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Show HN: Subtrace – Wireshark for Docker Containers

(github.com)
364 points adtac | 4 comments | 18 Feb 25 23:29 UTC | HN request time: 0.835s | source

Hey HN, we built Subtrace (https://subtrace.dev) to let you see all incoming and outgoing requests in your backend server—like Wireshark, but for Docker containers. It comes with a Chrome DevTools-like interface. Check out this video: https://www.youtube.com/watch?v=OsGa6ZwVxdA, and see our docs for examples: https://docs.subtrace.dev.

Subtrace lets you see every request with full payload, headers, status code, and latency details. Tools like Sentry and OpenTelemetry often leave out these crucial details, making prod debugging slow and annoying. Most of the time, all I want to see are the headers and JSON payload of real backend requests, but it's impossible to do that in today's tools without excessive logging, which just makes everything slower and more annoying.

Subtrace shows you every backend request flowing through your system. You can use simple filters to search for the requests you care about and inspect their details.

Internally, Subtrace intercepts all network-related Linux syscalls using Seccomp BPF so that it can act as a proxy for all incoming and outgoing TCP connections. It then parses HTTP requests out of the proxied TCP stream and sends them to the browser over WebSocket. The Chrome DevTools Network tab is already ubiquitous for viewing HTTP requests in the frontend, so we repurposed it to work in the browser like any other app (we were surprised that it's just a bunch of TypeScript).

Setup is just one command for any Linux program written in any language.

You can use Subtrace by adding a `subtrace run` prefix to your backend server startup command. No signup required. Try for yourself: https://docs.subtrace.dev

1. codegeek ◴[19 Feb 25 23:42 UTC] No.43109280[source]▶
Side question. Why not do a Launch HN instead of Show HN since you are backed by YC ? I thought YC companies can do a launch HN?
replies(1): >>43111524 #
2. dang ◴[20 Feb 25 05:44 UTC] No.43111524[source]▶
They can, but for open-source startups I recommend they do a Show HN first, for the following reasons:

(1) If the Show HN succeeds, then they can save their Launch HN card to play later; if it doesn't succeed, they can go ahead and do a Launch HN soon afterwards.

(2) Show HN is more about the project/tech, especially when it's open-source. Launch HN is more about the startup/business.

(3) Nowadays many startups offer an open-source (or open core) version for free, then make money with a hosted version. For these, it's a good fit to first do a Show HN about the open-source offering, and then later do a Launch HN about the cloud product.

replies(1): >>43111720 #
3. 0xbadcafebee ◴[20 Feb 25 06:24 UTC] No.43111720[source]▶
There needs to be a new term for this grassroots astroturf... Grasstroturf? Get the nerds' attention with free tech, down-playing the fact that it's a business, so later they can pump them for money easier. The pig doesn't want to see the knife, they just want the free trough.
replies(1): >>43111904 #
4. dang ◴[20 Feb 25 07:01 UTC] No.43111904{3}[source]▶
FWIW, I've spent time at YC open-source events where later-stage founders advise earlier-stage ones, and this isn't the kind of advice they give. In fact they would describe that as a terrible strategy and tell startups to avoid it.

If I were to give an example of actual advice I've heard, using the terms of your comment, it might be: keep the nerds happy with free open-source software that actually works, then charge money for things that companies (especially enterprise companies) actually prefer to pay for.

The "paid hosted offering" pattern is the most common of these, since nerds might want to run their own instances but many IT departments do not.