f4cfd6c81f
Milestone 8 (phases 1-4): - Shard-aware WAL segment naming, BatchHeader v2, ShardRouter - Transport trait, InProcessTransport, WalShipper, FollowerDb - HLC, PNCounter, LWWRegister, CrdtSignalState, ReconciliationEngine - Session replication bridge with SeqNo/HWM, idempotency store Forage application: - Multi-source discovery engine with MAB exploration - Embedding-based label system, server handlers, UI refresh Other: - QUICKSTART.md, README.md, milestone-8 planning docs - Hard negative union semantics, RLHF export enhancements - Recovery benchmark and visibility test expansions - Split 8 oversized source files per CODING_GUIDELINES §9 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
124 lines
3.5 KiB
Markdown
124 lines
3.5 KiB
Markdown
# Task 05: NodeConfig
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## Delivers
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Add `NodeConfig` struct to `tidal/src/db/config.rs` extending `Config` with cluster fields (`role`, `shard_id`, `region_id`, `peer_shards`). Defaults produce a single-node config with zero changes to existing embedders.
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## Complexity: S
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## Dependencies
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- Task 01 (ShardId, RegionId, NodeRole types)
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- Task 02 (ShardRouter)
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## Technical Design
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```rust
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// tidal/src/db/config.rs
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/// Cluster configuration for distributed tidalDB deployments.
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///
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/// Defaults produce a single-node configuration identical to M0-M7 behavior.
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/// Embedded deployments that do not set any cluster fields get single-node.
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#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
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pub struct NodeConfig {
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/// The role of this node.
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///
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/// Default: `NodeRole::Single` (standalone, accepts reads and writes).
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pub role: NodeRole,
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/// This node's shard identity.
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///
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/// Default: `ShardId(0)` (single-node shard).
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pub shard_id: ShardId,
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/// This node's region identity.
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///
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/// Default: `RegionId(0)` (single-node region).
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pub region_id: RegionId,
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/// Shards this node is aware of (including itself).
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///
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/// Empty for single-node deployments.
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pub peer_shards: Vec<ShardId>,
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/// Routing strategy for entity-to-shard assignment.
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///
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/// Default: `ShardRouter::single()` (all entities -> ShardId(0)).
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#[serde(skip)]
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pub router: ShardRouter,
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}
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impl Default for NodeConfig {
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fn default() -> Self {
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Self {
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role: NodeRole::Single,
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shard_id: ShardId::SINGLE,
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region_id: RegionId::SINGLE,
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peer_shards: vec![],
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router: ShardRouter::single(),
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}
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}
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}
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impl NodeConfig {
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/// Returns true if this is a standalone single-node deployment.
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pub fn is_single_node(&self) -> bool {
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self.role == NodeRole::Single
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}
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/// Returns true if this node accepts writes.
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pub fn accepts_writes(&self) -> bool {
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matches!(self.role, NodeRole::Single | NodeRole::Leader)
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}
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}
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```
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### Integration into Config
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```rust
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// tidal/src/db/config.rs -- extend existing Config struct
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pub struct Config {
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// ... existing fields ...
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/// Cluster configuration. Default: single-node.
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pub cluster: NodeConfig,
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}
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impl Default for Config {
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fn default() -> Self {
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Self {
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// ... existing defaults ...
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cluster: NodeConfig::default(),
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}
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}
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}
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```
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### Builder integration
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```rust
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// TidalDb::builder() -- add optional cluster config method
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impl TidalDbBuilder {
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/// Configure this instance for distributed deployment.
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///
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/// Not required for single-node embedded use.
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pub fn with_cluster(mut self, config: NodeConfig) -> Self {
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self.config.cluster = config;
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self
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}
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}
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```
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## Acceptance Criteria
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- [ ] `NodeConfig::default()` produces `role=Single`, `shard_id=ShardId(0)`, `region_id=RegionId(0)`, `peer_shards=[]`, `router=ShardRouter::single()`
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- [ ] `NodeConfig::is_single_node()` returns true for `Single`, false for `Leader`/`Follower`
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- [ ] `NodeConfig::accepts_writes()` returns true for `Single` and `Leader`, false for `Follower`
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- [ ] `Config` gains a `cluster: NodeConfig` field with default `NodeConfig::default()`
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- [ ] All existing tests that construct `Config` or use `TidalDb::builder()` pass unchanged (cluster field defaults to single-node)
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- [ ] `TidalDbBuilder::with_cluster(config)` sets the cluster config
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- [ ] `cargo clippy -D warnings` and `cargo fmt` pass
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