Previously, we use one Http2Session object per DownstreamAddrGroup.
This is not flexible, and we have to provision how many HTTP/2
connection is required in advance. The new strategy is we add
Http2Session object on demand. We measure the number of attached
downstream connection object and server advertised concurrency limit.
As long as former is smaller than the latter, we attach new downstream
connection to it. Once the limit is reached, we create new
Http2Session object. If the number lowers the limit, we start to
share Http2Session object again.
Header field related functions are now gathered into FieldStore class.
This commit only handles request. Subsequent commit will do the same
thing for response.
We modeled max_header_fields and header_field_buffer limit from Apache
configuration directives. In Apache, they are only applied to request
header fields, while we applied both request and response. Since
nghttpx is used as reverse proxy and backend server is relatively
"trusted", this commit removes the application to response header
fields.
This commits enables HTTP/2 server push from HTTP/2 backend to be
relayed to HTTP/2 frontend. To use this feature, --http2-bridge or
--client is required. Server push via Link header field contiues to
work.
This is a regression when we introduced SSL/TLS session resumption in
HTTP/2 backend. Before the introduction of session resumption,
conn_.tls.ssl is always nullptr when connection is made to proxy. But
we have to keep conn_.tls.ssl to enable session resumption, so our
code breaks when it is reused. This commit fixes this issue.
See GH-421
To achieve host-path backend routing, we changed behaviour of
--backend-http2-connections-per-worker. It now sets the number of
HTTP/2 physical connections per pattern group if pattern is used in -b
option.
Fixes GH-292
-b option syntax is now <HOST>,<PORT>[;<PATTERN>[:...]]. The optional
<PATTERN>s specify the request host and path it is used for. The
<PATTERN> can contain path, host + path or host. The matching rule is
closely designed to ServeMux in Go programming language.
Tatsuhiro Tsujikawa
Lucas Pardue