2 minute read

TL;DR: Milestone 7 gave AssetTrack a physical slot model. Milestone 8 adds atomic custody transitions — assets now move from STORAGE to IN_CUSTODY safely, transactionally, and without partial state corruption.

Project page: AssetTrack.

Context

At the end of Milestone 7, AssetTrack stopped being “just a scanner.”

It gained a physical storage abstraction:

  • Cases
  • Slot positions
  • One asset per slot
  • Hard-stop assignment rules
  • Atomic slot mutation

That gave the system structural integrity.
But it didn’t yet behave like a deployment system.

Assets could sit in storage.
Slots were enforced.
But custody — the real-world transfer of responsibility — didn’t exist.

That’s what Milestone 8 begins to solve.

The Problem

Inventory systems fail in subtle ways.

If you:

  • Update the asset table
  • Forget to clear the slot
  • Log the event separately
  • Or crash mid-operation

You create split state.

And split state is how audits go sideways.

I didn’t want “mostly correct.”
I wanted atomic.

What Changed

Issue 8-2 introduced atomic Stock-Out batch processing.

When Stock-Out mode is enabled and a custodian is selected, /preview/commit now performs a single transaction that:

  1. Validates every asset:
    • Exists
    • Is in STORAGE
    • Is currently slotted
  2. Transitions the asset:
    • location_type → IN_CUSTODY
    • Sets current_holder_id
  3. Vacates the slot
  4. Inserts a STOCK_OUT event with holder_id
  5. Commits or rolls back as one unit

If anything fails:

Nothing changes.

That’s the difference between a hobby script and a system.

The Subtle Bug We Caught

Scanner normalization was stripping dashes:


AT-SMOKE-0001 → ATSMOKE0001

But the database stored dashed values.

That meant lookups failed even when the asset existed.

Instead of rewriting the database or guessing formats, I implemented canonical matching:

  • Exact match
  • OR dash-stripped match
  • Use the canonical DB value for all mutations

No guessing digit counts. No auto-padding. No silent corrections.

Inventory systems must be exact.

What Is Now True

AssetTrack now enforces a real custody state machine:


STORAGE  (slot-bound)
IN_CUSTODY (holder-bound)

And that transition is:

  • Atomic
  • Validated
  • Logged
  • Slot-consistent
  • Rollback-safe

After a stock-out:

  • The asset is no longer in a slot
  • The slot is empty
  • The asset references its custodian
  • The event log records the transfer

There is no partial state.

Why This Matters

The slot system (Milestone 7) gave the system structure.

Atomic custody (Milestone 8) gave it discipline.

You can now:

  • Physically remove a device
  • Assign it to a person
  • Trust the database reflects reality
  • Trust the event log reflects history

That’s when an inventory system starts behaving like a deployment tool.

What’s Next

Milestone 8 continues with:

  • Stock-In return flow
  • Custody reporting
  • UX guardrails
  • Hardening around edge cases

But the most important part is already done:

The transition layer is safe.

What I Learned

Two things:

  1. Atomicity isn’t a luxury in inventory systems — it’s foundational.
  2. Normalization must be intentional, or it will bite you later.

AssetTrack is still small.

But it is now structurally honest.

And that’s how systems survive audits.

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