updated: prep for new updater (#31695)

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* proc

* release

* fix

* this should move here

* e2e update test

* that too

* fix

* fix

* fix running in docker

* don't think GHA will work

* also test switching branches

* it's a test

* lets not delete that yet

* fix

* fix2

* fix

* fix

* tests too

* fix

* cleanup / init

* test agnos update

* test agnos

* move this back up

* no diff

selfdrive/updated/common.py

@@ -0,0 +1,100 @@
+import abc
+import os
+
+from pathlib import Path
+import subprocess
+from typing import List
+
+from markdown_it import MarkdownIt
+from openpilot.common.params import Params
+from openpilot.common.swaglog import cloudlog
+
+
+LOCK_FILE = os.getenv("UPDATER_LOCK_FILE", "/tmp/safe_staging_overlay.lock")
+STAGING_ROOT = os.getenv("UPDATER_STAGING_ROOT", "/data/safe_staging")
+FINALIZED = os.path.join(STAGING_ROOT, "finalized")
+
+
+def run(cmd: list[str], cwd: str = None) -> str:
+  return subprocess.check_output(cmd, cwd=cwd, stderr=subprocess.STDOUT, encoding='utf8')
+
+
+class UpdateStrategy(abc.ABC):
+  def __init__(self):
+    self.params = Params()
+
+  @abc.abstractmethod
+  def init(self) -> None:
+    pass
+
+  @abc.abstractmethod
+  def cleanup(self) -> None:
+    pass
+
+  @abc.abstractmethod
+  def get_available_channels(self) -> List[str]:
+    """List of available channels to install, (branches, releases, etc)"""
+
+  @abc.abstractmethod
+  def current_channel(self) -> str:
+    """Current channel installed"""
+
+  @abc.abstractmethod
+  def fetched_path(self) -> str:
+    """Path to the fetched update"""
+
+  @property
+  def target_channel(self) -> str:
+    """Target Channel"""
+    b: str | None = self.params.get("UpdaterTargetBranch", encoding='utf-8')
+    if b is None:
+      b = self.current_channel()
+    return b
+
+  @abc.abstractmethod
+  def update_ready(self) -> bool:
+    """Check if an update is ready to be installed"""
+
+  @abc.abstractmethod
+  def update_available(self) -> bool:
+    """Check if an update is available for the current channel"""
+
+  @abc.abstractmethod
+  def describe_current_channel(self) -> tuple[str, str]:
+    """Describe the current channel installed, (description, release_notes)"""
+
+  @abc.abstractmethod
+  def describe_ready_channel(self) -> tuple[str, str]:
+    """Describe the channel that is ready to be installed, (description, release_notes)"""
+
+  @abc.abstractmethod
+  def fetch_update(self) -> None:
+    pass
+
+  @abc.abstractmethod
+  def finalize_update(self) -> None:
+    pass
+
+
+def set_consistent_flag(consistent: bool) -> None:
+  os.sync()
+  consistent_file = Path(os.path.join(FINALIZED, ".overlay_consistent"))
+  if consistent:
+    consistent_file.touch()
+  elif not consistent:
+    consistent_file.unlink(missing_ok=True)
+  os.sync()
+
+
+def parse_release_notes(releases_md: str) -> str:
+  try:
+    r = releases_md.split('\n\n', 1)[0]  # Slice latest release notes
+    try:
+      return str(MarkdownIt().render(r))
+    except Exception:
+      return r + "\n"
+  except FileNotFoundError:
+    pass
+  except Exception:
+    cloudlog.exception("failed to parse release notes")
+  return ""

selfdrive/updated/git.py

@@ -0,0 +1,241 @@
+import datetime
+import os
+import re
+import shutil
+import subprocess
+import time
+
+from collections import defaultdict
+from pathlib import Path
+from typing import List
+
+from openpilot.common.basedir import BASEDIR
+from openpilot.common.params import Params
+from openpilot.common.swaglog import cloudlog
+from openpilot.selfdrive.updated.common import FINALIZED, STAGING_ROOT, UpdateStrategy, parse_release_notes, set_consistent_flag, run
+
+
+OVERLAY_UPPER = os.path.join(STAGING_ROOT, "upper")
+OVERLAY_METADATA = os.path.join(STAGING_ROOT, "metadata")
+OVERLAY_MERGED = os.path.join(STAGING_ROOT, "merged")
+OVERLAY_INIT = Path(os.path.join(BASEDIR, ".overlay_init"))
+
+
+def setup_git_options(cwd: str) -> None:
+  # We sync FS object atimes (which NEOS doesn't use) and mtimes, but ctimes
+  # are outside user control. Make sure Git is set up to ignore system ctimes,
+  # because they change when we make hard links during finalize. Otherwise,
+  # there is a lot of unnecessary churn. This appears to be a common need on
+  # OSX as well: https://www.git-tower.com/blog/make-git-rebase-safe-on-osx/
+
+  # We are using copytree to copy the directory, which also changes
+  # inode numbers. Ignore those changes too.
+
+  # Set protocol to the new version (default after git 2.26) to reduce data
+  # usage on git fetch --dry-run from about 400KB to 18KB.
+  git_cfg = [
+    ("core.trustctime", "false"),
+    ("core.checkStat", "minimal"),
+    ("protocol.version", "2"),
+    ("gc.auto", "0"),
+    ("gc.autoDetach", "false"),
+  ]
+  for option, value in git_cfg:
+    run(["git", "config", option, value], cwd)
+
+
+def dismount_overlay() -> None:
+  if os.path.ismount(OVERLAY_MERGED):
+    cloudlog.info("unmounting existing overlay")
+    run(["sudo", "umount", "-l", OVERLAY_MERGED])
+
+
+def init_overlay() -> None:
+
+  # Re-create the overlay if BASEDIR/.git has changed since we created the overlay
+  if OVERLAY_INIT.is_file() and os.path.ismount(OVERLAY_MERGED):
+    git_dir_path = os.path.join(BASEDIR, ".git")
+    new_files = run(["find", git_dir_path, "-newer", str(OVERLAY_INIT)])
+    if not len(new_files.splitlines()):
+      # A valid overlay already exists
+      return
+    else:
+      cloudlog.info(".git directory changed, recreating overlay")
+
+  cloudlog.info("preparing new safe staging area")
+
+  params = Params()
+  params.put_bool("UpdateAvailable", False)
+  set_consistent_flag(False)
+  dismount_overlay()
+  run(["sudo", "rm", "-rf", STAGING_ROOT])
+  if os.path.isdir(STAGING_ROOT):
+    shutil.rmtree(STAGING_ROOT)
+
+  for dirname in [STAGING_ROOT, OVERLAY_UPPER, OVERLAY_METADATA, OVERLAY_MERGED]:
+    os.mkdir(dirname, 0o755)
+
+  if os.lstat(BASEDIR).st_dev != os.lstat(OVERLAY_MERGED).st_dev:
+    raise RuntimeError("base and overlay merge directories are on different filesystems; not valid for overlay FS!")
+
+  # Leave a timestamped canary in BASEDIR to check at startup. The device clock
+  # should be correct by the time we get here. If the init file disappears, or
+  # critical mtimes in BASEDIR are newer than .overlay_init, continue.sh can
+  # assume that BASEDIR has used for local development or otherwise modified,
+  # and skips the update activation attempt.
+  consistent_file = Path(os.path.join(BASEDIR, ".overlay_consistent"))
+  if consistent_file.is_file():
+    consistent_file.unlink()
+  OVERLAY_INIT.touch()
+
+  os.sync()
+  overlay_opts = f"lowerdir={BASEDIR},upperdir={OVERLAY_UPPER},workdir={OVERLAY_METADATA}"
+
+  mount_cmd = ["mount", "-t", "overlay", "-o", overlay_opts, "none", OVERLAY_MERGED]
+  run(["sudo"] + mount_cmd)
+  run(["sudo", "chmod", "755", os.path.join(OVERLAY_METADATA, "work")])
+
+  git_diff = run(["git", "diff"], OVERLAY_MERGED)
+  params.put("GitDiff", git_diff)
+  cloudlog.info(f"git diff output:\n{git_diff}")
+
+
+class GitUpdateStrategy(UpdateStrategy):
+
+  def init(self) -> None:
+    init_overlay()
+
+  def cleanup(self) -> None:
+    OVERLAY_INIT.unlink(missing_ok=True)
+
+  def sync_branches(self):
+    excluded_branches = ('release2', 'release2-staging')
+
+    output = run(["git", "ls-remote", "--heads"], OVERLAY_MERGED)
+
+    self.branches = defaultdict(lambda: None)
+    for line in output.split('\n'):
+      ls_remotes_re = r'(?P<commit_sha>\b[0-9a-f]{5,40}\b)(\s+)(refs\/heads\/)(?P<branch_name>.*$)'
+      x = re.fullmatch(ls_remotes_re, line.strip())
+      if x is not None and x.group('branch_name') not in excluded_branches:
+        self.branches[x.group('branch_name')] = x.group('commit_sha')
+
+    return self.branches
+
+  def get_available_channels(self) -> List[str]:
+    self.sync_branches()
+    return list(self.branches.keys())
+
+  def update_ready(self) -> bool:
+    consistent_file = Path(os.path.join(FINALIZED, ".overlay_consistent"))
+    if consistent_file.is_file():
+      hash_mismatch = self.get_commit_hash(BASEDIR) != self.branches[self.target_channel]
+      branch_mismatch = self.get_branch(BASEDIR) != self.target_channel
+      on_target_channel = self.get_branch(FINALIZED) == self.target_channel
+      return ((hash_mismatch or branch_mismatch) and on_target_channel)
+    return False
+
+  def update_available(self) -> bool:
+    if os.path.isdir(OVERLAY_MERGED) and len(self.get_available_channels()) > 0:
+      hash_mismatch = self.get_commit_hash(OVERLAY_MERGED) != self.branches[self.target_channel]
+      branch_mismatch = self.get_branch(OVERLAY_MERGED) != self.target_channel
+      return hash_mismatch or branch_mismatch
+    return False
+
+  def get_branch(self, path: str) -> str:
+    return run(["git", "rev-parse", "--abbrev-ref", "HEAD"], path).rstrip()
+
+  def get_commit_hash(self, path) -> str:
+    return run(["git", "rev-parse", "HEAD"], path).rstrip()
+
+  def get_current_channel(self) -> str:
+    return self.get_branch(BASEDIR)
+
+  def current_channel(self) -> str:
+    return self.get_branch(BASEDIR)
+
+  def describe_branch(self, basedir) -> str:
+    if not os.path.exists(basedir):
+      return ""
+
+    version = ""
+    branch = ""
+    commit = ""
+    commit_date = ""
+    try:
+      branch = self.get_branch(basedir)
+      commit = self.get_commit_hash(basedir)[:7]
+      with open(os.path.join(basedir, "common", "version.h")) as f:
+        version = f.read().split('"')[1]
+
+      commit_unix_ts = run(["git", "show", "-s", "--format=%ct", "HEAD"], basedir).rstrip()
+      dt = datetime.datetime.fromtimestamp(int(commit_unix_ts))
+      commit_date = dt.strftime("%b %d")
+    except Exception:
+      cloudlog.exception("updater.get_description")
+    return f"{version} / {branch} / {commit} / {commit_date}"
+
+  def release_notes_branch(self, basedir) -> str:
+    with open(os.path.join(basedir, "RELEASES.md"), "r") as f:
+      return parse_release_notes(f.read())
+
+  def describe_current_channel(self) -> tuple[str, str]:
+    return self.describe_branch(BASEDIR), self.release_notes_branch(BASEDIR)
+
+  def describe_ready_channel(self) -> tuple[str, str]:
+    if self.update_ready():
+      return self.describe_branch(FINALIZED), self.release_notes_branch(FINALIZED)
+
+    return "", ""
+
+  def fetch_update(self):
+    cloudlog.info("attempting git fetch inside staging overlay")
+
+    setup_git_options(OVERLAY_MERGED)
+
+    branch = self.target_channel
+    git_fetch_output = run(["git", "fetch", "origin", branch], OVERLAY_MERGED)
+    cloudlog.info("git fetch success: %s", git_fetch_output)
+
+    cloudlog.info("git reset in progress")
+    cmds = [
+      ["git", "checkout", "--force", "--no-recurse-submodules", "-B", branch, "FETCH_HEAD"],
+      ["git", "reset", "--hard"],
+      ["git", "clean", "-xdff"],
+      ["git", "submodule", "sync"],
+      ["git", "submodule", "update", "--init", "--recursive"],
+      ["git", "submodule", "foreach", "--recursive", "git", "reset", "--hard"],
+    ]
+    r = [run(cmd, OVERLAY_MERGED) for cmd in cmds]
+    cloudlog.info("git reset success: %s", '\n'.join(r))
+
+  def fetched_path(self):
+    return str(OVERLAY_MERGED)
+
+  def finalize_update(self) -> None:
+    """Take the current OverlayFS merged view and finalize a copy outside of
+    OverlayFS, ready to be swapped-in at BASEDIR. Copy using shutil.copytree"""
+
+    # Remove the update ready flag and any old updates
+    cloudlog.info("creating finalized version of the overlay")
+    set_consistent_flag(False)
+
+    # Copy the merged overlay view and set the update ready flag
+    if os.path.exists(FINALIZED):
+      shutil.rmtree(FINALIZED)
+    shutil.copytree(OVERLAY_MERGED, FINALIZED, symlinks=True)
+
+    run(["git", "reset", "--hard"], FINALIZED)
+    run(["git", "submodule", "foreach", "--recursive", "git", "reset", "--hard"], FINALIZED)
+
+    cloudlog.info("Starting git cleanup in finalized update")
+    t = time.monotonic()
+    try:
+      run(["git", "gc"], FINALIZED)
+      run(["git", "lfs", "prune"], FINALIZED)
+      cloudlog.event("Done git cleanup", duration=time.monotonic() - t)
+    except subprocess.CalledProcessError:
+      cloudlog.exception(f"Failed git cleanup, took {time.monotonic() - t:.3f} s")
+
+    set_consistent_flag(True)
+    cloudlog.info("done finalizing overlay")

selfdrive/updated/tests/test_base.py

@@ -1,4 +1,3 @@
-#!/usr/bin/env python3
 import os
 import pathlib
 import shutil
@@ -33,12 +32,14 @@ def update_release(directory, name, version, agnos_version, release_notes):
   with open(directory / "launch_env.sh", "w") as f:
     f.write(f'export AGNOS_VERSION="{agnos_version}"')
 
-  run(["git", "add", "."], cwd=directory)
-  run(["git", "commit", "-m", f"openpilot release {version}"], cwd=directory)
-
 
 @pytest.mark.slow # TODO: can we test overlayfs in GHA?
-class TestUpdateD(unittest.TestCase):
+class BaseUpdateTest(unittest.TestCase):
+  @classmethod
+  def setUpClass(cls):
+    if "Base" in cls.__name__:
+      raise unittest.SkipTest
+
   def setUp(self):
     self.tmpdir = tempfile.mkdtemp()
 
@@ -73,15 +74,15 @@ class TestUpdateD(unittest.TestCase):
   def setup_basedir_release(self, release):
     self.params = Params()
     self.set_target_branch(release)
-    run(["git", "clone", "-b", release, self.remote_dir, self.basedir])
 
   def update_remote_release(self, release):
-    update_release(self.remote_dir, release, *self.MOCK_RELEASES[release])
+    raise NotImplementedError("")
 
   def setup_remote_release(self, release):
-    run(["git", "init"], cwd=self.remote_dir)
-    run(["git", "checkout", "-b", release], cwd=self.remote_dir)
-    self.update_remote_release(release)
+    raise NotImplementedError("")
+
+  def additional_context(self):
+    raise NotImplementedError("")
 
   def tearDown(self):
     mock.patch.stopall()
@@ -134,7 +135,7 @@ class TestUpdateD(unittest.TestCase):
     self.setup_remote_release("release3")
     self.setup_basedir_release("release3")
 
-    with processes_context(["updated"]) as [updated]:
+    with self.additional_context(), processes_context(["updated"]) as [updated]:
       self._test_params("release3", False, False)
       self.wait_for_idle()
       self._test_params("release3", False, False)
@@ -150,7 +151,7 @@ class TestUpdateD(unittest.TestCase):
     self.setup_remote_release("release3")
     self.setup_basedir_release("release3")
 
-    with processes_context(["updated"]) as [updated]:
+    with self.additional_context(), processes_context(["updated"]) as [updated]:
       self._test_params("release3", False, False)
       self.wait_for_idle()
       self._test_params("release3", False, False)
@@ -177,7 +178,7 @@ class TestUpdateD(unittest.TestCase):
     self.setup_remote_release("master")
     self.setup_basedir_release("release3")
 
-    with processes_context(["updated"]) as [updated]:
+    with self.additional_context(), processes_context(["updated"]) as [updated]:
       self._test_params("release3", False, False)
       self.wait_for_idle()
       self._test_params("release3", False, False)
@@ -201,10 +202,11 @@ class TestUpdateD(unittest.TestCase):
     self.setup_remote_release("release3")
     self.setup_basedir_release("release3")
 
-    with mock.patch("openpilot.system.hardware.AGNOS", "True"), \
-         mock.patch("openpilot.system.hardware.tici.hardware.Tici.get_os_version", "1.2"), \
-         mock.patch("openpilot.system.hardware.tici.agnos.get_target_slot_number"), \
-         mock.patch("openpilot.system.hardware.tici.agnos.flash_agnos_update"), \
+    with self.additional_context(), \
+        mock.patch("openpilot.system.hardware.AGNOS", "True"), \
+        mock.patch("openpilot.system.hardware.tici.hardware.Tici.get_os_version", "1.2"), \
+        mock.patch("openpilot.system.hardware.tici.agnos.get_target_slot_number"), \
+        mock.patch("openpilot.system.hardware.tici.agnos.flash_agnos_update"), \
           processes_context(["updated"]) as [updated]:
 
       self._test_params("release3", False, False)
@@ -226,7 +228,3 @@ class TestUpdateD(unittest.TestCase):
 
       self._test_params("release3", False, True)
       self._test_update_params("release3", *self.MOCK_RELEASES["release3"])
-
-
-if __name__ == "__main__":
-  unittest.main()

selfdrive/updated/tests/test_git.py

@@ -0,0 +1,22 @@
+import contextlib
+from openpilot.selfdrive.updated.tests.test_base import BaseUpdateTest, run, update_release
+
+
+class TestUpdateDGitStrategy(BaseUpdateTest):
+  def update_remote_release(self, release):
+    update_release(self.remote_dir, release, *self.MOCK_RELEASES[release])
+    run(["git", "add", "."], cwd=self.remote_dir)
+    run(["git", "commit", "-m", f"openpilot release {release}"], cwd=self.remote_dir)
+
+  def setup_remote_release(self, release):
+    run(["git", "init"], cwd=self.remote_dir)
+    run(["git", "checkout", "-b", release], cwd=self.remote_dir)
+    self.update_remote_release(release)
+
+  def setup_basedir_release(self, release):
+    super().setup_basedir_release(release)
+    run(["git", "clone", "-b", release, self.remote_dir, self.basedir])
+
+  @contextlib.contextmanager
+  def additional_context(self):
+    yield

selfdrive/updated/updated.py

@@ -1,35 +1,21 @@
 #!/usr/bin/env python3
 import os
-import re
+from pathlib import Path
 import datetime
 import subprocess
 import psutil
-import shutil
 import signal
 import fcntl
-import time
 import threading
-from collections import defaultdict
-from pathlib import Path
-from markdown_it import MarkdownIt
 
-from openpilot.common.basedir import BASEDIR
 from openpilot.common.params import Params
 from openpilot.common.time import system_time_valid
+from openpilot.selfdrive.updated.common import LOCK_FILE, STAGING_ROOT, UpdateStrategy, run, set_consistent_flag
 from openpilot.system.hardware import AGNOS, HARDWARE
 from openpilot.common.swaglog import cloudlog
 from openpilot.selfdrive.controls.lib.alertmanager import set_offroad_alert
 from openpilot.system.version import is_tested_branch
-
-LOCK_FILE = os.getenv("UPDATER_LOCK_FILE", "/tmp/safe_staging_overlay.lock")
-STAGING_ROOT = os.getenv("UPDATER_STAGING_ROOT", "/data/safe_staging")
-
-OVERLAY_UPPER = os.path.join(STAGING_ROOT, "upper")
-OVERLAY_METADATA = os.path.join(STAGING_ROOT, "metadata")
-OVERLAY_MERGED = os.path.join(STAGING_ROOT, "merged")
-FINALIZED = os.path.join(STAGING_ROOT, "finalized")
-
-OVERLAY_INIT = Path(os.path.join(BASEDIR, ".overlay_init"))
+from openpilot.selfdrive.updated.git import GitUpdateStrategy
 
 DAYS_NO_CONNECTIVITY_MAX = 14     # do not allow to engage after this many days
 DAYS_NO_CONNECTIVITY_PROMPT = 10  # send an offroad prompt after this many days
@@ -71,147 +57,13 @@ def read_time_from_param(params, param) -> datetime.datetime | None:
     pass
   return None
 
-def run(cmd: list[str], cwd: str = None) -> str:
-  return subprocess.check_output(cmd, cwd=cwd, stderr=subprocess.STDOUT, encoding='utf8')
 
-
-def set_consistent_flag(consistent: bool) -> None:
-  os.sync()
-  consistent_file = Path(os.path.join(FINALIZED, ".overlay_consistent"))
-  if consistent:
-    consistent_file.touch()
-  elif not consistent:
-    consistent_file.unlink(missing_ok=True)
-  os.sync()
-
-def parse_release_notes(basedir: str) -> bytes:
-  try:
-    with open(os.path.join(basedir, "RELEASES.md"), "rb") as f:
-      r = f.read().split(b'\n\n', 1)[0]  # Slice latest release notes
-    try:
-      return bytes(MarkdownIt().render(r.decode("utf-8")), encoding="utf-8")
-    except Exception:
-      return r + b"\n"
-  except FileNotFoundError:
-    pass
-  except Exception:
-    cloudlog.exception("failed to parse release notes")
-  return b""
-
-def setup_git_options(cwd: str) -> None:
-  # We sync FS object atimes (which NEOS doesn't use) and mtimes, but ctimes
-  # are outside user control. Make sure Git is set up to ignore system ctimes,
-  # because they change when we make hard links during finalize. Otherwise,
-  # there is a lot of unnecessary churn. This appears to be a common need on
-  # OSX as well: https://www.git-tower.com/blog/make-git-rebase-safe-on-osx/
-
-  # We are using copytree to copy the directory, which also changes
-  # inode numbers. Ignore those changes too.
-
-  # Set protocol to the new version (default after git 2.26) to reduce data
-  # usage on git fetch --dry-run from about 400KB to 18KB.
-  git_cfg = [
-    ("core.trustctime", "false"),
-    ("core.checkStat", "minimal"),
-    ("protocol.version", "2"),
-    ("gc.auto", "0"),
-    ("gc.autoDetach", "false"),
-  ]
-  for option, value in git_cfg:
-    run(["git", "config", option, value], cwd)
-
-
-def dismount_overlay() -> None:
-  if os.path.ismount(OVERLAY_MERGED):
-    cloudlog.info("unmounting existing overlay")
-    run(["sudo", "umount", "-l", OVERLAY_MERGED])
-
-
-def init_overlay() -> None:
-
-  # Re-create the overlay if BASEDIR/.git has changed since we created the overlay
-  if OVERLAY_INIT.is_file() and os.path.ismount(OVERLAY_MERGED):
-    git_dir_path = os.path.join(BASEDIR, ".git")
-    new_files = run(["find", git_dir_path, "-newer", str(OVERLAY_INIT)])
-    if not len(new_files.splitlines()):
-      # A valid overlay already exists
-      return
-    else:
-      cloudlog.info(".git directory changed, recreating overlay")
-
-  cloudlog.info("preparing new safe staging area")
-
-  params = Params()
-  params.put_bool("UpdateAvailable", False)
-  set_consistent_flag(False)
-  dismount_overlay()
-  run(["sudo", "rm", "-rf", STAGING_ROOT])
-  if os.path.isdir(STAGING_ROOT):
-    shutil.rmtree(STAGING_ROOT)
-
-  for dirname in [STAGING_ROOT, OVERLAY_UPPER, OVERLAY_METADATA, OVERLAY_MERGED]:
-    os.mkdir(dirname, 0o755)
-
-  if os.lstat(BASEDIR).st_dev != os.lstat(OVERLAY_MERGED).st_dev:
-    raise RuntimeError("base and overlay merge directories are on different filesystems; not valid for overlay FS!")
-
-  # Leave a timestamped canary in BASEDIR to check at startup. The device clock
-  # should be correct by the time we get here. If the init file disappears, or
-  # critical mtimes in BASEDIR are newer than .overlay_init, continue.sh can
-  # assume that BASEDIR has used for local development or otherwise modified,
-  # and skips the update activation attempt.
-  consistent_file = Path(os.path.join(BASEDIR, ".overlay_consistent"))
-  if consistent_file.is_file():
-    consistent_file.unlink()
-  OVERLAY_INIT.touch()
-
-  os.sync()
-  overlay_opts = f"lowerdir={BASEDIR},upperdir={OVERLAY_UPPER},workdir={OVERLAY_METADATA}"
-
-  mount_cmd = ["mount", "-t", "overlay", "-o", overlay_opts, "none", OVERLAY_MERGED]
-  run(["sudo"] + mount_cmd)
-  run(["sudo", "chmod", "755", os.path.join(OVERLAY_METADATA, "work")])
-
-  git_diff = run(["git", "diff"], OVERLAY_MERGED)
-  params.put("GitDiff", git_diff)
-  cloudlog.info(f"git diff output:\n{git_diff}")
-
-
-def finalize_update() -> None:
-  """Take the current OverlayFS merged view and finalize a copy outside of
-  OverlayFS, ready to be swapped-in at BASEDIR. Copy using shutil.copytree"""
-
-  # Remove the update ready flag and any old updates
-  cloudlog.info("creating finalized version of the overlay")
-  set_consistent_flag(False)
-
-  # Copy the merged overlay view and set the update ready flag
-  if os.path.exists(FINALIZED):
-    shutil.rmtree(FINALIZED)
-  shutil.copytree(OVERLAY_MERGED, FINALIZED, symlinks=True)
-
-  run(["git", "reset", "--hard"], FINALIZED)
-  run(["git", "submodule", "foreach", "--recursive", "git", "reset", "--hard"], FINALIZED)
-
-  cloudlog.info("Starting git cleanup in finalized update")
-  t = time.monotonic()
-  try:
-    run(["git", "gc"], FINALIZED)
-    run(["git", "lfs", "prune"], FINALIZED)
-    cloudlog.event("Done git cleanup", duration=time.monotonic() - t)
-  except subprocess.CalledProcessError:
-    cloudlog.exception(f"Failed git cleanup, took {time.monotonic() - t:.3f} s")
-
-  set_consistent_flag(True)
-  cloudlog.info("done finalizing overlay")
-
-
-def handle_agnos_update() -> None:
+def handle_agnos_update(fetched_path) -> None:
   from openpilot.system.hardware.tici.agnos import flash_agnos_update, get_target_slot_number
 
   cur_version = HARDWARE.get_os_version()
   updated_version = run(["bash", "-c", r"unset AGNOS_VERSION && source launch_env.sh && \
-                          echo -n $AGNOS_VERSION"], OVERLAY_MERGED).strip()
+                          echo -n $AGNOS_VERSION"], fetched_path).strip()
 
   cloudlog.info(f"AGNOS version check: {cur_version} vs {updated_version}")
   if cur_version == updated_version:
@@ -223,61 +75,44 @@ def handle_agnos_update() -> None:
   cloudlog.info(f"Beginning background installation for AGNOS {updated_version}")
   set_offroad_alert("Offroad_NeosUpdate", True)
 
-  manifest_path = os.path.join(OVERLAY_MERGED, "system/hardware/tici/agnos.json")
+  manifest_path = os.path.join(fetched_path, "system/hardware/tici/agnos.json")
   target_slot_number = get_target_slot_number()
   flash_agnos_update(manifest_path, target_slot_number, cloudlog)
   set_offroad_alert("Offroad_NeosUpdate", False)
 
 
+STRATEGY = {
+  "git": GitUpdateStrategy,
+}
+
 
 class Updater:
   def __init__(self):
     self.params = Params()
-    self.branches = defaultdict(str)
     self._has_internet: bool = False
 
+    self.strategy: UpdateStrategy = STRATEGY[os.environ.get("UPDATER_STRATEGY", "git")]()
+
   @property
   def has_internet(self) -> bool:
     return self._has_internet
 
-  @property
-  def target_branch(self) -> str:
-    b: str | None = self.params.get("UpdaterTargetBranch", encoding='utf-8')
-    if b is None:
-      b = self.get_branch(BASEDIR)
-    return b
+  def init(self):
+    self.strategy.init()
 
-  @property
-  def update_ready(self) -> bool:
-    consistent_file = Path(os.path.join(FINALIZED, ".overlay_consistent"))
-    if consistent_file.is_file():
-      hash_mismatch = self.get_commit_hash(BASEDIR) != self.branches[self.target_branch]
-      branch_mismatch = self.get_branch(BASEDIR) != self.target_branch
-      on_target_branch = self.get_branch(FINALIZED) == self.target_branch
-      return ((hash_mismatch or branch_mismatch) and on_target_branch)
-    return False
-
-  @property
-  def update_available(self) -> bool:
-    if os.path.isdir(OVERLAY_MERGED) and len(self.branches) > 0:
-      hash_mismatch = self.get_commit_hash(OVERLAY_MERGED) != self.branches[self.target_branch]
-      branch_mismatch = self.get_branch(OVERLAY_MERGED) != self.target_branch
-      return hash_mismatch or branch_mismatch
-    return False
-
-  def get_branch(self, path: str) -> str:
-    return run(["git", "rev-parse", "--abbrev-ref", "HEAD"], path).rstrip()
-
-  def get_commit_hash(self, path: str = OVERLAY_MERGED) -> str:
-    return run(["git", "rev-parse", "HEAD"], path).rstrip()
+  def cleanup(self):
+    self.strategy.cleanup()
 
   def set_params(self, update_success: bool, failed_count: int, exception: str | None) -> None:
     self.params.put("UpdateFailedCount", str(failed_count))
-    self.params.put("UpdaterTargetBranch", self.target_branch)
 
-    self.params.put_bool("UpdaterFetchAvailable", self.update_available)
-    if len(self.branches):
-      self.params.put("UpdaterAvailableBranches", ','.join(self.branches.keys()))
+    if self.params.get("UpdaterTargetBranch") is None:
+      self.params.put("UpdaterTargetBranch", self.strategy.current_channel())
+
+    self.params.put_bool("UpdaterFetchAvailable", self.strategy.update_available())
+
+    available_channels = self.strategy.get_available_channels()
+    self.params.put("UpdaterAvailableBranches", ','.join(available_channels))
 
     last_update = datetime.datetime.utcnow()
     if update_success:
@@ -292,32 +127,14 @@ class Updater:
     else:
       self.params.put("LastUpdateException", exception)
 
-    # Write out current and new version info
-    def get_description(basedir: str) -> str:
-      if not os.path.exists(basedir):
-        return ""
+    description_current, release_notes_current = self.strategy.describe_current_channel()
+    description_ready, release_notes_ready = self.strategy.describe_ready_channel()
 
-      version = ""
-      branch = ""
-      commit = ""
-      commit_date = ""
-      try:
-        branch = self.get_branch(basedir)
-        commit = self.get_commit_hash(basedir)[:7]
-        with open(os.path.join(basedir, "common", "version.h")) as f:
-          version = f.read().split('"')[1]
-
-        commit_unix_ts = run(["git", "show", "-s", "--format=%ct", "HEAD"], basedir).rstrip()
-        dt = datetime.datetime.fromtimestamp(int(commit_unix_ts))
-        commit_date = dt.strftime("%b %d")
-      except Exception:
-        cloudlog.exception("updater.get_description")
-      return f"{version} / {branch} / {commit} / {commit_date}"
-    self.params.put("UpdaterCurrentDescription", get_description(BASEDIR))
-    self.params.put("UpdaterCurrentReleaseNotes", parse_release_notes(BASEDIR))
-    self.params.put("UpdaterNewDescription", get_description(FINALIZED))
-    self.params.put("UpdaterNewReleaseNotes", parse_release_notes(FINALIZED))
-    self.params.put_bool("UpdateAvailable", self.update_ready)
+    self.params.put("UpdaterCurrentDescription", description_current)
+    self.params.put("UpdaterCurrentReleaseNotes", release_notes_current)
+    self.params.put("UpdaterNewDescription", description_ready)
+    self.params.put("UpdaterNewReleaseNotes", release_notes_ready)
+    self.params.put_bool("UpdateAvailable", self.strategy.update_ready())
 
     # Handle user prompt
     for alert in ("Offroad_UpdateFailed", "Offroad_ConnectivityNeeded", "Offroad_ConnectivityNeededPrompt"):
@@ -341,67 +158,24 @@ class Updater:
   def check_for_update(self) -> None:
     cloudlog.info("checking for updates")
 
-    excluded_branches = ('release2', 'release2-staging')
-
-    try:
-      run(["git", "ls-remote", "origin", "HEAD"], OVERLAY_MERGED)
-      self._has_internet = True
-    except subprocess.CalledProcessError:
-      self._has_internet = False
-
-    setup_git_options(OVERLAY_MERGED)
-    output = run(["git", "ls-remote", "--heads"], OVERLAY_MERGED)
-
-    self.branches = defaultdict(lambda: None)
-    for line in output.split('\n'):
-      ls_remotes_re = r'(?P<commit_sha>\b[0-9a-f]{5,40}\b)(\s+)(refs\/heads\/)(?P<branch_name>.*$)'
-      x = re.fullmatch(ls_remotes_re, line.strip())
-      if x is not None and x.group('branch_name') not in excluded_branches:
-        self.branches[x.group('branch_name')] = x.group('commit_sha')
-
-    cur_branch = self.get_branch(OVERLAY_MERGED)
-    cur_commit = self.get_commit_hash(OVERLAY_MERGED)
-    new_branch = self.target_branch
-    new_commit = self.branches[new_branch]
-    if (cur_branch, cur_commit) != (new_branch, new_commit):
-      cloudlog.info(f"update available, {cur_branch} ({str(cur_commit)[:7]}) -> {new_branch} ({str(new_commit)[:7]})")
-    else:
-      cloudlog.info(f"up to date on {cur_branch} ({str(cur_commit)[:7]})")
+    self.strategy.update_available()
 
   def fetch_update(self) -> None:
-    cloudlog.info("attempting git fetch inside staging overlay")
-
     self.params.put("UpdaterState", "downloading...")
 
     # TODO: cleanly interrupt this and invalidate old update
     set_consistent_flag(False)
     self.params.put_bool("UpdateAvailable", False)
 
-    setup_git_options(OVERLAY_MERGED)
-
-    branch = self.target_branch
-    git_fetch_output = run(["git", "fetch", "origin", branch], OVERLAY_MERGED)
-    cloudlog.info("git fetch success: %s", git_fetch_output)
-
-    cloudlog.info("git reset in progress")
-    cmds = [
-      ["git", "checkout", "--force", "--no-recurse-submodules", "-B", branch, "FETCH_HEAD"],
-      ["git", "reset", "--hard"],
-      ["git", "clean", "-xdff"],
-      ["git", "submodule", "sync"],
-      ["git", "submodule", "update", "--init", "--recursive"],
-      ["git", "submodule", "foreach", "--recursive", "git", "reset", "--hard"],
-    ]
-    r = [run(cmd, OVERLAY_MERGED) for cmd in cmds]
-    cloudlog.info("git reset success: %s", '\n'.join(r))
+    self.strategy.fetch_update()
 
     # TODO: show agnos download progress
     if AGNOS:
-      handle_agnos_update()
+      handle_agnos_update(self.strategy.fetched_path())
 
     # Create the finalized, ready-to-swap update
     self.params.put("UpdaterState", "finalizing update...")
-    finalize_update()
+    self.strategy.finalize_update()
     cloudlog.info("finalize success!")
 
 
@@ -450,7 +224,7 @@ def main() -> None:
       exception = None
       try:
         # TODO: reuse overlay from previous updated instance if it looks clean
-        init_overlay()
+        updater.init()
 
         # ensure we have some params written soon after startup
         updater.set_params(False, update_failed_count, exception)
@@ -486,11 +260,11 @@ def main() -> None:
           returncode=e.returncode
         )
         exception = f"command failed: {e.cmd}\n{e.output}"
-        OVERLAY_INIT.unlink(missing_ok=True)
+        updater.cleanup()
       except Exception as e:
         cloudlog.exception("uncaught updated exception, shouldn't happen")
         exception = str(e)
-        OVERLAY_INIT.unlink(missing_ok=True)
+        updater.cleanup()
 
       try:
         params.put("UpdaterState", "idle")