iii-state-management（三、状态管理）

State Management

Comparable to: Redis, DynamoDB, Memcached

Key Concepts

Use the concepts below when they fit the task. Not every state operation needs all of them.

• State is a scoped key-value store accessed via built-in trigger functions
• state::set writes a value; state::get reads it (returns null for missing keys)
• state::list retrieves all keys in a scope; state::delete removes a key
• state::update performs a partial merge using an ops array for fine-grained changes
• Payloads use scope, key, and value to address state entries
• State is shared across all functions — use meaningful scope names to avoid collisions

Architecture

Function
  → trigger('state::set', { scope, key, value })
  → trigger('state::get', { scope, key })
  → trigger('state::update', { scope, key, ops })
  → trigger('state::delete', { scope, key })
  → trigger('state::list', { scope })
    → StateModule → KvStore / Redis adapter

iii Primitives Used

Reference Implementation

See ../references/state-management.js for the full working example — functions that read, write, update, and delete state entries across a shared scope.

Also available in Python: ../references/state-management.py

Also available in Rust: ../references/state-management.rs

Common Patterns

Code using this pattern commonly includes, when relevant:

• registerWorker(url, {workerName}) — worker initialization
• trigger({function_id: 'state::set', payload: {scope, key, value}}) — write state
• trigger({function_id: 'state::get', payload: {scope, key}}) — read state (returns null if missing)
• trigger({function_id: 'state::update', payload: {scope, key, ops}}) — partial merge
• trigger({function_id: 'state::list', payload: {scope}}) — enumerate keys
• trigger({function_id: 'state::delete', payload: {scope, key}}) — remove entry
• const logger = new Logger() — structured logging

Adapting This Pattern

Use the adaptations below when they apply to the task.

• Name scopes after your domain (e.g. user-sessions, order-data, config)
• Use state::get with a null check to handle missing keys gracefully
• Use state::update with ops for partial updates instead of read-modify-write cycles
• Combine with iii-queue-processing to persist results after async job completion

Engine Configuration

StateModule must be enabled in iii-config.yaml with a KvStore adapter (file-based or Redis). See ../references/iii-config.yaml for the full annotated config reference.

Pattern Boundaries

• If the task needs reactive side effects when state changes, prefer iii-state-reactions.
• If the task needs real-time client push when data updates, prefer iii-realtime-streams.
• Stay with iii-state-management when the primary need is reading and writing persistent key-value data.

When to Use

• Use this skill when the task is primarily about iii-state-management in the iii engine.
• Triggers when the request directly asks for this pattern or an equivalent implementation.

Boundaries

• Never use this skill as a generic fallback for unrelated tasks.
• You must not apply this skill when a more specific iii skill is a better fit.
• Always verify environment and safety constraints before applying examples from this skill.