Issue #477: Automatically reconnect a broken Redis connection.

Provide the `RedisOptions` directive for disabling this behavior if needed.

RELEASE_NOTES

@@ -22,6 +22,8 @@ ChangeLog files.
 
   + New Configuration Directives
 
+    RedisOptions (Issue #477)
+
     RedisSentinel (Issue #396)
 
 

doc/modules/mod_redis.html

@@ -22,6 +22,7 @@ <h2>Directives</h2>
   <li><a href="#RedisEngine">RedisEngine</a>
   <li><a href="#RedisLog">RedisLog</a>
   <li><a href="#RedisLogOnCommand">RedisLogOnCommand</a>
+  <li><a href="#RedisOptions">RedisOptions</a>
   <li><a href="#RedisSentinel">RedisSentinel</a>
   <li><a href="#RedisServer">RedisServer</a>
   <li><a href="#RedisTimeouts">RedisTimeouts</a>
@@ -103,6 +104,36 @@ <h3><a name="RedisLogOnCommand">RedisLogOnCommand</a></h3>
 <code>RedisLogOnCommand</code> does <b>not</b> currently support the logging
 <i>classes</i> that the <code>ExtendedLog</code> directive supports.
 
+<p>
+<hr>
+<h3><a name="RedisOptions">RedisOptions</a></h3>
+<strong>Syntax:</strong> RedisOptions <em>opt1 ...</em><br>
+<strong>Default:</strong> None<br>
+<strong>Context:</strong> server config, <code>&lt;VirtualHost&gt;</code>, <code>&lt;Global&gt;</code><br>
+<strong>Module:</strong> mod_redis<br>
+<strong>Compatibility:</strong> 1.3.7rc1 and later
+
+<p>
+The <code>RedisOptions</code> directive is used to configure various optional
+behavior of <code>mod_redis</code>.
+
+<p>
+Example:
+<pre>
+  RedisOptions NoReconnect
+</pre>
+
+<p>
+The currently implemented options are:
+<ul>
+  <li><code>NoReconnect</code><br>
+    <p>
+    If the connection to Redis breaks unexpectedly, <code>mod_redis</code>
+    will attempt to <em>reconnect</em> automatically.  Use this option to
+    disable the automatic reconnection.
+  </li>
+</ul>
+
 <p>
 <hr>
 <h3><a name="RedisSentinel">RedisSentinel</a></h3>

include/redis.h

@@ -36,8 +36,12 @@ typedef struct redis_rec pr_redis_t;
 /* This function returns the pr_redis_t for the current session; if one
  * does not exist, it will be allocated.
  */
-pr_redis_t *pr_redis_conn_get(pool *p);
+pr_redis_t *pr_redis_conn_get(pool *p, unsigned long flags);
 pr_redis_t *pr_redis_conn_new(pool *p, module *owner, unsigned long flags);
+
+/* These flags are used for tweaking connection behaviors. */
+#define PR_REDIS_CONN_FL_NO_RECONNECT		0x0001
+
 int pr_redis_conn_close(pr_redis_t *redis);
 int pr_redis_conn_destroy(pr_redis_t *redis);
 
@@ -298,8 +302,8 @@ int pr_redis_sentinel_get_masters(pool *p, pr_redis_t *redis,
   array_header **masters);
 
 /* For internal use only */
-int redis_set_server(const char *server, int port, const char *password,
-  const char *db_idx);
+int redis_set_server(const char *server, int port, unsigned long flags,
+  const char *password, const char *db_idx);
 int redis_set_sentinels(array_header *sentinels, const char *name);
 int redis_set_timeouts(unsigned long connect_millis, unsigned long io_millis);
 

modules/mod_redis.c

@@ -47,6 +47,7 @@ module redis_module;
 
 static int redis_engine = FALSE;
 static int redis_logfd = -1;
+static unsigned long redis_opts = 0UL;
 static pool *redis_pool = NULL;
 
 static void redis_exit_ev(const void *, void *);
@@ -1404,7 +1405,7 @@ static void log_event(cmd_rec *cmd, int flags) {
   pr_redis_t *redis;
   config_rec *c;
 
-  redis = pr_redis_conn_get(session.pool);
+  redis = pr_redis_conn_get(session.pool, redis_opts);
   if (redis == NULL) {
     (void) pr_log_writefile(redis_logfd, MOD_REDIS_VERSION,
       "error connecting to Redis: %s", strerror(errno));
@@ -1589,6 +1590,36 @@ MODRET set_redislogoncommand(cmd_rec *cmd) {
   return PR_HANDLED(cmd);
 }
 
+/* usage: RedisOptions opt1 opt2 ... */
+MODRET set_redisoptions(cmd_rec *cmd) {
+  config_rec *c = NULL;
+  register unsigned int i = 0;
+  unsigned long opts = 0UL;
+
+  if (cmd->argc-1 == 0) {
+    CONF_ERROR(cmd, "wrong number of parameters");
+  }
+
+  CHECK_CONF(cmd, CONF_ROOT|CONF_VIRTUAL|CONF_GLOBAL);
+
+  c = add_config_param(cmd->argv[0], 1, NULL);
+
+  for (i = 1; i < cmd->argc; i++) {
+    if (strcmp(cmd->argv[i], "NoReconnect") == 0) {
+      opts |= PR_REDIS_CONN_FL_NO_RECONNECT;
+
+    } else {
+      CONF_ERROR(cmd, pstrcat(cmd->tmp_pool, ": unknown RedisOption '",
+        cmd->argv[i], "'", NULL));
+    }
+  }
+
+  c->argv[0] = pcalloc(c->pool, sizeof(unsigned long));
+  *((unsigned long *) c->argv[0]) = opts;
+
+  return PR_HANDLED(cmd);
+}
+
 /* usage: RedisSentinel host[:port] ... [master name] */
 MODRET set_redissentinel(cmd_rec *cmd) {
   register unsigned int i;
@@ -1946,6 +1977,18 @@ static int redis_sess_init(void) {
     }
   }
 
+  c = find_config(main_server->conf, CONF_PARAM, "RedisOptions", FALSE);
+  while (c != NULL) {
+    unsigned long opts = 0;
+
+    pr_signals_handle();
+
+    opts = *((unsigned long *) c->argv[0]);
+    redis_opts |= opts;
+
+    c = find_config_next(c, c->next, CONF_PARAM, "RedisOptions", FALSE);
+  }
+
   c = find_config(main_server->conf, CONF_PARAM, "RedisSentinel", FALSE);
   if (c != NULL) {
     array_header *sentinels;
@@ -1998,6 +2041,7 @@ static conftable redis_conftab[] = {
   { "RedisEngine",		set_redisengine,	NULL },
   { "RedisLog",			set_redislog,		NULL },
   { "RedisLogOnCommand",	set_redislogoncommand,	NULL },
+  { "RedisOptions",		set_redisoptions,	NULL },
   { "RedisSentinel",		set_redissentinel,	NULL },
   { "RedisServer",		set_redisserver,	NULL },
   { "RedisTimeouts",		set_redistimeouts,	NULL },