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#!/usr/bin/env python3
"""Generate the spec PDF with embedded mockups via Playwright."""
import base64
import os
from playwright.sync_api import sync_playwright
BASE = "/root/projects/runs/b8eb8e1a-fb09-4fdf-bd9a-7f73f91733bf"
ATTACHMENTS = os.path.join(BASE, "attachments")
# Read and base64-encode all mockup PNGs
mockup_data = {}
for letter, slug in [
("A", "idle-state"),
("B", "webhook-received"),
("C", "validation"),
("D", "logging"),
("E", "success"),
("F", "health-check"),
("G", "error"),
]:
path = os.path.join(ATTACHMENTS, f"mockup-{letter.lower()}-{slug}.png")
with open(path, "rb") as f:
mockup_data[letter] = base64.b64encode(f.read()).decode("ascii")
def mockup_img(letter, caption):
return f'''
<div class="mockup-frame">
<img src="data:image/png;base64,{mockup_data[letter]}" style="width:100%;display:block;">
<div class="mockup-caption">{caption}</div>
</div>'''
html = f'''<!DOCTYPE html>
<html><head>
<link href="https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap" rel="stylesheet">
<style>
*, *::before, *::after {{ box-sizing: border-box; margin: 0; padding: 0; }}
body {{ font-family: 'Inter', system-ui, sans-serif; font-size: 13px; color: #1a1a2e; line-height: 1.6; }}
.cover {{ background: linear-gradient(135deg, #0f0c29 0%, #302b63 50%, #24243e 100%); color: #fff; height: 297mm; display: flex; flex-direction: column; justify-content: center; align-items: flex-start; padding: 60px 64px; page-break-after: always; }}
.cover h1 {{ font-size: 42px; font-weight: 700; line-height: 1.2; }}
.cover h1 span {{ color: #818cf8; }}
.cover .subtitle {{ font-size: 16px; color: rgba(255,255,255,0.7); margin-top: 16px; }}
.cover .meta {{ font-size: 12px; color: rgba(255,255,255,0.5); margin-top: 32px; }}
.page {{ padding: 28px 40px; }}
.page-break {{ page-break-before: always; }}
h1.section-title {{ font-size: 26px; font-weight: 700; color: #1e1b4b; border-bottom: 3px solid #6366f1; padding-bottom: 10px; margin: 32px 0 20px; }}
h2 {{ font-size: 16px; font-weight: 600; color: #312e81; margin: 28px 0 12px; border-left: 4px solid #6366f1; padding-left: 12px; }}
h3 {{ font-size: 14px; font-weight: 600; color: #4338ca; margin: 20px 0 8px; }}
pre {{ background: #1e1b4b; color: #c7d2fe; font-family: 'JetBrains Mono', monospace; font-size: 10.5px; padding: 16px 18px; border-radius: 8px; margin: 12px 0; line-height: 1.55; overflow-x: auto; }}
table {{ width: 100%; border-collapse: collapse; margin: 14px 0; font-size: 12px; }}
th {{ background: #312e81; color: #e0e7ff; font-weight: 600; padding: 8px 12px; text-align: left; font-size: 11px; }}
td {{ padding: 8px 12px; border-bottom: 1px solid #e5e7eb; vertical-align: top; }}
tr:nth-child(even) td {{ background: #f5f3ff; }}
.badge-ok {{ background: #dcfce7; color: #15803d; font-size: 10px; font-weight: 600; padding: 2px 8px; border-radius: 12px; }}
.badge-warn {{ background: #fef9c3; color: #92400e; font-size: 10px; font-weight: 600; padding: 2px 8px; border-radius: 12px; }}
.badge-fail {{ background: #fee2e2; color: #991b1b; font-size: 10px; font-weight: 600; padding: 2px 8px; border-radius: 12px; }}
.mockup-frame {{ border: 1px solid #e5e7eb; border-radius: 16px; overflow: hidden; box-shadow: 0 8px 30px rgba(0,0,0,0.1); margin: 16px 0; }}
.mockup-caption {{ font-size: 11px; font-weight: 600; color: #6b7280; text-align: center; padding: 10px; background: #f9fafb; border-top: 1px solid #e5e7eb; text-transform: uppercase; letter-spacing: 0.5px; }}
code {{ font-family: 'JetBrains Mono', monospace; font-size: 11px; background: #f1f0ff; color: #4338ca; padding: 1px 5px; border-radius: 4px; }}
.gap-critical {{ background: #fee2e2; border-left: 4px solid #ef4444; padding: 12px 16px; margin: 12px 0; border-radius: 0 8px 8px 0; }}
.gap-minor {{ background: #fef9c3; border-left: 4px solid #f59e0b; padding: 12px 16px; margin: 12px 0; border-radius: 0 8px 8px 0; }}
.checklist li {{ margin: 4px 0; list-style: none; }}
.checklist li::before {{ content: "☐"; margin-right: 8px; color: #6366f1; }}
ul {{ padding-left: 0; }}
p {{ margin: 8px 0; }}
</style>
</head><body>
<!-- COVER PAGE -->
<div class="cover">
<h1>Shopify Product Update<br><span>Webhook Service</span></h1>
<div class="subtitle">Technical & Functional Specification</div>
<div class="meta">
Version 1.0 • 2025-06-05 • Status: Planned<br>
FastAPI • structlog • Docker • Python 3.12
</div>
</div>
<!-- TABLE OF CONTENTS -->
<div class="page page-break">
<h1 class="section-title">Table of Contents</h1>
<ol style="font-size:13px;line-height:2.2;">
<li>Feature Overview</li>
<li>Architecture Diagram</li>
<li>Component Map</li>
<li>API Reference</li>
<li>Data Schema</li>
<li>Protocol / Event Reference</li>
<li>State Machine</li>
<li>Message / Data Flow Diagrams</li>
<li>Visual Mockups</li>
<li>Implementation Status</li>
<li>Gap Analysis</li>
<li>Testing Requirements</li>
<li>Test Coverage Map</li>
<li>Known Edge Cases</li>
<li>Acceptance Criteria</li>
<li>Out of Scope</li>
<li>Open Questions</li>
<li>Persistence / Session Behaviour</li>
</ol>
</div>
<!-- SECTION 1: Feature Overview -->
<div class="page page-break">
<h1 class="section-title">1. Feature Overview</h1>
<h2>What the feature does</h2>
<p>A lightweight FastAPI service that exposes a single webhook endpoint for Shopify <code>product/update</code> events. When Shopify (or any HTTP client) sends a POST request with a JSON payload to <code>POST /webhooks/shopify/product-update</code>, the service:</p>
<ol>
<li>Validates the payload against a Pydantic model (top-level Shopify product fields only).</li>
<li>Logs the entire payload as a single structured JSON line via <code>structlog</code>.</li>
<li>Returns <code>200 OK</code> with a minimal JSON body.</li>
</ol>
<p>A companion <code>GET /health</code> endpoint returns <code>200 OK</code> for container health checks and load-balancer probes.</p>
<p>The service runs inside a production-grade Docker container built with a multi-stage Dockerfile, runs as a non-root user, pins all dependency versions, and includes a <code>HEALTHCHECK</code> instruction.</p>
<h2>End-to-end user journey</h2>
<ol>
<li>Shopify sends a <code>product/update</code> webhook POST to the service's <code>/webhooks/shopify/product-update</code> endpoint.</li>
<li>Uvicorn receives the request and routes it to the FastAPI app.</li>
<li>The Pydantic model validates the top-level fields of the JSON payload.</li>
<li>If validation passes, <code>structlog</code> emits a single structured JSON log line containing the full payload plus metadata (timestamp, event type, product ID).</li>
<li>The service returns <code>200 OK</code> with body <code>{"status": "received"}</code>.</li>
<li>If validation fails, the service returns <code>422 Unprocessable Entity</code> with FastAPI's standard validation error detail.</li>
<li>A Docker <code>HEALTHCHECK</code> periodically hits <code>GET /health</code>; the endpoint returns <code>200 OK</code> with body <code>{"status": "ok"}</code>.</li>
</ol>
<h2>Key design decisions</h2>
<table>
<tr><th>Decision</th><th>Rationale</th></tr>
<tr><td>Skip HMAC verification</td><td>Per user clarification — simplifies initial deployment; can be added later as middleware</td></tr>
<tr><td>Pydantic model validates top-level fields only</td><td>Shopify's product schema is large and versioned; strict full validation is fragile and breaks on schema changes</td></tr>
<tr><td><code>structlog</code> for JSON logging</td><td>Single JSON line per event is easy for log shippers (Fluentd, Datadog, CloudWatch) to ingest</td></tr>
<tr><td>Multi-stage Dockerfile</td><td>Smaller final image; build tools not included in runtime image</td></tr>
<tr><td>Non-root user in container</td><td>Security best practice; required by most Kubernetes pod security policies</td></tr>
<tr><td>No database / no retry queue</td><td>Per user clarification — this is a fire-and-forget logging sink</td></tr>
<tr><td><code>GET /health</code> endpoint</td><td>Required for Docker <code>HEALTHCHECK</code> and load-balancer probes</td></tr>
<tr><td>Python 3.12 + pip</td><td>Per user clarification — keeps Dockerfile simpler than Poetry/pdm</td></tr>
</table>
</div>
<!-- SECTION 2: Architecture Diagram -->
<div class="page page-break">
<h1 class="section-title">2. Architecture Diagram</h1>
<pre>
┌─────────────────┐
│ Shopify │
│ (Webhook Sender)│
└────────┬────────┘
│
HTTPS POST (JSON)
│
▼
┌────────────────────────┐
│ Docker Container │
│ ┌──────────────────┐ │
│ │ Uvicorn │ │
│ │ (ASGI server) │ │
│ └────────┬─────────┘ │
│ │ │
│ ┌────────▼─────────┐ │
│ │ FastAPI App │ │
│ │ │ │
│ │ POST /webhooks/ │ │
│ │ shopify/ │ │
│ │ product-update │ │
│ │ │ │
│ │ GET /health │ │
│ └────────┬─────────┘ │
│ │ │
│ ┌────────▼─────────┐ │
│ │ structlog │ │
│ │ (JSON stdout) │ │
│ └────────┬─────────┘ │
│ │ │
│ ┌────────▼─────────┐ │
│ │ stdout │ │
│ │ (container log)│ │
│ └──────────────────┘ │
└────────────────────────┘
│
▼
┌─────────────────┐
│ Log Shipper │
│ (Fluentd, │
│ CloudWatch, │
│ Datadog, etc.)│
└─────────────────┘
</pre>
</div>
<!-- SECTION 3: Component Map -->
<div class="page page-break">
<h1 class="section-title">3. Component Map</h1>
<h2>Backend</h2>
<table>
<tr><th>File path</th><th>Role</th></tr>
<tr><td><code>app/__init__.py</code></td><td>Package marker; empty</td></tr>
<tr><td><code>app/main.py</code></td><td>App factory — creates FastAPI instance, configures structlog, includes routers</td></tr>
<tr><td><code>app/routers/__init__.py</code></td><td>Package marker; empty</td></tr>
<tr><td><code>app/routers/webhooks.py</code></td><td><code>POST /webhooks/shopify/product-update</code> endpoint and Pydantic model</td></tr>
<tr><td><code>app/routers/health.py</code></td><td><code>GET /health</code> endpoint</td></tr>
<tr><td><code>app/models.py</code></td><td>Pydantic models for Shopify product webhook payload</td></tr>
<tr><td><code>app/logging_config.py</code></td><td>structlog configuration — JSON renderer, processor chain</td></tr>
<tr><td><code>Dockerfile</code></td><td>Multi-stage production build</td></tr>
<tr><td><code>requirements.txt</code></td><td>Pinned Python dependencies</td></tr>
<tr><td><code>.dockerignore</code></td><td>Exclude unnecessary files from Docker build context</td></tr>
<tr><td><code>tests/__init__.py</code></td><td>Package marker; empty</td></tr>
<tr><td><code>tests/test_webhooks.py</code></td><td>Unit + integration tests for webhook endpoint</td></tr>
<tr><td><code>tests/test_health.py</code></td><td>Unit tests for health endpoint</td></tr>
<tr><td><code>tests/conftest.py</code></td><td>Shared fixtures (TestClient, etc.)</td></tr>
</table>
</div>
<!-- SECTION 4: API Reference -->
<div class="page page-break">
<h1 class="section-title">4. API Reference</h1>
<h2>POST /webhooks/shopify/product-update</h2>
<p>Receives a Shopify product update webhook payload, validates top-level fields, logs the payload as structured JSON, and returns 200.</p>
<h3>Request Body</h3>
<pre>{{
"id": 123456789,
"title": "Product Title",
"body_html": "<p>Description</p>",
"vendor": "Vendor Name",
"product_type": "Type",
"handle": "product-handle",
"published_at": "2025-01-01T00:00:00-00:00",
"created_at": "2025-01-01T00:00:00-00:00",
"updated_at": "2025-06-05T12:00:00-00:00",
"status": "active",
"variants": [],
"options": [],
"images": [],
"metafields": []
}}</pre>
<h3>Response — 200 OK</h3>
<pre>{{
"status": "received"
}}</pre>
<h3>Response — 422 Unprocessable Entity</h3>
<pre>{{
"detail": [
{{
"loc": ["body", "id"],
"msg": "field required",
"type": "value_error.missing"
}}
]
}}</pre>
<h3>Behaviour</h3>
<table>
<tr><th>Condition</th><th>Result</th></tr>
<tr><td>Valid JSON with required top-level fields</td><td>200, payload logged as structured JSON</td></tr>
<tr><td>Valid JSON but missing required field <code>id</code></td><td>422, FastAPI validation error</td></tr>
<tr><td>Valid JSON but missing optional fields</td><td>200, defaults applied per model</td></tr>
<tr><td>Invalid JSON (malformed body)</td><td>422, FastAPI request parsing error</td></tr>
<tr><td>Empty body</td><td>422, validation error</td></tr>
<tr><td>Request with extra nested fields</td><td>200, extra fields passed through to log (<code>extra="allow"</code>)</td></tr>
</table>
<h2>GET /health</h2>
<p>Health check endpoint for Docker <code>HEALTHCHECK</code> and load-balancer probes.</p>
<h3>Response — 200 OK</h3>
<pre>{{
"status": "ok"
}}</pre>
</div>
<!-- SECTION 5: Data Schema -->
<div class="page page-break">
<h1 class="section-title">5. Data Schema</h1>
<h2>Pydantic Model — ShopifyProductUpdatePayload</h2>
<pre>class ShopifyProductUpdatePayload(BaseModel):
model_config = ConfigDict(extra="allow")
id: int # Shopify product ID (required)
title: str # Product title (required)
body_html: str | None = None # HTML description
vendor: str | None = None # Vendor name
product_type: str | None = None # Product type
handle: str | None = None # URL handle
published_at: str | None = None # ISO 8601 datetime
created_at: str | None = None # ISO 8601 datetime
updated_at: str | None = None # ISO 8601 datetime
status: str | None = None # active, draft, archived
tags: str | None = None # Comma-separated tag string</pre>
<p>Only <code>id</code> and <code>title</code> are required — all other fields are optional with <code>None</code> defaults. <code>extra="allow"</code> — Shopify webhooks frequently include additional fields that are passed through to the log without validation. Nested objects (<code>variants</code>, <code>options</code>, <code>images</code>, <code>metafields</code>) are NOT modelled.</p>
<h2>Log Output Schema</h2>
<p>Each log line is a JSON object:</p>
<pre>{{
"event": "shopify.product_update",
"timestamp": "2025-06-05T12:00:00.000000Z",
"level": "info",
"product_id": 123456789,
"title": "Product Title",
"payload": {{ ... }}
}}</pre>
<table>
<tr><th>Field</th><th>Type</th><th>Description</th></tr>
<tr><td><code>event</code></td><td><code>str</code></td><td>Constant <code>"shopify.product_update"</code></td></tr>
<tr><td><code>timestamp</code></td><td><code>str</code></td><td>ISO 8601 UTC timestamp</td></tr>
<tr><td><code>level</code></td><td><code>str</code></td><td>Log level (<code>info</code>, <code>warning</code>, <code>error</code>)</td></tr>
<tr><td><code>product_id</code></td><td><code>int</code></td><td>Extracted from <code>payload.id</code> for quick filtering</td></tr>
<tr><td><code>title</code></td><td><code>str</code></td><td>Extracted from <code>payload.title</code> for quick filtering</td></tr>
<tr><td><code>payload</code></td><td><code>object</code></td><td>Full webhook payload as received</td></tr>
</table>
<h2>Redis / Database</h2>
<p>N/A — no persistence layer.</p>
</div>
<!-- SECTION 7: State Machine -->
<div class="page page-break">
<h1 class="section-title">7. State Machine</h1>
<p>This service is stateless. The per-request lifecycle is:</p>
<pre>
[Request Received] ──→ [Parse JSON Body] ──→ [Validate Pydantic Model]
│
┌──────────────┴──────────────┐
│ │
Valid Invalid
│ │
▼ ▼
[Log via structlog] [422 Validation Error]
│
▼
[200 OK Response]
</pre>
</div>
<!-- SECTION 8: Data Flow Diagrams -->
<div class="page page-break">
<h1 class="section-title">8. Message / Data Flow Diagrams</h1>
<h2>Normal happy path — product update webhook</h2>
<pre>
Shopify Uvicorn FastAPI structlog stdout
│ │ │ │ │
│ POST /webhooks/ │ │ │ │
│ shopify/ │ │ │ │
│ product-update │ │ │ │
│─────────────────────→│ │ │ │
│ │ route to │ │ │
│ │ webhook handler │ │ │
│ │──────────────────→│ │ │
│ │ │ validate │ │
│ │ │ payload │ │
│ │ │──────┐ │ │
│ │ │ │ valid │ │
│ │ │←─────┘ │ │
│ │ │ log payload │ │
│ │ │──────────────────→│ │
│ │ │ │ JSON line │
│ │ │ │────────────────→│
│ │ │ return 200 │ │
│ │←──────────────────│ │ │
│ 200 OK │ │ │ │
│←─────────────────────│ │ │ │
</pre>
<h2>Error path — invalid payload</h2>
<pre>
Client Uvicorn FastAPI
│ │ │
│ POST (invalid JSON) │ │
│─────────────────────→│ │
│ │ route to │
│ │ webhook handler │
│ │──────────────────→│
│ │ │ validate
│ │ │──────┐
│ │ │ │ invalid
│ │ │←─────┘
│ │ 422 error │
│ │←──────────────────│
│ 422 Unprocessable │ │
│←─────────────────────│ │
</pre>
</div>
<!-- SECTION 9: Visual Mockups -->
<div class="page page-break">
<h1 class="section-title">9. Visual Mockups</h1>
<p>As a backend-only service with no user interface, mockups are rendered as flow diagrams showing system states and data flows.</p>
<h3>A — Default / Idle State</h3>
<p>Service is running, listening on port 8080, no active requests.</p>
{mockup_img("A", "A — Default / Idle State")}
<h3>B — Webhook Received</h3>
<p>A POST request arrives at the webhook endpoint; the service begins parsing and validation.</p>
{mockup_img("B", "B — Webhook Received")}
<div class="page-break"></div>
<h3>C — Validation State</h3>
<p>The Pydantic model is validating the incoming payload against the schema.</p>
{mockup_img("C", "C — Validation State")}
<h3>D — Active / Logging State</h3>
<p>Validation passed; structlog is writing the structured JSON line to stdout.</p>
{mockup_img("D", "D — Active / Logging State")}
<div class="page-break"></div>
<h3>E — Success / Completion State</h3>
<p>200 OK response returned to Shopify; log line emitted to stdout.</p>
{mockup_img("E", "E — Success / Completion State")}
<h3>F — Health Check</h3>
<p>Load balancer or Docker HEALTHCHECK hits GET /health; service responds 200 OK.</p>
{mockup_img("F", "F — Health Check")}
<div class="page-break"></div>
<h3>G — Error State</h3>
<p>Invalid payload fails Pydantic validation; 422 Unprocessable Entity returned.</p>
{mockup_img("G", "G — Error State")}
</div>
<!-- SECTION 10: Implementation Status -->
<div class="page page-break">
<h1 class="section-title">10. Implementation Status</h1>
<table>
<tr><th>Story</th><th>Description</th><th>Status</th><th>Notes</th></tr>
<tr><td>WH-1</td><td>FastAPI app factory with structlog config</td><td><span class="badge-fail">❌ Not built</span></td><td>Greenfield</td></tr>
<tr><td>WH-2</td><td>POST /webhooks/shopify/product-update endpoint</td><td><span class="badge-fail">❌ Not built</span></td><td>Greenfield</td></tr>
<tr><td>WH-3</td><td>Pydantic model for Shopify product payload</td><td><span class="badge-fail">❌ Not built</span></td><td>Greenfield</td></tr>
<tr><td>WH-4</td><td>GET /health endpoint</td><td><span class="badge-fail">❌ Not built</span></td><td>Greenfield</td></tr>
<tr><td>WH-5</td><td>Production Dockerfile (multi-stage, non-root, healthcheck)</td><td><span class="badge-fail">❌ Not built</span></td><td>Greenfield</td></tr>
<tr><td>WH-6</td><td>Unit + integration tests</td><td><span class="badge-fail">❌ Not built</span></td><td>Greenfield</td></tr>
<tr><td>WH-7</td><td>requirements.txt with pinned versions</td><td><span class="badge-fail">❌ Not built</span></td><td>Greenfield</td></tr>
</table>
</div>
<!-- SECTION 11: Gap Analysis -->
<div class="page page-break">
<h1 class="section-title">11. Gap Analysis</h1>
<div class="gap-critical">
<h3>🔴 GAP-1: No HMAC verification</h3>
<p>Shopify webhooks include an <code>X-Shopify-Hmac-Sha256</code> header for request authenticity. Skipping it means any client can send payloads to the endpoint.</p>
<p><strong>Recommended fix:</strong> Add optional HMAC verification middleware in a future iteration. Configurable via environment variable <code>VERIFY_HMAC=true|false</code> so it can be enabled without code changes. The HMAC secret should be read from <code>SHOPIFY_HMAC_SECRET</code> env var.</p>
</div>
<div class="gap-minor">
<h3>🟡 GAP-2: No rate limiting</h3>
<p>Without rate limiting, the endpoint is vulnerable to abuse or accidental flood (e.g., a Shopify misconfiguration sending thousands of updates).</p>
<p><strong>Recommended fix:</strong> Add an in-memory rate limiter (e.g., <code>slowapi</code>) configurable via <code>RATE_LIMIT</code> env var. Default: 100 requests/minute.</p>
</div>
<div class="gap-minor">
<h3>🟡 GAP-3: No request ID / correlation ID</h3>
<p>Log lines have no request-level correlation ID, making it hard to trace a single webhook through downstream systems (if added later).</p>
<p><strong>Recommended fix:</strong> Add a <code>request_id</code> field to every log entry. Generate UUID4 per request, or read from <code>X-Request-ID</code> header if provided.</p>
</div>
<div class="gap-minor">
<h3>🟡 GAP-4: No graceful shutdown handling</h3>
<p>Uvicorn's default shutdown may drop in-flight requests.</p>
<p><strong>Recommended fix:</strong> Configure Uvicorn with <code>--graceful-timeout 5</code> and handle <code>SIGTERM</code> to drain connections before exiting.</p>
</div>
</div>
<!-- SECTION 12: Testing Requirements -->
<div class="page page-break">
<h1 class="section-title">12. Testing Requirements</h1>
<h2>Unit Tests</h2>
<table>
<tr><th>Test</th><th>File</th><th>Assertions</th></tr>
<tr><td><code>test_webhook_valid_payload</code></td><td><code>tests/test_webhooks.py</code></td><td>POST with valid top-level fields returns 200; body contains <code>{"status": "received"}</code></td></tr>
<tr><td><code>test_webhook_minimal_payload</code></td><td><code>tests/test_webhooks.py</code></td><td>POST with only <code>id</code> and <code>title</code> returns 200</td></tr>
<tr><td><code>test_webhook_missing_id</code></td><td><code>tests/test_webhooks.py</code></td><td>POST without <code>id</code> field returns 422; error detail mentions <code>id</code></td></tr>
<tr><td><code>test_webhook_missing_title</code></td><td><code>tests/test_webhooks.py</code></td><td>POST without <code>title</code> field returns 422; error detail mentions <code>title</code></td></tr>
<tr><td><code>test_webhook_extra_fields_allowed</code></td><td><code>tests/test_webhooks.py</code></td><td>POST with extra nested fields returns 200; extra fields not rejected</td></tr>
<tr><td><code>test_webhook_invalid_json</code></td><td><code>tests/test_webhooks.py</code></td><td>POST with malformed JSON body returns 422</td></tr>
<tr><td><code>test_webhook_empty_body</code></td><td><code>tests/test_webhooks.py</code></td><td>POST with empty body returns 422</td></tr>
<tr><td><code>test_webhook_logs_payload</code></td><td><code>tests/test_webhooks.py</code></td><td>POST with valid payload causes structlog to emit a log line with <code>event=shopify.product_update</code>, correct <code>product_id</code>, and full <code>payload</code></td></tr>
<tr><td><code>test_health_endpoint</code></td><td><code>tests/test_health.py</code></td><td>GET /health returns 200 with <code>{"status": "ok"}</code></td></tr>
<tr><td><code>test_health_method_not_allowed</code></td><td><code>tests/test_health.py</code></td><td>POST /health returns 405 Method Not Allowed</td></tr>
</table>
<h2>E2E Browser Tests</h2>
<p>N/A — this is a pure backend API service with no browser UI. All testing is done via HTTP requests using <code>httpx</code>/<code>TestClient</code>.</p>
<h2>Test Infrastructure</h2>
<ul>
<li><strong>Framework:</strong> <code>pytest</code> with <code>httpx</code> (via FastAPI <code>TestClient</code>)</li>
<li><strong>Location:</strong> <code>tests/</code> directory at project root</li>
<li><strong>Run command:</strong> <code>docker run --rm <image> pytest tests/ -v</code> or <code>pytest tests/ -v</code> locally</li>
<li><strong>CI-runnable:</strong> Yes — all tests are unit/integration via <code>TestClient</code>, no external dependencies</li>
<li><strong>structlog capture:</strong> Use <code>capfd</code> or a custom structlog processor to capture log output in tests</li>
</ul>
</div>
<!-- SECTION 13: Test Coverage Map -->
<div class="page page-break">
<h1 class="section-title">13. Test Coverage Map</h1>
<table>
<tr><th>Test File</th><th>What it covers</th><th>Status</th></tr>
<tr><td><code>tests/test_webhooks.py</code></td><td>Webhook endpoint validation, response codes, logging</td><td><span class="badge-fail">❌ Missing</span></td></tr>
<tr><td><code>tests/test_health.py</code></td><td>Health endpoint response</td><td><span class="badge-fail">❌ Missing</span></td></tr>
<tr><td><code>tests/conftest.py</code></td><td>Shared fixtures (TestClient)</td><td><span class="badge-fail">❌ Missing</span></td></tr>
</table>
<h2>Coverage Summary</h2>
<table>
<tr><th>Area</th><th>Coverage Level</th></tr>
<tr><td>Webhook endpoint — valid payloads</td><td><span class="badge-fail">❌ Not tested</span></td></tr>
<tr><td>Webhook endpoint — invalid payloads</td><td><span class="badge-fail">❌ Not tested</span></td></tr>
<tr><td>Webhook endpoint — logging output</td><td><span class="badge-fail">❌ Not tested</span></td></tr>
<tr><td>Health endpoint</td><td><span class="badge-fail">❌ Not tested</span></td></tr>
<tr><td>Docker build</td><td><span class="badge-fail">❌ Not tested</span> (manual)</td></tr>
</table>
</div>
<!-- SECTION 14: Known Edge Cases -->
<div class="page page-break">
<h1 class="section-title">14. Known Edge Cases</h1>
<table>
<tr><th>Case</th><th>Current Handling</th></tr>
<tr><td>Very large payload (>1 MB)</td><td>Uvicorn default limits apply; no explicit cap configured. Could cause memory issues under sustained high volume.</td></tr>
<tr><td>Payload with null <code>id</code></td><td>Pydantic rejects — <code>id</code> is <code>int</code> (required), <code>null</code> fails validation → 422</td></tr>
<tr><td>Payload with string <code>id</code> instead of int</td><td>Pydantic rejects — type mismatch → 422</td></tr>
<tr><td>Payload with nested variants/images containing thousands of items</td><td>Accepted (<code>extra="allow"</code>), logged as-is. Could produce very large log lines.</td></tr>
<tr><td>Concurrent requests</td><td>Uvicorn handles async; no locking needed (stateless)</td></tr>
<tr><td>Missing <code>Content-Type: application/json</code></td><td>FastAPI still parses body as JSON if valid; otherwise 422</td></tr>
<tr><td>Shopify retries webhook (if we returned non-200)</td><td>Not applicable — service always returns 200 for valid payloads; no downstream failures possible</td></tr>
<tr><td>Container OOM under high load</td><td>No memory limit in Dockerfile; rely on orchestrator/resource limits</td></tr>
</table>
</div>
<!-- SECTION 15: Acceptance Criteria -->
<div class="page page-break">
<h1 class="section-title">15. Acceptance Criteria</h1>
<ul class="checklist">
<li>POST /webhooks/shopify/product-update with a valid JSON payload containing id and title returns 200 OK with body {"status": "received"}</li>
<li>POST /webhooks/shopify/product-update logs the full payload as a single structured JSON line via structlog with event="shopify.product_update", product_id, title, and payload fields</li>
<li>POST /webhooks/shopify/product-update with missing id field returns 422 Unprocessable Entity</li>
<li>POST /webhooks/shopify/product-update with missing title field returns 422 Unprocessable Entity</li>
<li>POST /webhooks/shopify/product-update with extra nested fields (variants, images, etc.) returns 200 OK — extra fields are not rejected</li>
<li>POST /webhooks/shopify/product-update with malformed JSON returns 422</li>
<li>GET /health returns 200 OK with body {"status": "ok"}</li>
<li>Dockerfile uses multi-stage build (builder stage + runtime stage)</li>
<li>Dockerfile runs the application as a non-root user</li>
<li>Dockerfile includes a HEALTHCHECK instruction targeting GET /health</li>
<li>All dependency versions in requirements.txt are pinned (e.g., fastapi==0.111.0, not fastapi>=0.111)</li>
<li>Application uses Python 3.12</li>
<li>Application uses structlog for structured JSON logging to stdout</li>
<li>No HMAC verification is performed (per requirement)</li>
<li>No database, no retry queue, no background tasks (per requirement)</li>
<li>All unit tests pass via pytest</li>
</ul>
</div>
<!-- SECTION 16: Out of Scope -->
<div class="page page-break">
<h1 class="section-title">16. Out of Scope</h1>
<ul>
<li>HMAC signature verification — explicitly skipped per user clarification</li>
<li>Any form of persistence (database, file, cache) — fire-and-forget logging only</li>
<li>Retry queue or background task processing</li>
<li>Rate limiting or throttling</li>
<li>Authentication or authorization on the endpoint</li>
<li>Webhook topic verification (verifying the <code>X-Shopify-Topic</code> header)</li>
<li>Webhook deduplication (idempotency keys)</li>
<li>Docker Compose or multi-container orchestration</li>
<li>CI/CD pipeline configuration</li>
<li>Kubernetes manifests or Helm charts</li>
<li>Monitoring / metrics endpoints (Prometheus, etc.)</li>
<li>API documentation UI (Swagger/Redoc) — FastAPI provides this by default; not a deliverable</li>
<li>Internationalization (i18n) — English-only error messages</li>
</ul>
</div>
<!-- SECTION 17: Open Questions -->
<div class="page page-break">
<h1 class="section-title">17. Open Questions</h1>
<table>
<tr><th>#</th><th>Question</th><th>Owner</th></tr>
<tr><td>—</td><td>All clarifications resolved. No open questions.</td><td>—</td></tr>
</table>
</div>
<!-- SECTION 18: Persistence / Session Behaviour -->
<div class="page">
<h1 class="section-title">18. Persistence / Session Behaviour</h1>
<p>N/A — the service is entirely stateless. No data is persisted between requests. Each webhook request is processed independently: validate → log → respond. There is no session state, no cookies, no tokens, and no in-memory caches that survive across requests.</p>
</div>
</body></html>
'''
with sync_playwright() as p:
browser = p.chromium.launch(
executable_path="/usr/local/bin/chromium",
args=["--no-sandbox"],
)
page = browser.new_page()
page.set_content(html, wait_until="networkidle")
page.wait_for_timeout(2000)
out_path = os.path.join(BASE, "spec.pdf")
page.pdf(
path=out_path,
format="A4",
margin={"top": "15mm", "bottom": "15mm", "left": "15mm", "right": "15mm"},
print_background=True,
)
page.close()
browser.close()
print(f"✓ PDF saved to {out_path}")