commit 5722b1933d734ffed9681c2a53a9a583666ce87a
parent 5aebd54e339d86a6f268459c472523f9aade37c6
Author: Christian Grothoff <christian@grothoff.org>
Date: Mon, 24 Apr 2023 00:41:35 +0200
skeleton for taler-merchant-exchange (#6363)
Diffstat:
1 file changed, 339 insertions(+), 0 deletions(-)
diff --git a/src/backend/taler-merchant-exchange.c b/src/backend/taler-merchant-exchange.c
@@ -0,0 +1,339 @@
+/*
+ This file is part of TALER
+ Copyright (C) 2023 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
+ Foundation; either version 3, or (at your option) any later version.
+
+ TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License along with
+ TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file taler-merchant-exchange.c
+ * @brief Process that reconciles information about incoming bank transfers with orders by asking the exchange
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <gnunet/gnunet_util_lib.h>
+#include <jansson.h>
+#include <pthread.h>
+#include <taler/taler_dbevents.h>
+#include "taler_merchant_bank_lib.h"
+#include "taler_merchantdb_lib.h"
+#include "taler_merchantdb_plugin.h"
+
+/**
+ * Timeout for the exchange interaction. Rather long as we should do
+ * long-polling and do not want to wake up too often.
+ */
+#define EXCHANGE_TIMEOUT GNUNET_TIME_relative_multiply ( \
+ GNUNET_TIME_UNIT_MINUTES, \
+ 30)
+
+/**
+ * Information about a inquiry job.
+ */
+struct Inquiry
+{
+ /**
+ * Kept in a DLL.
+ */
+ struct Inquiry *next;
+
+ /**
+ * Kept in a DLL.
+ */
+ struct Inquiry *prev;
+
+};
+
+
+/**
+ * Head of active inquiryes.
+ */
+static struct Inquiry *w_head;
+
+/**
+ * Tail of active inquiryes.
+ */
+static struct Inquiry *w_tail;
+
+/**
+ * The merchant's configuration.
+ */
+static const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+/**
+ * Our database plugin.
+ */
+static struct TALER_MERCHANTDB_Plugin *db_plugin;
+
+/**
+ * Handle to the context for interacting with the bank.
+ */
+static struct GNUNET_CURL_Context *ctx;
+
+/**
+ * Scheduler context for running the @e ctx.
+ */
+static struct GNUNET_CURL_RescheduleContext *rc;
+
+/**
+ * Event handler to learn that there are new transfers
+ * to check.
+ */
+static struct GNUNET_DB_EventHandler *eh;
+
+/**
+ * Value to return from main(). 0 on success, non-zero on errors.
+ */
+static int global_ret;
+
+/**
+ * How many transactions should we fetch at most per batch?
+ */
+static unsigned int batch_size = 32;
+
+/**
+ * #GNUNET_YES if we are in test mode and should exit when idle.
+ */
+static int test_mode;
+
+
+/**
+ * Free resources of @a w.
+ *
+ * @param w inquiry job to terminate
+ */
+static void
+end_inquiry (struct Inquiry *w)
+{
+ GNUNET_CONTAINER_DLL_remove (w_head,
+ w_tail,
+ w);
+ GNUNET_free (w);
+}
+
+
+/**
+ * We're being aborted with CTRL-C (or SIGTERM). Shut down.
+ *
+ * @param cls closure
+ */
+static void
+shutdown_task (void *cls)
+{
+ (void) cls;
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+ "Running shutdown\n");
+ while (NULL != w_head)
+ {
+ struct Inquiry *w = w_head;
+
+ save (w);
+ end_inquiry (w);
+ }
+ if (NULL != eh)
+ {
+ db_plugin->event_listen_cancel (eh);
+ eh = NULL;
+ }
+ TALER_MERCHANTDB_plugin_unload (db_plugin);
+ db_plugin = NULL;
+ cfg = NULL;
+ if (NULL != ctx)
+ {
+ GNUNET_CURL_fini (ctx);
+ ctx = NULL;
+ }
+ if (NULL != rc)
+ {
+ GNUNET_CURL_gnunet_rc_destroy (rc);
+ rc = NULL;
+ }
+}
+
+
+/**
+ * Run next iteration.
+ *
+ * @param cls a `struct Inquiry *`
+ */
+static void
+do_work (void *cls);
+
+
+/**
+ * Function called with information about a transfer we
+ * should ask the exchange about.
+ *
+ * @param cls closure (NULL)
+ */
+static void
+start_inquiry (
+ void *cls,
+ ...)
+{
+ struct Inquiry *w = GNUNET_new (struct Inquiry);
+
+ (void) cls;
+
+ GNUNET_CONTAINER_DLL_insert (w_head,
+ w_tail,
+ w);
+ w->job = TALER_EXCHANGE_ (...);
+}
+
+
+static void
+find_work (void *cls)
+{
+ enum GNUNET_DB_QueryStatus qs;
+
+ task = NULL;
+ qs = db_plugin->select_open_transfers (db_plugin->cls,
+ &start_inquiry,
+ NULL);
+ if (qs < 0)
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "Failed to obtain open transfers from database\n");
+ GNUNET_SCHEDULER_shutdown ();
+ return;
+ }
+}
+
+
+/**
+ * Function called when transfers are added to the merchant database. We look
+ * for more work.
+ *
+ * @param cls closure (NULL)
+ * @param extra additional event data provided
+ * @param extra_size number of bytes in @a extra
+ */
+static void
+transfer_added (void *cls,
+ const void *extra,
+ size_t extra_size)
+{
+ (void) cls;
+ (void) extra;
+ (void) extra_size;
+ if (NULL != task)
+ return;
+ task = GNUNET_SCHEDULER_add_now (&find_work,
+ NULL);
+}
+
+
+/**
+ * First task.
+ *
+ * @param cls closure, NULL
+ * @param args remaining command-line arguments
+ * @param cfgfile name of the configuration file used (for saving, can be NULL!)
+ * @param c configuration
+ */
+static void
+run (void *cls,
+ char *const *args,
+ const char *cfgfile,
+ const struct GNUNET_CONFIGURATION_Handle *c)
+{
+ (void) args;
+ (void) cfgfile;
+
+ cfg = c;
+ GNUNET_SCHEDULER_add_shutdown (&shutdown_task,
+ NULL);
+ ctx = GNUNET_CURL_init (&GNUNET_CURL_gnunet_scheduler_reschedule,
+ &rc);
+ rc = GNUNET_CURL_gnunet_rc_create (ctx);
+ if (NULL == ctx)
+ {
+ GNUNET_break (0);
+ GNUNET_SCHEDULER_shutdown ();
+ return;
+ }
+ if (NULL ==
+ (db_plugin = TALER_MERCHANTDB_plugin_load (cfg)))
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "Failed to initialize DB subsystem\n");
+ GNUNET_SCHEDULER_shutdown ();
+ return;
+ }
+ if (GNUNET_OK !=
+ db_plugin->connect (db_plugin->cls))
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "Failed to connect to database\n");
+ GNUNET_SCHEDULER_shutdown ();
+ return;
+ }
+ {
+ struct GNUNET_DB_EventHeaderP es = {
+ .size = htons (sizeof (es)),
+ .type = htons (TALER_DBEVENT_MERCHANT_XXX)
+ };
+
+ eh = db_plugin->event_listen (db_plugin->cls,
+ &es,
+ GNUNET_TIME_UNIT_FOREVER_REL,
+ &transfer_added,
+ NULL);
+ }
+ task = GNUNET_SCHEDULER_add_now (&find_work,
+ NULL);
+}
+
+
+/**
+ * The main function of taler-merchant-exchange
+ *
+ * @param argc number of arguments from the command line
+ * @param argv command line arguments
+ * @return 0 ok, 1 on error
+ */
+int
+main (int argc,
+ char *const *argv)
+{
+ struct GNUNET_GETOPT_CommandLineOption options[] = {
+ GNUNET_GETOPT_option_flag ('t',
+ "test",
+ "run in test mode and exit when idle",
+ &test_mode),
+ GNUNET_GETOPT_option_version (VERSION "-" VCS_VERSION),
+ GNUNET_GETOPT_OPTION_END
+ };
+ enum GNUNET_GenericReturnValue ret;
+
+ if (GNUNET_OK !=
+ GNUNET_STRINGS_get_utf8_args (argc, argv,
+ &argc, &argv))
+ return EXIT_INVALIDARGUMENT;
+ TALER_OS_init ();
+ ret = GNUNET_PROGRAM_run (
+ argc, argv,
+ "taler-merchant-exchange",
+ gettext_noop (
+ "background process that reconciles bank transfers with orders by asking the exchange"),
+ options,
+ &run, NULL);
+ GNUNET_free_nz ((void *) argv);
+ if (GNUNET_SYSERR == ret)
+ return EXIT_INVALIDARGUMENT;
+ if (GNUNET_NO == ret)
+ return EXIT_SUCCESS;
+ return global_ret;
+}
+
+
+/* end of taler-merchant-exchange.c */
