skeleton for taler-exchange-drain command (#4960)

src/exchange/Makefile.am

@@ -19,6 +19,7 @@ pkgcfg_DATA = \
 bin_PROGRAMS = \
   taler-exchange-aggregator \
   taler-exchange-closer \
+  taler-exchange-drain \
   taler-exchange-expire \
   taler-exchange-httpd \
   taler-exchange-router \
@@ -52,6 +53,19 @@ taler_exchange_closer_LDADD = \
   -lgnunetutil \
   $(XLIB)
 
+taler_exchange_drain_SOURCES = \
+  taler-exchange-drain.c
+taler_exchange_drain_LDADD = \
+  $(LIBGCRYPT_LIBS) \
+  $(top_builddir)/src/json/libtalerjson.la \
+  $(top_builddir)/src/util/libtalerutil.la \
+  $(top_builddir)/src/bank-lib/libtalerbank.la \
+  $(top_builddir)/src/exchangedb/libtalerexchangedb.la \
+  -ljansson \
+  -lgnunetcurl \
+  -lgnunetutil \
+  $(XLIB)
+
 taler_exchange_expire_SOURCES = \
   taler-exchange-expire.c
 taler_exchange_expire_LDADD = \

src/exchange/taler-exchange-drain.c

@@ -0,0 +1,275 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2022 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-exchange-drain.c
+ * @brief Process that drains exchange profits from the escrow account
+ *        and puts them into some regular account of the exchange.
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <gnunet/gnunet_util_lib.h>
+#include <jansson.h>
+#include <pthread.h>
+#include "taler_exchangedb_lib.h"
+#include "taler_exchangedb_plugin.h"
+#include "taler_json_lib.h"
+#include "taler_bank_service.h"
+
+
+/**
+ * The exchange's configuration.
+ */
+static const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+/**
+ * Our database plugin.
+ */
+static struct TALER_EXCHANGEDB_Plugin *db_plugin;
+
+/**
+ * Next task to run, if any.
+ */
+static struct GNUNET_SCHEDULER_Task *task;
+
+/**
+ * Value to return from main(). 0 on success, non-zero on errors.
+ */
+static int global_ret;
+
+
+/**
+ * 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");
+  if (NULL != task)
+  {
+    GNUNET_SCHEDULER_cancel (task);
+    task = NULL;
+  }
+  db_plugin->rollback (db_plugin->cls); /* just in case */
+  TALER_EXCHANGEDB_plugin_unload (db_plugin);
+  db_plugin = NULL;
+  TALER_EXCHANGEDB_unload_accounts ();
+  cfg = NULL;
+}
+
+
+/**
+ * Parse the configuration for drain.
+ *
+ * @return #GNUNET_OK on success
+ */
+static enum GNUNET_GenericReturnValue
+parse_drain_config (void)
+{
+  if (NULL ==
+      (db_plugin = TALER_EXCHANGEDB_plugin_load (cfg)))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Failed to initialize DB subsystem\n");
+    return GNUNET_SYSERR;
+  }
+  if (GNUNET_OK !=
+      TALER_EXCHANGEDB_load_accounts (cfg,
+                                      TALER_EXCHANGEDB_ALO_DEBIT
+                                      | TALER_EXCHANGEDB_ALO_AUTHDATA))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "No wire accounts configured for debit!\n");
+    TALER_EXCHANGEDB_plugin_unload (db_plugin);
+    db_plugin = NULL;
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+
+/**
+ * Perform a database commit. If it fails, print a warning.
+ *
+ * @return status of commit
+ */
+static enum GNUNET_DB_QueryStatus
+commit_or_warn (void)
+{
+  enum GNUNET_DB_QueryStatus qs;
+
+  qs = db_plugin->commit (db_plugin->cls);
+  if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
+    return qs;
+  GNUNET_log ((GNUNET_DB_STATUS_SOFT_ERROR == qs)
+              ? GNUNET_ERROR_TYPE_INFO
+              : GNUNET_ERROR_TYPE_ERROR,
+              "Failed to commit database transaction!\n");
+  return qs;
+}
+
+
+/**
+ * Execute a wire drain.
+ *
+ * @param cls NULL
+ */
+static void
+run_drain (void *cls)
+{
+  enum GNUNET_DB_QueryStatus qs;
+
+  (void) cls;
+  task = NULL;
+  if (GNUNET_OK !=
+      db_plugin->start (db_plugin->cls,
+                        "run drain"))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Failed to start database transaction!\n");
+    global_ret = EXIT_FAILURE;
+    GNUNET_SCHEDULER_shutdown ();
+    return;
+  }
+#if 0
+  qs = db_plugin->profit_drains_get_pending (db_plugin->cls);
+#else
+  qs = -1;
+#endif
+  switch (qs)
+  {
+  case GNUNET_DB_STATUS_HARD_ERROR:
+    db_plugin->rollback (db_plugin->cls);
+    GNUNET_break (0);
+    global_ret = EXIT_FAILURE;
+    GNUNET_SCHEDULER_shutdown ();
+    return;
+  case GNUNET_DB_STATUS_SOFT_ERROR:
+    /* try again */
+    db_plugin->rollback (db_plugin->cls);
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Serialization failure on simple SELECT!?\n");
+    global_ret = EXIT_FAILURE;
+    GNUNET_SCHEDULER_shutdown ();
+    return;
+  case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
+    /* no more profit drains, go sleep a bit! */
+    db_plugin->rollback (db_plugin->cls);
+    GNUNET_assert (NULL == task);
+    GNUNET_log (GNUNET_ERROR_TYPE_MESSAGE,
+                "No profit drains pending. Exiting.\n");
+    GNUNET_SCHEDULER_shutdown ();
+    return;
+  default:
+    /* continued below */
+    break;
+  }
+  // FIXME: check signature (again!)
+  // FIMXE: display for human check
+  // FIXME: insert into pre-wire
+  // FIXME: mark as done
+  // FIXME: commit transaction + report success + exit
+  if (0 >= commit_or_warn ())
+    GNUNET_log (GNUNET_ERROR_TYPE_MESSAGE,
+                "Profit drain triggered. Exiting.\n");
+  GNUNET_SCHEDULER_shutdown ();
+}
+
+
+/**
+ * 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) cls;
+  (void) args;
+  (void) cfgfile;
+
+  cfg = c;
+  if (GNUNET_OK != parse_drain_config ())
+  {
+    cfg = NULL;
+    global_ret = EXIT_NOTCONFIGURED;
+    return;
+  }
+  if (GNUNET_SYSERR ==
+      db_plugin->preflight (db_plugin->cls))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Failed to obtain database connection!\n");
+    global_ret = EXIT_FAILURE;
+    GNUNET_SCHEDULER_shutdown ();
+    return;
+  }
+  GNUNET_assert (NULL == task);
+  task = GNUNET_SCHEDULER_add_now (&run_drain,
+                                   NULL);
+  GNUNET_SCHEDULER_add_shutdown (&shutdown_task,
+                                 cls);
+}
+
+
+/**
+ * The main function of the taler-exchange-drain.
+ *
+ * @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_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-exchange-drain",
+    gettext_noop (
+      "process that executes a single profit drain"),
+    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-exchange-drain.c */

src/exchange/taler-exchange-transfer.c

@@ -264,7 +264,7 @@ shutdown_task (void *cls)
 
 
 /**
- * Parse the configuration for wirewatch.
+ * Parse the configuration for taler-exchange-transfer.
  *
  * @return #GNUNET_OK on success
  */