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.
This commit changes nghttpx's mruby script handling. Previously we
have 2 options to specify the mruby script file to be run on request
and on response. Now they are merged into 1 option, namely
--mruby-file. It now must return object. On request, the object's
on_req(env) method is invoked with env object. Similarly, on
response, the object's on_resp(env) method is invoked. The
specification of Env object has not changed.
The control process handles signals, reads configuration, reads
private keys, and bind port (which may be privileged one). It never
drop privileges, so that it can execute new binary with the same
privilege. It forks worker process. The worker process handles all
incoming connections. It drops privilege.
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.
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.
When same SSL_CTX is used by multiple thread simultaneously we have to
setup some number of mutex locks for it. We could not check how this
locking affects scalability since we have 4 cores at best in our
development machine. Good side of sharing SSL_CTX across threads is
we can share session ID pool.
If --tls-ctx-per-worker is enabled, SSL_CTX is created per thread
basis and we can eliminate mutex locks. The downside is session ID is
no longer shared, which means if session ID generated by one thread
cannot be acceptable by another thread. But we have now session
ticket enabled and its keys are shared by all threads.
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.
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.
The existing options --{read,write}-{rate,burst} are per connection.
The new options --worker-{read,write}-{rate,burst} are per worker
thread, which is overall rate limit of all connections worker handles.
In client mode, now SPDY connection to the backend server is
established per thread. The frontend connections which belong to the
same thread share the SPDY connection.
To distinguish the to-be-installed programs and non-installable
example source code, the former programs, spdycat, spdydyd and shrpx,
were moved to src directory. spdynative was removed from Makefile
because it does not appeal to any users much.
Tatsuhiro Tsujikawa