fix: prevent crash looping hello world

[biswapanda]

Overview:

Prevent crashloops in helloworld k8s example

nvbug: https://nvbugspro.nvidia.com/bug/5471412
closes: DYN-926

Details:

Where should the reviewer start?

Related Issues: (use one of the action keywords Closes / Fixes / Resolves / Relates to)

• closes GitHub issue: #xxx

Summary by CodeRabbit

• New Features
  • The hello_world example now continuously issues streaming requests at 1-second intervals, labeling each request sequentially and printing all streamed responses.
• Documentation
  • Updated the example to demonstrate repeated, tagged streaming requests instead of a single run, helping users see continuous streaming behavior in practice.

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[biswapanda]

/ok to test d65ae5f

[nealvaidya]

LGTM. In future we can replace client with an http listener

[biswapanda]

LGTM. In future we can replace client with an http listener

yeah a simple fastapi service would be better. this is just a quick fix for now

[coderabbitai]

Walkthrough

The example client now runs an infinite loop issuing successive streaming requests. Each iteration increments an index embedded in the query string, opens a new stream, prints all received data chunks, then sleeps for one second before repeating. Previously, it performed a single streaming generate call.

Changes

Cohort / File(s)	Summary
Hello world runtime example behavior examples/runtime/hello_world/client.py	Replace single streaming call with an infinite loop: build f"Query[{idx}] world,sun,moon,star", open stream per iteration, print response.data(), then sleep(1).

Sequence Diagram(s)

sequenceDiagram
  autonumber
  actor User
  participant Client
  participant Runtime as Runtime Service
  loop Repeat every 1s
    rect rgba(200,230,255,0.25)
      Note over Client: Build request with incremented idx
      Client->>Runtime: Open streaming request "Query[idx] world,sun,moon,star"
      activate Runtime
      Runtime-->>Client: Stream chunk(s)
      Runtime-->>Client: [end of stream]
      deactivate Runtime
      Note over Client: Print all received data
    end
    Client->>Client: sleep(1s)
  end

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Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

I tap my paws and set the loop,
Query by query, a hopping troupe.
Stars and moons stream nibble-bright,
I print each crumb of data-light.
One-second nap—then off I zoom,
Hello, world, from this burrowed room! 🐇✨

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[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (2)

examples/runtime/hello_world/client.py (2)

41-42: Parameterize request cadence to reduce log spam and allow tuning.

Hardcoding sleep(1) is fine for a demo, but making it configurable via an env var improves UX in clusters with stricter rate limits.

Add this outside the shown block:

# imports
import os  # at top-level

# before the loop, near idx initialization
period = float(os.getenv("HELLO_WORLD_PERIOD_SEC", "1.0"))

Then change the sleep to:

await asyncio.sleep(period)

---

38-40: Ensure the generated stream is always closed on errors

Our inspection of the Python bindings shows that client.generate(...) returns a bare async generator (no __aenter__/__aexit__ support), so using async with won’t work. To avoid leaking the underlying TCP/NATS connection if an exception occurs during iteration, wrap the loop in a try/finally and call await stream.aclose().

• examples/runtime/hello_world/client.py (around lines 38–41)

Suggested diff:

-        stream = await client.generate(f"Query[{idx}] world,sun,moon,star")
-        async for response in stream:
-            print(response.data())
+        stream = await client.generate(f"Query[{idx}] world,sun,moon,star")
+        try:
+            async for response in stream:
+                print(response.data())
+        finally:
+            # ensure the async generator is closed to free network resources
+            await stream.aclose()

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📥 Commits

Reviewing files that changed from the base of the PR and between 105436c and d65ae5f.

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• examples/runtime/hello_world/client.py (1 hunks)

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