Files
ngit-grasp/docs/explanation
DanConwayDev 3733846aaf fix(sync): defer permanently refused coverage
Archive-mode production burn-in exposed a self-amplifying live-subscription loop: permanent CLOSED responses rebuilt complete coverage immediately, and each replacement generated more refusals. More than 11,000 CLOSED/rebuild cycles were observed in one minute while the relay connection itself remained healthy.

Classify blocked, restricted, membership-required, and filter-incompatible responses into bounded categories. Preserve the WebSocket session, remove any rejected transient batch, pause new subscription work through the existing relay health tracker, and issue one coverage probe after the dead-relay 24-hour cadence. Export the bounded category as a counter and retain the raw reason only in logs.

Correctness assumes these explicit policy messages are not transient rate limits; rate-limit-shaped messages retain their shorter adaptive cooldown. Repeated refusals do not extend the daily deadline, connection handshakes do not clear it, and expiry yields exactly one recovery probe.

Adaptive filter-count learning and per-repository Git fetch single-flight are deliberately excluded. The former needs relay-implementation evidence; the latter is tracked separately.

Validation: nix develop -c cargo test --lib passed all 669 tests; focused policy classification and daily-probe tests passed; nix develop -c cargo check --lib passed. Repository-wide cargo fmt --check still reports pre-existing formatting drift in unrelated integration fixtures.
2026-08-08 15:03:55 +00:00
..

Explanation

Understanding-oriented documentation - Concepts, design decisions, and the "why" behind ngit-grasp.


What Is Explanation?

Explanation documentation helps you understand concepts and design decisions, providing context and discussing alternatives.

Characteristics:

  • ✅ Understanding-oriented (clarify concepts)
  • ✅ Theoretical (ideas and design)
  • ✅ Discuss alternatives
  • ✅ Provide context and background
  • ✅ Answer "why" questions

Not explanation:

  • ❌ Step-by-step lessons (those are Tutorials)
  • ❌ Problem-solving recipes (those are How-To)
  • ❌ Technical specifications (those are Reference)

Available Explanation Documentation

Architecture Overview

Understand the system design and component interaction

Topics:

  • Overall architecture
  • Component responsibilities
  • Data flows
  • Technology choices
  • Design patterns

Read when: You want to understand how ngit-grasp works as a system


Inline Authorization

Why we validate pushes inline instead of using Git hooks

Topics:

  • The authorization problem
  • Git hooks approach
  • Inline approach
  • Comparison and trade-offs
  • Implementation details

Read when: You want to understand the core architectural decision


Design Decisions

Key architectural choices and their rationale

Topics:

  • Inline authorization vs hooks
  • Technology stack choices
  • Storage design
  • API design
  • Performance considerations

Read when: You want to know why things are the way they are


Comparison with ngit-relay

How ngit-grasp differs from the reference implementation

Topics:

  • Architecture comparison
  • Component differences
  • Trade-offs
  • Migration path
  • Compatibility

Read when: You're familiar with ngit-relay and want to understand differences


Purgatory Design

In-memory holding area for events awaiting git data

Topics:

  • The "which arrives first?" problem
  • Separate storage for state vs PR events
  • Late binding for state events
  • Bidirectional waiting for PR events
  • Authorization during push

Read when: You want to understand how ngit-grasp handles out-of-order event/git data arrival


GRASP-02 Proactive Sync

Relay-to-relay synchronization for repository discovery

Topics:

  • Negentropy-based event sync
  • Repository announcement discovery
  • Relay management and reconnection
  • Layer 2 filtering
  • Bootstrap and dynamic relay discovery

Read when: You want to understand how ngit-grasp discovers and syncs repositories across relays


Sync Scaling Constraints and Budgets

Relay-imposed limits and how sync spends them at scale

Topics:

  • Verified relay limits (strfry, live NIP-11, our embedded relay)
  • Per-connection budget ledger (live vs historic vs fallback)
  • Byte-budgeted filter chunking and REQ packing
  • Bounded negentropy concurrency
  • Multi-connection escalation and serving-side obligations

Read when: You're changing filter construction, subscription management, or sync concurrency, and need the constraint justification


GRASP-02 Purgatory Git Data Fetching

Proactive git data fetching from remote servers

Topics:

  • Identifier-based batching
  • Exponential backoff with fresh start
  • Domain throttling (5 concurrent, 30/min)
  • Debounced delays (3min user, 500ms sync)
  • 30-minute expiry
  • Mock-based testability

Read when: You want to understand how purgatory automatically fetches missing git data


Unified Git Data Sync

Shared processing for git push and purgatory sync paths

Topics:

  • Why unify push and sync processing
  • OID syncing to owner repos
  • Ref alignment logic
  • Event release from purgatory
  • WebSocket notification

Read when: You want to understand how git data is processed consistently regardless of arrival method


Monitoring Overview

Prometheus metrics and observability

Topics:

  • Metrics philosophy
  • Connection tracking
  • Git operation metrics
  • Nostr event metrics
  • Privacy considerations

Read when: You want to understand how to monitor ngit-grasp in production


Defensive Measures & Rate Limiting

Protection against abuse, spam, and denial-of-service attacks

Topics:

  • Connection and subscription management
  • Event publishing rate limits
  • Content filtering (blacklists/whitelists)
  • Event validation plugin system (WritePolicy/QueryPolicy)
  • Relay health management (naughty list, exponential backoff)
  • Privacy-preserving IP tracking
  • Future enhancements (per-IP rate limiting)

Read when: You want to understand how ngit-grasp protects against abuse and what defensive features are available


GRASP-05 Archive Mode

Read-only mirroring of repositories

Topics:

  • Archive whitelist configuration
  • Archive-all mode
  • Read-only mode defaults
  • Use cases for backup/mirror relays

Read when: You want to understand how to run an archive/backup relay


Repository Lifecycle

Handling repository removal, holding, archive, recovery, and purgatory

Topics:

  • Repository lifecycle architecture
  • Delete disrespector concept
  • Preventing left-pad scenarios
  • Archival policies
  • Holding, recovery, purgatory, and operator curation flows

Read when: You want to understand how ngit-grasp keeps nostr state and git data aligned across deletion, vanish, moderation, recovery, and purgatory flows


Planned Explanation Documentation

GRASP Protocol Design

Status: 🔜 Planned

Topics:

  • Why Nostr for Git?
  • Authorization model
  • Trust and verification
  • Decentralization benefits

Storage Architecture

Status: 🔜 Planned

Topics:

  • Why separate Git and Nostr storage?
  • Indexing strategy
  • Performance considerations
  • Scaling approach

Testing Philosophy

Status: 🔜 Planned

Topics:

  • Why test isolation?
  • Integration vs unit tests
  • Compliance testing approach
  • Test-driven development

Performance Considerations

Status: 🔜 Planned

Topics:

  • Async architecture
  • Caching strategy
  • Database choices
  • Bottlenecks and solutions

How to Use Explanation Documentation

  1. Read to understand - Not to accomplish a task
  2. Follow your curiosity - Read what interests you
  3. Connect concepts - Link ideas together
  4. Question and explore - Think critically

Not sure if this is what you need?


Contributing Explanation Documentation

When writing explanation:

DO:

  • ✅ Discuss concepts and ideas
  • ✅ Provide context and background
  • ✅ Explain alternatives
  • ✅ Use analogies and examples
  • ✅ Connect to broader context
  • ✅ Answer "why" questions

DON'T:

  • ❌ Provide step-by-step instructions (link to Tutorials/How-To)
  • ❌ List technical details (link to Reference)
  • ❌ Assume you must be comprehensive
  • ❌ Avoid opinions (explanation can be opinionated)

Template:

# Explanation: [Topic]

**Purpose:** [What concept/decision this explains]  
**Audience:** [Who wants to understand this]

---

## The Problem/Question

[What are we trying to understand?]

---

## Background

[Context and history]

---

## Our Approach

[How we address it]

### Why This Works

[Explanation of benefits]

### Trade-offs

[What we gain and lose]

---

## Alternatives Considered

### [Alternative 1]

**Pros:**
- [Benefits]

**Cons:**
- [Drawbacks]

**Why we didn't choose it:**
[Reasoning]

---

## Conclusion

[Summary of understanding]

---

## Related Documentation
- [Links to relevant docs]

See Diátaxis: Explanation for detailed guidance.


Part of the ngit-grasp documentation using the Diátaxis framework.