donau

plugin_donaudb_postgres.c (5889B)

---

 /*
    This file is part of TALER
    Copyright (C) 2024 Taler Systems SA
 
    TALER is free software; you can redistribute it and/or modify it under the
    terms of the GNU 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 General Public License for more details.
 
    You should have received a copy of the GNU General Public License along with
    TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
  */
 
 /**
  * @file plugin_donaudb_postgres.c
  * @brief Low-level (statement-level) Postgres database access for the donau
  * @author Johannes Casaburi
  */
 #include "donau_config.h"
 #include <poll.h>
 #include <pthread.h>
 #include <libpq-fe.h>
 struct DONAUDB_PostgresContext;
 #define GNUNET_PQ_RECONNECT_CALLBACK_CLOSURE \
         struct DONAUDB_PostgresContext
 #include "helper.h"
 
 /**
  * Set to 1 to enable Postgres auto_explain module. This will
  * slow down things a _lot_, but also provide extensive logging
  * in the Postgres database logger for performance analysis.
  */
 #define AUTO_EXPLAIN 0
 
 
 /**
  * Function called each time we connect or reconnect to the
  * database. Gives the application a chance to run some
  * per-connection initialization logic.
  *
  * @param pg database conntext in the donau
  * @param pq database connection handle
  */
 static void
 reconnect_cb (struct DONAUDB_PostgresContext *pg,
               struct GNUNET_PQ_Context *pq)
 {
 #if AUTO_EXPLAIN
   /* Enable verbose logging to see where queries do not
      properly use indices */
   struct GNUNET_PQ_ExecuteStatement es[] = {
     GNUNET_PQ_make_try_execute ("LOAD 'auto_explain';"),
     GNUNET_PQ_make_try_execute ("SET auto_explain.log_min_duration=50;"),
     GNUNET_PQ_make_try_execute ("SET auto_explain.log_timing=TRUE;"),
     GNUNET_PQ_make_try_execute ("SET auto_explain.log_analyze=TRUE;"),
     /* https://wiki.postgresql.org/wiki/Serializable suggests to really
        force the default to 'serializable' if SSI is to be used. */
     GNUNET_PQ_make_try_execute (
       "SET SESSION CHARACTERISTICS AS TRANSACTION ISOLATION LEVEL SERIALIZABLE;"),
     GNUNET_PQ_make_try_execute ("SET enable_sort=OFF;"),
     GNUNET_PQ_make_try_execute ("SET enable_seqscan=OFF;"),
     GNUNET_PQ_make_try_execute ("SET search_path TO donau;"),
     GNUNET_PQ_EXECUTE_STATEMENT_END
   };
 #else
   struct GNUNET_PQ_ExecuteStatement es[] = {
     GNUNET_PQ_make_try_execute (
       "SET SESSION CHARACTERISTICS AS TRANSACTION ISOLATION LEVEL SERIALIZABLE;"),
     GNUNET_PQ_make_try_execute ("SET enable_sort=OFF;"),
     GNUNET_PQ_make_try_execute ("SET enable_seqscan=OFF;"),
     GNUNET_PQ_make_try_execute ("SET autocommit=OFF;"),
     GNUNET_PQ_make_try_execute ("SET search_path TO donau;"),
     GNUNET_PQ_EXECUTE_STATEMENT_END
   };
 #endif
 
   if (GNUNET_OK !=
       GNUNET_PQ_exec_statements (pq,
                                  es))
   {
     GNUNET_break (0);
     return;
   }
   pg->prep_gen++;
 }
 
 
 /**
  * Connect to the database if the connection does not exist yet.
  *
  * @param pg the plugin-specific state
  * @return #GNUNET_OK on success
  */
 static enum GNUNET_GenericReturnValue
 internal_setup (struct DONAUDB_PostgresContext *pg)
 {
   struct GNUNET_PQ_Context *db_conn;
 
   if (NULL != pg->conn)
     return GNUNET_OK;
   db_conn = GNUNET_PQ_init (pg->cfg,
                             "donaudb-postgres",
                             &reconnect_cb,
                             pg);
   if (NULL == db_conn)
     return GNUNET_SYSERR;
   if (0 == pg->prep_gen)
   {
     GNUNET_PQ_disconnect (db_conn);
     return GNUNET_SYSERR;
   }
   pg->conn = db_conn;
   return GNUNET_OK;
 }
 
 
 /**
  * Initialize the database connection.
  *
  * @param cfg configuration to use
  * @param check_current true to check if the database schema is current
  * @return NULL on failure
  */
 static struct DONAUDB_PostgresContext *
 do_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
             bool check_current)
 {
   struct DONAUDB_PostgresContext *pg;
 
   pg = GNUNET_new (struct DONAUDB_PostgresContext);
   pg->cfg = cfg;
   if (GNUNET_OK !=
       GNUNET_CONFIGURATION_get_value_string (cfg,
                                              "donau",
                                              "BASE_URL",
                                              &pg->donau_url))
   {
     GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
                                "donau",
                                "BASE_URL");
     goto fail;
   }
   if (GNUNET_OK !=
       TALER_config_get_currency (cfg,
                                  "donau",
                                  &pg->currency))
   {
     goto fail;
   }
   if (GNUNET_OK !=
       internal_setup (pg))
     goto fail;
   if (check_current &&
       (GNUNET_OK !=
        GNUNET_PQ_check_current (pg->conn,
                                 "donau-")) )
   {
     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                 "Database schema is not up-to-date. Try running donau-dbinit or donau-dbconfig!\n");
     goto fail;
   }
 
   return pg;
 fail:
   DONAUDB_disconnect (pg);
   return NULL;
 }
 
 
 struct DONAUDB_PostgresContext *
 DONAUDB_connect (
   const struct GNUNET_CONFIGURATION_Handle *cfg)
 {
   return do_connect (cfg,
                      true);
 }
 
 
 struct DONAUDB_PostgresContext *
 DONAUDB_connect_admin (
   const struct GNUNET_CONFIGURATION_Handle *cfg)
 {
   return do_connect (cfg,
                      false);
 }
 
 
 void
 DONAUDB_disconnect (struct DONAUDB_PostgresContext *pg)
 {
   if (NULL == pg)
     return;
   if (NULL != pg->conn)
   {
     GNUNET_PQ_disconnect (pg->conn);
     pg->conn = NULL;
   }
   GNUNET_free (pg->donau_url);
   GNUNET_free (pg->currency);
   GNUNET_free (pg);
 }
 
 
 /* end of plugin_donaudb_postgres.c */