dnsdist: add RedisKVStore docs

Signed-off-by: Ensar Sarajčić <dev@ensarsarajcic.com>

Author: esensar

.github/actions/spell-check/expect.txt

@@ -561,6 +561,7 @@ Hendriks
 Henk
 Hensbergen
 Heuer
+hexists
 HHIT
 hidesoadetails
 hidettl

pdns/dnsdistdist/docs/reference/actions.rst

@@ -139,7 +139,7 @@ The following actions exist.
 
   Does a lookup into the key value store referenced by 'kvs' using the key returned by 'lookupKey',
   and storing the result if any into the tag named 'destinationTag'.
-  The store can be a CDB (:func:`newCDBKVStore`) or a LMDB database (:func:`newLMDBKVStore`).
+  The store can be a CDB (:func:`newCDBKVStore`), a LMDB database (:func:`newLMDBKVStore`) or a Redis instance (:func:`newRedisKVStore`).
   The key can be based on the qname (:func:`KeyValueLookupKeyQName` and :func:`KeyValueLookupKeySuffix`),
   source IP (:func:`KeyValueLookupKeySourceIP`) or the value of an existing tag (:func:`KeyValueLookupKeyTag`).
   Subsequent rules are processed after this action.

pdns/dnsdistdist/docs/reference/config.rst

@@ -2539,6 +2539,48 @@ LuaRingEntry
 
 .. _timespec:
 
+Redis
+~~~~~
+
+.. class:: RedisClient
+
+  .. versionadded:: 2.2.0
+
+  .. method:: get(key)
+
+    Returns the (string) value of a key in Redis, if it exists (GET command).
+
+    :param str key: Key to look up.
+
+  .. method:: exists(key)
+
+    Checks if the given key exists in Redis (EXISTS command).
+
+    :param str key: Key to look up.
+
+  .. method:: hget(hash_key, key)
+
+    Returns the value of a field in the hash stored at hash_key in Redis, if it exists (HGET command).
+
+    :param str hash_key: Key the hash is stored at.
+    :param str key: Field in hash to look up.
+
+  .. method:: hexists(hash_key, key)
+
+    Checks if the given field exists in hash stored at hash_key in Redis (HEXISTS command).
+
+    :param str hash_key: Key the hash is stored at.
+    :param str key: Field in hash to look up.
+
+.. function:: newRedisClient(url)
+
+  .. versionadded:: 2.2.0
+
+  Creates a new Redis client, connecting to the instance at the provided url.
+
+  :param string url: URL to the Redis instance.
+  :returns:  The :class:`RedisClient` object
+
 timespec
 ~~~~~~~~
 

pdns/dnsdistdist/docs/reference/kvs.rst

@@ -11,6 +11,7 @@ The first step is to get a :class:`KeyValueStore` object via one of the followin
 
  * :func:`newCDBKVStore` for a CDB database ;
  * :func:`newLMDBKVStore` for a LMDB one.
+ * :func:`newRedisKVStore` for a Redis client.
 
 Then the key used for the lookup can be selected via one of the following functions:
 
@@ -126,3 +127,22 @@ If the value found in the LMDB database for the key '\\8powerdns\\3com\\0' was '
   :param string filename: The path to an existing LMDB database created with ``MDB_NOSUBDIR``
   :param string dbName: The name of the database to use
   :param bool noLock: Whether to open the database with the ``MDB_NOLOCK`` flag. Default is false
+
+.. function:: newRedisKVStore(redis[, options]) -> KeyValueStore
+
+  .. versionadded:: 2.2.0
+
+  Return a new KeyValueStore object associated to the provided Redis client. The client can be created using :func:`newRedisClient`.
+
+  :param RedisClient redis: The reference to an existing Redis client created with :func:`newRedisClient`.
+  :param table options: A table with key: value pairs with options.
+
+  Options:
+
+  * ``lookupAction``: str - Command to use when looking up keys in Redis. Check below for supported lookup actions.
+  * ``dataName``: str - Additional value with different behavior depending on the lookup action.
+
+  Lookup actions:
+
+  * ``get``: str - The default lookup action. Uses Redis GET command to look up keys. ``dataName`` can be used to define a prefix to be added to all keys before looking up.
+  * ``hget``: str - Uses Redis HGET command to look up keys as fields of a hash. ``dataName`` is required for this action and defines the key hash is stored at.

pdns/dnsdistdist/docs/reference/selectors.rst

@@ -81,7 +81,7 @@ Selectors can be combined via :func:`AndRule`, :func:`OrRule` and :func:`NotRule
 .. function:: KeyValueStoreLookupRule(kvs, lookupKey)
 
   Return true if the key returned by 'lookupKey' exists in the key value store referenced by 'kvs'.
-  The store can be a CDB (:func:`newCDBKVStore`) or a LMDB database (:func:`newLMDBKVStore`).
+  The store can be a CDB (:func:`newCDBKVStore`), a LMDB database (:func:`newLMDBKVStore`) or a Redis instance (:func:`newRedisKVStore`).
   The key can be based on the qname (:func:`KeyValueLookupKeyQName` and :func:`KeyValueLookupKeySuffix`),
   source IP (:func:`KeyValueLookupKeySourceIP`) or the value of an existing tag (:func:`KeyValueLookupKeyTag`).