Yupeng Ma
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Case study · Ruizhi Rongke · 2016-12 — 2017-07

Lightweight OA Workflow Engine

A reusable tree-based workflow engine for conditional, parallel, transitional, and rollback-aware approval paths.

Role · Designer and implementer of the workflow engine core

  • Python
  • Django
  • MySQL
  • Workflow orchestration
An approval request enters a tree-based engine, moves through branching nodes, and persists transitions that support rollback.

  1. 01

    Overview

    Context
    Internal and client approval systems needed configurable workflows instead of hard-coded approval paths.
    My contribution
    Designed the workflow model and implemented the reusable engine core.
    Technology
    Python, Django, MySQL, and explicit workflow orchestration.
    Result
    Applied the engine to internal and client systems and documented its design publicly.

  2. 02

    The Problem

    Approval products needed conditional branches, parallel gateways, transitions, and rollbacks without coupling every rule to one product's forms.

  3. 03

    My Role

    Designer and implementer of the workflow engine core

    • Designed a tree-based workflow representation with explicit nodes and transitions.
    • Implemented the engine with Django and MySQL.
    • Applied the reusable core to internal and client approval systems.

  4. 04

    Architecture

    A focused map of the components and responsibility boundaries that matter to this project.

    Component map

    Reusable workflow-engine model

    1. 01Approval request

      Product-specific form and input

    2. 02Tree engine

      Reusable workflow rules

    3. 03Branching nodes

      Conditional and parallel paths

    4. 04Transitions

      Explicit movement between nodes

    5. 05Persisted state

      Execution history and rollback support

    • Approval requestTree engineinput
    • Tree engineBranching nodesevaluate
    • Branching nodesTransitionsadvance
    • TransitionsPersisted statepersist
    A product-specific request enters a reusable tree-based engine. Explicit nodes represent conditional and parallel paths, transitions persist execution state, and that state supports rollback. Product forms remain outside the engine core.

  5. 05

    Key Technical Decisions

    Problem
    Scattered product conditionals made complex approval paths difficult to reason about.
    Choice
    Represent workflows as a tree of explicit nodes and transitions.
    Why
    Conditional paths, parallel gateways, and rollback behavior could share one visible domain model.
    Trade-off
    The engine required explicit state-transition rules instead of relying on simple linear form status.
    Problem
    Embedding form-specific behavior in the engine would limit reuse.
    Choice
    Keep the workflow core separate from product-specific approval forms.
    Why
    The same orchestration model could support multiple internal and client systems.
    Trade-off
    Products needed a clear integration boundary for supplying inputs and handling workflow output.

  6. 06

    Challenges

    • Expressing conditional and parallel behavior without scattering workflow rules across product code.
    • Preserving enough state to support explicit transitions and rollback behavior.

  7. 07

    Outcome

    • Used the engine in internal and client approval systems, including a GF Securities project.
    • Documented the core design concepts in a public technical article.

    Related public work

  8. 08

    What I Learned

    Learned
    A small explicit domain model made complex approval paths easier to understand than scattered product conditionals.
    Reflection
    The public article preserves the reusable design concepts while the case study keeps client-specific implementation details private.

This was an employer-owned production system. Architecture and implementation details shown here are simplified to protect confidential information.