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-implement long polling support on reserve status (but not yet in C client library)

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This commit is contained in:
Christian Grothoff 2021-08-22 00:12:18 +02:00
parent 9ad3469f07
commit 10f9272e45
No known key found for this signature in database
GPG Key ID: 939E6BE1E29FC3CC
6 changed files with 313 additions and 33 deletions
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2
contrib/gana

@ -1 +1 @@
Subproject commit 2e967c48b395a3edb85982e2e349cb82e76dcb27
Subproject commit efb2a1fd64e17159c56ff3674083837b5a657a64

26
src/exchange/taler-exchange-httpd.c
View File

@ -1430,8 +1430,14 @@ run_single_request (void)
}
MHD_run (mhd);
}
TEH_resume_keys_requests (true);
MHD_stop_daemon (mhd);
{
MHD_socket sock = MHD_quiesce_daemon (mhd);
TEH_resume_keys_requests (true);
TEH_reserves_get_cleanup ();
MHD_stop_daemon (mhd);
GNUNET_break (0 == close (sock));
}
mhd = NULL;
if (cld != waitpid (cld,
&status,
@ -1494,8 +1500,15 @@ run_main_loop (int fh,
{
case GNUNET_OK:
case GNUNET_SYSERR:
TEH_resume_keys_requests (true);
MHD_stop_daemon (mhd);
{
MHD_socket sock = MHD_quiesce_daemon (mhd);
TEH_resume_keys_requests (true);
TEH_reserves_get_cleanup ();
MHD_stop_daemon (mhd);
GNUNET_break (0 == close (sock));
}
mhd = NULL;
break;
case GNUNET_NO:
{
@ -1507,7 +1520,9 @@ run_main_loop (int fh,
flags = fcntl (sock, F_GETFD);
GNUNET_assert (-1 != flags);
flags &= ~FD_CLOEXEC;
GNUNET_assert (-1 != fcntl (sock, F_SETFD, flags));
GNUNET_assert (-1 != fcntl (sock,
F_SETFD,
flags));
chld = fork ();
if (-1 == chld)
{
@ -1551,6 +1566,7 @@ run_main_loop (int fh,
sleep (1);
/* Now we're really done, practice clean shutdown */
TEH_resume_keys_requests (true);
TEH_reserves_get_cleanup ();
MHD_stop_daemon (mhd);
}
break;

176
src/exchange/taler-exchange-httpd_reserves_get.c
View File

@ -1,6 +1,6 @@
/*
This file is part of TALER
Copyright (C) 2014-2020 Taler Systems SA
Copyright (C) 2014-2021 Taler Systems SA
TALER is free software; you can redistribute it and/or modify it under the
terms of the GNU Affero General Public License as published by the Free Software
@ -25,6 +25,7 @@
#include <jansson.h>
#include "taler_mhd_lib.h"
#include "taler_json_lib.h"
#include "taler_dbevents.h"
#include "taler-exchange-httpd_reserves_get.h"
#include "taler-exchange-httpd_responses.h"
@ -49,25 +50,113 @@ struct ReservePoller
*/
struct MHD_Connection *connection;
/**
* Entry in the timeout heap.
*/
struct GNUNET_CONTAINER_HeapNode *hn;
/**
* Subscription for the database event we are
* waiting for.
*/
struct GNUNET_DB_EventHandler *eh;
struct TALER_EXCHANGEDB_EventHandler *eh;
/**
* When will this request time out?
*/
struct GNUNET_TIME_Absolute timeout;
/**
* True if we are still suspended.
*/
bool suspended;
};
/**
* Head of list of requests in long polling.
*/
static struct ReservePoller *rp_head;
/**
* Tail of list of requests in long polling.
*/
static struct ReservePoller *rp_tail;
void
TEH_reserves_get_cleanup ()
{
struct ReservePoller *rp;
while (NULL != (rp = rp_head))
{
GNUNET_CONTAINER_DLL_remove (rp_head,
rp_tail,
rp);
if (rp->suspended)
{
rp->suspended = false;
MHD_resume_connection (rp->connection);
}
}
}
/**
* Function called once a connection is done to
* clean up the `struct ReservePoller` state.
*
* @param rc context to clean up for
*/
static void
rp_cleanup (struct TEH_RequestContext *rc)
{
struct ReservePoller *rp = rc->rh_ctx;
if (NULL != rp->eh)
{
TEH_plugin->event_listen_cancel (TEH_plugin->cls,
rp->eh);
rp->eh = NULL;
}
GNUNET_free (rp);
}
/**
* Function called on events received from Postgres.
* Wakes up long pollers.
*
* @param cls the `struct TEH_RequestContext *`
* @param extra additional event data provided
* @param extra_size number of bytes in @a extra
*/
static void
db_event_cb (void *cls,
const void *extra,
size_t extra_size)
{
struct TEH_RequestContext *rc = cls;
struct ReservePoller *rp = rc->rh_ctx;
struct GNUNET_AsyncScopeSave old_scope;
(void) extra;
(void) extra_size;
if (NULL == rp)
return; /* event triggered while main transaction
was still running */
if (! rp->suspended)
return; /* might get multiple wake-up events */
rp->suspended = false;
GNUNET_async_scope_enter (&rc->async_scope_id,
&old_scope);
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Resuming from long-polling on reserve\n");
GNUNET_CONTAINER_DLL_remove (rp_head,
rp_tail,
rp);
MHD_resume_connection (rp->connection);
GNUNET_async_scope_restore (&old_scope);
}
/**
* Send reserve history to client.
*
@ -157,6 +246,8 @@ TEH_handler_reserves_get (struct TEH_RequestContext *rc,
{
struct ReserveHistoryContext rsc;
MHD_RESULT mhd_ret;
struct GNUNET_TIME_Relative timeout;
struct TALER_EXCHANGEDB_EventHandler *eh = NULL;
if (GNUNET_OK !=
GNUNET_STRINGS_string_to_data (args[0],
@ -170,6 +261,47 @@ TEH_handler_reserves_get (struct TEH_RequestContext *rc,
TALER_EC_MERCHANT_GENERIC_RESERVE_PUB_MALFORMED,
args[0]);
}
{
const char *long_poll_timeout_ms;
long_poll_timeout_ms
= MHD_lookup_connection_value (rc->connection,
MHD_GET_ARGUMENT_KIND,
"timeout_ms");
if (NULL != long_poll_timeout_ms)
{
unsigned int timeout_ms;
char dummy;
if (1 != sscanf (long_poll_timeout_ms,
"%u%c",
&timeout_ms,
&dummy))
{
GNUNET_break_op (0);
return TALER_MHD_reply_with_error (rc->connection,
MHD_HTTP_BAD_REQUEST,
TALER_EC_GENERIC_PARAMETER_MALFORMED,
"timeout_ms (must be non-negative number)");
}
timeout = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS,
timeout_ms);
}
}
if (! GNUNET_TIME_relative_is_zero (timeout))
{
struct TALER_ReserveEventP rep = {
.header.size = htons (sizeof (rep)),
.header.type = htons (TALER_DBEVENT_EXCHANGE_RESERVE_INCOMING),
.reserve_pub = rsc.reserve_pub
};
eh = TEH_plugin->event_listen (TEH_plugin->cls,
timeout,
&rep.header,
&db_event_cb,
rc);
}
rsc.rh = NULL;
if (GNUNET_OK !=
TEH_DB_run_transaction (rc->connection,
@ -178,13 +310,33 @@ TEH_handler_reserves_get (struct TEH_RequestContext *rc,
&reserve_history_transaction,
&rsc))
return mhd_ret;
/* generate proper response */
if (NULL == rsc.rh)
return TALER_MHD_reply_with_error (rc->connection,
MHD_HTTP_NOT_FOUND,
TALER_EC_EXCHANGE_RESERVES_GET_STATUS_UNKNOWN,
args[0]);
{
struct ReservePoller *rp = rc->rh_ctx;
if ( (NULL != rp) ||
(GNUNET_TIME_relative_is_zero (timeout)) )
{
return TALER_MHD_reply_with_error (rc->connection,
MHD_HTTP_NOT_FOUND,
TALER_EC_EXCHANGE_RESERVES_GET_STATUS_UNKNOWN,
args[0]);
}
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Long-polling on reserve for %s\n",
GNUNET_STRINGS_relative_time_to_string (timeout,
GNUNET_YES));
rp = GNUNET_new (struct ReservePoller);
rp->connection = rc->connection;
rp->timeout = GNUNET_TIME_relative_to_absolute (timeout);
rp->eh = eh;
rc->rh_ctx = rp;
rc->rh_cleaner = &rp_cleanup;
rp->suspended = true;
MHD_suspend_connection (rc->connection);
return MHD_YES;
}
mhd_ret = reply_reserve_history_success (rc->connection,
rsc.rh);
TEH_plugin->free_reserve_history (TEH_plugin->cls,

9
src/exchange/taler-exchange-httpd_reserves_get.h
View File

@ -27,6 +27,15 @@
#include "taler-exchange-httpd.h"
/**
* Shutdown reserves-get subsystem. Resumes all
* suspended long-polling clients and cleans up
* data structures.
*/
void
TEH_reserves_get_cleanup (void);
/**
* Handle a GET "/reserves/" request. Parses the
* given "reserve_pub" in @a args (which should contain the

102
src/exchangedb/plugin_exchangedb_postgres.c
View File

@ -109,6 +109,39 @@ struct TALER_EXCHANGEDB_Session
};
/**
* Event registration record.
*/
struct TALER_EXCHANGEDB_EventHandler
{
/**
* Underlying GNUnet event handler.
*/
struct GNUNET_DB_EventHandler *geh;
/**
* Entry in the heap.
*/
struct GNUNET_CONTAINER_HeapNode *hn;
/**
* Our timeout.
*/
struct GNUNET_TIME_Absolute timeout;
/**
* Callback to invoke (on @e timeout).
*/
GNUNET_DB_EventCallback cb;
/**
* Closure for @e cb.
*/
void *cb_cls;
};
/**
* Type of the "cls" argument given to each of the functions in
* our API.
@ -132,6 +165,12 @@ struct PostgresClosure
*/
char *sql_dir;
/**
* Heap of `struct TALER_EXCHANGEDB_EventHandler`
* by timeout.
*/
struct GNUNET_CONTAINER_Heap *event_heap;
/**
* After how long should idle reserves be closed?
*/
@ -2832,18 +2871,41 @@ handle_events (void *cls)
}
};
nfds_t nfds = (-1 == pg->pg_sock) ? 1 : 2;
struct TALER_EXCHANGEDB_EventHandler *r;
GNUNET_assert (0 ==
pthread_mutex_lock (&pg->event_lock));
while (0 != pg->listener_count)
{
int ret;
int timeout = -1; /* no timeout */
GNUNET_assert (0 ==
pthread_mutex_unlock (&pg->event_lock));
while (1)
{
r = GNUNET_CONTAINER_heap_peek (pg->event_heap);
if (NULL == r)
break;
if (GNUNET_TIME_absolute_is_future (r->timeout))
break;
GNUNET_assert (r ==
GNUNET_CONTAINER_heap_remove_root (pg->event_heap));
r->hn = NULL;
r->cb (r->cb_cls,
NULL,
0);
}
if (NULL != r)
{
struct GNUNET_TIME_Relative rem;
rem = GNUNET_TIME_absolute_get_remaining (r->timeout);
timeout = rem.rel_value_us / GNUNET_TIME_UNIT_MILLISECONDS.rel_value_us;
}
ret = poll (pfds,
nfds,
-1 /* no timeout */);
timeout);
if (-1 == ret)
GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
"poll");
@ -2909,16 +2971,30 @@ pq_socket_cb (void *cls,
* @param cb_cls closure for @a cb
* @return handle useful to cancel the listener
*/
static struct GNUNET_DB_EventHandler *
static struct TALER_EXCHANGEDB_EventHandler *
postgres_event_listen (void *cls,
struct TALER_EXCHANGEDB_Session *session,
struct GNUNET_TIME_Relative timeout,
const struct GNUNET_DB_EventHeaderP *es,
GNUNET_DB_EventCallback cb,
void *cb_cls)
{
struct PostgresClosure *pg = cls;
struct GNUNET_DB_EventHandler *eh;
struct TALER_EXCHANGEDB_EventHandler *eh;
struct TALER_EXCHANGEDB_Session *session;
session = postgres_get_session (pg);
eh = GNUNET_new (struct TALER_EXCHANGEDB_EventHandler);
eh->cb = cb;
eh->cb_cls = cb_cls;
eh->timeout = GNUNET_TIME_relative_to_absolute (timeout);
eh->geh = GNUNET_PQ_event_listen (session->conn,
es,
cb,
cb_cls);
GNUNET_assert (NULL != eh->geh);
eh->hn = GNUNET_CONTAINER_heap_insert (pg->event_heap,
eh,
eh->timeout.abs_value_us);
GNUNET_assert (0 ==
pthread_mutex_lock (&pg->event_lock));
pg->listener_count++;
@ -2932,11 +3008,6 @@ postgres_event_listen (void *cls,
}
GNUNET_assert (0 ==
pthread_mutex_unlock (&pg->event_lock));
eh = GNUNET_PQ_event_listen (session->conn,
es,
cb,
cb_cls);
GNUNET_assert (NULL != eh);
return eh;
}
@ -2949,7 +3020,7 @@ postgres_event_listen (void *cls,
*/
static void
postgres_event_listen_cancel (void *cls,
struct GNUNET_DB_EventHandler *eh)
struct TALER_EXCHANGEDB_EventHandler *eh)
{
struct PostgresClosure *pg = cls;
@ -2971,7 +3042,13 @@ postgres_event_listen_cancel (void *cls,
}
GNUNET_assert (0 ==
pthread_mutex_unlock (&pg->event_lock));
GNUNET_PQ_event_listen_cancel (eh);
if (NULL != eh->hn)
{
GNUNET_CONTAINER_heap_remove_node (eh->hn);
eh->hn = NULL;
}
GNUNET_PQ_event_listen_cancel (eh->geh);
GNUNET_free (eh);
}
@ -10917,6 +10994,8 @@ libtaler_plugin_exchangedb_postgres_init (void *cls)
pg = GNUNET_new (struct PostgresClosure);
pg->cfg = cfg;
pg->event_heap = GNUNET_CONTAINER_heap_create (
GNUNET_CONTAINER_HEAP_ORDER_MIN);
pg->main_self = pthread_self (); /* loaded while single-threaded! */
if (GNUNET_OK !=
GNUNET_CONFIGURATION_get_value_filename (cfg,
@ -11166,6 +11245,7 @@ libtaler_plugin_exchangedb_postgres_done (void *cls)
GNUNET_break (0 ==
close (pg->event_fd));
pthread_mutex_destroy (&pg->event_lock);
GNUNET_CONTAINER_heap_destroy (pg->event_heap);
GNUNET_free (pg->sql_dir);
GNUNET_free (pg->currency);
GNUNET_free (pg);

31
src/include/taler_exchangedb_plugin.h
View File

@ -73,8 +73,31 @@ struct TALER_EXCHANGEDB_DenominationKeyInformationP
};
/**
* Signature of events signalling a reseve got funding.
*/
struct TALER_ReserveEventP
{
/**
* Of type #TALER_DBEVENT_EXCHANGE_RESERVE_INCOMING.
*/
struct GNUNET_DB_EventHeaderP header;
/**
* Public key of the reserve the event is about.
*/
struct TALER_ReservePublicKeyP reserve_pub;
};
GNUNET_NETWORK_STRUCT_END
/**
* Event registration record.
*/
struct TALER_EXCHANGEDB_EventHandler;
/**
* Meta data about an exchange online signing key.
*/
@ -2149,16 +2172,16 @@ struct TALER_EXCHANGEDB_Plugin
* Register callback to be invoked on events of type @a es.
*
* @param cls database context to use
* @param session connection to use
* @param timeout how long to wait at most
* @param es specification of the event to listen for
* @param cb function to call when the event happens, possibly
* multiple times (until cancel is invoked)
* @param cb_cls closure for @a cb
* @return handle useful to cancel the listener
*/
struct GNUNET_DB_EventHandler *
struct TALER_EXCHANGEDB_EventHandler *
(*event_listen)(void *cls,
struct TALER_EXCHANGEDB_Session *session,
struct GNUNET_TIME_Relative timeout,
const struct GNUNET_DB_EventHeaderP *es,
GNUNET_DB_EventCallback cb,
void *cb_cls);
@ -2171,7 +2194,7 @@ struct TALER_EXCHANGEDB_Plugin
*/
void
(*event_listen_cancel)(void *cls,
struct GNUNET_DB_EventHandler *eh);
struct TALER_EXCHANGEDB_EventHandler *eh);
/**