Redis

Prerequisites

This node-type requires hiredis (>= 1.0.0) and redis++ (>= 1.2.3).

Implementation

The source code of the node-type is available here: https://git.rwth-aachen.de/acs/public/villas/node/blob/master/lib/nodes/redis.cpp

Configuration

mode (string: "key" | "hash" | "channel") = "key"

• key: Get/Set of Redis strings
  • The implementation uses the Redis MSET and MGET commands.
• hash: Hashtables using hash data-type
  • The implementation uses the Redis HMSET and HGETALL commands.
• channel: Publish/subscribe
  • The implementation uses the Redis PUBLISH and SUBSCRIBE commands.

uri (string: _Redis URI_)

A Redis connection URI in the form of: redis://<user>:<password>@<host>:<post>/<db>.

host (string) = "localhost"

The hostname or IP address of the Redis server.

You can also connect to Redis server with a URI:

• tcp://[[username:]password@]host[:port][/db]
• unix://[[username:]password@]path-to-unix-domain-socket[/db]

port (integer) = 6379

The port number of the Redis server to connect to.

path (string)

A path of a Unix socket which should be used for the connection.

user (string) = "default"

The username which should be used for authentication.

See: https://redis.io/commands/auth

password (string)

The password which should be used for authentication.

See: https://redis.io/commands/auth

db (integer) = 0

The logical database which should be used by the Redis client.

See: https://redis.io/commands/select

timeout.connect (double: seconds)

The timeout in seconds for the initial connection establishment.

timeout.socket (double: seconds)

The timeout in seconds for executing commands against the Redis server.

keepalive (boolean) = false

Enable periodic keepalive packets.

key (string) = _node-name_

The key which this node will use in the Redis keyspace.

channel (string) = _node-name_

The channel which this node will use in mode (string: "key" | "hash" | "channel") = "key" is channel.

notify (boolean) = true

Use Redis keyspace notifications to listen for new updates. This setting is only used if mode (string: "key" | "hash" | "channel") = "key" is set to key or hash.

ssl.enabled (boolean) = true

If enabled the connection to the Redis server will be encrypted via SSL/TLS.

ssl.cacert (string: path)

A path to a CA certificate file.

ssl.cacertdir (string: path)

A path to a directory containing CA certificates.

ssl.cert (string: path)

A path to a client certificate file.

ssl.key (string: path)

A path to the private key file.

Example

nodes = {
        redis_node = {
                type = "redis",

                format = "json",                # only valid for mode = 'channel' and 'key'
                                                # With mode = 'hash' we will use a simple human readable format

                key = "my_key"                  # The Redis key to be used for mode = 'key' or 'hash' (default is the node name)
                channel = "my_channel"          # the Redis channel tp be used for mode = 'channel' (default is the node name)

                mode = "key",                   # one of:
                                                # - 'channel' (publish/subscribe)
                                                # - 'key'     (set/get)
                                                # - 'hash'    (hmset/hgetall)

                notify = false                  # Whether or not to use Redis keyspace event notifications to get notified about updates
                
                rate = 1.0                      # The polling rate when notify = false

                uri = "tcp://localhost:6379/0", # The Redis connection URI

                # host = "localhost"            # Alternatively the connection options can be specified independently
                # port = 6379                   # Note: options here will overwrite the respective part of the URI if both are given.
                # db = 0

                # path = "/var/run/redis.sock"

                # user = "guest",
                # password = "guest"

                # ssl = {
                #       enabled: true
                #       cacert: "/etc/ssl/certs/ca-certificates.crt",
                #       cacertdir: "/etc/ssl/certs"
                #       cert: "./my_cert.crt",
                #       key, "./my_key.key"
                # }
        }
}