Settings

Settings — Technical Spec

app/im2.py, template app/templates/settings.html.

Routes

Storage and resolution

• Table app_settings(key pk, value, updated_by, updated_at).
• settings(conn=None) builds a dict from SETTING_DEFS defaults + HIDDEN_SETTINGS, then overlays non-NULL app_settings rows. Table beats code; code default is the fallback. No caching — every call opens a connection unless one is passed.
• Helpers: setting_bool(key) (true only for exactly yes, case-insensitive, trimmed), setting_list(value) (newline list, case-insensitive de-dupe, alphabetical), setting_uoms(vals) (commas also parsed, upper-cased, falls back to code UOMS), setting_classes(vals) → [{"name","id"}] parsed from Name = qb_class_id lines.
• BOOL_SETTINGS = allow_fp_watcher, allow_auto_po, wb_count_before_release, rush_notify_slack, rush_notify_sms, rush_notify_tech_sms.
• LIST_SETTINGS = uoms(no column), item_groups→item_group, gen_locs→gen_loc, count_groups→count_group, ro_classes(no column). Keys with a column and no saved row are pre-filled from list_values(conn, key, column) (in-use values).
• HIDDEN_SETTINGS = qb_income_account_id, qb_expense_account_id, qb_asset_account_id, defaulting to qb.INCOME_ACCOUNT_ID / EXPENSE_ACCOUNT_ID / ASSET_ACCOUNT_ID (714/638/815, env-overridable in /opt/im2/env). Not rendered, not saveable here.

Save semantics (POST /api/settings)

Per key in SETTING_KEYS, skipped entirely if absent from the form (so a partial form only touches what it posts):

1. trim; list keys re-serialized through setting_list; bool keys coerced to Yes/No; uoms upper-cased; default_lead_time_days must parse as a number → stored as int, else 400 "Default lead time must be a whole number of days".
2. Unchanged vs settings(conn) → skipped, not counted.
3. val == "" → delete from app_settings where key = %s (revert to code default; an empty override is never stored).
4. Otherwise upsert with updated_by, updated_at = now().
5. One audit_log row per change: sku = NULL, field_name = key, old→new, source='settings'.

Consumers

allow_fp_watcher → ro_watch.py; allow_auto_po + wb_count_before_release → po.py workbench/buy list; ro_classes → RO screens and ro_post.py; uoms → grid, new item, RO lines; income_gl/expense_gl + hidden account ids → qb.py new-item push; default_lead_time_days → Purchasing Workbench; rush_notify_* → notify.py.

Known limits / defects

1. Account names are free text and never validated against QuickBooks; a typo surfaces later as a rejected item push.
2. ro_classes ids are not validated either — a wrong id posts to the wrong QB class silently.
3. settings() / setting_bool() open a fresh connection per call when no conn is passed (notify.py and several route paths do exactly that). Cheap per request, but it is a real DB round trip inside best-effort notification code.
4. No CSRF token; cookie auth + samesite=lax only. A single POST can change every setting, including turning allow_auto_po on.
5. scripts/schema.sql in this package does not contain app_settings; the live DB has it. Replaying that DDL clean would not produce a working Settings screen.
6. updated_at.strftime is called unguarded in the template — a row with a NULL updated_at (only reachable by hand-written SQL) would 500 the screen.