refactor

zfs_backup/commands/zpool.py

@@ -0,0 +1,96 @@
+from __future__ import annotations
+
+from datetime import timedelta, datetime
+from pathlib import Path
+
+from ._core import CommandInterface
+from ..pool import Pool
+from ..misc import assert_type
+from ..time import Time
+
+
+class ZPool(CommandInterface):
+    _BINARY = Path("/usr/bin/zpool")
+
+    class _Subcommands:
+        # -N: no mount
+        # -d: directory to search the pool in
+        import_ = ["import", "-N", "-d"]
+        export = ["export"]
+        scrub = ["scrub"]
+        status = ["status"]
+        wait = ["wait", "-t", "scrub"]
+
+    @classmethod
+    def import_from_directory(cls, pool: Pool, directory: Path) -> None:
+        """Search `directory` for `pool` and import it."""
+        assert_type(pool, Pool, "Can only import Pool objects")
+        cls._run_command(*cls._Subcommands.import_, str(directory), pool.name)
+
+    @classmethod
+    def export(cls, pool: Pool) -> None:
+        """Export the pool."""
+        assert_type(pool, Pool, "Can only export Pool objects")
+        cls._run_command(*cls._Subcommands.export, pool.name)
+
+    @classmethod
+    def scrub(
+        cls,
+        pool: Pool,
+        *,
+        skip_if_recently_scrubbed: bool,
+        recent_scrub_timedelta: timedelta,
+        wait_for_finish: bool = True,
+    ) -> None:
+        """Scrub the pool.
+
+        Waits for the scrub to finish. Raise an IOError if the pool reports as not healthy after the scrub."""
+        assert_type(pool, Pool, "Can only scrub pools.")
+        cls._scrub_if_necessary(pool, skip_if_recently_scrubbed, recent_scrub_timedelta)
+        if wait_for_finish:
+            cls._run_command(*cls._Subcommands.wait, pool.name)
+        if not cls._is_healthy(pool):
+            raise IOError(f"Pool {pool.name} is not healthy.")
+
+    @classmethod
+    def _scrub_if_necessary(
+        cls,
+        pool: Pool,
+        skip_if_recently_scrubbed: bool,
+        recent_scrub_timedelta: timedelta,
+    ) -> None:
+        """Scrub the pool. If"""
+
+        def do_scrub():
+            cls._run_command(*cls._Subcommands.scrub, pool.name)
+
+        if cls._scrub_in_progress(pool):
+            return
+        if not skip_if_recently_scrubbed:
+            do_scrub()
+        else:
+            if not cls._recently_scrubbed(pool, recent_scrub_timedelta):
+                do_scrub()
+
+    @classmethod
+    def _recently_scrubbed(cls, pool: Pool, recent_scrub_timedelta: timedelta) -> bool:
+        """Is the interval after the last scrub smaller than the minimum timedelta?"""
+        return datetime.now() - cls._last_scrub(pool) < recent_scrub_timedelta
+
+    @classmethod
+    def _scrub_in_progress(cls, pool: Pool) -> bool:
+        return "scrub in progress" in cls._get_pool_status_output(pool)
+
+    @classmethod
+    def _is_healthy(cls, pool: Pool) -> bool:
+        return "ONLINE" in cls._get_pool_status_output(pool)
+
+    @classmethod
+    def _get_pool_status_output(cls, pool: Pool) -> str:
+        """Return output of `zpool status [pool]`."""
+        return cls._get_output(*cls._Subcommands.status, pool.name)
+
+    @classmethod
+    def _last_scrub(cls, pool: Pool) -> datetime:
+        """Get time of the last scrub."""
+        return Time.get_last_scrub_from_status_output(cls._get_pool_status_output(pool))