Crate Dependency Map

Workspace Layout

parallax/
├── Cargo.toml                     # Workspace root
├── crates/
│   ├── parallax-core/             # Shared types, zero external deps
│   ├── parallax-store/            # Storage engine (WAL + MemTable + Segments)
│   ├── parallax-graph/            # Graph traversal and reasoning
│   ├── parallax-query/            # PQL parse + plan + execute
│   ├── parallax-policy/           # Policy rule evaluation
│   ├── parallax-ingest/           # Sync protocol (diff + commit)
│   ├── parallax-connect/          # Integration SDK
│   ├── parallax-server/           # REST HTTP server
│   └── parallax-cli/              # CLI binary
└── specs/                         # Architectural specifications

Dependency Graph

parallax-core          (no workspace deps; blake3, serde, compact_str, thiserror)
       │
       ├──► parallax-store     (core; arc-swap, crc32c, lz4_flex, postcard, tracing)
       │           │
       │           ├──► parallax-graph     (core, store)
       │           │           │
       │           │           ├──► parallax-query      (core, graph)
       │           │           └──► parallax-policy     (core, graph)
       │           │
       │           └──► parallax-ingest    (core, store)
       │                       │
       │                       └──► parallax-connect    (core, ingest)
       │
parallax-server  (core, store, graph, query, policy, ingest, connect;
       │          axum, tower, tower-http, tokio, serde_json, uuid, compact_str)
       │
parallax-cli     (server; clap, anyhow, tokio)

External Dependencies by Crate

parallax-core

Crate	Version	Purpose
`serde`	1	Serialization derive macros
`compact_str`	0.8	Small-string optimization (entity types/classes are short)
`blake3`	1	Deterministic ID hashing (SIMD-accelerated)
`thiserror`	1	Error derive macros

parallax-store

Crate	Version	Purpose
`arc-swap`	1	Lock-free atomic Arc swap for snapshot publishing
`crc32c`	0.6	WAL entry checksums
`lz4_flex`	0.11	Block compression for segment files
`postcard`	1	Compact binary serialization for WAL + Segments
`tracing`	0.1	Structured logging
`tempfile`	3	(dev) Temporary directories for tests

parallax-graph

Crate	Purpose
`tracing`	Structured logging

parallax-query

Crate	Purpose
`tracing`	Structured logging

parallax-policy

Crate	Purpose
`serde`	Policy rule serialization
`tracing`	Structured logging

parallax-ingest

Crate	Purpose
`tracing`	Structured logging
`tempfile`	(dev) Temporary directories for tests

parallax-connect

Crate	Purpose
`async-trait`	Async trait support for the `Connector` trait
`serde`	Builder serialization
`tokio`	Async runtime
`tracing`	Structured logging
`compact_str`	Small-string optimization
`thiserror`	Error types

parallax-server

Crate	Purpose
`axum`	HTTP/REST server framework
`tower`	Middleware stack
`tower-http`	HTTP middleware (trace, request-id, sensitive-headers)
`tokio`	Async runtime
`serde_json`	JSON serialization for REST responses
`uuid`	UUID v4 for request IDs
`compact_str`	Small-string optimization
`tracing`	Structured logging
`thiserror`	Error types

parallax-cli

Crate	Purpose
`clap`	Command-line argument parsing
`anyhow`	Error handling in binary context
`tokio`	Async runtime
`serde_json`	JSON output formatting

What We Explicitly Do Not Use

Crate	Why Not
`rocksdb`	We own storage. No C++ FFI dependency.
`diesel` / `sqlx`	No SQL database.
`neo4j-*`	The whole point is to not depend on Neo4j.
`sled`	Correctness concerns in early versions.
`tonic` / `prost`	gRPC deferred to v0.2; REST-only for v0.1.

Adding a New External Dependency

Before adding a new crate:

Is there a std equivalent? Prefer std.
Does an existing approved crate already cover this? Reuse it.
Is the crate well-maintained, zero-unsound-unsafe, and Apache/MIT licensed?
Does adding it violate the acyclic dep constraint?

Add a justification comment in Cargo.toml for non-obvious dependencies.

Parallax