wireproto: buffer output frames when in half duplex mode
Previously, when told that a response was ready, the server reactor
would instruct the caller to send frames immediately. This was OK
as an initial implementation. But it would not work for half-duplex
connections where the sender can't receive until all data has been
transmitted - such as httplib based clients.
In this commit, we teach the reactor that output frames should
be buffered until end of input is seen. This required a new
event to inform the reactor of end of input. The result from that
event will instruct the consumer to send all buffered frames.
The HTTP server is buffered by default.
This change effectively hides the complexity of buffering within
the reactor so that transports need not be concerned about it.
This helps keep the transports "dumb" and will make implementing
multiple requests-responses per atomic exchange (like an HTTP
request) much simpler.
Differential Revision: https://phab.mercurial-scm.org/D2860
$ HTTPV2=exp-http-v2-0001
$ MEDIATYPE=application/mercurial-exp-framing-0001
$ send() {
> hg --verbose debugwireproto --peer raw http://$LOCALIP:$HGPORT/
> }
$ cat > dummycommands.py << EOF
> from mercurial import wireprototypes, wireproto
> @wireproto.wireprotocommand('customreadonly', permission='pull')
> def customreadonly(repo, proto):
> return wireprototypes.bytesresponse(b'customreadonly bytes response')
> @wireproto.wireprotocommand('customreadwrite', permission='push')
> def customreadwrite(repo, proto):
> return wireprototypes.bytesresponse(b'customreadwrite bytes response')
> EOF
$ cat >> $HGRCPATH << EOF
> [extensions]
> dummycommands = $TESTTMP/dummycommands.py
> EOF
$ hg init server
$ cat > server/.hg/hgrc << EOF
> [experimental]
> web.apiserver = true
> EOF
$ hg -R server serve -p $HGPORT -d --pid-file hg.pid
$ cat hg.pid > $DAEMON_PIDS
HTTP v2 protocol not enabled by default
$ send << EOF
> httprequest GET api/$HTTPV2
> user-agent: test
> EOF
using raw connection to peer
s> GET /api/exp-http-v2-0001 HTTP/1.1\r\n
s> Accept-Encoding: identity\r\n
s> user-agent: test\r\n
s> host: $LOCALIP:$HGPORT\r\n (glob)
s> \r\n
s> makefile('rb', None)
s> HTTP/1.1 404 Not Found\r\n
s> Server: testing stub value\r\n
s> Date: $HTTP_DATE$\r\n
s> Content-Type: text/plain\r\n
s> Content-Length: 33\r\n
s> \r\n
s> API exp-http-v2-0001 not enabled\n
Restart server with support for HTTP v2 API
$ killdaemons.py
$ cat > server/.hg/hgrc << EOF
> [experimental]
> web.apiserver = true
> web.api.http-v2 = true
> EOF
$ hg -R server serve -p $HGPORT -d --pid-file hg.pid
$ cat hg.pid > $DAEMON_PIDS
Request to unknown command yields 404
$ send << EOF
> httprequest POST api/$HTTPV2/ro/badcommand
> user-agent: test
> EOF
using raw connection to peer
s> POST /api/exp-http-v2-0001/ro/badcommand HTTP/1.1\r\n
s> Accept-Encoding: identity\r\n
s> user-agent: test\r\n
s> host: $LOCALIP:$HGPORT\r\n (glob)
s> \r\n
s> makefile('rb', None)
s> HTTP/1.1 404 Not Found\r\n
s> Server: testing stub value\r\n
s> Date: $HTTP_DATE$\r\n
s> Content-Type: text/plain\r\n
s> Content-Length: 42\r\n
s> \r\n
s> unknown wire protocol command: badcommand\n
GET to read-only command yields a 405
$ send << EOF
> httprequest GET api/$HTTPV2/ro/customreadonly
> user-agent: test
> EOF
using raw connection to peer
s> GET /api/exp-http-v2-0001/ro/customreadonly HTTP/1.1\r\n
s> Accept-Encoding: identity\r\n
s> user-agent: test\r\n
s> host: $LOCALIP:$HGPORT\r\n (glob)
s> \r\n
s> makefile('rb', None)
s> HTTP/1.1 405 Method Not Allowed\r\n
s> Server: testing stub value\r\n
s> Date: $HTTP_DATE$\r\n
s> Allow: POST\r\n
s> Content-Length: 30\r\n
s> \r\n
s> commands require POST requests
Missing Accept header results in 406
$ send << EOF
> httprequest POST api/$HTTPV2/ro/customreadonly
> user-agent: test
> EOF
using raw connection to peer
s> POST /api/exp-http-v2-0001/ro/customreadonly HTTP/1.1\r\n
s> Accept-Encoding: identity\r\n
s> user-agent: test\r\n
s> host: $LOCALIP:$HGPORT\r\n (glob)
s> \r\n
s> makefile('rb', None)
s> HTTP/1.1 406 Not Acceptable\r\n
s> Server: testing stub value\r\n
s> Date: $HTTP_DATE$\r\n
s> Content-Type: text/plain\r\n
s> Content-Length: 85\r\n
s> \r\n
s> client MUST specify Accept header with value: application/mercurial-exp-framing-0001\n
Bad Accept header results in 406
$ send << EOF
> httprequest POST api/$HTTPV2/ro/customreadonly
> accept: invalid
> user-agent: test
> EOF
using raw connection to peer
s> POST /api/exp-http-v2-0001/ro/customreadonly HTTP/1.1\r\n
s> Accept-Encoding: identity\r\n
s> accept: invalid\r\n
s> user-agent: test\r\n
s> host: $LOCALIP:$HGPORT\r\n (glob)
s> \r\n
s> makefile('rb', None)
s> HTTP/1.1 406 Not Acceptable\r\n
s> Server: testing stub value\r\n
s> Date: $HTTP_DATE$\r\n
s> Content-Type: text/plain\r\n
s> Content-Length: 85\r\n
s> \r\n
s> client MUST specify Accept header with value: application/mercurial-exp-framing-0001\n
Bad Content-Type header results in 415
$ send << EOF
> httprequest POST api/$HTTPV2/ro/customreadonly
> accept: $MEDIATYPE
> user-agent: test
> content-type: badmedia
> EOF
using raw connection to peer
s> POST /api/exp-http-v2-0001/ro/customreadonly HTTP/1.1\r\n
s> Accept-Encoding: identity\r\n
s> accept: application/mercurial-exp-framing-0001\r\n
s> content-type: badmedia\r\n
s> user-agent: test\r\n
s> host: $LOCALIP:$HGPORT\r\n (glob)
s> \r\n
s> makefile('rb', None)
s> HTTP/1.1 415 Unsupported Media Type\r\n
s> Server: testing stub value\r\n
s> Date: $HTTP_DATE$\r\n
s> Content-Type: text/plain\r\n
s> Content-Length: 88\r\n
s> \r\n
s> client MUST send Content-Type header with value: application/mercurial-exp-framing-0001\n
Request to read-only command works out of the box
$ send << EOF
> httprequest POST api/$HTTPV2/ro/customreadonly
> accept: $MEDIATYPE
> content-type: $MEDIATYPE
> user-agent: test
> frame command-name eos customreadonly
> EOF
using raw connection to peer
s> POST /api/exp-http-v2-0001/ro/customreadonly HTTP/1.1\r\n
s> Accept-Encoding: identity\r\n
s> accept: application/mercurial-exp-framing-0001\r\n
s> content-type: application/mercurial-exp-framing-0001\r\n
s> user-agent: test\r\n
s> content-length: 18\r\n
s> host: $LOCALIP:$HGPORT\r\n (glob)
s> \r\n
s> \x0e\x00\x00\x11customreadonly
s> makefile('rb', None)
s> HTTP/1.1 200 OK\r\n
s> Server: testing stub value\r\n
s> Date: $HTTP_DATE$\r\n
s> Content-Type: application/mercurial-exp-framing-0001\r\n
s> Transfer-Encoding: chunked\r\n
s> \r\n
s> 21\r\n
s> \x1d\x00\x00Bcustomreadonly bytes response
s> \r\n
s> 0\r\n
s> \r\n
Request to read-write command fails because server is read-only by default
GET to read-write request yields 405
$ send << EOF
> httprequest GET api/$HTTPV2/rw/customreadonly
> user-agent: test
> EOF
using raw connection to peer
s> GET /api/exp-http-v2-0001/rw/customreadonly HTTP/1.1\r\n
s> Accept-Encoding: identity\r\n
s> user-agent: test\r\n
s> host: $LOCALIP:$HGPORT\r\n (glob)
s> \r\n
s> makefile('rb', None)
s> HTTP/1.1 405 Method Not Allowed\r\n
s> Server: testing stub value\r\n
s> Date: $HTTP_DATE$\r\n
s> Allow: POST\r\n
s> Content-Length: 30\r\n
s> \r\n
s> commands require POST requests
Even for unknown commands
$ send << EOF
> httprequest GET api/$HTTPV2/rw/badcommand
> user-agent: test
> EOF
using raw connection to peer
s> GET /api/exp-http-v2-0001/rw/badcommand HTTP/1.1\r\n
s> Accept-Encoding: identity\r\n
s> user-agent: test\r\n
s> host: $LOCALIP:$HGPORT\r\n (glob)
s> \r\n
s> makefile('rb', None)
s> HTTP/1.1 405 Method Not Allowed\r\n
s> Server: testing stub value\r\n
s> Date: $HTTP_DATE$\r\n
s> Allow: POST\r\n
s> Content-Length: 30\r\n
s> \r\n
s> commands require POST requests
SSL required by default
$ send << EOF
> httprequest POST api/$HTTPV2/rw/customreadonly
> user-agent: test
> EOF
using raw connection to peer
s> POST /api/exp-http-v2-0001/rw/customreadonly HTTP/1.1\r\n
s> Accept-Encoding: identity\r\n
s> user-agent: test\r\n
s> host: $LOCALIP:$HGPORT\r\n (glob)
s> \r\n
s> makefile('rb', None)
s> HTTP/1.1 403 ssl required\r\n
s> Server: testing stub value\r\n
s> Date: $HTTP_DATE$\r\n
s> Content-Length: 17\r\n
s> \r\n
s> permission denied
Restart server to allow non-ssl read-write operations
$ killdaemons.py
$ cat > server/.hg/hgrc << EOF
> [experimental]
> web.apiserver = true
> web.api.http-v2 = true
> [web]
> push_ssl = false
> allow-push = *
> EOF
$ hg -R server serve -p $HGPORT -d --pid-file hg.pid -E error.log
$ cat hg.pid > $DAEMON_PIDS
Authorized request for valid read-write command works
$ send << EOF
> httprequest POST api/$HTTPV2/rw/customreadonly
> user-agent: test
> accept: $MEDIATYPE
> content-type: $MEDIATYPE
> frame command-name eos customreadonly
> EOF
using raw connection to peer
s> POST /api/exp-http-v2-0001/rw/customreadonly HTTP/1.1\r\n
s> Accept-Encoding: identity\r\n
s> accept: application/mercurial-exp-framing-0001\r\n
s> content-type: application/mercurial-exp-framing-0001\r\n
s> user-agent: test\r\n
s> content-length: 18\r\n
s> host: $LOCALIP:$HGPORT\r\n (glob)
s> \r\n
s> \x0e\x00\x00\x11customreadonly
s> makefile('rb', None)
s> HTTP/1.1 200 OK\r\n
s> Server: testing stub value\r\n
s> Date: $HTTP_DATE$\r\n
s> Content-Type: application/mercurial-exp-framing-0001\r\n
s> Transfer-Encoding: chunked\r\n
s> \r\n
s> 21\r\n
s> \x1d\x00\x00Bcustomreadonly bytes response
s> \r\n
s> 0\r\n
s> \r\n
Authorized request for unknown command is rejected
$ send << EOF
> httprequest POST api/$HTTPV2/rw/badcommand
> user-agent: test
> accept: $MEDIATYPE
> EOF
using raw connection to peer
s> POST /api/exp-http-v2-0001/rw/badcommand HTTP/1.1\r\n
s> Accept-Encoding: identity\r\n
s> accept: application/mercurial-exp-framing-0001\r\n
s> user-agent: test\r\n
s> host: $LOCALIP:$HGPORT\r\n (glob)
s> \r\n
s> makefile('rb', None)
s> HTTP/1.1 404 Not Found\r\n
s> Server: testing stub value\r\n
s> Date: $HTTP_DATE$\r\n
s> Content-Type: text/plain\r\n
s> Content-Length: 42\r\n
s> \r\n
s> unknown wire protocol command: badcommand\n
debugreflect isn't enabled by default
$ send << EOF
> httprequest POST api/$HTTPV2/ro/debugreflect
> user-agent: test
> EOF
using raw connection to peer
s> POST /api/exp-http-v2-0001/ro/debugreflect HTTP/1.1\r\n
s> Accept-Encoding: identity\r\n
s> user-agent: test\r\n
s> host: $LOCALIP:$HGPORT\r\n (glob)
s> \r\n
s> makefile('rb', None)
s> HTTP/1.1 404 Not Found\r\n
s> Server: testing stub value\r\n
s> Date: $HTTP_DATE$\r\n
s> Content-Type: text/plain\r\n
s> Content-Length: 34\r\n
s> \r\n
s> debugreflect service not available
Restart server to get debugreflect endpoint
$ killdaemons.py
$ cat > server/.hg/hgrc << EOF
> [experimental]
> web.apiserver = true
> web.api.debugreflect = true
> web.api.http-v2 = true
> [web]
> push_ssl = false
> allow-push = *
> EOF
$ hg -R server serve -p $HGPORT -d --pid-file hg.pid -E error.log
$ cat hg.pid > $DAEMON_PIDS
Command frames can be reflected via debugreflect
$ send << EOF
> httprequest POST api/$HTTPV2/ro/debugreflect
> accept: $MEDIATYPE
> content-type: $MEDIATYPE
> user-agent: test
> frame command-name have-args command1
> frame command-argument 0 \x03\x00\x04\x00fooval1
> frame command-argument eoa \x04\x00\x03\x00bar1val
> EOF
using raw connection to peer
s> POST /api/exp-http-v2-0001/ro/debugreflect HTTP/1.1\r\n
s> Accept-Encoding: identity\r\n
s> accept: application/mercurial-exp-framing-0001\r\n
s> content-type: application/mercurial-exp-framing-0001\r\n
s> user-agent: test\r\n
s> content-length: 42\r\n
s> host: $LOCALIP:$HGPORT\r\n (glob)
s> \r\n
s> \x08\x00\x00\x12command1\x0b\x00\x00 \x03\x00\x04\x00fooval1\x0b\x00\x00"\x04\x00\x03\x00bar1val
s> makefile('rb', None)
s> HTTP/1.1 200 OK\r\n
s> Server: testing stub value\r\n
s> Date: $HTTP_DATE$\r\n
s> Content-Type: text/plain\r\n
s> Content-Length: 310\r\n
s> \r\n
s> received: 1 2 command1\n
s> ["wantframe", {"state": "command-receiving-args"}]\n
s> received: 2 0 \x03\x00\x04\x00fooval1\n
s> ["wantframe", {"state": "command-receiving-args"}]\n
s> received: 2 2 \x04\x00\x03\x00bar1val\n
s> ["runcommand", {"args": {"bar1": "val", "foo": "val1"}, "command": "command1", "data": null}]\n
s> received: <no frame>\n
s> {"action": "noop"}
$ cat error.log