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.
Previously nghttp2_session_send() and nghttp2_session_mem_send() did
not send 24 bytes client magic byte string (MAGIC). We made
nghttp2_session_recv() and nghttp2_session_mem_recv() process MAGIC by
default, so it is natural to make library send MAGIC as well. This
commit makes nghttp2_session_send() and nghttp2_session_mem_send()
send MAGIC. This commit also replace "connection preface" with
"client magic", since we call MAGIC as "connection preface" but it is
just a part of connection preface. NGHTTP2_CLIENT_CONNECTION_PREFACE
macro was replaced with NGHTTP2_CLIENT_MAGIC. The already deprecated
NGHTTP2_CLIENT_CONNECTION_HEADER macro was removed permanently.
nghttp2_option_set_no_recv_client_preface() was renamed as
nghttp2_option_set_no_recv_client_magic(). NGHTTP2_ERR_BAD_PREFACE
was renamed as NGHTTP2_ERR_BAD_CLIENT_MAGIC.
Currently, we use same number of HTTP/2 sessions per worker with given
backend addresses. New option to specify the number of HTTP/2 session
per worker will follow.
It turns out that writing successfully to network is not enough.
After apparently successful network write, read fails and then we
first know network has been lost (at least my android mobile network).
In this change, we say connection check is successful only when
successful read. We already send PING in this case, so we just wait
PING ACK with short timeout. If timeout has expired, drop connection.
Since waiting for PING ACK could degrade performance for fast reliably
connected network, we decided to disable connection check by default.
Use --backend-http2-connection-check to enable it.
Previously we did not check HTTP semantics and it is left out for
application. Although checking is relatively easy, but they are
scattered and error prone. We have implemented these checks in our
applications and also feel they are tedious. To make application
development a bit easier, this commit adds basic HTTP semantics
validation to library code. We do following checks:
server:
* HEADERS is either request header or trailer header. Other type of
header is disallowed.
client:
* HEADERS is either zero or more non-final response header or final
response header or trailer header. Other type of header is
disallowed.
For both:
* Check mandatory pseudo header fields.
* Make sure that content-length matches the amount of DATA we
received.
If validation fails, RST_STREAM of type PROTOCOL_ERROR is issued.
Previously if HTTP/1 proxy is used for backend connection, we read all
incoming bytes from proxy including response body, which may be part
of HTTP/2 protocol. While investigating this issue, we found that
http_parser_execute() returns 1-less length when we call
http_parser_pause() inside on_headers_complete callback. To
workaround this, we increment the return value by 1. This commit also
fixes possible segmentation fault error, which could be caused by the
lack of stopping libev watcher in disconnect().
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.
For HTTP/1 backend, -b option can be used several times to specify
multiple backend address. HTTP/2 backend does not support multiple
addresses and only uses first address even if multiple addresses are
specified.
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.
Even after on_stream_close_callback, Http2DownstreamConnection is
still alive and upstream keeps sending response to the client. The
consumed bytes are processed normally (data_source_read_callback) and
also we have a code to consume all allocated bytes for
Http2DownstreamConnection object when it is deleted. This means that
we don't need to and should not consume response data in downstream
on_stream_close_callback. If we do, we may get assertion error in
Http2DownstreamConnection::resume_read().
It is not used by library for a while. It could be used to pass
unsupported extension frames to application, but its interface
requires library to buffer entire frame, which we'd like to avoid.
For unsupported extension frames, we will add new callbacks which does
not require buffering if they are required.
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.
To make it possible to add new callbacks without bumping so name, we
decided to hide details of nghttp2_session_callbacks. We provide
setter like functions to set individual callback function.
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.
libnghttp2 will call on_stream_close callback when RST_STREAM is
received. So we can use on_stream_close callback to handle existing
stream, instead of on_frame_recv callback.
nghttpx supports hot deploy feature using signals. The host deploy in
nghttpx is multi step process. First send USR2 signal to nghttpx
process. It will do fork and execute new executable, using same
command-line arguments and environment variables. At this point, both
current and new processes can accept requests. To gracefully shutdown
current process, send QUIT signal to current nghttpx process. When
all existing frontend connections are done, the current process will
exit. At this point, only new nghttpx process exists and serves
incoming requests.
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.
Tatsuhiro Tsujikawa
Lucas Pardue