Previously when requests are issued to HTTP/2 downstream connection,
but it turns out that connection is down, handlers of those requests
are deleted. In some situations, we only know connection is down when
we write something to network, so we'd like to handle this kind of
situation in more robust manner. In this change, certain seconds
passed after last network activity, we first issue PING frame to
downstream connection before issuing new HTTP request. If writing
PING frame is failed, it means connection was lost. In this case,
instead of deleting handler, pending requests are migrated to new
HTTP2/ downstream connection, so that it can continue without
affecting upstream connection.
This commit adds functionality to customize access logging format in
nghttpx. The format variables are inspired by nginx. The default
format is combined format.
With the combination of HTTP/1 upstream and HTTP/2 downstream,
downstream tells SHRPX_NO_BUFFER while connecting to the backend
server. Previously, we did not call upstream resume_read and upload
was blocked. This commit now calls upstream resume_read to unblock.
This commit also remove pending output buffer size of Http2Session
when calculating downstream connection's buffer is full. This is
desirable since we only operate resume_read by stream basis.
Previously we empties request headers after they are sent to
downstream in order to free memory. But it turns out that we use
request headers when rewriting location header response field. Also
user reported that request headers are useful to add new features.
This commits defers the deletion of request headers to the point when
response headers are deleted (which is after response headers are sent
to upstream client).
h2-14 now allows extensions to define new error codes. To allow
application callback to access such error codes, we uses uint32_t as
error_code type for structs and function parameters. Previously we
treated unknown error code as INTERNAL_ERROR, but this change removes
this and unknown error code is passed to application callback as is.
Previously we only update consumed flow control window when number of
bytes read in nghttp2 and spdylay callback is 0. Now we notify
nghttp2 library the consumed bytes even if number of bytes read > 0.
This change also uses newly added spdylay_session_consume() API, so we
require spdylay >= 1.3.0.
Reworked no automatic WINDOW_UPDATE feature. We added new API
nghttp2_session_consume() which tells the library how many bytes are
consumed by the application. Instead of submitting WINDOW_UPDATE by
the application, the library is now responsible to submit
WINDOW_UPDATE based on consumed bytes. This is more reliable method,
since it enables us to properly send WINDOW_UPDATE for stream and
connection individually. The previous implementation of nghttpx had
broken connection window management.
Now concatenating header values with 0x00 as delimiter is not
necessary because HPACK reference set is removed and the order of
header field fed into HPACK encoder is preserved when they are
decoded.
This change rewrites logging system of nghttpx. Previously access log
and error log are written to stderr or syslog and there was no option
to change stderr to something else. With this change, file path of
access log and error log can be configured separately and logging to
regular file is now added. To support rotating log, if SIGUSR1 signal
is received by nghttpx, it closes the current log files and reopen it
with the same name. The format of access log is changed and has same
look of apache's. But not all columns are not supported yet.
We thought that this kind of rewrite can be achieved by the configuration
of the backend severs, but in some configuration, however, it may get
complicated. So we decided to implement at least location rewrite in
nghttpx.
This commit also contains a fix to the bug which prevents the http2
backend request from concatenating header fields with the same value.
Tatsuhiro Tsujikawa
Lucas Pardue