bot-bottle/tests/unit/test_git_http_backend.py

"""Unit: smart-HTTP git-gate wrapper."""

import os
import subprocess
import tempfile
import threading
import unittest
import urllib.request
from pathlib import Path
from unittest import mock

from bot_bottle.git_gate import GIT_GATE_TIMEOUT_SECS
from bot_bottle.git_http_backend import GitHttpHandler, MAX_BODY_BYTES


# The git-http backend is resolver-only: every request is attributed to a
# bottle namespace by source IP. These tests wire a fixed resolver and nest the
# bare repo under `<GIT_PROJECT_ROOT>/<_BID>/`.
_BID = "bottletest"


class _FixedResolver:
    """Maps every source IP to one bottle id."""

    def __init__(self, bottle_id: str) -> None:
        self._bottle_id = bottle_id

    def resolve_bottle_id(self, source_ip: str, identity_token: str = "") -> str:
        del source_ip, identity_token
        return self._bottle_id


class TestGitHttpBackend(unittest.TestCase):
    def test_real_git_push_reaches_bare_repo(self):
        from http.server import ThreadingHTTPServer

        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            bare = root / _BID / "repo.git"
            subprocess.run(["git", "init", "--bare", str(bare)],
                           check=True, capture_output=True, text=True)
            subprocess.run(
                ["git", "-C", str(bare), "config", "http.receivepack", "true"],
                check=True,
            )

            old_root = os.environ.get("GIT_PROJECT_ROOT")
            os.environ["GIT_PROJECT_ROOT"] = str(root)
            self.addCleanup(self._restore_env, old_root)
            old_hook = os.environ.get("GIT_GATE_ACCESS_HOOK")
            hook = root / "access-hook"
            hook.write_text("#!/bin/sh\nexit 0\n")
            hook.chmod(0o700)
            os.environ["GIT_GATE_ACCESS_HOOK"] = str(hook)
            self.addCleanup(self._restore_hook, old_hook)

            server = ThreadingHTTPServer(("127.0.0.1", 0), GitHttpHandler)
            server.policy_resolver = _FixedResolver(_BID)  # type: ignore[attr-defined]
            thread = threading.Thread(target=server.serve_forever, daemon=True)
            thread.start()
            self.addCleanup(server.shutdown)
            self.addCleanup(server.server_close)

            work = root / "work"
            work.mkdir()
            subprocess.run(["git", "init"], cwd=work, check=True,
                           capture_output=True, text=True)
            subprocess.run(["git", "config", "user.name", "test"],
                           cwd=work, check=True)
            subprocess.run(["git", "config", "user.email", "test@example.invalid"],
                           cwd=work, check=True)
            (work / "README.md").write_text("test\n")
            subprocess.run(["git", "add", "README.md"], cwd=work, check=True)
            subprocess.run(["git", "commit", "-m", "init"], cwd=work,
                           check=True, capture_output=True, text=True)

            url = f"http://127.0.0.1:{server.server_port}/repo.git"
            subprocess.run(
                ["git", "push", url, "HEAD:refs/heads/main"],
                cwd=work,
                check=True,
                capture_output=True,
                text=True,
                timeout=5,
            )

            pushed = subprocess.check_output(
                ["git", "-C", str(bare), "rev-parse", "refs/heads/main"],
                text=True,
            ).strip()
            head = subprocess.check_output(
                ["git", "-C", str(work), "rev-parse", "HEAD"],
                text=True,
            ).strip()
            self.assertEqual(head, pushed)
            subprocess.run(
                ["git", "-C", str(bare), "symbolic-ref", "HEAD", "refs/heads/main"],
                check=True,
            )

            clone = root / "clone"
            subprocess.run(
                ["git", "clone", url, str(clone)],
                check=True,
                capture_output=True,
                text=True,
                timeout=5,
            )
            cloned = subprocess.check_output(
                ["git", "-C", str(clone), "rev-parse", "HEAD"],
                text=True,
            ).strip()
            self.assertEqual(head, cloned)

    def test_consolidated_push_stamps_bottle_slug_for_the_hook(self):
        # In consolidated mode the backend attributes the push by source IP and
        # stamps SUPERVISE_BOTTLE_SLUG=<bottle_id> into the CGI env, so the
        # gitleaks-allow pre-receive hook queues its proposal under the right
        # bottle. The hook here just records what it received.
        from http.server import ThreadingHTTPServer

        bottle_id = "bottleab12"
        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            bare = root / bottle_id / "repo.git"  # namespaced per bottle (slice 10)
            bare.parent.mkdir(parents=True)
            subprocess.run(["git", "init", "--bare", str(bare)],
                           check=True, capture_output=True, text=True)
            subprocess.run(
                ["git", "-C", str(bare), "config", "http.receivepack", "true"],
                check=True,
            )
            capture = root / "slug-capture"
            hook = bare / "hooks" / "pre-receive"
            hook.write_text(
                f"#!/bin/sh\nprintf '%s' \"${{SUPERVISE_BOTTLE_SLUG:-UNSET}}\" > "
                f"{capture}\ncat >/dev/null\nexit 0\n"
            )
            hook.chmod(0o755)

            old_root = os.environ.get("GIT_PROJECT_ROOT")
            os.environ["GIT_PROJECT_ROOT"] = str(root)  # base; backend nests per bottle
            self.addCleanup(self._restore_env, old_root)

            server = ThreadingHTTPServer(("127.0.0.1", 0), GitHttpHandler)
            server.policy_resolver = _FixedResolver(bottle_id)  # type: ignore[attr-defined]
            thread = threading.Thread(target=server.serve_forever, daemon=True)
            thread.start()
            self.addCleanup(server.shutdown)
            self.addCleanup(server.server_close)

            work = root / "work"
            work.mkdir()
            subprocess.run(["git", "init"], cwd=work, check=True,
                           capture_output=True, text=True)
            subprocess.run(["git", "config", "user.name", "test"], cwd=work, check=True)
            subprocess.run(["git", "config", "user.email", "t@example.invalid"],
                           cwd=work, check=True)
            (work / "README.md").write_text("test\n")
            subprocess.run(["git", "add", "README.md"], cwd=work, check=True)
            subprocess.run(["git", "commit", "-m", "init"], cwd=work,
                           check=True, capture_output=True, text=True)

            url = f"http://127.0.0.1:{server.server_port}/repo.git"
            subprocess.run(
                ["git", "push", url, "HEAD:refs/heads/main"],
                cwd=work, check=True, capture_output=True, text=True, timeout=5,
            )
            self.assertEqual(bottle_id, capture.read_text())

    def test_post_forwards_git_cgi_headers(self):
        from http.server import ThreadingHTTPServer

        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            (root / _BID / "repo.git").mkdir(parents=True)

            old_root = os.environ.get("GIT_PROJECT_ROOT")
            os.environ["GIT_PROJECT_ROOT"] = str(root)
            self.addCleanup(self._restore_env, old_root)

            server = ThreadingHTTPServer(("127.0.0.1", 0), GitHttpHandler)
            server.policy_resolver = _FixedResolver(_BID)  # type: ignore[attr-defined]
            thread = threading.Thread(target=server.serve_forever, daemon=True)
            thread.start()
            self.addCleanup(server.shutdown)
            self.addCleanup(server.server_close)

            backend_response = (
                b"Status: 200 OK\r\n"
                b"Content-Type: application/x-git-upload-pack-result\r\n"
                b"\r\n"
                b"0000"
            )
            calls = [
                subprocess.CompletedProcess(["hook"], 0, b"", b""),
                subprocess.CompletedProcess(["git"], 0, backend_response, b""),
            ]
            with mock.patch(
                "bot_bottle.git_http_backend.subprocess.run",
                side_effect=calls,
            ) as run:
                request = urllib.request.Request(
                    f"http://127.0.0.1:{server.server_port}"
                    "/repo.git/git-upload-pack",
                    data=b"compressed",
                    headers={
                        "Accept": "application/x-git-upload-pack-result",
                        "Content-Encoding": "gzip",
                        "Content-Type": "application/x-git-upload-pack-request",
                        "Git-Protocol": "version=2",
                        "User-Agent": "git/test",
                    },
                    method="POST",
                )
                with urllib.request.urlopen(request, timeout=5) as response:
                    self.assertEqual(200, response.status)
                    self.assertEqual(b"0000", response.read())

            env = run.call_args_list[1].kwargs["env"]
            self.assertEqual("gzip", env["HTTP_CONTENT_ENCODING"])
            self.assertEqual("version=2", env["HTTP_GIT_PROTOCOL"])
            self.assertEqual(
                "application/x-git-upload-pack-result",
                env["HTTP_ACCEPT"],
            )
            self.assertEqual("git/test", env["HTTP_USER_AGENT"])

    def test_subprocess_calls_include_timeout(self):
        """Both subprocess.run calls (access-hook and git http-backend) must
        pass timeout= so a hung upstream cannot wedge the gateway."""
        from http.server import ThreadingHTTPServer

        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            (root / _BID / "repo.git").mkdir(parents=True)

            old_root = os.environ.get("GIT_PROJECT_ROOT")
            os.environ["GIT_PROJECT_ROOT"] = str(root)
            self.addCleanup(self._restore_env, old_root)
            old_hook = os.environ.get("GIT_GATE_ACCESS_HOOK")
            hook = root / "access-hook"
            hook.write_text("#!/bin/sh\nexit 0\n")
            hook.chmod(0o700)
            os.environ["GIT_GATE_ACCESS_HOOK"] = str(hook)
            self.addCleanup(self._restore_hook, old_hook)

            server = ThreadingHTTPServer(("127.0.0.1", 0), GitHttpHandler)
            server.policy_resolver = _FixedResolver(_BID)  # type: ignore[attr-defined]
            thread = threading.Thread(target=server.serve_forever, daemon=True)
            thread.start()
            self.addCleanup(server.shutdown)
            self.addCleanup(server.server_close)

            backend_response = (
                b"Status: 200 OK\r\n"
                b"Content-Type: application/x-git-upload-pack-result\r\n"
                b"\r\n"
                b"0000"
            )
            calls = [
                subprocess.CompletedProcess(["hook"], 0, b"", b""),
                subprocess.CompletedProcess(["git"], 0, backend_response, b""),
            ]
            with mock.patch(
                "bot_bottle.git_http_backend.subprocess.run",
                side_effect=calls,
            ) as run:
                req = urllib.request.Request(
                    f"http://127.0.0.1:{server.server_port}"
                    "/repo.git/git-upload-pack",
                    data=b"",
                    method="POST",
                )
                with urllib.request.urlopen(req, timeout=5):
                    pass

            for call in run.call_args_list:
                self.assertEqual(
                    GIT_GATE_TIMEOUT_SECS,
                    call.kwargs.get("timeout"),
                    f"subprocess.run call missing timeout: {call}",
                )

    def test_access_hook_denial_is_logged_to_stdout(self):
        """When the access-hook exits non-zero we still return 403 to the
        client, but the hook's stderr must also appear on the handler's
        stdout so docker logs surface *why* — otherwise the agent sees
        the message and the operator just sees `403 -`."""
        from http.server import ThreadingHTTPServer
        import io
        import sys

        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            (root / _BID / "repo.git").mkdir(parents=True)
            old_root = os.environ.get("GIT_PROJECT_ROOT")
            os.environ["GIT_PROJECT_ROOT"] = str(root)
            self.addCleanup(self._restore_env, old_root)

            server = ThreadingHTTPServer(("127.0.0.1", 0), GitHttpHandler)
            server.policy_resolver = _FixedResolver(_BID)  # type: ignore[attr-defined]
            thread = threading.Thread(target=server.serve_forever, daemon=True)
            thread.start()
            self.addCleanup(server.shutdown)
            self.addCleanup(server.server_close)

            denial = b"git-gate: upstream fetch failed; refusing to serve stale data\n"
            with mock.patch(
                "bot_bottle.git_http_backend.subprocess.run",
                return_value=subprocess.CompletedProcess(
                    ["hook"], 1, b"", denial,
                ),
            ):
                buf = io.StringIO()
                with mock.patch.object(sys, "stdout", buf):
                    req = urllib.request.Request(
                        f"http://127.0.0.1:{server.server_port}"
                        "/repo.git/info/refs?service=git-upload-pack",
                        method="GET",
                    )
                    try:
                        urllib.request.urlopen(req, timeout=5)
                        self.fail("expected HTTPError 403")
                    except urllib.error.HTTPError as e:  # type: ignore
                        self.assertEqual(403, e.code)
                        self.assertIn(b"upstream fetch failed", e.read())

                logged = buf.getvalue()
                self.assertIn("access-hook denied", logged)
                self.assertIn("upstream fetch failed", logged)

    def test_access_hook_denial_without_output_logs_exit_code(self):
        """If the hook exits non-zero but produces no stderr/stdout, the
        log line should still say *something* — the exit code — instead
        of silently emitting an empty line."""
        from http.server import ThreadingHTTPServer
        import io
        import sys

        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            (root / _BID / "repo.git").mkdir(parents=True)
            old_root = os.environ.get("GIT_PROJECT_ROOT")
            os.environ["GIT_PROJECT_ROOT"] = str(root)
            self.addCleanup(self._restore_env, old_root)

            server = ThreadingHTTPServer(("127.0.0.1", 0), GitHttpHandler)
            server.policy_resolver = _FixedResolver(_BID)  # type: ignore[attr-defined]
            thread = threading.Thread(target=server.serve_forever, daemon=True)
            thread.start()
            self.addCleanup(server.shutdown)
            self.addCleanup(server.server_close)

            with mock.patch(
                "bot_bottle.git_http_backend.subprocess.run",
                return_value=subprocess.CompletedProcess(
                    ["hook"], 2, b"", b"",
                ),
            ):
                buf = io.StringIO()
                with mock.patch.object(sys, "stdout", buf):
                    req = urllib.request.Request(
                        f"http://127.0.0.1:{server.server_port}"
                        "/repo.git/info/refs?service=git-upload-pack",
                        method="GET",
                    )
                    try:
                        urllib.request.urlopen(req, timeout=5)
                        self.fail("expected HTTPError 403")
                    except urllib.error.HTTPError as e:  # type: ignore
                        self.assertEqual(403, e.code)

                logged = buf.getvalue()
                self.assertIn("access-hook denied", logged)
                self.assertIn("exit=2", logged)

    def test_access_hook_that_cannot_run_fails_closed_503(self):
        """Regression: when the access-hook can't be exec'd (missing / not
        executable — a PermissionError from subprocess.run), the handler must
        fail closed with a real HTTP status instead of letting the exception
        kill the thread, which closes the socket with no response and the
        client sees an opaque "empty reply from server"."""
        from http.server import ThreadingHTTPServer
        import io
        import sys

        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            (root / _BID / "repo.git").mkdir(parents=True)
            old_root = os.environ.get("GIT_PROJECT_ROOT")
            os.environ["GIT_PROJECT_ROOT"] = str(root)
            self.addCleanup(self._restore_env, old_root)

            server = ThreadingHTTPServer(("127.0.0.1", 0), GitHttpHandler)
            server.policy_resolver = _FixedResolver(_BID)  # type: ignore[attr-defined]
            thread = threading.Thread(target=server.serve_forever, daemon=True)
            thread.start()
            self.addCleanup(server.shutdown)
            self.addCleanup(server.server_close)

            with mock.patch(
                "bot_bottle.git_http_backend.subprocess.run",
                side_effect=PermissionError(13, "Permission denied"),
            ):
                buf = io.StringIO()
                with mock.patch.object(sys, "stdout", buf):
                    req = urllib.request.Request(
                        f"http://127.0.0.1:{server.server_port}"
                        "/repo.git/info/refs?service=git-upload-pack",
                        method="GET",
                    )
                    try:
                        urllib.request.urlopen(req, timeout=5)
                        self.fail("expected HTTPError 503")
                    except urllib.error.HTTPError as e:  # type: ignore
                        self.assertEqual(503, e.code)

                self.assertIn("access-hook could not run", buf.getvalue())

    @staticmethod
    def _restore_env(value: str | None) -> None:
        if value is None:
            os.environ.pop("GIT_PROJECT_ROOT", None)
        else:
            os.environ["GIT_PROJECT_ROOT"] = value

    @staticmethod
    def _restore_hook(value: str | None) -> None:
        if value is None:
            os.environ.pop("GIT_GATE_ACCESS_HOOK", None)
        else:
            os.environ["GIT_GATE_ACCESS_HOOK"] = value


class TestMalformedStatusHeader(unittest.TestCase):
    """Malformed CGI Status: headers must not propagate as unhandled exceptions;
    the handler should fall back to HTTP 500."""

    def setUp(self):
        from http.server import ThreadingHTTPServer
        import tempfile
        self._tmp = tempfile.mkdtemp()
        os.environ["GIT_PROJECT_ROOT"] = self._tmp
        self._server = ThreadingHTTPServer(("127.0.0.1", 0), GitHttpHandler)
        self._server.policy_resolver = _FixedResolver(_BID)  # type: ignore[attr-defined]
        self._thread = threading.Thread(
            target=self._server.serve_forever, daemon=True,
        )
        self._thread.start()
        self._port = self._server.server_port

    def tearDown(self):
        self._server.shutdown()
        self._server.server_close()
        os.environ.pop("GIT_PROJECT_ROOT", None)
        import shutil
        shutil.rmtree(self._tmp, ignore_errors=True)

    def _get_with_backend_response(self, cgi_response: bytes) -> int:
        with mock.patch(
            "bot_bottle.git_http_backend.subprocess.run",
            return_value=mock.Mock(returncode=0, stdout=cgi_response),
        ):
            req = urllib.request.Request(
                f"http://127.0.0.1:{self._port}/repo.git/info/refs",
                method="GET",
            )
            try:
                with urllib.request.urlopen(req, timeout=3) as resp:
                    return resp.status
            except urllib.error.HTTPError as e:  # type: ignore
                return e.code

    def test_empty_status_value_returns_500(self):
        status = self._get_with_backend_response(
            b"Status: \r\nContent-Type: text/plain\r\n\r\n"
        )
        self.assertEqual(500, status)

    def test_non_numeric_status_returns_500(self):
        status = self._get_with_backend_response(
            b"Status: bad\r\nContent-Type: text/plain\r\n\r\n"
        )
        self.assertEqual(500, status)


class TestContentLengthBounds(unittest.TestCase):
    """PRD 0041: malformed or oversized Content-Length is rejected before
    git http-backend is invoked."""

    def setUp(self):
        from http.server import ThreadingHTTPServer
        import tempfile, os
        self._tmp = tempfile.mkdtemp()
        os.environ["GIT_PROJECT_ROOT"] = self._tmp
        self._server = ThreadingHTTPServer(("127.0.0.1", 0), GitHttpHandler)
        self._server.policy_resolver = _FixedResolver(_BID)  # type: ignore[attr-defined]
        self._thread = threading.Thread(
            target=self._server.serve_forever, daemon=True,
        )
        self._thread.start()
        self._port = self._server.server_port

    def tearDown(self):
        self._server.shutdown()
        self._server.server_close()
        os.environ.pop("GIT_PROJECT_ROOT", None)
        import shutil
        shutil.rmtree(self._tmp, ignore_errors=True)

    def _post(self, path: str, *, content_length_header: str,
              body: bytes = b"x") -> int:
        req = urllib.request.Request(
            f"http://127.0.0.1:{self._port}{path}",
            data=body,
            method="POST",
        )
        req.add_header("Content-Length", content_length_header)
        req.add_header("Content-Type", "application/x-git-receive-pack-request")
        try:
            with urllib.request.urlopen(req, timeout=3) as resp:
                return resp.status
        except urllib.error.HTTPError as e:  # type: ignore
            return e.code

    def test_non_numeric_content_length_returns_400(self):
        status = self._post("/repo.git/git-receive-pack",
                            content_length_header="abc")
        self.assertEqual(400, status)

    def test_negative_content_length_returns_400(self):
        status = self._post("/repo.git/git-receive-pack",
                            content_length_header="-1")
        self.assertEqual(400, status)

    def test_oversized_content_length_returns_413(self):
        status = self._post("/repo.git/git-receive-pack",
                            content_length_header=str(MAX_BODY_BYTES + 1))
        self.assertEqual(413, status)

    def test_valid_small_body_passes_through(self):
        # With a valid Content-Length the handler proceeds into
        # git http-backend; that will fail (no real git repo) but the
        # status won't be 400 or 413.
        with mock.patch("bot_bottle.git_http_backend.subprocess.run") as run:
            run.return_value = mock.Mock(
                returncode=0,
                stdout=(
                    b"Status: 200 OK\r\n"
                    b"Content-Type: application/x-git-receive-pack-result\r\n"
                    b"\r\n"
                ),
            )
            status = self._post("/repo.git/git-receive-pack",
                                content_length_header="1", body=b"x")
        self.assertNotIn(status, (400, 413))


if __name__ == "__main__":
    unittest.main()