From 8651e6a10d7f156692c909065ecbe8f0fca5f783 Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Thu, 17 Oct 2019 17:49:33 +0200
Subject: [PATCH] Modules: add new flags to context, replica state + more.

---
 src/module.c      | 32 ++++++++++++++++++++++++++++++++
 src/redismodule.h | 17 ++++++++++++++++-
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/src/module.c b/src/module.c
index 0d83817f..fe497f5d 100644
--- a/src/module.c
+++ b/src/module.c
@@ -1551,6 +1551,21 @@ int RM_GetSelectedDb(RedisModuleCtx *ctx) {
  *
  *  * REDISMODULE_CTX_FLAGS_OOM_WARNING: Less than 25% of memory remains before
  *                                       reaching the maxmemory level.
+ *
+ *  * REDISMODULE_CTX_FLAGS_REPLICA_IS_STALE: No active link with the master.
+ *
+ *  * REDISMODULE_CTX_FLAGS_REPLICA_IS_CONNECTING: The replica is trying to
+ *                                                 connect with the master.
+ *
+ *  * REDISMODULE_CTX_FLAGS_REPLICA_IS_TRANSFERRING: Master -> Replica RDB
+ *                                                   transfer is in progress.
+ *
+ *  * REDISMODULE_CTX_FLAGS_REPLICA_IS_ONLINE: The replica has an active link
+ *                                             with its master. This is the
+ *                                             contrary of STALE state.
+ *
+ *  * REDISMODULE_CTX_FLAGS_ACTIVE_CHILD: There is currently some background
+ *                                        process active (RDB, AUX or module).
  */
 int RM_GetContextFlags(RedisModuleCtx *ctx) {
 
@@ -1593,6 +1608,20 @@ int RM_GetContextFlags(RedisModuleCtx *ctx) {
         flags |= REDISMODULE_CTX_FLAGS_SLAVE;
         if (server.repl_slave_ro)
             flags |= REDISMODULE_CTX_FLAGS_READONLY;
+
+        /* Replica state flags. */
+        if (server.repl_state == REPL_STATE_CONNECT ||
+            server.repl_state == REPL_STATE_CONNECTING)
+        {
+            flags |= REDISMODULE_CTX_FLAGS_REPLICA_IS_CONNECTING;
+        } else if (server.repl_state == REPL_STATE_TRANSFER) {
+            flags |= REDISMODULE_CTX_FLAGS_REPLICA_IS_TRANSFERRING;
+        } else if (server.repl_state == REPL_STATE_CONNECTED) {
+            flags |= REDISMODULE_CTX_FLAGS_REPLICA_IS_ONLINE;
+        }
+
+        if (server.repl_state != REPL_STATE_CONNECTED)
+            flags |= REDISMODULE_CTX_FLAGS_REPLICA_IS_STALE;
     }
 
     /* OOM flag. */
@@ -1601,6 +1630,9 @@ int RM_GetContextFlags(RedisModuleCtx *ctx) {
     if (retval == C_ERR) flags |= REDISMODULE_CTX_FLAGS_OOM;
     if (level > 0.75) flags |= REDISMODULE_CTX_FLAGS_OOM_WARNING;
 
+    /* Presence of children processes. */
+    if (hasActiveChildProcess()) flags |= REDISMODULE_CTX_FLAGS_ACTIVE_CHILD;
+
     return flags;
 }
 
diff --git a/src/redismodule.h b/src/redismodule.h
index 851bb8cd..a7e69f7b 100644
--- a/src/redismodule.h
+++ b/src/redismodule.h
@@ -89,7 +89,22 @@
 #define REDISMODULE_CTX_FLAGS_REPLICATED (1<<12)
 /* Redis is currently loading either from AOF or RDB. */
 #define REDISMODULE_CTX_FLAGS_LOADING (1<<13)
-
+/* The replica has no link with its master, note that
+ * there is the inverse flag as well:
+ *
+ *  REDISMODULE_CTX_FLAGS_REPLICA_IS_ONLINE
+ *
+ * The two flags are exclusive, one or the other can be set. */
+#define REDISMODULE_CTX_FLAGS_REPLICA_IS_STALE (1<<14)
+/* The replica is trying to connect with the master.
+ * (REPL_STATE_CONNECT and REPL_STATE_CONNECTING states) */
+#define REDISMODULE_CTX_FLAGS_REPLICA_IS_CONNECTING (1<<15)
+/* THe replica is receiving an RDB file from its master. */
+#define REDISMODULE_CTX_FLAGS_REPLICA_IS_TRANSFERRING (1<<16)
+/* The replica is online, receiving updates from its master. */
+#define REDISMODULE_CTX_FLAGS_REPLICA_IS_ONLINE (1<<17)
+/* There is currently some background process active. */
+#define REDISMODULE_CTX_FLAGS_ACTIVE_CHILD (1<<18)
 
 #define REDISMODULE_NOTIFY_GENERIC (1<<2)     /* g */
 #define REDISMODULE_NOTIFY_STRING (1<<3)      /* $ */