It is very hard to support multiple protocols in backend while
retaining multiple mode settings. Therefore, we dropped modes except
for default and HTTP/2 proxy mode. The other removed modes can be
emulated using combinations of options. Now the backend connection is
not encrypted by default. To enable encryption on backend connection,
use --backend-tls option.
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.
It seems that using ev_feed_event to signal write operation is much
faster than starting watcher. This is probably due to the fact that
we don't need to wait in event loop. The same thing cannot be done in
HTTP/2 frontend, since this will raise write operation for each stream
HEADER/DATA write, which leads to very small packets, hurting
performance. Interestingly, HTTP/1 frontend also suffers the same
performance hit.
This change is required to show path attribute to mruby script. It is
desirable to construct URI from parts. Just checking method and path
is "*" is awkward.
Tatsuhiro Tsujikawa
Lucas Pardue