homelab client add --finalize-pubkey: grant shared secrets atomically

Setting the age_pubkey is half the enrollment; the new client also needs
to be a recipient on shared secrets (hello.yaml, gitea-pat.yaml) to
actually use them. Now --finalize-pubkey:

  1. writes hosts.<name>.age_pubkey
  2. appends the pubkey to each shared-secret rule in .sops.yaml
     (preserving comments via line-by-line edit, not yaml round-trip)
  3. runs sops updatekeys -y on each shared file
  4. commits inventory + hosts/ + .sops.yaml + secrets/ as one commit

Also: cmd_client_add now re-execs via sudo when invoked as a regular
user (matches the pattern in cmd_secret + cmd_refresh_creds).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

bin/homelab

@@ -103,11 +103,14 @@ def service_backend_host(name: str) -> str:
     return service(name)["backend"]
 
 
-def push_inventory(message: str) -> None:
-    """Stage + commit + push inventory + regenerated hosts/."""
+def push_inventory(message: str, extra_paths: list[str] | None = None) -> None:
+    """Stage + commit + push inventory + regenerated hosts/ (+ any extras)."""
     subprocess.run(["python3", str(CONTEXT / "mcp" / "build_host_files.py")],
                    check=True, cwd=CONTEXT)
-    subprocess.run(["git", "add", "inventory.yaml", "hosts/"], check=True, cwd=CONTEXT)
+    paths = ["inventory.yaml", "hosts/"]
+    if extra_paths:
+        paths.extend(extra_paths)
+    subprocess.run(["git", "add"] + paths, check=True, cwd=CONTEXT)
     if subprocess.run(["git", "diff", "--cached", "--quiet"], cwd=CONTEXT).returncode == 0:
         print("(no changes to commit)")
         return
@@ -115,6 +118,83 @@ def push_inventory(message: str) -> None:
     subprocess.run(["git", "push"], check=True, cwd=CONTEXT)
 
 
+# Secrets every enrolled client should be a recipient on. Each entry is
+# (secret-file-path-relative-to-CONTEXT, path_regex used in .sops.yaml).
+SHARED_SECRETS = [
+    ("secrets/hello.yaml",     "^secrets/hello\\.yaml$"),
+    ("secrets/gitea-pat.yaml", "^secrets/gitea-pat\\.yaml$"),
+]
+
+
+def _add_recipient_to_sops_policy(sops_path: Path, path_regex_pattern: str, pubkey: str) -> bool:
+    """Append `pubkey` to the `age:` list of the .sops.yaml rule whose
+    `path_regex:` line contains `path_regex_pattern`. Preserves comments.
+
+    Returns True if added (or already present), False if no matching rule.
+    """
+    if not sops_path.exists():
+        return False
+    lines = sops_path.read_text().splitlines(keepends=True)
+    in_target_rule = False
+    age_block_start = None
+    age_block_last_idx = None
+    for i, line in enumerate(lines):
+        stripped = line.strip()
+        if stripped.startswith("- path_regex:"):
+            in_target_rule = path_regex_pattern in line
+            age_block_start = None
+            age_block_last_idx = None
+            continue
+        if not in_target_rule:
+            continue
+        if "age: >-" in line:
+            age_block_start = i
+            continue
+        if age_block_start is None:
+            continue
+        # Inside the age block; track the last age1... line.
+        if "age1" in stripped:
+            if pubkey in line:
+                return True  # already a recipient
+            age_block_last_idx = i
+        elif stripped == "" or stripped.startswith("#"):
+            continue  # blank / comment inside the block
+        else:
+            break  # next key, age block ended
+    if age_block_last_idx is None:
+        return False
+    last_line = lines[age_block_last_idx]
+    indent = last_line[: len(last_line) - len(last_line.lstrip())]
+    if not last_line.rstrip().endswith(","):
+        lines[age_block_last_idx] = last_line.rstrip() + ",\n"
+    lines.insert(age_block_last_idx + 1, f"{indent}{pubkey}\n")
+    sops_path.write_text("".join(lines))
+    return True
+
+
+def _grant_shared_secrets(pubkey: str) -> None:
+    """Add `pubkey` to the recipient list of every shared secret + re-key."""
+    sops_path = CONTEXT / ".sops.yaml"
+    env = {**os.environ, "SOPS_AGE_KEY_FILE": str(AGE_KEY)}
+    for rel_path, pattern in SHARED_SECRETS:
+        target = CONTEXT / rel_path
+        if not target.exists():
+            print(f"  skipping {rel_path}: file does not exist yet")
+            continue
+        added = _add_recipient_to_sops_policy(sops_path, pattern, pubkey)
+        if not added:
+            print(f"  warning: no matching rule in .sops.yaml for {rel_path} — skipping")
+            continue
+        proc = subprocess.run(
+            ["sops", "updatekeys", "-y", rel_path],
+            capture_output=True, text=True, env=env, cwd=str(CONTEXT),
+        )
+        if proc.returncode == 0:
+            print(f"  re-keyed {rel_path} (added {pubkey[:20]}…)")
+        else:
+            print(f"  warning: sops updatekeys failed for {rel_path}: {proc.stderr.strip()}")
+
+
 # ---------- subcommands ----------
 
 def cmd_whoami(args: argparse.Namespace) -> int:
@@ -347,6 +427,13 @@ def cmd_mcp(args: argparse.Namespace) -> int:
 
 
 def cmd_client_add(args: argparse.Namespace) -> int:
+    # client add edits root-owned files and may need to read the age key
+    # for sops updatekeys. Re-exec under sudo if not root.
+    if os.geteuid() != 0:
+        return subprocess.call(["sudo", "-E", sys.argv[0], "client", "add"]
+                               + ([args.name] if args.name else [])
+                               + (["--finalize-pubkey", args.finalize_pubkey]
+                                  if args.finalize_pubkey else []))
     name = args.name
     inv = inventory()
     if not args.finalize_pubkey:
@@ -379,10 +466,17 @@ def cmd_client_add(args: argparse.Namespace) -> int:
     # finalize_pubkey path
     if name not in inv["hosts"]:
         die(f"{name} not in inventory — run 'homelab client add {name}' first (no --finalize-pubkey)")
-    inv["hosts"][name]["age_pubkey"] = args.finalize_pubkey
+    pubkey = args.finalize_pubkey
+    inv["hosts"][name]["age_pubkey"] = pubkey
     INVENTORY.write_text(yaml.safe_dump(inv, sort_keys=False))
-    push_inventory(f"client-add: {name} (finalize age_pubkey)")
-    print(f"finalized age_pubkey for {name}.")
+    print(f"set age_pubkey for {name}")
+    print("granting shared secrets...")
+    _grant_shared_secrets(pubkey)
+    push_inventory(
+        f"client-add: {name} (finalize age_pubkey + grant shared secrets)",
+        extra_paths=[".sops.yaml", "secrets/"],
+    )
+    print(f"finalized {name}.")
     return 0