Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

docs: improving websocket docs #8156

Merged
merged 3 commits into from
Sep 9, 2019
Merged

docs: improving websocket docs #8156

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
3cfa147
docs: improving websocket docs
alyssawilk Sep 5, 2019
4dbe38c
reviewer comments
alyssawilk Sep 5, 2019
fa3a7a4
docs build
alyssawilk Sep 5, 2019
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
16 changes: 9 additions & 7 deletions docs/root/intro/arch_overview/http/websocket.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -36,19 +36,21 @@ Note that the statistics for upgrades are all bundled together so WebSocket
:ref:`statistics <config_http_conn_man_stats>` are tracked by stats such as
downstream_cx_upgrades_total and downstream_cx_upgrades_active

Handling H2 hops
^^^^^^^^^^^^^^^^
Handling HTTP/2 hops
^^^^^^^^^^^^^^^^^^^^

Envoy supports tunneling WebSockets over H2 streams for deployments that prefer a uniform
H2 mesh throughout; this enables, for example, a deployment of the form:
While HTTP/2 support for WebSockets is off by default, Envoy does support tunneling WebSockets over
HTTP/2 streams for deployments that prefer a uniform HTTP/2 mesh throughout; this enables, for example,
a deployment of the form:

[Client] ---- HTTP/1.1 ---- [Front Envoy] ---- HTTP/2 ---- [Sidecar Envoy ---- H1 ---- App]

In this case, if a client is for example using WebSocket, we want the Websocket to arrive at the
upstream server functionally intact, which means it needs to traverse the HTTP/2 hop.

This is accomplished via
`extended CONNECT <https://tools.ietf.org/html/rfc8441>`_ support. The
This is accomplished via `extended CONNECT <https://tools.ietf.org/html/rfc8441>`_ support,
turned on by setting :ref:`allow_connect <envoy_api_field_core.Http2ProtocolOptions.allow_connect>`
true at the second layer Envoy. The
WebSocket request will be transformed into an HTTP/2 CONNECT stream, with :protocol header
indicating the original upgrade, traverse the HTTP/2 hop, and be downgraded back into an HTTP/1
WebSocket Upgrade. This same Upgrade-CONNECT-Upgrade transformation will be performed on any
Expand All @@ -57,5 +59,5 @@ Non-WebSocket upgrades are allowed to use any valid HTTP method (i.e. POST) and
upgrade/downgrade mechanism will drop the original method and transform the Upgrade request to
a GET method on the final Envoy-Upstream hop.

Note that the H2 upgrade path has very strict HTTP/1.1 compliance, so will not proxy WebSocket
Note that the HTTP/2 upgrade path has very strict HTTP/1.1 compliance, so will not proxy WebSocket
upgrade requests or responses with bodies.