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construct/modules/vm_fetch.cc
2018-10-01 14:00:51 -07:00

487 lines
8.4 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
using namespace ircd;
#include "vm_fetch.int.h"
//
// init
//
void
_init()
{
m::vm::fetch::context = ctx::context
{
"fetcher",
128_KiB,
std::bind(&m::vm::fetch::worker),
ctx::context::POST
};
log::debug
{
m::vm::log, "Fetch unit ready."
};
}
void
_fini()
{
log::debug
{
m::vm::log, "Shutting down fetch unit..."
};
m::vm::fetch::context.terminate();
m::vm::fetch::context.join();
log::debug
{
m::vm::log, "Fetch unit complete."
};
}
//
// fetch_phase
//
decltype(m::vm::fetch::hook)
m::vm::fetch::hook
{
enter,
{
{ "_site", "vm.fetch" }
}
};
void
m::vm::fetch::enter(const event &event,
eval &eval)
{
assert(eval.opts);
const auto &opts{*eval.opts};
const m::room::id &room_id{at<"room_id"_>(event)};
int64_t top;
id::event::buf head;
std::tie(head, top, std::ignore) = m::top(std::nothrow, room_id);
if(top < 0 && (opts.head_must_exist || opts.history))
{
const auto &type{at<"type"_>(event)};
if(type == "m.room.member" && membership(event) == "invite")
{
const auto &user_id{at<"state_key"_>(event)};
//m::join(m::room{room_id}, user_id);
}
else if(type != "m.room.create")
throw error
{
fault::STATE, "Found nothing for room %s", string_view{room_id}
};
}
const event::prev prev
{
*eval.event_
};
const auto &prev_events
{
json::get<"prev_events"_>(prev)
};
const size_t &prev_count
{
size(prev_events)
};
for(size_t i(0); i < prev_count; ++i)
{
const auto &prev_id{prev.prev_event(i)};
if(!exists(prev_id))
{
log::warning
{
log, "Missing prev %s in %s in %s",
string_view{prev_id},
json::get<"event_id"_>(*eval.event_),
json::get<"room_id"_>(*eval.event_)
};
}
if(eval.opts->prev_check_exists && !exists(prev_id))
throw error
{
fault::EVENT, "Missing prev event %s", prev_id
};
}
}
//
// API interface
//
m::vm::fetch::request &
m::vm::fetch::fetch(const m::room::id &room_id,
const m::event::id &event_id)
{
auto it
{
fetching.lower_bound(event_id)
};
if(it == end(fetching) || it->event_id != event_id)
it = fetching.emplace_hint(it, room_id, event_id);
else
return const_cast<struct request &>(*it);
auto &request
{
const_cast<struct request &>(*it)
};
request.start();
dock.notify_all();
return request;
}
//
// fetcher
//
decltype(m::vm::fetch::dock)
m::vm::fetch::dock;
decltype(m::vm::fetch::fetching)
m::vm::fetch::fetching;
/// The fetch context is an internal worker which drives the fetch process
/// and then indicates completion to anybody waiting on a fetch. This involves
/// handling errors/timeouts from a fetch attempt and retrying with another
/// server etc.
///
decltype(m::vm::fetch::context)
m::vm::fetch::context;
void
ircd::m::vm::fetch::worker()
try
{
while(1)
{
dock.wait(requesting);
handle();
}
}
catch(const std::exception &e)
{
log::critical
{
"Fetch worker :%s", e.what()
};
}
bool
ircd::m::vm::fetch::handle()
try
{
auto next
{
ctx::when_any(begin(fetching), end(fetching))
};
if(!next.wait(seconds(2), std::nothrow))
return true;
const auto it
{
next.get()
};
if(it == end(fetching))
{
std::cout << "got nil" << std::endl;
return false;
}
auto &request
{
const_cast<struct request &>(*it)
};
if(request.finished || request.eptr)
return true;
request.handle();
return true;
}
catch(const std::exception &e)
{
log::error
{
"Fetch worker :%s", e.what()
};
return true;
}
bool
ircd::m::vm::fetch::requesting()
{
return std::any_of(begin(fetching), end(fetching), []
(const request &request)
{
return !request.finished;
});
}
//
// fetch::request
//
ircd::m::vm::fetch::request::request(const m::room::id &room_id,
const m::event::id &event_id,
const mutable_buffer &buf)
:room_id{room_id}
,event_id{event_id}
,_buf
{
!buf?
unique_buffer<mutable_buffer>{96_KiB}:
unique_buffer<mutable_buffer>{}
}
,buf
{
empty(buf)? _buf: buf
}
{
// Ensure buffer has enough room for a worst-case event, request
// headers and response headers.
assert(size(this->buf) >= 64_KiB + 8_KiB + 8_KiB);
}
void
ircd::m::vm::fetch::request::start()
{
m::v1::event::opts opts;
opts.dynamic = false;
opts.remote = origin?: select_random_origin();
start(std::move(opts));
}
void
ircd::m::vm::fetch::request::start(m::v1::event::opts &&opts)
{
if(!started)
started = ircd::time();
last = ircd::time();
static_cast<m::v1::event &>(*this) =
{
this->event_id, this->buf, std::move(opts)
};
}
ircd::string_view
ircd::m::vm::fetch::request::select_random_origin()
{
const m::room::origins origins
{
room_id
};
// copies randomly selected origin into the attempted set.
const auto closure{[this]
(const string_view &origin)
{
this->select_origin(origin);
}};
// Tests if origin is potentially viable
const auto proffer{[this]
(const string_view &origin)
{
// Don't want to request from myself.
if(my_host(origin))
return false;
// Don't want to use a peer we already tried and failed with.
if(attempted.count(origin))
return false;
// Don't want to use a peer marked with an error by ircd::server
if(ircd::server::errmsg(origin))
return false;
return true;
}};
if(!origins.random(closure, proffer))
throw m::NOT_FOUND
{
"Cannot find any server to fetch %s in %s",
string_view{event_id},
string_view{room_id},
};
return this->origin;
}
ircd::string_view
ircd::m::vm::fetch::request::select_origin(const string_view &origin)
{
const auto iit
{
attempted.emplace(std::string{origin})
};
this->origin = *iit.first;
return this->origin;
}
void
ircd::m::vm::fetch::request::handle()
{
auto &future
{
static_cast<m::v1::event &>(*this)
};
future.wait(); try
{
future.get();
}
catch(...)
{
eptr = std::current_exception();
}
if(!eptr)
finish();
else
retry();
}
void
ircd::m::vm::fetch::request::retry()
try
{
eptr = std::exception_ptr{};
origin = {};
start();
}
catch(...)
{
eptr = std::current_exception();
finish();
}
void
ircd::m::vm::fetch::request::finish()
{
finished = ircd::time();
dock.notify_all();
}
bool
ircd::m::vm::fetch::request::operator()(const request &a,
const request &b)
const
{
return a.event_id < b.event_id;
}
bool
ircd::m::vm::fetch::request::operator()(const request &a,
const string_view &b)
const
{
return a.event_id < b;
}
bool
ircd::m::vm::fetch::request::operator()(const string_view &a,
const request &b)
const
{
return a < b.event_id;
}
//
//
//
extern "C" void
auth_chain_fetch(const m::room::id &room_id,
const m::event::id &event_id,
const net::hostport &remote,
const milliseconds &timeout,
const std::function<bool (const m::event &)> &closure)
{
m::v1::event_auth::opts opts;
opts.remote = remote;
opts.dynamic = true;
const unique_buffer<mutable_buffer> buf
{
16_KiB
};
m::v1::event_auth request
{
room_id, event_id, buf, std::move(opts)
};
request.wait(timeout);
request.get();
const json::array &auth_chain
{
request
};
std::vector<m::event> events{auth_chain.count()};
std::transform(begin(auth_chain), end(auth_chain), begin(events), []
(const json::object &pdu)
{
return m::event{pdu};
});
std::sort(begin(events), end(events));
for(const auto &event : events)
if(!closure(event))
return;
}
extern "C" void
auth_chain_eval(const m::room::id &room_id,
const m::event::id &event_id,
const net::hostport &remote)
{
m::vm::opts opts;
opts.non_conform.set(m::event::conforms::MISSING_PREV_STATE);
opts.non_conform.set(m::event::conforms::MISSING_MEMBERSHIP);
opts.infolog_accept = true;
opts.warnlog |= m::vm::fault::STATE;
opts.warnlog &= ~m::vm::fault::EXISTS;
opts.errorlog &= ~m::vm::fault::STATE;
auth_chain_fetch(room_id, event_id, remote, seconds(30), [&opts]
(const auto &event)
{
m::vm::eval
{
event, opts
};
return true;
});
}