Crate triplets 

triplets

WORK IN PROGRESS.

Composable data sampling primitives for deterministic multi-source ML/AI training-data orchestration.

triplets is a reusable core for ML/AI training-data orchestration. It provides sampler primitives, split/state persistence, chunking and weighting mechanics, and source abstractions (DataSource, DataRecord) without tying behavior to proprietary corpora.

CI is configured to run tests/linting on macOS, Linux, and Windows.

High-level features

• Automatic deterministic splits (train/validation/test) from record IDs + seed.
• Runtime batch sampling via next_triplet_batch, next_pair_batch, and next_text_batch.
• Recipe-driven sample construction for triplet/pair/text generation (anchor/positive/negative selectors).
• Weight-aware sampling controls across source weights, recipe weights, and chunk trust/quality weighting.
• Resume support via persist_state() and split-store persistence.
• Source-agnostic backends (DataSource or IndexableSource + IndexableAdapter).
• Supply-chain style orchestration (core layer): multi-source intake (refresh) with per-call parallel ingest, optional per-source weighting, staged buffering, deterministic split routing, and batch assembly into train-ready outputs.
• Bounded ingestion windows instead of loading full corpora into memory.
• Per-call source threading: during refresh, each source is fetched on its own short-lived thread, then merged deterministically for batch assembly.
• Streaming-friendly: sources can be finite or unbounded.

This crate does not perform semantic mining/retrieval scoring by itself; instead, it gives you deterministic, metadata-driven sampling primitives you can feed into your downstream mining/retrieval stack.

Metadata-driven sampling flow

Use triplets to build deterministic training batches that carry metadata context:

• Put structural tags in DataRecord.taxonomy (source/date/category/etc.) for filtering and analysis.
• Use recipes/selectors to choose which sections become anchor/positive/negative text.
• Attach optional KVP metadata prefixes (below) so sampled text can include lightweight context headers.
• Keep split assignment deterministic while changing recipe or weighting behavior at runtime.

This gives you metadata-aware sampling orchestration, while semantic retrieval/mining logic stays in your downstream pipeline.

KVP data decorator

• Each DataRecord can carry an optional meta_prefix sampler (KvpPrefixSampler).
• At sample time, the sampler can prepend a header line to chunk text, formatted like: meta: key=value | key2=value2.
• KvpField supports multiple value renderings per key and optional per-field presence probability.
• KvpPrefixSampler supports variant selection and overall dropout (emit prefix sometimes, or always).
• This is designed to give the model useful context signals (date/source/category/etc.) without making a single rigid header pattern easy to memorize.
• Multi-render values, per-field presence control, field-order variation, and prefix dropout reduce shortcut learning and encourage reliance on the underlying content.
• KVP prefixes decorate sampled text; they do not change deterministic split assignment.

Getting started

Add triplets to a downstream crate:

cargo add triplets

To run the included examples in this repository (for exploration/contributor workflow):

cargo run --example multi_source_demo -- --help

For contributors (development check):

cargo test

Minimal shape:

1. Implement one or more DataSource backends.
2. Create SamplerConfig (chunking, recipes, split policy).
3. Open a split store (DeterministicSplitStore or FileSplitStore).
4. Construct PairSampler and register sources.
5. Call one of the batch APIs: next_triplet_batch(split), next_pair_batch(split), or next_text_batch(split).
6. Call persist_state() when you want restart-resume behavior.

Examples

From the triplets crate:

# sample triplet batches
cargo run --example multi_source_demo

# inspect CLI flags
cargo run --example multi_source_demo -- --help

# metadata-only capacity estimation
cargo run --example estimate_capacity -- --help
cargo run --example estimate_capacity

Source roots can be overridden with repeatable flags:

cargo run --example multi_source_demo -- \
  --source-root /path/to/source_1 \
  --source-root /path/to/source_2

Split-store path configuration

The multi_source_demo example persists sampler/split state by default to:

• .sampler_store/split_store.bin

You can override persistence location with either:

• --split-store-path <FILE> for an explicit file path
• --split-store-dir <DIR> to keep filename split_store.bin in a custom directory

Usage flow

Short version:

• Call sampler.next_triplet_batch(split), sampler.next_pair_batch(split), or sampler.next_text_batch(split) to sample batches (ingestion happens automatically).
• Call sampler.persist_state() when you want restart-resume behavior.
• Optionally call sampler.set_epoch(n) for explicit epoch control.

Step-by-step:

1. Build config + open the split store.
2. Register sources.
3. Call one of sampler.next_triplet_batch(split), sampler.next_pair_batch(split), or sampler.next_text_batch(split).
4. Call sampler.persist_state() when you want to write persisted sampler/split state (typically at the end of an epoch or at explicit checkpoint boundaries). Do not call this every step. Very frequent writes can create high I/O overhead and, at very large write counts (for example, tens of millions), can also adversely affect split-store initialization time.
5. Optionally call sampler.set_epoch(n) for explicit epoch replay/order.

Operational notes:

• File-backed indexing is rebuilt per process/run and stored in an OS temp-backed index store.
• Persisting sampler/split state is explicit and manual.
• One split-store file shares sampler/source cursor + RNG state unless you use separate store files.
• Batch calls are thread-safe but serialized; refresh work within a call can be parallelized per source.
• Source cursors advance independently per source, so one source can continue making progress even if another source is sparse or slower.
• Refresh concurrency is per call: source refreshes run in parallel for that call, then the sampler joins all refresh threads before merging buffers (not an always-on per-source background ingest loop).
• Prefetchers smooth latency by filling bounded queues from the existing batch APIs (next_triplet_batch, next_pair_batch, next_text_batch).
• New data from streaming sources is pulled in on the next batch call.
• sampler.persist_state() is manual; skipping it means no resume state after restart.
• sampler.set_epoch(n) is an advanced override and is not required for normal resume behavior.
• IngestionManager::source_refresh_stats() exposes per-source refresh duration/records/throughput/errors.
• metrics::source_skew summarizes per-source sample imbalance for a batch.

Example:

use std::sync::Arc;
use triplets::{
  DeterministicSplitStore, PairSampler, Sampler, SamplerConfig, SplitLabel, SplitRatios,
};

let sampler = Arc::new(PairSampler::new(config, store));
// register sources...

let prefetcher = Arc::clone(&sampler).prefetch_triplet_batches(SplitLabel::Train, 4);
let batch = prefetcher.next().unwrap();
let _ = batch;

• For per-call source weighting, use next_triplet_batch_with_weights(...), next_pair_batch_with_weights(...), or next_text_batch_with_weights(...).
• Missing source ids default to 1.0; 0.0 disables a source for that call.

Example (different source mix across consecutive batches):

use std::collections::HashMap;
use std::sync::Arc;
use triplets::{
  DeterministicSplitStore, PairSampler, Sampler, SamplerConfig, SplitLabel, SplitRatios,
};


let mut weights_a = HashMap::new();
weights_a.insert("source_a".to_string(), 1.0);
weights_a.insert("source_b".to_string(), 0.2);

let mut weights_b = HashMap::new();
weights_b.insert("source_a".to_string(), 0.2);
weights_b.insert("source_b".to_string(), 1.0);

let batch_a = sampler
  .next_triplet_batch_with_weights(SplitLabel::Train, &weights_a)
  .unwrap();
let batch_b = sampler
  .next_triplet_batch_with_weights(SplitLabel::Train, &weights_b)
  .unwrap();

let _ = (batch_a, batch_b);

• Production readiness note: if len_hint drifts in streaming/append-only sources, epoch order/coverage can repeat/skip records within an epoch, even though split assignment remains deterministic.

Sampling behavior (current)

This reflects the built-in file-corpus helpers (FileCorpusIndex) used by filesystem-backed sources.

• Ingestion: next_triplet_batch(split), next_pair_batch(split), and next_text_batch(split) trigger refresh; per-source buffers refill when empty (or on force refresh).
• Memory bound: refresh/cache limits are bounded by ingestion_max_records with a floor at batch_size.
• File indexing: deterministic path ordering + deterministic index permutation for paging.
• Source ordering: round-robin by source, deterministic within-source ordering by seed/epoch.
• Splits: labels are deterministic from record_id + seed + ratios; split APIs enforce allowed_splits.
• Coverage caveat: if len_hint drifts mid-epoch in streaming backends, strict single-pass coverage is not guaranteed.
• Weights: recipe/source/chunk weights affect scaling, not deterministic ordering.
• Scale note: full scan/sort/index rebuild cost grows roughly linearly with file count and path bytes.
• Order note: index batching preserves permutation order; chunked index reads do not remove deterministic shuffling.
• Manual epoch control: sampler.set_epoch(n) resets per-source cursors and reshuffles deterministically for that epoch.
• Persisted state scope: epoch tracking is split-aware, but sampler/source cursors + RNG/round-robin state are persisted per store file.
• Triplet recipe behavior: per-source recipes are scanned from per-source round-robin hints until a match is found.
• Pair batches: derived from triplets and follow the same source/recipe selection behavior.
• Text recipes: follow per-source behavior when provided; otherwise config recipes are used.
• Oversampling: when sources run dry, cached records may be reused (no global no-repeat guarantee).

New-source implementation pattern

For any new backend (file/API/DB/stream), centralize backend configuration/state access in one helper reused by both refresh(...) and reported_record_count().

Why this matters: capacity estimates and runtime sampling stay aligned only when both methods represent the same logical corpus slice.

File-backed pattern:

fn source_index(&self) -> FileCorpusIndex {
  FileCorpusIndex::new(&self.root, &self.id)
    .with_follow_links(true)
    .with_text_files_only(true)
    .with_directory_grouping(true)
}

fn refresh(
  &self,
  cursor: Option<&SourceCursor>,
  limit: Option<usize>,
) -> Result<SourceSnapshot, SamplerError> {
  self.source_index()
    .refresh_indexable(cursor, limit, |path| self.build_record(path))
}

fn reported_record_count(&self) -> Option<u128> {
  self.source_index().indexed_record_count().ok().map(|n| n as u128)
}

If your records are time-ordered (oldest → newest), use these APIs:

• IndexableSource (you provide len_hint() + record_at(idx)).
• IndexableAdapter (easiest: turns your IndexableSource into a DataSource).
• IndexablePager (use directly only if you are writing a custom refresh(...)).

That is the built-in path for shuffled paging + cursor resume.

Helper-based path (uses the APIs above):

use triplets::source::{IndexableAdapter, IndexableSource};
use triplets::{data::DataRecord, SamplerError};

struct MyIndexableSource {
  // Could be DB/API client, manifest reader, etc.
  // No in-memory ID list required.
  total_records: usize,
}

impl MyIndexableSource {
  fn load_record(&self, _idx: usize) -> Result<Option<DataRecord>, SamplerError> {
    // Fetch by numeric position from your backend.
    // `None` means "no record at this index".
    todo!("load one record by index")
  }
}

impl IndexableSource for MyIndexableSource {
  fn id(&self) -> &str { "my_source" }
  fn len_hint(&self) -> Option<usize> { Some(self.total_records) }
  fn record_at(&self, idx: usize) -> Result<Option<DataRecord>, SamplerError> {
    self.load_record(idx)
  }
}

// register as a normal DataSource:
// sampler.register_source(Box::new(IndexableAdapter::new(MyIndexableSource { total_records }))); 

Manual path (does NOT use IndexableSource/IndexableAdapter directly):

use chrono::Utc;
use std::collections::hash_map::DefaultHasher;
use std::hash::{Hash, Hasher};
use triplets::data::DataRecord;
use triplets::source::{SourceCursor, SourceSnapshot};
use triplets::SamplerError;

struct MySource {
  // Canonical record IDs for this source.
  // We keep IDs separate from record payloads so refresh can page deterministically.
  ids: Vec<String>,
}

impl MySource {
  fn load_record(&self, _id: &str) -> Result<DataRecord, SamplerError> {
    // Put your real fetch logic here (database call, API request, file read, etc.).
    // The sampler expects each loaded item to be returned as a DataRecord.
    todo!("load record from storage")
  }

  fn stable_hash(id: &str) -> u64 {
    // Convert each ID to a repeatable number so ordering is the same every run.
    // This avoids "newest-first" bias when IDs are naturally time-ordered.
    let mut hasher = DefaultHasher::new();
    id.hash(&mut hasher);
    hasher.finish()
  }

  fn refresh(
    &self,
    cursor: Option<&SourceCursor>,
    limit: Option<usize>,
  ) -> Result<SourceSnapshot, SamplerError> {
    // Make a sorted copy of IDs so this call runs in a repeatable order.
    // Note: this copy holds all IDs in memory for this refresh call.
    let mut ids = self.ids.clone();
    ids.sort_by_key(|id| Self::stable_hash(id));

    // How many records exist right now.
    let total = ids.len();

    // `revision` means "where to resume next time".
    // No cursor yet means this is the first run, so start at index 0.
    let mut start = cursor.map(|c| c.revision as usize).unwrap_or(0);

    // If data size changed and start is now invalid, safely reset to the beginning.
    if total > 0 && start >= total {
      start = 0;
    }

    // Hard cap for this call.
    // - If `limit` is Some(n), we load at most `n` records this call.
    // - If `limit` is None, we allow one full pass (`total` records).
    let max = limit.unwrap_or(total);
    let mut records = Vec::new();

    // Load records one-by-one, starting at `start`, and wrap at the end.
    // We stop as soon as `records.len() == max`.
    // So this does NOT always load everything; it only loads up to `max`.
    for idx in 0..total {
      if records.len() >= max {
        break;
      }
      let pos = (start + idx) % total;
      records.push(self.load_record(&ids[pos])?);
    }

    // Save where the next call should continue.
    let next_start = (start + records.len()) % total.max(1);
    Ok(SourceSnapshot {
      records,
      cursor: SourceCursor {
        // Record when this refresh happened.
        last_seen: Utc::now(),
        // Store resume position for the next refresh call.
        revision: next_start as u64,
      },
    })
  }
}

Capacity estimates

The estimate helpers compute metadata-only approximations from source-reported counts and recipe structure.

• They do not call source refresh.
• They are floor-like approximations for real chunked training.
• Effective triplet estimates use bounded assumptions (positives/negatives per anchor).

Potential future directions (optional)

These are ideas, not commitments.

• Add more backend adapters in downstream crates (APIs, DBs, manifests, streams)
• Improve strict-coverage options for drifting/streaming corpora
• Add optional split-keyed sampler cursor state in a single store file
• Extend observability hooks for ingestion latency/skew/error diagnostics

License

triplets is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0).

See LICENSE-APACHE and LICENSE-MIT for details.

Re-exports

pub use config::ChunkingStrategy;

pub use config::NegativeStrategy;

pub use config::SamplerConfig;

pub use config::Selector;

pub use config::TextRecipe;

pub use config::TripletRecipe;

pub use data::DataRecord;

pub use data::PairLabel;

pub use data::QualityScore;

pub use data::RecordChunk;

pub use data::SampleBatch;

pub use data::SamplePair;

pub use data::SampleTriplet;

pub use data::SectionRole;

pub use data::TextBatch;

pub use data::TextSample;

pub use data::TripletBatch;

pub use ingestion::IngestionManager;

pub use ingestion::RecordCache;

pub use kvp::KvpField;

pub use kvp::KvpPrefixSampler;

pub use sampler::BatchPrefetcher;

pub use sampler::PairSampler;

pub use sampler::Sampler;

pub use source::DataSource;

pub use source::SourceCursor;

pub use splits::DeterministicSplitStore;

pub use splits::FileSplitStore;

pub use splits::SplitLabel;

pub use splits::SplitRatios;

pub use splits::SplitStore;

pub use types::CategoryId;

pub use types::HashPart;

pub use types::KvpValue;

pub use types::LogMessage;

pub use types::MetaValue;

pub use types::PathString;

pub use types::RecipeKey;

pub use types::RecordId;

pub use types::Sentence;

pub use types::SourceId;

pub use types::TaxonomyValue;

Modules

config

Sampling configuration types.

constants

Centralized constants used across sampler, splits, and sources.

data

Data record and sample batch types.

example_apps

Reusable example runners shared by downstream crates.

heuristics

Capacity and sampling estimation helpers.

ingestion

Background ingestion and caching infrastructure.

kvp

Key/value prefix sampling helpers.

metadata

Metadata keys and helpers.

metrics

Aggregate metrics helpers.

sampler

Sampler implementations and public sampling API.

source

Data source traits and built-in sources. Data source interfaces and paging helpers.

splits

Split stores and persistence helpers.

transport

Input transports used by sources (filesystem today; DBs later).

types

Shared type aliases.

utils

Text normalization helpers. Text normalization helpers shared by source implementations.

Enums

SamplerError

Error type for sampler configuration, IO, and persistence failures.