Re: [tarantool-patches] [PATCH 0/5] session: introduce box.session.push

["v.shpilevoy@tarantool.org" <v.shpilevoy@tarantool.org>]

Sorry, forgot a description.

Box.session.push() allows to send a message to a client with no
finishing a main request. It means, that a client can split a big
response in several pushes, or send notifications from a long
polling request.

Tarantool now supports two push types: via text protocol and via
binary protocol. Text pushes are needed mainly for printing,
logging and all other stdout output, written on a host side from
a client console connection. Text protocol push message contains
"push:" prefix followed by a YAML formatted text, where as a final
response always has '---' prefix. To catch pushed messages client
uses console.connect() on_push option, which takes a function
with a single argument - message.

IProto message is encoded just like a regular response, but instead
of IPROTO_DATA it has IPROTO_PUSH with a single element - pushed
MessagePack encoded data.

Text push is trivial - it is just blocking write into a socket with
a prefix. Binary push is more complex.
    
TX thread to notify IProto thread about new data in obuf sends a
message 'push_msg'. IProto thread, got this message, notifies libev
about new data, and then sends 'push_msg' back with updated write
position. TX thread, received the message back, updates its version
of a write position. If IProto do not send a write position, then
TX would write to the same obuf again and again, because it can not
know that IProto already flushed another obuf.

To avoid multiple 'push_msg' in fly between IProto and TX, the only
one 'push_msg' per connection is used. To deliver pushes, appeared
when 'push_msg' was in fly, TX thread sets a flag every time when
sees, that 'push_msg' is sent, and there is a new push. When
'push_msg' returns, it checks this flag, and if it is set, then the
IProto is notified again.

> 19 марта 2018 г., в 16:34, Vladislav Shpilevoy <v.shpilevoy@tarantool.org> написал(а):
> 
> Branch: http://github.com/tarantool/tarantool/tree/gh-2677-box-session-push
> Issue: https://github.com/tarantool/tarantool/issues/2677
> 
> Vladislav Shpilevoy (5):
>  session: forbid creation from Lua binary and applier sessions
>  lua: port console yaml formatting to C
>  Remove empty function declaration
>  session: introduce session_owner
>  session: introduce box.session.push
> 
> src/box/applier.cc                       |   4 +-
> src/box/authentication.cc                |   4 +-
> src/box/authentication.h                 |   3 +-
> src/box/box.cc                           |   4 +-
> src/box/box.h                            |   2 +-
> src/box/iproto.cc                        | 321 +++++++++++++++++++++++----
> src/box/iproto_constants.c               |   3 +-
> src/box/iproto_constants.h               |   8 +
> src/box/lua/call.c                       |   1 +
> src/box/lua/console.c                    |  42 ++++
> src/box/lua/console.h                    |   8 +
> src/box/lua/console.lua                  |  40 +---
> src/box/lua/net_box.c                    |  37 ++++
> src/box/lua/net_box.lua                  |  97 ++++++--
> src/box/lua/session.c                    | 252 ++++++++++++++++++++-
> src/box/port.c                           |   7 +
> src/box/port.h                           |  15 ++
> src/box/session.cc                       |  86 +++++++-
> src/box/session.h                        | 106 +++++++--
> src/box/vinyl.c                          |   3 +-
> src/box/xrow.c                           |  40 +++-
> src/box/xrow.h                           |  26 ++-
> src/fio.c                                |  12 +
> src/fio.h                                |  16 ++
> src/lua/socket.h                         |   2 -
> test/app-tap/console.test.lua            |   9 +-
> test/box-tap/session.test.lua            |  12 +-
> test/box/net.box.result                  |   2 +-
> test/box/net.box.test.lua                |   2 +-
> test/box/push.result                     | 364 +++++++++++++++++++++++++++++++
> test/box/push.test.lua                   | 163 ++++++++++++++
> test/replication/before_replace.result   |  14 ++
> test/replication/before_replace.test.lua |  11 +
> third_party/lua-yaml/lyaml.cc            |   9 +-
> third_party/lua-yaml/lyaml.h             |   3 +
> 35 files changed, 1576 insertions(+), 152 deletions(-)
> create mode 100644 test/box/push.result
> create mode 100644 test/box/push.test.lua
> 
> -- 
> 2.14.3 (Apple Git-98)
> 
>