App Platform: Http/2 Support

Posted on October 13, 2020

Heya -

Tried to deploy a gRPC application with App Platform the other day, and found that calls would hang. My naïve guess is that HTTP/2 is unsupported.

Is that the case, or is http/2 expected to work? If not, any plans to add that support?

Thanks!

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Cody Baker

October 13, 2020

While the App Platform may express your application as HTTP/2 in connections from your end-users to our edge gateways, connections from our edge to your application are currently always made using plaintext HTTP.

HTTP/2 must be negotiated via ALPN extensions on a TLS encrypted connection. This means that in order to support HTTP/2 your application server would need to listen as a TLS server with keys and certificates recognized by our edge gateways. Offering this functionality in the future would require either both our router and your application explicitly enable h2c (which is not widely supported), OR injecting a key/certificate pair into the application. Neither option offers a gentle fallback or is broadly standardized. We may implement this functionality in the future if standardization improves, or the functionality is frequently requested.