Start without git, and say what that costs

A `pip install` on a locked-down host — the case the CLI exists for —
may have no git, and the store shelled out to it while building the flow
repository, so the engine refused to start at all. The store is files;
git is their history. Missing it is now one warning and no commits
rather than a stack trace, which is the difference between a machine
that runs your experiments and one that does not.

Found by installing the wheels into a bare python:3.12-slim and pairing
it with the portal: `fluksio enroll` took the code, `fluksio serve`
dialled out, and the hub was proxying requests through the tunnel.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

README.md

@@ -29,6 +29,8 @@ fluksio enroll <code> --portal https://hub.fluksio.com   # watch it from the por
 
 Nothing else has to be running. `--data-dir` puts the installation somewhere else —
 worth it on a cluster, where `$HOME` is often a network filesystem SQLite cannot use.
+`git` is not required but is worth having: flows are files either way, and it is what
+turns each save into a commit.
 The dashboard is served by the portal, so a machine with no inbound route is reached
 without opening a port: it dials out.
 

backend/fluksio/cli.py

@@ -124,14 +124,17 @@ def _enroll(portal: str, code: str, as_email: str | None) -> int:
     from fluksio.core.db import engine
 
     with Session(engine) as session:
-        _, generated = ensure_superuser(session, email=as_email)
+        admin, generated = ensure_superuser(session, email=as_email)
         if generated:
-            _print_new_admin(session, generated)
+            _print_new_admin(admin.email, generated)
         try:
             user = pick_superuser(session, as_email)
         except LookupError as exc:
             print(f"error: {exc}", file=sys.stderr, flush=True)
             return 1
+        # Read before the session closes: the instance is detached after it,
+        # and touching an attribute then goes back to a database that is gone.
+        email = user.email
         try:
             config = enroll_mod.enroll(session, user, portal, code)
         except enroll_mod.AlreadyEnrolled as exc:
@@ -146,22 +149,14 @@ def _enroll(portal: str, code: str, as_email: str | None) -> int:
             return 1
 
     _say(
-        f"Connected to {config.portal_url} as {user.email} "
+        f"Connected to {config.portal_url} as {email} "
         f"(installation {config.installation_id})."
     )
     return 0
 
 
-def _print_new_admin(session: object, password: str) -> None:
+def _print_new_admin(email: str, password: str) -> None:
-    from sqlmodel import Session, select
+    _say(f"Created the admin account {email}")
-
-    from fluksio.models import User
-
-    assert isinstance(session, Session)
-    user = session.exec(
-        select(User).where(User.is_superuser == True)  # noqa: E712
-    ).first()
-    _say(f"Created the admin account {user.email if user else ''}")
     _say(f"  password: {password}")
     _say("  Shown once. Change it from the dashboard.")
 
@@ -177,11 +172,11 @@ def cmd_serve(args: argparse.Namespace) -> int:
     from fluksio.core.db import engine
 
     with Session(engine) as session:
-        _, generated = ensure_superuser(
+        admin, generated = ensure_superuser(
             session, email=args.admin_email, password=args.admin_password
         )
         if generated:
-            _print_new_admin(session, generated)
+            _print_new_admin(admin.email, generated)
 
     if args.enroll:
         if not args.portal:

backend/fluksio/flow/store.py

@@ -94,6 +94,9 @@ def _same_content(left: FlowDef, right: FlowDef) -> bool:
 class FlowStore:
     """Reads and writes flows, committing every change."""
 
+    #: One warning per process when there is no git to commit with.
+    _warned_no_git = False
+
     def __init__(self, root: Path) -> None:
         self.root = root
         self.root.mkdir(parents=True, exist_ok=True)
@@ -109,12 +112,27 @@ class FlowStore:
     # -------------------------------------------------------------------------
 
     def _git(self, *args: str) -> subprocess.CompletedProcess[str]:
+        try:
             return subprocess.run(
                 ["git", "-C", str(self.root), *args],
                 capture_output=True,
                 text=True,
                 check=False,
             )
+        except FileNotFoundError:
+            # No git on this machine — a `pip install` on a locked-down host is
+            # where this happens. The flows are files either way, which is what
+            # the store is; what is lost is their history, so say it once and
+            # carry on rather than refusing to start.
+            if not FlowStore._warned_no_git:
+                FlowStore._warned_no_git = True
+                logger.warning(
+                    "git is not installed, so flow changes are not versioned. "
+                    "Install it to get a commit per save."
+                )
+            return subprocess.CompletedProcess(
+                args=list(args), returncode=1, stdout="", stderr="git is not installed"
+            )
 
     def _commit(self, message: str, allow_empty: bool = False) -> None:
         self._git("add", "-A")
@@ -129,7 +147,11 @@ class FlowStore:
             "-m",
             message,
         )
-        if result.returncode != 0 and "nothing to commit" not in result.stdout:
+        if result.returncode == 0 or "nothing to commit" in result.stdout:
+            return
+        if result.stderr == "git is not installed":
+            # Already said once, in `_git`. Repeating it per save is noise.
+            return
         logger.warning("Could not commit flow change: %s", result.stdout.strip())
 
     # -------------------------------------------------------------------------

backend/tests/test_cli.py

@@ -34,3 +34,29 @@ def test_the_secret_key_is_kept_rather_than_regenerated(tmp_path: Path) -> None:
     first = load_or_create_secret_key(path)
     assert load_or_create_secret_key(path) == first
     assert path.stat().st_mode & 0o777 == 0o600
+
+
+def test_the_store_works_without_git(tmp_path: Path, monkeypatch) -> None:
+    """A pip install on a locked-down host may have no git.
+
+    Flows are files, and that is what the store is for; the history is the part
+    that needs git. Losing it must not be a refusal to start.
+    """
+    import subprocess as sp
+
+    from fluksio.flow.store import FlowStore
+
+    real_run = sp.run
+
+    def no_git(cmd, *args, **kwargs):
+        if cmd and cmd[0] == "git":
+            raise FileNotFoundError(2, "No such file or directory", "git")
+        return real_run(cmd, *args, **kwargs)
+
+    monkeypatch.setattr(sp, "run", no_git)
+    monkeypatch.setattr(FlowStore, "_warned_no_git", False)
+
+    store = FlowStore(tmp_path / "flows")
+    assert store.head() == ""
+    store.write_requirements("numpy\n")
+    assert store.read_requirements() == "numpy\n"