[taler-merchant] branch master updated: skeleton for taler-merchant-exchange (#6363)

[gnunet]

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grothoff pushed a commit to branch master
in repository merchant.

The following commit(s) were added to refs/heads/master by this push:
     new 5722b193 skeleton for taler-merchant-exchange (#6363)
5722b193 is described below

commit 5722b1933d734ffed9681c2a53a9a583666ce87a
Author: Christian Grothoff <christian@grothoff.org>
AuthorDate: Mon Apr 24 00:41:35 2023 +0200

    skeleton for taler-merchant-exchange (#6363)
---
 src/backend/taler-merchant-exchange.c | 339 ++++++++++++++++++++++++++++++++++
 1 file changed, 339 insertions(+)

diff --git a/src/backend/taler-merchant-exchange.c 
b/src/backend/taler-merchant-exchange.c
new file mode 100644
index 00000000..e25ab98a
--- /dev/null
+++ 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 */

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