Design engineering module (design_engineering)

The design_engineering module in src/cluster_erp/modules/design_engineering/ holds designs and engineering change notes (ECN). A design belongs to a project, can name the part it describes, links its drawing, 3D model, and DXF documents, and goes through review and approval. An approved design is locked; a change goes through an ECN, which creates the next design version and supersedes the old one. Approving a design with a part makes the bom module create a BOM card.

At a glance¶

What the module does¶

• Records designs of type concept, detail, or manufacturing, each with a number, a project, an optional part, a version number, CAD file entries, document links, specifications, and a description (src/cluster_erp/modules/design_engineering/designs/models.py:17-78, src/cluster_erp/modules/design_engineering/designs/schemas.py:9).
• Moves a design through review and approval (src/cluster_erp/modules/design_engineering/designs/services.py:37-41).
• Records change notes against approved designs and implements them as new design versions (src/cluster_erp/modules/design_engineering/ecns/services.py:94-111, src/cluster_erp/modules/design_engineering/ecns/services.py:252-314).
• Answers other modules' questions about a design (src/cluster_erp/modules/design_engineering/module.py:49-92).

Sub-modules¶

Data model¶

project_id and part_id are plain UUID columns. The module asks no other module about them; a grep for query contracts constructed in the package finds none.

Screens and metadata¶

get_metadata declares a sidebar group Design & Engineering (Turkish Tasarım & Mühendislik) with two lists, Designs and Change Notes (src/cluster_erp/modules/design_engineering/module.py:109-150). Both entities accept tenant-defined fields in extra (src/cluster_erp/modules/design_engineering/designs/models.py:19-22, src/cluster_erp/modules/design_engineering/ecns/models.py:19-22).

Status and actions¶

Design statuses are draft, in_review, approved, and superseded (src/cluster_erp/modules/design_engineering/designs/schemas.py:10). ECN statuses are proposed, approved, rejected, and implemented (src/cluster_erp/modules/design_engineering/ecns/schemas.py:9).

The diagram shows both lifecycles.

stateDiagram-v2
 state Design {
 [*] --> draft
 draft --> in_review: submit_review
 in_review --> approved: approve
 in_review --> draft: reject
 approved --> superseded: ECN implement
 }
 state ECN {
 [*] --> proposed
 proposed --> approved_ecn: approve
 proposed --> rejected: reject
 approved_ecn --> implemented: implement
 }

In prose: a design starts as draft, is submitted to in_review, and is then approved or sent back to draft (src/cluster_erp/modules/design_engineering/designs/services.py:37-41). An approved design becomes superseded only when an ECN against it is implemented. An ECN starts as proposed and is approved or rejected; an approved ECN can be implemented (src/cluster_erp/modules/design_engineering/ecns/services.py:29-32). In the diagram, approved_ecn stands for the ECN status approved.

Business rules¶

• A design of type concept cannot be approved; the answer is DESIGN_CONCEPT_NO_APPROVAL (src/cluster_erp/modules/design_engineering/designs/services.py:282-287).
• Approval commits the transaction before DesignApproved is emitted, so that the BOM created by the subscriber depends on a stored approval; the code comment states this reason (src/cluster_erp/modules/design_engineering/designs/services.py:298-315).
• An approved or superseded design cannot be edited (src/cluster_erp/modules/design_engineering/designs/services.py:189-199); only a draft design can be deleted (src/cluster_erp/modules/design_engineering/designs/services.py:229-233).
• An ECN can be created only for an approved design (src/cluster_erp/modules/design_engineering/ecns/services.py:94-111); only a proposed ECN can be edited or deleted (src/cluster_erp/modules/design_engineering/ecns/services.py:150-153, src/cluster_erp/modules/design_engineering/ecns/services.py:184-187).
• Implementing an ECN creates a new draft design with the next version number, the same project, part, type, files, and specifications, and the old design as parent; the old design becomes superseded; the ECN stores the new design id (src/cluster_erp/modules/design_engineering/ecns/services.py:252-314).
• design_no and ecn_no come from the yearly sequences design and ecn (src/cluster_erp/modules/design_engineering/designs/services.py:144, src/cluster_erp/modules/design_engineering/ecns/services.py:112).
• GET /designs/{id}/files returns the CAD file list and the three document ids (src/cluster_erp/modules/design_engineering/designs/services.py:108-117).

Events and queries¶

The module consumes 2 contracts and produces 6, counted as on the parties module page.

DesignApproved is consumed by the bom module, which creates a BOM card for the design's part; see BOM module. The contracts reference finds no consumer for the other five events at this commit.

Permissions¶

Privacy, retention, and history¶

The module stores user ids of authors and approvers but no personal fields of its own, and it has no privacy_handlers.py. Changes are captured by change history.

Analytics facts¶

This module has no analytics_facts.py.

Settings and reference data¶

The module has no settings section and seeds nothing (src/cluster_erp/modules/design_engineering/module.py:28-30). Design types and statuses are fixed literals in the schemas (src/cluster_erp/modules/design_engineering/designs/schemas.py:9-10).

Tests¶

Found by a grep for design_engineering in tests/ and web-client/.

No pytest file imports the module.

Discrepancies¶

Terms introduced¶

Related pages¶

• Modules index
• BOM module
• Projects module
• Documents module
• API reference for this module

Verified against commit 92f8051 on 2026-11-13.