Sentinel fixes

Smithsonian · Jan 6, 2025 · 918c911 · 918c911
1 parent a961435
commit 918c911
Showing 1 changed file with 64 additions and 53 deletions.
diff --git a/src/redisx-sentinel.c b/src/redisx-sentinel.c
@@ -33,71 +33,23 @@ static int rTryConnectSentinel(Redis *redis, int serverIndex) {
   char desc[80];
   int status;
 
+  redisxDisconnect(redis);
+
   sprintf(desc, "sentinel server %d", serverIndex);
   prop_error(fn, rSetServerAsync(redis, desc, server.host, server.port));
 
   status = rConnectClient(redis, REDISX_INTERACTIVE_CHANNEL);
   if(status != X_SUCCESS) return status; // No error propagation. It's OK if server is down...
 
-  // Move server to the top of the list, so next time we try this one first...
-  memmove(&s->servers[1], s->servers, serverIndex * sizeof(RedisServer));
-  s->servers[0] = server;
-
   return X_SUCCESS;
 }
 
 
 /// \cond PRIVATE
 
 /**
- * Obtains the current Sentinel master from the given participating node.
- *
- * @param redis     A Redis server instance
- * @return          X_SUCCESS (0) if successful, or else an error code &lt;0.
- */
-int rDiscoverSentinel(Redis *redis) {
-  static const char *fn = "rConnectSentinel";
-
-  RedisPrivate *p = (RedisPrivate *) redis->priv;
-  const RedisSentinel *s = p->sentinel;
-  int i, savedTimeout = p->timeoutMillis;
-
-  p->timeoutMillis = s->timeoutMillis > 0 ? s->timeoutMillis : REDISX_DEFAULT_SENTINEL_TIMEOUT_MILLIS;
-
-  for(i = 0; i < s->nServers; i++) if(rTryConnectSentinel(redis, i) == X_SUCCESS) {
-    RESP *reply;
-    int status;
-
-    // Get the name of the master...
-    reply = redisxRequest(redis, "SENTINEL", "get-master-addr-by-name", s->serviceName, NULL, &status);
-    rCloseClientAsync(redis->interactive);
-
-    if(status) continue;
-
-    if(redisxCheckDestroyRESP(reply, RESP_ARRAY, 2) == X_SUCCESS) {
-      RESP **component = (RESP **) reply->value;
-      int port = (int) strtol((char *) component[1]->value, NULL, 10);
-
-      status = rSetServerAsync(redis, "sentinel master", (char *) component[0]->value, port);
-
-      redisxDestroyRESP(reply);
-      p->timeoutMillis = savedTimeout;
-
-      prop_error(fn, status);
-
-      // TODO update sentinel server list...
-
-      return X_SUCCESS;
-    }
-  }
-
-  p->timeoutMillis = savedTimeout;
-  return x_error(X_NO_SERVICE, ENOTCONN, fn, "no Sentinel server available");
-}
-
-/**
- * Verifies that a given Redis instance is in the master role. User's should always communicate
- * to the master, not to replicas.
+ * Verifies that a given Redis instance is in the master role. It is assumed that we have a live
+ * interactive connection to the server.
  *
  * @param redis     A redis server instance
  * @return          X_SUCCESS (0) if the server is confirmed to be the master, or else an error
@@ -139,11 +91,70 @@ int rConfirmMasterRole(Redis *redis) {
   redisxDestroyRESP(reply);
 
   if(status) return x_error(X_FAILURE, EAGAIN, fn, "Replica is not master");
+
   return X_SUCCESS;
 }
 
-/// \endcond
+/**
+ * Obtains the current Sentinel master from the given participating node.
+ *
+ * @param redis     A Redis server instance
+ * @return          X_SUCCESS (0) if successful, or else an error code &lt;0.
+ */
+int rDiscoverSentinel(Redis *redis) {
+  static const char *fn = "rConnectSentinel";
+
+  RedisPrivate *p = (RedisPrivate *) redis->priv;
+  const RedisSentinel *s = p->sentinel;
+  int i, savedTimeout = p->timeoutMillis;
+
+  p->timeoutMillis = s->timeoutMillis > 0 ? s->timeoutMillis : REDISX_DEFAULT_SENTINEL_TIMEOUT_MILLIS;
+
+  for(i = 0; i < s->nServers; i++) if(rTryConnectSentinel(redis, i) == X_SUCCESS) {
+    RedisServer server = s->servers[i]; // A local copy of the server data
+    RESP *reply;
+    int status;
+
+    if(i > 0) {
+      // Move to the top of the list, so next time we try this one first...
+      memmove(&s->servers[1], s->servers, i * sizeof(RedisServer));
+      s->servers[0] = server;
+    }
+
+    // Check if this is master...
+    if(rConfirmMasterRole(redis)) goto success; // @suppress("Goto statement used")
+
+    // Get the name of the master...
+    reply = redisxRequest(redis, "SENTINEL", "get-master-addr-by-name", s->serviceName, NULL, &status);
+    if(status) continue;
 
+    if(redisxCheckDestroyRESP(reply, RESP_ARRAY, 2) == X_SUCCESS) {
+      RESP **component = (RESP **) reply->value;
+      int port = (int) strtol((char *) component[1]->value, NULL, 10);
+
+      status = rSetServerAsync(redis, "sentinel master", (char *) component[0]->value, port);
+
+      redisxDestroyRESP(reply);
+      prop_error(fn, status);
+
+      // TODO update sentinel server list?...
+
+      goto success; // @suppress("Goto statement used")
+    }
+  }
+
+  p->timeoutMillis = savedTimeout;
+  return x_error(X_NO_SERVICE, ENOTCONN, fn, "no Sentinel server available");
+
+  // --------------------------------------------------------------------------------------------------
+  success:
+
+  p->timeoutMillis = savedTimeout;
+  return X_SUCCESS;
+
+}
+
+/// \endcond
 
 /**
  * Validates a Sentinel configuration.