Simple script to get all package updates since boot

.gitignore

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+/.dir-locals.el
+*.pyc

diff_packages.py

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+#!/usr/bin/env python
+import json
+import tempfile
+import subprocess
+import datetime
+from pathlib import Path
+
+
+def get_last_boot():
+    with subprocess.Popen(
+        ["journalctl", "--list-boots"], stdout=subprocess.PIPE
+    ) as proc:
+        for line in proc.stdout.read().decode().split("\n"):
+            info, end_time = line.split(chr(8212))
+            info = list(filter(bool, info.split(" ")))
+            bootnum = info[0]
+            if bootnum == "0":
+                start_date_string = " ".join(info[3:5])
+                return datetime.datetime.fromisoformat(start_date_string).replace(
+                    tzinfo=datetime.timezone.utc
+                )
+
+
+def get_snapshot__after_datetime(start: datetime.datetime):
+    with subprocess.Popen(
+        ["snapper", "--utc", "--iso", "--jsonout", "list", "-t", "pre-post"],
+        stdout=subprocess.PIPE,
+    ) as proc:
+        if proc.wait() != 0:
+            raise PermissionError("Snapper needs root privileges to read snapshots")
+        data = json.loads(proc.stdout.read().decode())
+        # ten years
+        td = 3153600000
+        ret = None
+        for snapshot in data["root"]:
+            snapshot_date = datetime.datetime.fromisoformat(snapshot["date"]).replace(
+                tzinfo=datetime.timezone.utc
+            )
+            d = (snapshot_date - start).total_seconds()
+            if 0 < d < td:
+                td = d
+                ret = snapshot
+        return ret
+
+
+def get_snapshot_path(snapshot):
+    return (
+        Path(snapshot["subvolume"])
+        / ".snapshots"
+        / Path(str(snapshot["number"]))
+        / "snapshot"
+    )
+
+
+def write_pacman_output(path):
+    out_file = tempfile.NamedTemporaryFile("wt")
+    proc = subprocess.Popen(["pacman", "-Q", "--dbpath", str(path)], stdout=out_file)
+    proc.wait()
+    return out_file
+
+
+def diff_tempfiles(old, new):
+    subprocess.Popen(["diff", old.name, new.name, "--color=always", "--minimal"])
+
+
+if __name__ == "__main__":
+    snapshot_data = get_snapshot__after_datetime(get_last_boot())
+    snapshot_root = get_snapshot_path(snapshot_data)
+    db_root = "var/lib/pacman"
+    old = write_pacman_output(snapshot_root / db_root)
+    new = write_pacman_output(Path(snapshot_data["subvolume"]) / db_root)
+    diff_tempfiles(old, new)