# Replay Manifest Guide

> **Sprint:** SPRINT_20251228_001_BE_replay_manifest_ci (T6)
> **Purpose:** Complete reference for Replay Manifest export, verification, and CI integration.

## Overview

The Replay Manifest is a self-contained JSON document that captures everything needed to reproduce a scan: inputs, toolchain versions, policies, and expected outputs. When verified, it provides cryptographic proof that a scan is deterministic and reproducible.

## Quick Start

```bash
# Export replay manifest after scanning
stella replay export --scan-id <scan-uuid> --output replay.json

# Or export for a specific image
stella replay export --image myregistry/app:v1.0.0 --output replay.json

# Verify determinism (strict mode)
stella replay verify --manifest replay.json --strict-mode

# Verify with drift failure (for CI)
stella replay verify --manifest replay.json --fail-on-drift
```

---

## Schema Reference

### Schema Version

Current version: `1.0.0`

Schema location: `src/__Libraries/StellaOps.Replay.Core/Schemas/replay-export.schema.json`

### Top-Level Structure

```json
{
  "version": "1.0.0",
  "snapshot": { ... },
  "toolchain": { ... },
  "inputs": { ... },
  "outputs": { ... },
  "verification": { ... }
}
```

### `snapshot` Object

Identifies the scan snapshot this manifest represents.

| Field | Type | Description |
|-------|------|-------------|
| `id` | string | Unique snapshot ID (`snapshot:<sha256>`) |
| `createdAt` | ISO 8601 | UTC timestamp when scan completed |
| `artifact` | object | Reference to scanned artifact (digest, repository, tag) |

Example:
```json
{
  "id": "snapshot:a1b2c3d4e5f6...",
  "createdAt": "2025-12-28T14:30:00Z",
  "artifact": {
    "digest": "sha256:abc123...",
    "repository": "myregistry/app",
    "tag": "v1.0.0"
  }
}
```

### `toolchain` Object

Captures exact versions of all tools used during the scan.

| Field | Type | Description |
|-------|------|-------------|
| `scannerVersion` | string | StellaOps Scanner version |
| `policyEngineVersion` | string | Policy Engine version |
| `platform` | string | Platform identifier (e.g., `linux-x64`) |
| `sbomerVersion` | string | SBOM generator version |
| `vexerVersion` | string | VEX processor version |

Example:
```json
{
  "scannerVersion": "0.42.0",
  "policyEngineVersion": "0.42.0",
  "platform": "linux-x64",
  "sbomerVersion": "0.42.0",
  "vexerVersion": "0.42.0"
}
```

### `inputs` Object

All inputs consumed during the scan, with content hashes.

| Field | Type | Description |
|-------|------|-------------|
| `sboms` | array | SBOM inputs (if layered) |
| `vex` | array | VEX documents used |
| `feeds` | array | Vulnerability feed snapshots |
| `policies` | object | Policy bundle reference |

Feed snapshot example:
```json
{
  "feeds": [
    {
      "name": "nvd",
      "snapshotId": "nvd:2025-12-28T00:00:00Z",
      "digest": "sha256:def456...",
      "recordCount": 245678
    }
  ]
}
```

### `outputs` Object

Expected outputs from the scan, used for verification.

| Field | Type | Description |
|-------|------|-------------|
| `verdictDigest` | string | SHA256 of verdict JSON |
| `decision` | enum | `allow`, `deny`, or `review` |
| `sbomDigest` | string | SHA256 of generated SBOM |
| `findingsDigest` | string | SHA256 of findings JSON |

### `verification` Object

Helper commands and expected hashes for verification.

| Field | Type | Description |
|-------|------|-------------|
| `command` | string | CLI command to reproduce scan |
| `expectedSbomHash` | string | Expected SBOM content hash |
| `expectedVerdictHash` | string | Expected verdict content hash |

---

## CLI Commands

### `stella replay export`

Export a replay manifest from a completed scan.

```bash
stella replay export [OPTIONS]
```

| Option | Required | Description |
|--------|----------|-------------|
| `--scan-id <uuid>` | One of | Scan ID to export |
| `--image <ref>` | One of | Image reference (uses latest scan) |
| `--output <path>` | No | Output path (default: `replay.json`) |
| `--include-feed-snapshots` | No | Include full feed snapshot refs |
| `--no-verification-script` | No | Skip verification command generation |

### `stella replay verify`

Verify a replay manifest by re-executing the scan and comparing outputs.

```bash
stella replay verify [OPTIONS]
```

| Option | Required | Description |
|--------|----------|-------------|
| `--manifest <path>` | Yes | Path to replay manifest |
| `--strict-mode` | No | Require bit-for-bit identical outputs |
| `--fail-on-drift` | No | Exit code 1 on any drift |
| `--output-diff <path>` | No | Write diff report to file |

### Exit Codes

| Code | Meaning |
|------|---------|
| `0` | Verification passed, outputs match |
| `1` | Drift detected, outputs differ |
| `2` | Verification error (missing inputs, invalid manifest, etc.) |

---

## CI Integration

### Gitea Actions

```yaml
name: SBOM Replay Verification

on:
  push:
    branches: [main]
  pull_request:

jobs:
  verify-determinism:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Build image
        run: docker build -t ${{ github.repository }}:${{ github.sha }} .

      - name: Scan with replay export
        run: |
          stellaops scan \
            --image ${{ github.repository }}:${{ github.sha }} \
            --output-sbom sbom.json \
            --output-replay replay.json

      - name: Verify determinism
        run: |
          stellaops replay verify \
            --manifest replay.json \
            --fail-on-drift \
            --strict-mode

      - name: Upload replay manifest
        uses: actions/upload-artifact@v4
        with:
          name: replay-manifest
          path: replay.json
          retention-days: 90
```

### GitHub Actions

```yaml
name: SBOM Replay Verification

on:
  push:
    branches: [main]
  pull_request:

jobs:
  verify-determinism:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Set up StellaOps
        uses: stellaops/setup-stella@v1
        with:
          version: '0.42.0'

      - name: Build and scan
        run: |
          docker build -t myapp:${{ github.sha }} .
          stella scan --image myapp:${{ github.sha }} \
            --output-sbom sbom.json \
            --output-replay replay.json

      - name: Verify replay
        run: stella replay verify --manifest replay.json --fail-on-drift

      - name: Upload attestations
        uses: actions/upload-artifact@v4
        with:
          name: sbom-attestations
          path: |
            sbom.json
            replay.json
```

### GitLab CI

```yaml
sbom-replay:
  stage: security
  image: stellaops/cli:latest
  script:
    - docker build -t $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA .
    - stella scan --image $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA --output-replay replay.json
    - stella replay verify --manifest replay.json --fail-on-drift
  artifacts:
    paths:
      - replay.json
    expire_in: 90 days
  rules:
    - if: $CI_PIPELINE_SOURCE == "merge_request_event"
    - if: $CI_COMMIT_BRANCH == "main"
```

---

## Troubleshooting Drift Detection

### Common Drift Causes

| Cause | Symptom | Fix |
|-------|---------|-----|
| Feed update | `findingsDigest` differs | Pin feed snapshot version |
| Policy change | `verdictDigest` differs | Version policy bundles |
| Tool upgrade | All digests differ | Lock toolchain versions |
| Non-deterministic SBOM | `sbomDigest` differs | Enable deterministic mode |
| Timezone issues | Timestamps drift | Ensure UTC everywhere |

### Debugging Steps

1. **Export diff report:**
   ```bash
   stella replay verify --manifest replay.json --output-diff drift-report.json
   ```

2. **Compare inputs:**
   ```bash
   stella replay diff --manifest-a old.json --manifest-b new.json --show-inputs
   ```

3. **Check feed versions:**
   ```bash
   stella feeds list --show-snapshots
   ```

4. **Verify toolchain:**
   ```bash
   stella version --all
   ```

### Feed Snapshot Pinning

For reproducible CI, pin feed snapshots:

```bash
# List available snapshots
stella feeds snapshots --feed nvd

# Pin specific snapshot
stella scan --image myapp:v1.0.0 \
  --feed-snapshot nvd:2025-12-28T00:00:00Z \
  --output-replay replay.json
```

---

## Best Practices for Deterministic Builds

### 1. Lock All Dependencies

```yaml
# In CI, always specify exact versions
stellaops/cli:0.42.0  # Not :latest
```

### 2. Pin Feed Snapshots

```bash
# Export current snapshot ID
stella feeds export-snapshot --output feeds-snapshot.json

# Use in subsequent scans
stella scan --feed-snapshot-file feeds-snapshot.json
```

### 3. Version Policy Bundles

```bash
# Store policies in version control
git add policies/
git commit -m "Policy bundle v2.3.0"

# Reference by commit in manifest
stella scan --policy-ref policies@abc123
```

### 4. Use Strict Mode in CI

```bash
# Always use strict mode in CI pipelines
stella replay verify --manifest replay.json --strict-mode --fail-on-drift
```

### 5. Archive Replay Manifests

Store replay manifests alongside release artifacts for audit trail:

```bash
# Archive with release
cp replay.json releases/v1.0.0/replay.json
```

---

## API Reference

### `IReplayManifestExporter`

```csharp
public interface IReplayManifestExporter
{
    /// <summary>
    /// Exports a replay manifest for a completed scan.
    /// </summary>
    Task<ReplayExportResult> ExportAsync(
        string scanId,
        ReplayExportOptions options,
        CancellationToken ct = default);
}
```

### `ReplayExportOptions`

```csharp
public sealed record ReplayExportOptions
{
    /// <summary>Include exact toolchain versions.</summary>
    public bool IncludeToolchainVersions { get; init; } = true;

    /// <summary>Include feed snapshot references.</summary>
    public bool IncludeFeedSnapshots { get; init; } = true;

    /// <summary>Generate verification shell command.</summary>
    public bool GenerateVerificationScript { get; init; } = true;

    /// <summary>Output file path.</summary>
    public string OutputPath { get; init; } = "replay.json";
}
```

### `ReplayExportResult`

```csharp
public sealed record ReplayExportResult
{
    /// <summary>Path to exported manifest.</summary>
    public required string ManifestPath { get; init; }

    /// <summary>SHA256 digest of manifest content.</summary>
    public required string ManifestDigest { get; init; }

    /// <summary>Path to verification script (if generated).</summary>
    public string? VerificationScriptPath { get; init; }
}
```

---

## Related Documentation

- [Deterministic Replay](DETERMINISTIC_REPLAY.md) - Core concepts and architecture
- [Developer Guide: Replay](DEVS_GUIDE_REPLAY.md) - Implementation details
- [Replay Manifest v2 Acceptance](replay-manifest-v2-acceptance.md) - Schema evolution
- [Test Strategy](TEST_STRATEGY.md) - Replay testing approach

---

## Changelog

| Version | Date | Changes |
|---------|------|---------|
| 1.0.0 | 2025-12-28 | Initial schema and CLI commands |