71 lines
2.1 KiB
Text
71 lines
2.1 KiB
Text
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= websocket SOP
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websocket communication with Fedora apps.
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see-also: `fedmsg-gateway.txt`
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== Contact Information
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Owner::
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Messaging SIG, Fedora Infrastructure Team
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Contact::
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#fedora-apps, #fedora-admin, #fedora-noc
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Servers::
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busgateway01, proxy0*, app0*
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Purpose::
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Expose a websocket server for FI apps to use
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== Description
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WebSocket is a protocol (an extension of HTTP/1.1) by which client web
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browsers can establish full-duplex socket communications with a server
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--the "real-time web".
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In our case, webapps served from app0* and packages0* will include
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javascript code instructing client browsers to establish a second
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connection to our WebSocket server. They point browsers to the following
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addresses:
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production::
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wss://hub.fedoraproject.org:9939
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staging::
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wss://stg.fedoraproject.org:9939
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The websocket server itself is a fedmsg-hub daemon running on
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busgateway01. It is configured to enable its websocket server component
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in the presence of certain configuration values.
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haproxy mediates connections to the fedmsg-hub websocket server daemon.
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An stunnel daemon provides SSL support.
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== Connection Flow
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The connection flow is much the same as in the fedmsg-gateway.txt SOP,
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but is somewhat more complicated.
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"Normal" HTTP requests to our app servers traverse the following chain:
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....
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Client -> apache(proxy01) -> haproxy(proxy01) -> apache(app01)
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....
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The flow for a websocket requests looks something like this:
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....
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Client -> stunnel(proxy01) -> haproxy(proxy01) -> fedmsg-hub(busgateway01)
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....
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stunnel is listening on a public port, negotiates the SSL connection,
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and redirects the connection to haproxy who in turn hands it off to the
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fedmsg-hub websocket server listening on busgateway01.
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At the time of this writing, haproxy does not actually load balance
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zeromq session requests across multiple busgateway0* machines, but there
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is nothing stopping us from adding them. New hosts can be added in
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ansible and pressed from busgateway01's template. Add them to the
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fedmsg-websockets listen in haproxy's config and it should Just Work.
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== RHIT
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We had RHIT open up port 9939 special to proxy01.phx2 for this.
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