treestamps 2.5.0

Create timestamp records for recursive operations on directory trees.

📦 Treestamps

Fast, persistent timestamps for recursive filesystem operations.

Treestamps lets you skip work you’ve already done.

If your program walks directory trees and processes files (optimization, transcoding, validation, etc.), Treestamps tracks what you've already handled—so subsequent runs are incremental, not repetitive.

---

🚀 Why Treestamps?

Treestamps gives you:

• Persistent state across runs
• O(1) “have I seen this file before?” checks
• Automatic invalidation when config changes
• No database dependency (just YAML files)
• Safe writes via WAL (write-ahead log)

🧠 Mental model

Treestamps is built around three concepts:

1. Grove

A Grovestamps instance manages timestamps across multiple root paths.

2. Tree

Each configured path (e.g. /photos) is a tree.

3. Stamp

Each file gets a timestamp keyed by its relative path within the tree.

Examples

Full use

from pathlib import Path
from treestamps import Grovestamps, GrovestampsConfig

config = GrovestampsConfig(
    "MyProgram",
    paths=("/data/photos", "/data/videos"),
    program_config={"quality": 90}
)

gs = Grovestamps(config)

ts = gs[Path("/data/photos")].get()

if ts.get("img001.jpg") is None:
    process("img001.jpg")
    ts.set("img001.jpg")

gs.dump()

Skip unchanged files

for file in files:
    if ts.get(file) is not None:
        continue  # already processed

    process(file)
    ts.set(file)

Invalidate when config changes

GrovestampsConfig(
    "MyProgram",
    paths=("/data",),
    program_config={"quality": 80}
)

If you later change:

program_config={"quality": 90}

👉 All timestamps are invalidated automatically.

Multi-root trees

config = GrovestampsConfig(
    "MyProgram",
    paths=("/a", "/b"),
)

Each root gets its own timestamp file, but shares config logic.

⚙️ How it works

Treestamps uses two files per root directory:

1. WAL file (write-ahead log)

.MyProgram_treestamps.wal.yaml

• Appended during runtime
• Fast writes
• Crash-safe

2. Final snapshot

.MyProgram_treestamps.yaml

• Written on dump()
• Compact
• Used on next startup

Lifecycle

1. Load .yaml (if exists)
2. Replay .wal.yaml (if exists)
3. Serve reads/writes in memory
4. Append writes to WAL
5. On dump():
   • Merge everything
   • Write .yaml
   • Delete WAL

💾 When to call dump()

dump() commits the in memory treestamps data to disk.

Call it when

• At the end of a successful run
• After processing a large batch
• Before shutdown in long-running processes

Don’t call it

• After every file (too slow)
• If the run failed (you may want to discard progress)

🧨 Error handling

Treestamps is designed to be robust but not magical.

Corrupt YAML

If .yaml is unreadable or treated as missing the WAL may still recover recent writes

WAL corruption

• Partial WAL entries may be ignored
• Worst case: last few writes lost (not the entire dataset)

Config mismatch

• If program_config changes:
  • Old timestamps are ignored
  • No partial reuse

Missing files

• If a file disappears:
  • Its stamp remains
  • It is your responsibility to handle filesystem drift

🧩 Configuration (GrovestampsConfig)

GrovestampsConfig(
    program_name: str,
    paths: Iterable[str | Path],
    program_config: dict = None,
    wal: bool = True,
)

Fields

program_name

• Used in filenames:

  .<program_name>_treestamps.yaml
  

paths

• Root directories to manage
• Each gets its own stamp file

program_config

• Arbitrary dict
• Included in hash/signature
• Changing it invalidates all timestamps

wal (if supported)

• Enables/disables WAL behavior
• Disabling may reduce safety but simplify writes

🧾 YAML file format

Snapshot file

version: 1
program: MyProgram
config_hash: abc123

timestamps:
    img001.jpg: 1700000000.123
    img002.jpg: 1700000001.456

WAL file

- set:
      path: img003.jpg
      time: 1700000002.789
- set:
      path: img004.jpg
      time: 1700000003.000

Notes

• Paths are relative to root
• Timestamps are typically float seconds
• WAL is append-only

🧪 Real-world use cases

🖼️ Image optimization (picopt)

In picopt:

• Avoid re-optimizing unchanged images
• Skip entire archives if contents are unchanged
• Handle millions of files efficiently
• Handle config changes (e.g. compression settings) by invalidating stamps ([New Releases][1])

🎬 Media cleanup (nudebomb)

In nudebomb:

• Avoid reprocessing already-cleaned MKVs
• Track work across large media libraries
• Resume interrupted runs safely

🧰 General pattern

Treestamps is ideal for anything that

• walks a tree
• does expensive work
• runs repeatedly

🛠️ Troubleshooting

“Everything is reprocessing every run”

• Did program_config change?
• Did program_name change?
• Are you calling dump()?

“Timestamps not persisting”

• Ensure dump() is called
• Check write permissions in root directories

“Unexpected invalidation”

• Any change in program_config invalidates all stamps
• Even ordering or defaults may matter

“WAL file keeps growing”

• You’re not calling dump()
• WAL is expected to grow until committed

“Files moved or renamed”

• Treestamps uses relative paths
• Renames = treated as new files