Emulate offline about puppeteer HOT 11 CLOSED

wait, we still want to have page.setOfflineMode implemented :)

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If you don't want to run as root but still want to have some level of automated traffic shaping (even if low fidelity). Then what you'd want to do is setup a proxy for those tests. Do it where any tests that need throttling use an instance that is talking to your proxy that will handle the network manipulation. You'd pass the proxy in when launching an instance just like you would from the command line as an arg option.

let instance = puppeteer.launch({
  args: [
   '--proxy-server=127.0.0.1:9876', // Or whatever the address is 
  ]
});

This allows you to use other external tools to manage the network shaping. Such as Charles Proxy on Mac OS. Finding a good cross-platform solution for testing is difficult though, as Windows in particular is dramatically different to talk to.

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A proxy should. Since that is an entire external man-in-the-middle between the program and the network interface.

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@paulirish @ebidel how do you guys feel about the page.setOfflineMode? This seems to be trivial to implement but really useful. We can add a page.setNetworkConditions(condition) method later if there's a need to, and keep the setOfflineMode as an alias for setNetworkConditions('offline').

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This is blocked on Chrome Headless network emulation support: https://bugs.chromium.org/p/chromium/issues/detail?id=728451

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As discussed with @pavelfeldman, we should not do anything other then setOfflineMode - we're pretty bad at network shaping. There's a specific tooling which does this much better and on a much lower level.

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@aslushnikov do you mind elaborating on this? I would love to be able to do network emulation to test scenarios in my app.

Alternatively, a docker container image that runs something that does do network condition throttling would be great.

For example I need to test a scenario where 2 clients are communicating with a server.

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@benjamingr The devtools throttling has some issues: Network Throttling & Chrome - status

Alternatively, a docker container image that runs something that does do network condition throttling would be great.

I've discussed this with Pat Meenan of webpagetest and he indicates docker isn't a reliable solution for network shaping as you cannot modify the network interface within the container; the network interface is bridged with the host. This was unfortunate news to me as well. :)

Using dummynet to change the entire system's network shaping (and requiring sudo) are just required on the host machine for high quality throttling. Not ideal but that's what it is.

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Thanks @Garbee that's very helpful.

@paulirish that makes sense. I think we'll go ahead with a proxy server solution.

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@Garbee would that also intercept DataChannels traffic?

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Thanks, I think that this can be closed now.

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