Guardrail·E-commerce

Saleor Migrations

Rules for writing safe Django migrations in Saleor that don't lock tables or break zero-downtime deploys.

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Buy it · $39 Read it before you buy $39 Written by saleor · unverified publisher
Context cost
950 tokensestimated from the bundle, loaded when it triggers
Bundle
1 file · 3.8 kBtext throughout, nothing executable
Licence
BSD-3-Clausepaid listing
Last change
no release on file
Servers it uses
Noneruns standalone

What it does

Rules for writing safe Django migrations in Saleor that don't lock tables or break zero-downtime deploys. Use whenever creating or editing a migration (schema or data), including field removals and index/constraint changes.

Installed, it changes the agent in these ways.

What this skill changes about the agent is not written down here yet. The listing was collected from its source, and the description is in its own SKILL.md.

Guardrail

Constrains what the agent is allowed to do.

saleordjangomigrationsdeploy
Filed under

E-commerce

The skill itself

This is the whole product. A skill is instructions the model reads, so there is nothing behind the listing you cannot see first — the front matter loads with every session, and the body below it loads when the skill triggers.

SKILL.md3.8 kB · 70 lines
--- name: saleor-migrations description: Rules for writing safe Django migrations in Saleor that don't lock tables or break zero-downtime deploys. Use whenever creating or editing a migration (schema or data), including field removals and index/constraint changes. ---
6# Writing Saleor migrations
7
8Saleor deploys with zero downtime across many pods against a shared Postgres. A migration that takes a
9long table lock stalls every pod. Follow these rules.
10
11## Keep locks short: split migrations
12
13- **One model per migration, and one field change per migration.** Each schema operation holds a lock
14 on the table for its duration; batching several into one migration multiplies the locked time.
15- The only valid reason to combine is separating a schema migration from its data migration.
16- Always separate schema changes and data migration.
17- Don't add a migration that re-alters a column an earlier migration already changed — check the
18 existing migration history first.
19- Give migrations descriptive names that reflect the actual operation
20 (0070_add_payment_gift_card_brand, not 0070_alter_payment_partial_add_db_default for something
21 else).
22
23## Indexes and constraints: create concurrently
24
25- **Add unique constraints/indexes concurrently** using the established non-blocking pattern (see e.g.
26 page migration 0030_slug_translation_unique_constraint) — a plain AddConstraint /
27 AddIndex takes a blocking ACCESS EXCLUSIVE lock and can stall writes across all pods.
28- Enforce value invariants (e.g. non-negative balance) with a DB CheckConstraint, not just
29 application logic.
30
31## Removing a field: stage it
32
33Removing a NOT NULL / defaulted column in one step can fail mid-deploy while old and new pods coexist.
34Stage it across releases:
35
361. Add a db_default so the DB can write the column without the ORM.
372. Remove the field from the ORM model (column still present).
383. **Drop the column in a later version**, tracked by an explicit follow-up issue.
39
40Keep any legacy enum values / code retained only for migration safety tracked as a removal task with a
41"remove in X.Y" note.
42
43## Data migrations
44
45- A data migration must be **all-or-nothing**: process everything or nothing. Don't abort partway on a
46 fixed depth/count cap and leave a partial migration.
47- **post_migrate sender must be the migration's own app config** — a common copy-paste bug is
48 registry.get_app_config("product") inside an account/order migration.
49- Use a module/task **constant** (like BATCH_SIZE) for internal tuning knobs, not an env var nobody
50 will set.
51- When cleaning up (e.g. removing a permission), address **all** models that hold the value
52 (App, AppExtension, AppInstallation, …), or document why one is handled elsewhere.
53- Watch for per-iteration DB queries (O(N) vs O(1)); batch related lookups.
54
55## Cross-branch ports
56
57- Keep a ported migration's **filename identical** to its counterpart on the other branch, and add a
58 merge migration where histories diverge.
59- Keep a ported migration's **filename identical** to its counterpart on the other branch, and add a
60 merge migration where histories diverge using ./manage.py makemigrations --merge.
61## Before requesting review
62
63- Confirm each migration touches a single model and a single field, and that any index or constraint
64 is created concurrently rather than with a blocking operation.
65- Confirm every destructive column change is staged across releases (add db_default, then remove the
66 field from the ORM, then drop the column in a later version).
67- Confirm each post_migrate handler passes its own app config as the sender, and that every data
68 migration is all-or-nothing rather than aborting partway.
69- Run the migration locally with manage.py migrate and confirm it applies cleanly.
70
In the file
SKILL.md562 words
Files1
LicenceBSD-3-Clause
Why you can read it

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≈70
always loaded
The name and description, so the model knows the skill exists and when to reach for it.
880
on trigger
The instruction body, read only when the skill fires.
0.47%
of a 200k window
Ten skills this size would take about 5% of the window before you open a file.
050k100k150k200k context window

950 tokens, estimated from the bundle at four bytes to the token, held for the rest of the session once it triggers. Small enough to keep loaded permanently without thinking about it.

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Prose, not code

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What it asks for
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Network accessno

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What is in the bundle

1 file, 3.8 kB on disk. A bundle is text throughout: the instructions the model reads, plus the templates it fills in.

  • SKILL.md3.8 kB
What is not in it

No dependencies and nothing executable: a skill is text the agent reads, so the bundle is 1 file you can review in full before installing. The BSD-3-Clause licence covers the templates and examples as well as the instructions.

Install

Installing copies the bundle into your project. Nothing runs at install time — the files sit on disk until the model reads them.

$39 once
Saleor Migrations · BSD-3-Clause · saleor
one-time
Price$39 once
LicenceBSD-3-Clause — the author’s, unchanged by this purchase
Paid throughStripe, once, on the card you add at the checkout
Keeps workingfor good — the files are yours once they are on disk
Updatesevery update its author ships, delivered through this account

You can read the whole bundle before paying — the SKILL.md above is the product, not a preview of it. What the money buys is the delivery: the folder packaged and handed to your machine by key, every update its author ships, and our support if it does not do what this listing says. The terms of use are BSD-3-Clause, set by the author and unchanged by buying it here.

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Claude Code.claude/skills/
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This release
Versionnot versioned
Publishedno release date on file
Price$39
Referencesaleor/saleor-migrations

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v
  • No earlier releases have been published to the marketplace.
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