3.9/fileutils.h",
+        "include/python3.9/floatobject.h",
+        "include/python3.9/frameobject.h",
+        "include/python3.9/funcobject.h",
+        "include/python3.9/genericaliasobject.h",
+        "include/python3.9/genobject.h",
+        "include/python3.9/graminit.h",
+        "include/python3.9/grammar.h",
+        "include/python3.9/import.h",
+        "include/python3.9/interpreteridobject.h",
+        "include/python3.9/intrcheck.h",
+        "include/python3.9/iterobject.h",
+        "include/python3.9/listobject.h",
+        "include/python3.9/longintrepr.h",
+        "include/python3.9/longobject.h",
+        "include/python3.9/marshal.h",
+        "include/python3.9/memoryobject.h",
+        "include/python3.9/methodobject.h",
+        "include/python3.9/modsupport.h",
+        "include/python3.9/moduleobject.h",
+        "include/python3.9/namespaceobject.h",
+        "include/python3.9/node.h",
+        "include/python3.9/object.h",
+        "include/python3.9/objimpl.h",
+        "include/python3.9/odictobject.h",
+        "include/python3.9/opcode.h",
+        "include/python3.9/osdefs.h",
+        "include/python3.9/osmodule.h",
+        "include/python3.9/parsetok.h",
+        "include/python3.9/patchlevel.h",
+        "include/python3.9/picklebufobject.h",
+        "include/python3.9/py_curses.h",
+        "include/python3.9/pyarena.h",
+        "include/python3.9/pycapsule.h",
+        "include/python3.9/pyconfig.h",
+        "include/python3.9/pyctype.h",
+        "include/python3.9/pydebug.h",
+        "include/python3.9/pydtrace.h",
+        "include/python3.9/pyerrors.h",
+        "include/python3.9/pyexpat.h",
+        "include/python3.9/pyfpe.h",
+        "include/python3.9/pyframe.h",
+        "include/python3.9/pyhash.h",
+        "include/python3.9/pylifecycle.h",
+        "include/python3.9/pymacconfig.h",
+        "include/python3.9/pymacro.h",
+        "include/python3.9/pymath.h",
+        "include/python3.9/pymem.h",
+        "include/python3.9/pyport.h",
+        "include/python3.9/pystate.h",
+        "include/python3.9/pystrcmp.h",
+        "include/python3.9/pystrhex.h",
+        "include/python3.9/pystrtod.h",
+        "include/python3.9/Python-ast.h",
+        "include/python3.9/Python.h",
+        "include/python3.9/pythonrun.h",
+        "include/python3.9/pythread.h",
+        "include/python3.9/pytime.h",
+        "include/python3.9/rangeobject.h",
+        "include/python3.9/setobject.h",
+        "include/python3.9/sliceobject.h",
+        "include/python3.9/structmember.h",
+        "include/python3.9/structseq.h",
+        "include/python3.9/symtable.h",
+        "include/python3.9/sysmodule.h",
+        "include/python3.9/token.h",
+        "include/python3.9/traceback.h",
+        "include/python3.9/tracemalloc.h",
+        "include/python3.9/tupleobject.h",
+        "include/python3.9/typeslots.h",
+        "include/python3.9/ucnhash.h",
+        "include/python3.9/unicodeobject.h",
+        "include/python3.9/warnings.h",
+        "include/python3.9/weakrefobject.h",
+        "include/python3.9/cpython/abstract.h",
+        "include/python3.9/cpython/bytearrayobject.h",
+        "include/python3.9/cpython/bytesobject.h",
+        "include/python3.9/cpython/ceval.h",
+        "include/python3.9/cpython/code.h",
+        "include/python3.9/cpython/dictobject.h",
+        "include/python3.9/cpython/fileobject.h",
+        "include/python3.9/cpython/fileutils.h",
+        "include/python3.9/cpython/frameobject.h",
+        "include/python3.9/cpython/import.h",
+        "include/python3.9/cpython/initconfig.h",
+        "include/python3.9/cpython/interpreteridobject.h",
+        "include/python3.9/cpython/listobject.h",
+        "include/python3.9/cpython/methodobject.h",
+        "include/python3.9/cpython/object.h",
+        "include/python3.9/cpython/objimpl.h",
+        "include/python3.9/cpython/pyerrors.h",
+        "include/python3.9/cpython/pylifecycle.h",
+        "include/python3.9/cpython/pymem.h",
+        "include/python3.9/cpython/pystate.h",
+        "include/python3.9/cpython/sysmodule.h",
+        "include/python3.9/cpython/traceback.h",
+        "include/python3.9/cpython/tupleobject.h",
+        "include/python3.9/cpython/unicodeobject.h",
+        "include/python3.9/internal/pegen_interface.h",
+        "include/python3.9/internal/pycore_abstract.h",
+        "include/python3.9/internal/pycore_accu.h",
+        "include/python3.9/internal/pycore_atomic.h",
+        "include/python3.9/internal/pycore_bytes_methods.h",
+        "include/python3.9/internal/pycore_byteswap.h",
+        "include/python3.9/internal/pycore_call.h",
+        "include/python3.9/internal/pycore_ceval.h",
+        "include/python3.9/internal/pycore_code.h",
+        "include/python3.9/internal/pycore_condvar.h",
+        "include/python3.9/internal/pycore_context.h",
+        "include/python3.9/internal/pycore_dtoa.h",
+        "include/python3.9/internal/pycore_fileutils.h",
+        "include/python3.9/internal/pycore_gc.h",
+        "include/python3.9/internal/pycore_getopt.h",
+        "include/python3.9/internal/pycore_gil.h",
+        "include/python3.9/internal/pycore_hamt.h",
+        "include/python3.9/internal/pycore_hashtable.h",
+        "include/python3.9/internal/pycore_import.h",
+        "include/python3.9/internal/pycore_initconfig.h",
+        "include/python3.9/internal/pycore_interp.h",
+        "include/python3.9/internal/pycore_object.h",
+        "include/python3.9/internal/pycore_pathconfig.h",
+        "include/python3.9/internal/pycore_pyerrors.h",
+        "include/python3.9/internal/pycore_pyhash.h",
+        "include/python3.9/internal/pycore_pylifecycle.h",
+        "include/python3.9/internal/pycore_pymem.h",
+        "include/python3.9/internal/pycore_pystate.h",
+        "include/python3.9/internal/pycore_runtime.h",
+        "include/python3.9/internal/pycore_sysmodule.h",
+        "include/python3.9/internal/pycore_traceback.h",
+        "include/python3.9/internal/pycore_tupleobject.h",
+        "include/python3.9/internal/pycore_warnings.h",
+    ],
+    cmd = """
+        OUT_DIR=$$PWD/$(@D)
+        rm -rf $$OUT_DIR
+        mkdir $$OUT_DIR
+        #
+        cd external/python
+        INSTALL_DIR=$$PWD/out
+        #
+        CFLAGS=-fPIC ./configure \
+            --prefix=$$OUT_DIR \
+            --exec_prefix=$$OUT_DIR \
+            --enable-loadable-sqlite-extensions \
+            --enable-optimizations \
+            --enable-shared=no
+
+        make && make install
+        #
+        if ! $$OUT_DIR/bin/python3 -c "import ssl"
+        then
+            echo "ERROR: Python was built *WITHOUT* the SSL module. This will break PyPI downloads. Please re-run this script after installing libssl-dev (see the README)."
+            exit 1
+        fi
+        if ! $$OUT_DIR/bin/python3 -c "import zlib"
+        then
+            echo "ERROR: Python was built *WITHOUT* the zlib module. If needed, please re-run this script after installing zlib1g-dev (see the README)."
+            exit 1
+        fi
+    """,
+    visibility = ["//visibility:public"],
+)
+
+cc_library(
+    name = "python",
+    srcs = glob(["lib/*.a"]) + [":build_python"],
+    hdrs = glob([
+        "include/**/*.h",
+        "include/**/**/*.h",
+    ]),
+    includes = ["include/python3.9"],
+    linkstatic = 1,
+    visibility = ["//visibility:public"],
+)
diff --git a/pywrapper.sh b/pywrapper.sh
index 647a487..2ec3398 100755
--- a/pywrapper.sh
+++ b/pywrapper.sh
@@ -6,8 +6,17 @@
 # bazel_out/.../[mainworkspace]. This searches for the first matching path then
 # exits, so it should be reasonably fast in most cases.
 # https://unix.stackexchange.com/questions/68414/only-find-first-few-matched-files-using-find
-venv_path=$((find -L . -path "*/bazel_python_venv_installed/bin/activate" & ) | head -n 1)
+venv_activate=$((find -L $PWD -path "*/bazel_python_venv_installed/bin/activate" & ) | head -n 1)
+venv_path=$(dirname $(dirname $venv_activate))
 # If venv_path was not found it will be empty and the below will throw an
 # error, alerting Bazel something went wrong.
-source $venv_path || exit 1
-python $@
+source $venv_activate || exit 1
+
+# Not sure should we expose $PATH or not.
+export PATH=$venv_path/bin:$PATH #:$venv_path/include:$venv_path/lib:$venv_path/share:$PATH
+export LD_LIBRARY_PATH=$venv_path/lib #:${LD_LIBRARY_PATH}
+
+# export PYTHONPATH=$venv_path:$venv_path/bin:$venv_path/include:$venv_path/lib:$venv_path/share
+export PYTHONPATH=$(/usr/bin/dirname $1):$PYTHONPATH
+
+$venv_path/bin/python3 $@
diff --git a/setup_python.sh b/setup_python.sh
index e05c139..b350012 100755
--- a/setup_python.sh
+++ b/setup_python.sh
@@ -25,9 +25,9 @@ then
     tar -xzf Python-$version.tgz
     cd Python-$version
 
-    ./configure --prefix=$install_dir $@
+    CFLAGS=-fPIC ./configure --prefix=$install_dir $@
 
-    make -j
+    make
     make install
     cd $install_dir
     rm -rf Python-$version
@@ -49,4 +49,4 @@ then
     fi
 else
     echo "Aborting."
-fi
+fi
\ No newline at end of file