Add durable objects + containers example

16-containers-do/README.md

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+# Containers-backed Durable Objects Example
+
+A Python Worker that proxies requests to a [container-backed Durable Object](https://developers.cloudflare.com/containers/). The container runs a Pillow-based image generation server — every request returns a random abstract art PNG.
+
+## Architecture
+
+```
+Request → Python Worker → Durable Object → Container (Pillow image server on port 8080)
+```
+
+The Worker forwards all requests to a single container-backed DO instance. The DO starts the container on first access and proxies HTTP to it.
+
+## Usage
+
+```sh
+# Generate a random 512x512 image
+curl -o art.png https://<your-worker>.workers.dev/
+
+# Custom size
+curl -o art.png "https://<your-worker>.workers.dev/?w=800&h=600"
+
+# Reproducible output with a seed
+curl -o art.png "https://<your-worker>.workers.dev/?seed=42"
+```

16-containers-do/container/Dockerfile

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+FROM python:3.12-slim
+
+WORKDIR /app
+RUN pip install --no-cache-dir pillow
+COPY server.py .
+
+EXPOSE 8080
+
+CMD ["python", "-u", "server.py"]

16-containers-do/container/server.py

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+"""Image generation server that runs inside a Cloudflare Container.
+
+Generates random abstract art using Pillow and serves it over HTTP.
+"""
+
+from http.server import HTTPServer, BaseHTTPRequestHandler
+from io import BytesIO
+from urllib.parse import parse_qs, urlparse
+import random
+
+from PIL import Image, ImageDraw, ImageFilter
+
+
+def generate_image(width=512, height=512, seed=None):
+    """Generate a random abstract art image."""
+    if seed is not None:
+        random.seed(seed)
+
+    img = Image.new("RGB", (width, height), _random_color(pastel=True))
+    draw = ImageDraw.Draw(img)
+
+    # Layer random shapes
+    for _ in range(random.randint(15, 40)):
+        shape = random.choice(["circle", "rect", "line"])
+        color = _random_color()
+
+        if shape == "circle":
+            cx = random.randint(0, width)
+            cy = random.randint(0, height)
+            r = random.randint(10, min(width, height) // 3)
+            draw.ellipse([cx - r, cy - r, cx + r, cy + r], fill=color)
+        elif shape == "rect":
+            x1 = random.randint(0, width)
+            y1 = random.randint(0, height)
+            x2 = x1 + random.randint(20, width // 2)
+            y2 = y1 + random.randint(20, height // 2)
+            draw.rectangle([x1, y1, x2, y2], fill=color)
+        else:
+            points = [
+                (random.randint(0, width), random.randint(0, height))
+                for _ in range(random.randint(2, 5))
+            ]
+            draw.line(points, fill=color, width=random.randint(1, 8))
+
+    img = img.filter(ImageFilter.GaussianBlur(radius=random.uniform(0.5, 2.0)))
+    return img
+
+
+def _random_color(pastel=False):
+    if pastel:
+        return tuple(random.randint(180, 255) for _ in range(3))
+    return tuple(random.randint(0, 255) for _ in range(3))
+
+
+class Handler(BaseHTTPRequestHandler):
+    def do_GET(self):
+        parsed = urlparse(self.path)
+        params = parse_qs(parsed.query)
+
+        width = min(int(params.get("w", [512])[0]), 2048)
+        height = min(int(params.get("h", [512])[0]), 2048)
+        seed = params.get("seed", [None])[0]
+        if seed is not None:
+            seed = int(seed)
+
+        img = generate_image(width, height, seed)
+
+        buf = BytesIO()
+        img.save(buf, format="PNG")
+        body = buf.getvalue()
+
+        self.send_response(200)
+        self.send_header("Content-Type", "image/png")
+        self.send_header("Content-Length", str(len(body)))
+        self.end_headers()
+        self.wfile.write(body)
+
+    def log_message(self, format, *args):
+        print(f"[container] {format % args}")
+
+
+if __name__ == "__main__":
+    server = HTTPServer(("0.0.0.0", 8080), Handler)
+    print("[container] listening on port 8080")
+    server.serve_forever()