Crate adaptive_pipeline_domain 

Pipeline Domain

The pipeline domain represents the core business logic and rules of the pipeline system. It implements Domain-Driven Design (DDD) patterns and is completely independent of external concerns like databases, file systems, or user interfaces.

Module Structure

Domain-Driven Design Concepts

Entities

Entities are objects that have a distinct identity that runs through time and different representations. They can change state while maintaining their identity.

Key Characteristics:

• Have unique identifiers
• Can be mutated (state changes)
• Identity persists through changes
• Equality based on identity, not attributes

Examples in this domain:

• Pipeline: A processing workflow with stages
• PipelineStage: An individual processing step
• ProcessingContext: Runtime execution context
• SecurityContext: Security and permission management
• ProcessingMetrics: Performance and operational metrics

Value Objects

Value objects are immutable objects that represent concepts without identity. They are defined by their attributes and two value objects with the same attributes are considered equal.

Key Characteristics:

• Immutable (cannot be changed after creation)
• No identity (equality based on attributes)
• Self-validating (enforce business rules)
• Side-effect free operations

Examples in this domain:

• ChunkSize: Represents the size of data chunks
• FileChunk: Represents a piece of file data
• Algorithm: Represents compression/encryption algorithms
• PipelineId: Type-safe pipeline identifier
• StageOrder: Stage ordering within pipelines
• WorkerCount: Validated parallel worker count

Domain Services

Domain services contain business logic that doesn’t naturally fit within an entity or value object. They are stateless and operate on domain objects.

Key Characteristics:

• Stateless operations
• Express domain concepts
• Coordinate between domain objects
• Implement complex business rules

Examples in this domain:

• CompressionService: Handles data compression logic
• EncryptionService: Manages data encryption/decryption
• ChecksumService: Calculates and verifies data integrity
• PipelineService: Orchestrates pipeline execution
• FileProcessorService: High-level file processing

Repositories

Repositories provide an abstraction over data persistence, allowing the domain to work with collections of objects without knowing about storage details.

Key Characteristics:

• Abstract data access
• Collection-oriented interface
• Hide persistence technology
• Support domain queries

Domain Events

Domain events represent significant occurrences within the domain that other parts of the system might be interested in.

Key Characteristics:

• Represent past occurrences
• Immutable
• Carry relevant data
• Enable loose coupling

Examples in this domain:

• PipelineCreated: Emitted when a new pipeline is created
• ProcessingStarted: Emitted when file processing begins
• ProcessingCompleted: Emitted when processing finishes
• SecurityContextCreated: Emitted for new security contexts

Business Rules and Invariants

The domain layer enforces important business rules:

Pipeline Rules

• Pipelines must have at least one stage
• Stage order must be sequential and valid
• Pipeline names must be unique within a context

Chunk Processing Rules

• Chunks must have non-zero size
• Chunk sequence numbers must be sequential
• Final chunks must be properly marked

Security Rules

• Security contexts must be validated
• Encryption keys must meet strength requirements
• Access permissions must be checked

Error Handling

The domain uses a comprehensive error system that categorizes different types of failures:

Testing Domain Logic

Domain objects are designed to be easily testable:

Re-exports

pub use entities::Pipeline;

pub use entities::PipelineStage;

pub use entities::ProcessingContext;

pub use entities::ProcessingMetrics;

pub use entities::SecurityContext;

pub use entities::SecurityLevel;

pub use error::PipelineError;

pub use value_objects::ChunkSize;

pub use value_objects::FileChunk;

pub use events::*;

Modules

aggregates

Domain Aggregates

entities

Domain Entities

error

Domain Error Module

events

Domain Events

repositories

Domain Repositories

services

Domain Services

value_objects

Domain Value Objects