postgresql plugin: Added {Min,Max}PGVersion configuration options.

Those options may be used to specify the minimum and maximum version of
PostgreSQL which is required for some query. This may be used to automatically
configure the plugin for a heterogeneous environment while using the same
configuration file on all hosts.

Signed-off-by: Sebastian Harl <sh@tokkee.org>
Signed-off-by: Florian Forster <octo@huhu.verplant.org>

diff --git a/src/postgresql.c b/src/postgresql.c
index ed55ee7..046cf5a 100644 (file)
--- a/src/postgresql.c
+++ b/src/postgresql.c
@@ -97,6 +97,9 @@ typedef struct {
 
        c_psql_col_t *cols;
        int           cols_num;
+
+       int min_pg_version;
+       int max_pg_version;
 } c_psql_query_t;
 
 typedef struct {
@@ -161,6 +164,9 @@ static c_psql_query_t *c_psql_query_new (const char *name)
 
        query->cols     = NULL;
        query->cols_num = 0;
+
+       query->min_pg_version = 0;
+       query->max_pg_version = INT_MAX;
        return query;
 } /* c_psql_query_new */
 
@@ -183,12 +189,15 @@ static void c_psql_query_delete (c_psql_query_t *query)
        return;
 } /* c_psql_query_delete */
 
-static c_psql_query_t *c_psql_query_get (const char *name)
+static c_psql_query_t *c_psql_query_get (const char *name, int server_version)
 {
        int i;
 
        for (i = 0; i < queries_num; ++i)
-               if (0 == strcasecmp (name, queries[i].name))
+               if (0 == strcasecmp (name, queries[i].name)
+                               && ((-1 == server_version)
+                                       || ((queries[i].min_pg_version <= server_version)
+                                               && (server_version <= queries[i].max_pg_version))))
                        return queries + i;
        return NULL;
 } /* c_psql_query_get */
@@ -535,6 +544,8 @@ static int c_psql_init (void)
                char *server_host;
                int   server_version;
 
+               int j;
+
                status = ssnprintf (buf, buf_len, "dbname = '%s'", db->database);
                if (0 < status) {
                        buf     += status;
@@ -568,6 +579,33 @@ static int c_psql_init (void)
                if (3 > db->proto_version)
                        log_warn ("Protocol version %d does not support parameters.",
                                        db->proto_version);
+
+               /* Now that we know the PostgreSQL server version, we can get the
+                * right version of each query definition. */
+               for (j = 0; j < db->queries_num; ++j) {
+                       c_psql_query_t *tmp;
+
+                       tmp = c_psql_query_get (db->queries[j]->name, server_version);
+
+                       if (tmp == db->queries[j])
+                               continue;
+
+                       if (NULL == tmp) {
+                               log_err ("Query \"%s\" not found for server version %i - "
+                                               "please check your configuration.",
+                                               db->queries[j]->name, server_version);
+
+                               if (db->queries_num - j - 1 > 0)
+                                       memmove (db->queries + j, db->queries + j + 1,
+                                                       (db->queries_num - j - 1) * sizeof (*db->queries));
+
+                               --db->queries_num;
+                               --j;
+                               continue;
+                       }
+
+                       db->queries[j] = tmp;
+               }
        }
 
        plugin_register_read ("postgresql", c_psql_read);
@@ -588,6 +626,18 @@ static int config_set_s (char *name, char **var, const oconfig_item_t *ci)
        return 0;
 } /* config_set_s */
 
+static int config_set_i (char *name, int *var, const oconfig_item_t *ci)
+{
+       if ((0 != ci->children_num) || (1 != ci->values_num)
+                       || (OCONFIG_TYPE_NUMBER != ci->values[0].type)) {
+               log_err ("%s expects a single number argument.", name);
+               return 1;
+       }
+
+       *var = (int)ci->values[0].value.number;
+       return 0;
+} /* config_set_i */
+
 static int config_set_param (c_psql_query_t *query, const oconfig_item_t *ci)
 {
        c_psql_param_t param;
@@ -662,7 +712,7 @@ static int set_query (c_psql_database_t *db, const char *name)
 {
        c_psql_query_t *query;
 
-       query = c_psql_query_get (name);
+       query = c_psql_query_get (name, -1);
        if (NULL == query) {
                log_err ("Query \"%s\" not found - please check your configuration.",
                                name);
@@ -716,6 +766,10 @@ static int c_psql_config_query (oconfig_item_t *ci)
                        config_set_param (query, c);
                else if (0 == strcasecmp (c->key, "Column"))
                        config_set_column (query, c);
+               else if (0 == strcasecmp (c->key, "MinPGVersion"))
+                       config_set_i ("MinPGVersion", &query->min_pg_version, c);
+               else if (0 == strcasecmp (c->key, "MaxPGVersion"))
+                       config_set_i ("MaxPGVersion", &query->max_pg_version, c);
                else
                        log_warn ("Ignoring unknown config key \"%s\".", c->key);
        }